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79d956db34b694a2463d7ed5fe2df7543bafa41f
systemd/src/core/execute.c
Lennart Poettering 79d956db34 namespace: make setup_namespace() less crazy 
Let's replace the ridiculous number of arguments with a structure, to
make this function less weird.

No change in behaviour, just some refactoring.
2023-10-11 12:39:30 +09:00

7273 lines
275 KiB
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/eventfd.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/personality.h>
#include <sys/prctl.h>
#include <sys/shm.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <utmpx.h>
#include <linux/fs.h> /* Must be included after <sys/mount.h> */
#if HAVE_PAM
#include <security/pam_appl.h>
#endif
#if HAVE_SELINUX
#include <selinux/selinux.h>
#endif
#if HAVE_APPARMOR
#include <sys/apparmor.h>
#endif
#include "sd-messages.h"
#include "af-list.h"
#include "alloc-util.h"
#if HAVE_APPARMOR
#include "apparmor-util.h"
#endif
#include "argv-util.h"
#include "async.h"
#include "barrier.h"
#include "bpf-lsm.h"
#include "btrfs-util.h"
#include "cap-list.h"
#include "capability-util.h"
#include "chattr-util.h"
#include "cgroup-setup.h"
#include "chase.h"
#include "chown-recursive.h"
#include "constants.h"
#include "cpu-set-util.h"
#include "data-fd-util.h"
#include "env-file.h"
#include "env-util.h"
#include "errno-list.h"
#include "escape.h"
#include "exec-credential.h"
#include "execute.h"
#include "exit-status.h"
#include "fd-util.h"
#include "format-util.h"
#include "glob-util.h"
#include "hexdecoct.h"
#include "io-util.h"
#include "ioprio-util.h"
#include "lock-util.h"
#include "log.h"
#include "macro.h"
#include "manager.h"
#include "manager-dump.h"
#include "memory-util.h"
#include "missing_fs.h"
#include "missing_ioprio.h"
#include "missing_prctl.h"
#include "mkdir-label.h"
#include "namespace.h"
#include "parse-util.h"
#include "path-util.h"
#include "proc-cmdline.h"
#include "process-util.h"
#include "psi-util.h"
#include "rlimit-util.h"
#include "rm-rf.h"
#include "seccomp-util.h"
#include "securebits-util.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "smack-util.h"
#include "socket-util.h"
#include "sort-util.h"
#include "special.h"
#include "stat-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "syslog-util.h"
#include "terminal-util.h"
#include "tmpfile-util.h"
#include "umask-util.h"
#include "unit-serialize.h"
#include "user-util.h"
#include "utmp-wtmp.h"
#define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
#define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
#define SNDBUF_SIZE (8*1024*1024)
static int shift_fds(int fds[], size_t n_fds) {
if (n_fds <= 0)
return 0;
/* Modifies the fds array! (sorts it) */
assert(fds);
for (int start = 0;;) {
int restart_from = -1;
for (int i = start; i < (int) n_fds; i++) {
int nfd;
/* Already at right index? */
if (fds[i] == i+3)
continue;
nfd = fcntl(fds[i], F_DUPFD, i + 3);
if (nfd < 0)
return -errno;
safe_close(fds[i]);
fds[i] = nfd;
/* Hmm, the fd we wanted isn't free? Then
* let's remember that and try again from here */
if (nfd != i+3 && restart_from < 0)
restart_from = i;
}
if (restart_from < 0)
break;
start = restart_from;
}
return 0;
}
static int flags_fds(
const int fds[],
size_t n_socket_fds,
size_t n_fds,
bool nonblock) {
int r;
if (n_fds <= 0)
return 0;
assert(fds);
/* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags.
* O_NONBLOCK only applies to socket activation though. */
for (size_t i = 0; i < n_fds; i++) {
if (i < n_socket_fds) {
r = fd_nonblock(fds[i], nonblock);
if (r < 0)
return r;
}
/* We unconditionally drop FD_CLOEXEC from the fds,
* since after all we want to pass these fds to our
* children */
r = fd_cloexec(fds[i], false);
if (r < 0)
return r;
}
return 0;
}
static const char *exec_context_tty_path(const ExecContext *context) {
assert(context);
if (context->stdio_as_fds)
return NULL;
if (context->tty_path)
return context->tty_path;
return "/dev/console";
}
static int exec_context_tty_size(const ExecContext *context, unsigned *ret_rows, unsigned *ret_cols) {
unsigned rows, cols;
const char *tty;
assert(context);
assert(ret_rows);
assert(ret_cols);
rows = context->tty_rows;
cols = context->tty_cols;
tty = exec_context_tty_path(context);
if (tty)
(void) proc_cmdline_tty_size(tty, rows == UINT_MAX ? &rows : NULL, cols == UINT_MAX ? &cols : NULL);
*ret_rows = rows;
*ret_cols = cols;
return 0;
}
static void exec_context_tty_reset(const ExecContext *context, const ExecParameters *p) {
_cleanup_close_ int fd = -EBADF;
const char *path = exec_context_tty_path(ASSERT_PTR(context));
/* Take a lock around the device for the duration of the setup that we do here.
* systemd-vconsole-setup.service also takes the lock to avoid being interrupted.
* We open a new fd that will be closed automatically, and operate on it for convenience.
*/
if (p && p->stdin_fd >= 0) {
fd = xopenat_lock(p->stdin_fd, NULL,
O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY, 0, 0, LOCK_BSD, LOCK_EX);
if (fd < 0)
return;
} else if (path) {
fd = open_terminal(path, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
if (fd < 0)
return;
if (lock_generic(fd, LOCK_BSD, LOCK_EX) < 0)
return;
} else
return; /* nothing to do */
if (context->tty_vhangup)
(void) terminal_vhangup_fd(fd);
if (context->tty_reset)
(void) reset_terminal_fd(fd, true);
if (p && p->stdin_fd >= 0) {
unsigned rows = context->tty_rows, cols = context->tty_cols;
(void) exec_context_tty_size(context, &rows, &cols);
(void) terminal_set_size_fd(p->stdin_fd, path, rows, cols);
}
if (context->tty_vt_disallocate && path)
(void) vt_disallocate(path);
}
static bool is_terminal_input(ExecInput i) {
return IN_SET(i,
EXEC_INPUT_TTY,
EXEC_INPUT_TTY_FORCE,
EXEC_INPUT_TTY_FAIL);
}
static bool is_terminal_output(ExecOutput o) {
return IN_SET(o,
EXEC_OUTPUT_TTY,
EXEC_OUTPUT_KMSG_AND_CONSOLE,
EXEC_OUTPUT_JOURNAL_AND_CONSOLE);
}
static bool is_kmsg_output(ExecOutput o) {
return IN_SET(o,
EXEC_OUTPUT_KMSG,
EXEC_OUTPUT_KMSG_AND_CONSOLE);
}
static bool exec_context_needs_term(const ExecContext *c) {
assert(c);
/* Return true if the execution context suggests we should set $TERM to something useful. */
if (is_terminal_input(c->std_input))
return true;
if (is_terminal_output(c->std_output))
return true;
if (is_terminal_output(c->std_error))
return true;
return !!c->tty_path;
}
static int open_null_as(int flags, int nfd) {
int fd;
assert(nfd >= 0);
fd = open("/dev/null", flags|O_NOCTTY);
if (fd < 0)
return -errno;
return move_fd(fd, nfd, false);
}
static int connect_journal_socket(
int fd,
const char *log_namespace,
uid_t uid,
gid_t gid) {
uid_t olduid = UID_INVALID;
gid_t oldgid = GID_INVALID;
const char *j;
int r;
j = log_namespace ?
strjoina("/run/systemd/journal.", log_namespace, "/stdout") :
"/run/systemd/journal/stdout";
if (gid_is_valid(gid)) {
oldgid = getgid();
if (setegid(gid) < 0)
return -errno;
}
if (uid_is_valid(uid)) {
olduid = getuid();
if (seteuid(uid) < 0) {
r = -errno;
goto restore_gid;
}
}
r = connect_unix_path(fd, AT_FDCWD, j);
/* If we fail to restore the uid or gid, things will likely fail later on. This should only happen if
an LSM interferes. */
if (uid_is_valid(uid))
(void) seteuid(olduid);
restore_gid:
if (gid_is_valid(gid))
(void) setegid(oldgid);
return r;
}
static int connect_logger_as(
const Unit *unit,
const ExecContext *context,
const ExecParameters *params,
ExecOutput output,
const char *ident,
int nfd,
uid_t uid,
gid_t gid) {
_cleanup_close_ int fd = -EBADF;
int r;
assert(context);
assert(params);
assert(output < _EXEC_OUTPUT_MAX);
assert(ident);
assert(nfd >= 0);
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd < 0)
return -errno;
r = connect_journal_socket(fd, context->log_namespace, uid, gid);
if (r < 0)
return r;
if (shutdown(fd, SHUT_RD) < 0)
return -errno;
(void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
if (dprintf(fd,
"%s\n"
"%s\n"
"%i\n"
"%i\n"
"%i\n"
"%i\n"
"%i\n",
context->syslog_identifier ?: ident,
params->flags & EXEC_PASS_LOG_UNIT ? unit->id : "",
context->syslog_priority,
!!context->syslog_level_prefix,
false,
is_kmsg_output(output),
is_terminal_output(output)) < 0)
return -errno;
return move_fd(TAKE_FD(fd), nfd, false);
}
static int open_terminal_as(const char *path, int flags, int nfd) {
int fd;
assert(path);
assert(nfd >= 0);
fd = open_terminal(path, flags | O_NOCTTY);
if (fd < 0)
return fd;
return move_fd(fd, nfd, false);
}
static int acquire_path(const char *path, int flags, mode_t mode) {
_cleanup_close_ int fd = -EBADF;
int r;
assert(path);
if (IN_SET(flags & O_ACCMODE, O_WRONLY, O_RDWR))
flags |= O_CREAT;
fd = open(path, flags|O_NOCTTY, mode);
if (fd >= 0)
return TAKE_FD(fd);
if (errno != ENXIO) /* ENXIO is returned when we try to open() an AF_UNIX file system socket on Linux */
return -errno;
/* So, it appears the specified path could be an AF_UNIX socket. Let's see if we can connect to it. */
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd < 0)
return -errno;
r = connect_unix_path(fd, AT_FDCWD, path);
if (IN_SET(r, -ENOTSOCK, -EINVAL))
/* Propagate initial error if we get ENOTSOCK or EINVAL, i.e. we have indication that this
* wasn't an AF_UNIX socket after all */
return -ENXIO;
if (r < 0)
return r;
if ((flags & O_ACCMODE) == O_RDONLY)
r = shutdown(fd, SHUT_WR);
else if ((flags & O_ACCMODE) == O_WRONLY)
r = shutdown(fd, SHUT_RD);
else
r = 0;
if (r < 0)
return -errno;
return TAKE_FD(fd);
}
static int fixup_input(
const ExecContext *context,
int socket_fd,
bool apply_tty_stdin) {
ExecInput std_input;
assert(context);
std_input = context->std_input;
if (is_terminal_input(std_input) && !apply_tty_stdin)
return EXEC_INPUT_NULL;
if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0)
return EXEC_INPUT_NULL;
if (std_input == EXEC_INPUT_DATA && context->stdin_data_size == 0)
return EXEC_INPUT_NULL;
return std_input;
}
static int fixup_output(ExecOutput output, int socket_fd) {
if (output == EXEC_OUTPUT_SOCKET && socket_fd < 0)
return EXEC_OUTPUT_INHERIT;
return output;
}
static int setup_input(
const ExecContext *context,
const ExecParameters *params,
int socket_fd,
const int named_iofds[static 3]) {
ExecInput i;
int r;
assert(context);
assert(params);
assert(named_iofds);
if (params->stdin_fd >= 0) {
if (dup2(params->stdin_fd, STDIN_FILENO) < 0)
return -errno;
/* Try to make this the controlling tty, if it is a tty, and reset it */
if (isatty(STDIN_FILENO)) {
unsigned rows = context->tty_rows, cols = context->tty_cols;
(void) exec_context_tty_size(context, &rows, &cols);
(void) ioctl(STDIN_FILENO, TIOCSCTTY, context->std_input == EXEC_INPUT_TTY_FORCE);
(void) reset_terminal_fd(STDIN_FILENO, true);
(void) terminal_set_size_fd(STDIN_FILENO, NULL, rows, cols);
}
return STDIN_FILENO;
}
i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
switch (i) {
case EXEC_INPUT_NULL:
return open_null_as(O_RDONLY, STDIN_FILENO);
case EXEC_INPUT_TTY:
case EXEC_INPUT_TTY_FORCE:
case EXEC_INPUT_TTY_FAIL: {
unsigned rows, cols;
int fd;
fd = acquire_terminal(exec_context_tty_path(context),
i == EXEC_INPUT_TTY_FAIL ? ACQUIRE_TERMINAL_TRY :
i == EXEC_INPUT_TTY_FORCE ? ACQUIRE_TERMINAL_FORCE :
ACQUIRE_TERMINAL_WAIT,
USEC_INFINITY);
if (fd < 0)
return fd;
r = exec_context_tty_size(context, &rows, &cols);
if (r < 0)
return r;
r = terminal_set_size_fd(fd, exec_context_tty_path(context), rows, cols);
if (r < 0)
return r;
return move_fd(fd, STDIN_FILENO, false);
}
case EXEC_INPUT_SOCKET:
assert(socket_fd >= 0);
return RET_NERRNO(dup2(socket_fd, STDIN_FILENO));
case EXEC_INPUT_NAMED_FD:
assert(named_iofds[STDIN_FILENO] >= 0);
(void) fd_nonblock(named_iofds[STDIN_FILENO], false);
return RET_NERRNO(dup2(named_iofds[STDIN_FILENO], STDIN_FILENO));
case EXEC_INPUT_DATA: {
int fd;
fd = acquire_data_fd(context->stdin_data, context->stdin_data_size, 0);
if (fd < 0)
return fd;
return move_fd(fd, STDIN_FILENO, false);
}
case EXEC_INPUT_FILE: {
bool rw;
int fd;
assert(context->stdio_file[STDIN_FILENO]);
rw = (context->std_output == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDOUT_FILENO])) ||
(context->std_error == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDERR_FILENO]));
fd = acquire_path(context->stdio_file[STDIN_FILENO], rw ? O_RDWR : O_RDONLY, 0666 & ~context->umask);
if (fd < 0)
return fd;
return move_fd(fd, STDIN_FILENO, false);
}
default:
assert_not_reached();
}
}
static bool can_inherit_stderr_from_stdout(
const ExecContext *context,
ExecOutput o,
ExecOutput e) {
assert(context);
/* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the
* stderr fd */
if (e == EXEC_OUTPUT_INHERIT)
return true;
if (e != o)
return false;
if (e == EXEC_OUTPUT_NAMED_FD)
return streq_ptr(context->stdio_fdname[STDOUT_FILENO], context->stdio_fdname[STDERR_FILENO]);
if (IN_SET(e, EXEC_OUTPUT_FILE, EXEC_OUTPUT_FILE_APPEND, EXEC_OUTPUT_FILE_TRUNCATE))
return streq_ptr(context->stdio_file[STDOUT_FILENO], context->stdio_file[STDERR_FILENO]);
return true;
}
static int setup_output(
const Unit *unit,
const ExecContext *context,
const ExecParameters *params,
int fileno,
int socket_fd,
const int named_iofds[static 3],
const char *ident,
uid_t uid,
gid_t gid,
dev_t *journal_stream_dev,
ino_t *journal_stream_ino) {
ExecOutput o;
ExecInput i;
int r;
assert(unit);
assert(context);
assert(params);
assert(ident);
assert(journal_stream_dev);
assert(journal_stream_ino);
if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) {
if (dup2(params->stdout_fd, STDOUT_FILENO) < 0)
return -errno;
return STDOUT_FILENO;
}
if (fileno == STDERR_FILENO && params->stderr_fd >= 0) {
if (dup2(params->stderr_fd, STDERR_FILENO) < 0)
return -errno;
return STDERR_FILENO;
}
i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
o = fixup_output(context->std_output, socket_fd);
if (fileno == STDERR_FILENO) {
ExecOutput e;
e = fixup_output(context->std_error, socket_fd);
/* This expects the input and output are already set up */
/* Don't change the stderr file descriptor if we inherit all
* the way and are not on a tty */
if (e == EXEC_OUTPUT_INHERIT &&
o == EXEC_OUTPUT_INHERIT &&
i == EXEC_INPUT_NULL &&
!is_terminal_input(context->std_input) &&
getppid() != 1)
return fileno;
/* Duplicate from stdout if possible */
if (can_inherit_stderr_from_stdout(context, o, e))
return RET_NERRNO(dup2(STDOUT_FILENO, fileno));
o = e;
} else if (o == EXEC_OUTPUT_INHERIT) {
/* If input got downgraded, inherit the original value */
if (i == EXEC_INPUT_NULL && is_terminal_input(context->std_input))
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
/* If the input is connected to anything that's not a /dev/null or a data fd, inherit that... */
if (!IN_SET(i, EXEC_INPUT_NULL, EXEC_INPUT_DATA))
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
/* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
if (getppid() != 1)
return fileno;
/* We need to open /dev/null here anew, to get the right access mode. */
return open_null_as(O_WRONLY, fileno);
}
switch (o) {
case EXEC_OUTPUT_NULL:
return open_null_as(O_WRONLY, fileno);
case EXEC_OUTPUT_TTY:
if (is_terminal_input(i))
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
/* We don't reset the terminal if this is just about output */
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
case EXEC_OUTPUT_KMSG:
case EXEC_OUTPUT_KMSG_AND_CONSOLE:
case EXEC_OUTPUT_JOURNAL:
case EXEC_OUTPUT_JOURNAL_AND_CONSOLE:
r = connect_logger_as(unit, context, params, o, ident, fileno, uid, gid);
if (r < 0) {
log_unit_warning_errno(unit, r, "Failed to connect %s to the journal socket, ignoring: %m",
fileno == STDOUT_FILENO ? "stdout" : "stderr");
r = open_null_as(O_WRONLY, fileno);
} else {
struct stat st;
/* If we connected this fd to the journal via a stream, patch the device/inode into the passed
* parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits
* services to detect whether they are connected to the journal or not.
*
* If both stdout and stderr are connected to a stream then let's make sure to store the data
* about STDERR as that's usually the best way to do logging. */
if (fstat(fileno, &st) >= 0 &&
(*journal_stream_ino == 0 || fileno == STDERR_FILENO)) {
*journal_stream_dev = st.st_dev;
*journal_stream_ino = st.st_ino;
}
}
return r;
case EXEC_OUTPUT_SOCKET:
assert(socket_fd >= 0);
return RET_NERRNO(dup2(socket_fd, fileno));
case EXEC_OUTPUT_NAMED_FD:
assert(named_iofds[fileno] >= 0);
(void) fd_nonblock(named_iofds[fileno], false);
return RET_NERRNO(dup2(named_iofds[fileno], fileno));
case EXEC_OUTPUT_FILE:
case EXEC_OUTPUT_FILE_APPEND:
case EXEC_OUTPUT_FILE_TRUNCATE: {
bool rw;
int fd, flags;
assert(context->stdio_file[fileno]);
rw = context->std_input == EXEC_INPUT_FILE &&
streq_ptr(context->stdio_file[fileno], context->stdio_file[STDIN_FILENO]);
if (rw)
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
flags = O_WRONLY;
if (o == EXEC_OUTPUT_FILE_APPEND)
flags |= O_APPEND;
else if (o == EXEC_OUTPUT_FILE_TRUNCATE)
flags |= O_TRUNC;
fd = acquire_path(context->stdio_file[fileno], flags, 0666 & ~context->umask);
if (fd < 0)
return fd;
return move_fd(fd, fileno, 0);
}
default:
assert_not_reached();
}
}
static int chown_terminal(int fd, uid_t uid) {
int r;
assert(fd >= 0);
/* Before we chown/chmod the TTY, let's ensure this is actually a tty */
if (isatty(fd) < 1) {
if (IN_SET(errno, EINVAL, ENOTTY))
return 0; /* not a tty */
return -errno;
}
/* This might fail. What matters are the results. */
r = fchmod_and_chown(fd, TTY_MODE, uid, GID_INVALID);
if (r < 0)
return r;
return 1;
}
static int setup_confirm_stdio(
const ExecContext *context,
const char *vc,
int *ret_saved_stdin,
int *ret_saved_stdout) {
_cleanup_close_ int fd = -EBADF, saved_stdin = -EBADF, saved_stdout = -EBADF;
unsigned rows, cols;
int r;
assert(ret_saved_stdin);
assert(ret_saved_stdout);
saved_stdin = fcntl(STDIN_FILENO, F_DUPFD, 3);
if (saved_stdin < 0)
return -errno;
saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD, 3);
if (saved_stdout < 0)
return -errno;
fd = acquire_terminal(vc, ACQUIRE_TERMINAL_WAIT, DEFAULT_CONFIRM_USEC);
if (fd < 0)
return fd;
r = chown_terminal(fd, getuid());
if (r < 0)
return r;
r = reset_terminal_fd(fd, true);
if (r < 0)
return r;
r = exec_context_tty_size(context, &rows, &cols);
if (r < 0)
return r;
r = terminal_set_size_fd(fd, vc, rows, cols);
if (r < 0)
return r;
r = rearrange_stdio(fd, fd, STDERR_FILENO); /* Invalidates 'fd' also on failure */
TAKE_FD(fd);
if (r < 0)
return r;
*ret_saved_stdin = TAKE_FD(saved_stdin);
*ret_saved_stdout = TAKE_FD(saved_stdout);
return 0;
}
static void write_confirm_error_fd(int err, int fd, const Unit *u) {
assert(err < 0);
if (err == -ETIMEDOUT)
dprintf(fd, "Confirmation question timed out for %s, assuming positive response.\n", u->id);
else {
errno = -err;
dprintf(fd, "Couldn't ask confirmation for %s: %m, assuming positive response.\n", u->id);
}
}
static void write_confirm_error(int err, const char *vc, const Unit *u) {
_cleanup_close_ int fd = -EBADF;
assert(vc);
fd = open_terminal(vc, O_WRONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return;
write_confirm_error_fd(err, fd, u);
}
static int restore_confirm_stdio(int *saved_stdin, int *saved_stdout) {
int r = 0;
assert(saved_stdin);
assert(saved_stdout);
release_terminal();
if (*saved_stdin >= 0)
if (dup2(*saved_stdin, STDIN_FILENO) < 0)
r = -errno;
if (*saved_stdout >= 0)
if (dup2(*saved_stdout, STDOUT_FILENO) < 0)
r = -errno;
*saved_stdin = safe_close(*saved_stdin);
*saved_stdout = safe_close(*saved_stdout);
return r;
}
enum {
CONFIRM_PRETEND_FAILURE = -1,
CONFIRM_PRETEND_SUCCESS = 0,
CONFIRM_EXECUTE = 1,
};
static int ask_for_confirmation(const ExecContext *context, const char *vc, Unit *u, const char *cmdline) {
int saved_stdout = -1, saved_stdin = -1, r;
_cleanup_free_ char *e = NULL;
char c;
/* For any internal errors, assume a positive response. */
r = setup_confirm_stdio(context, vc, &saved_stdin, &saved_stdout);
if (r < 0) {
write_confirm_error(r, vc, u);
return CONFIRM_EXECUTE;
}
/* confirm_spawn might have been disabled while we were sleeping. */
if (manager_is_confirm_spawn_disabled(u->manager)) {
r = 1;
goto restore_stdio;
}
e = ellipsize(cmdline, 60, 100);
if (!e) {
log_oom();
r = CONFIRM_EXECUTE;
goto restore_stdio;
}
for (;;) {
r = ask_char(&c, "yfshiDjcn", "Execute %s? [y, f, s – h for help] ", e);
if (r < 0) {
write_confirm_error_fd(r, STDOUT_FILENO, u);
r = CONFIRM_EXECUTE;
goto restore_stdio;
}
switch (c) {
case 'c':
printf("Resuming normal execution.\n");
manager_disable_confirm_spawn();
r = 1;
break;
case 'D':
unit_dump(u, stdout, " ");
continue; /* ask again */
case 'f':
printf("Failing execution.\n");
r = CONFIRM_PRETEND_FAILURE;
break;
case 'h':
printf(" c - continue, proceed without asking anymore\n"
" D - dump, show the state of the unit\n"
" f - fail, don't execute the command and pretend it failed\n"
" h - help\n"
" i - info, show a short summary of the unit\n"
" j - jobs, show jobs that are in progress\n"
" s - skip, don't execute the command and pretend it succeeded\n"
" y - yes, execute the command\n");
continue; /* ask again */
case 'i':
printf(" Description: %s\n"
" Unit: %s\n"
" Command: %s\n",
u->id, u->description, cmdline);
continue; /* ask again */
case 'j':
manager_dump_jobs(u->manager, stdout, /* patterns= */ NULL, " ");
continue; /* ask again */
case 'n':
/* 'n' was removed in favor of 'f'. */
printf("Didn't understand 'n', did you mean 'f'?\n");
continue; /* ask again */
case 's':
printf("Skipping execution.\n");
r = CONFIRM_PRETEND_SUCCESS;
break;
case 'y':
r = CONFIRM_EXECUTE;
break;
default:
assert_not_reached();
}
break;
}
restore_stdio:
restore_confirm_stdio(&saved_stdin, &saved_stdout);
return r;
}
static int get_fixed_user(
const char *username,
const char **ret_user,
uid_t *ret_uid,
gid_t *ret_gid,
const char **ret_home,
const char **ret_shell) {
int r;
assert(username);
assert(ret_user);
/* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway
* (i.e. are "/" or "/bin/nologin"). */
r = get_user_creds(&username, ret_uid, ret_gid, ret_home, ret_shell, USER_CREDS_CLEAN);
if (r < 0)
return r;
*ret_user = username;
return 0;
}
static int get_fixed_group(
const char *groupname,
const char **ret_group,
gid_t *ret_gid) {
int r;
assert(groupname);
assert(ret_group);
r = get_group_creds(&groupname, ret_gid, /* flags = */ 0);
if (r < 0)
return r;
*ret_group = groupname;
return 0;
}
static int get_supplementary_groups(const ExecContext *c, const char *user,
const char *group, gid_t gid,
gid_t **supplementary_gids, int *ngids) {
int r, k = 0;
int ngroups_max;
bool keep_groups = false;
gid_t *groups = NULL;
_cleanup_free_ gid_t *l_gids = NULL;
assert(c);
/*
* If user is given, then lookup GID and supplementary groups list.
* We avoid NSS lookups for gid=0. Also we have to initialize groups
* here and as early as possible so we keep the list of supplementary
* groups of the caller.
*/
if (user && gid_is_valid(gid) && gid != 0) {
/* First step, initialize groups from /etc/groups */
if (initgroups(user, gid) < 0)
return -errno;
keep_groups = true;
}
if (strv_isempty(c->supplementary_groups))
return 0;
/*
* If SupplementaryGroups= was passed then NGROUPS_MAX has to
* be positive, otherwise fail.
*/
errno = 0;
ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
if (ngroups_max <= 0)
return errno_or_else(EOPNOTSUPP);
l_gids = new(gid_t, ngroups_max);
if (!l_gids)
return -ENOMEM;
if (keep_groups) {
/*
* Lookup the list of groups that the user belongs to, we
* avoid NSS lookups here too for gid=0.
*/
k = ngroups_max;
if (getgrouplist(user, gid, l_gids, &k) < 0)
return -EINVAL;
} else
k = 0;
STRV_FOREACH(i, c->supplementary_groups) {
const char *g;
if (k >= ngroups_max)
return -E2BIG;
g = *i;
r = get_group_creds(&g, l_gids+k, 0);
if (r < 0)
return r;
k++;
}
/*
* Sets ngids to zero to drop all supplementary groups, happens
* when we are under root and SupplementaryGroups= is empty.
*/
if (k == 0) {
*ngids = 0;
return 0;
}
/* Otherwise get the final list of supplementary groups */
groups = memdup(l_gids, sizeof(gid_t) * k);
if (!groups)
return -ENOMEM;
*supplementary_gids = groups;
*ngids = k;
groups = NULL;
return 0;
}
static int enforce_groups(gid_t gid, const gid_t *supplementary_gids, int ngids) {
int r;
/* Handle SupplementaryGroups= if it is not empty */
if (ngids > 0) {
r = maybe_setgroups(ngids, supplementary_gids);
if (r < 0)
return r;
}
if (gid_is_valid(gid)) {
/* Then set our gids */
if (setresgid(gid, gid, gid) < 0)
return -errno;
}
return 0;
}
static int set_securebits(unsigned bits, unsigned mask) {
unsigned applied;
int current;
current = prctl(PR_GET_SECUREBITS);
if (current < 0)
return -errno;
/* Clear all securebits defined in mask and set bits */
applied = ((unsigned) current & ~mask) | bits;
if ((unsigned) current == applied)
return 0;
if (prctl(PR_SET_SECUREBITS, applied) < 0)
return -errno;
return 1;
}
static int enforce_user(
const ExecContext *context,
uid_t uid,
uint64_t capability_ambient_set) {
assert(context);
int r;
if (!uid_is_valid(uid))
return 0;
/* Sets (but doesn't look up) the UIS and makes sure we keep the capabilities while doing so. For
* setting secure bits the capability CAP_SETPCAP is required, so we also need keep-caps in this
* case. */
if ((capability_ambient_set != 0 || context->secure_bits != 0) && uid != 0) {
/* First step: If we need to keep capabilities but drop privileges we need to make sure we
* keep our caps, while we drop privileges. Add KEEP_CAPS to the securebits */
r = set_securebits(1U << SECURE_KEEP_CAPS, 0);
if (r < 0)
return r;
}
/* Second step: actually set the uids */
if (setresuid(uid, uid, uid) < 0)
return -errno;
/* At this point we should have all necessary capabilities but are otherwise a normal user. However,
* the caps might got corrupted due to the setresuid() so we need clean them up later. This is done
* outside of this call. */
return 0;
}
#if HAVE_PAM
static int null_conv(
int num_msg,
const struct pam_message **msg,
struct pam_response **resp,
void *appdata_ptr) {
/* We don't support conversations */
return PAM_CONV_ERR;
}
#endif
static int setup_pam(
const char *name,
const char *user,
uid_t uid,
gid_t gid,
const char *tty,
char ***env, /* updated on success */
const int fds[], size_t n_fds) {
#if HAVE_PAM
static const struct pam_conv conv = {
.conv = null_conv,
.appdata_ptr = NULL
};
_cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
_cleanup_strv_free_ char **e = NULL;
pam_handle_t *handle = NULL;
sigset_t old_ss;
int pam_code = PAM_SUCCESS, r;
bool close_session = false;
pid_t pam_pid = 0, parent_pid;
int flags = 0;
assert(name);
assert(user);
assert(env);
/* We set up PAM in the parent process, then fork. The child
* will then stay around until killed via PR_GET_PDEATHSIG or
* systemd via the cgroup logic. It will then remove the PAM
* session again. The parent process will exec() the actual
* daemon. We do things this way to ensure that the main PID
* of the daemon is the one we initially fork()ed. */
r = barrier_create(&barrier);
if (r < 0)
goto fail;
if (log_get_max_level() < LOG_DEBUG)
flags |= PAM_SILENT;
pam_code = pam_start(name, user, &conv, &handle);
if (pam_code != PAM_SUCCESS) {
handle = NULL;
goto fail;
}
if (!tty) {
_cleanup_free_ char *q = NULL;
/* Hmm, so no TTY was explicitly passed, but an fd passed to us directly might be a TTY. Let's figure
* out if that's the case, and read the TTY off it. */
if (getttyname_malloc(STDIN_FILENO, &q) >= 0)
tty = strjoina("/dev/", q);
}
if (tty) {
pam_code = pam_set_item(handle, PAM_TTY, tty);
if (pam_code != PAM_SUCCESS)
goto fail;
}
STRV_FOREACH(nv, *env) {
pam_code = pam_putenv(handle, *nv);
if (pam_code != PAM_SUCCESS)
goto fail;
}
pam_code = pam_acct_mgmt(handle, flags);
if (pam_code != PAM_SUCCESS)
goto fail;
pam_code = pam_setcred(handle, PAM_ESTABLISH_CRED | flags);
if (pam_code != PAM_SUCCESS)
log_debug("pam_setcred() failed, ignoring: %s", pam_strerror(handle, pam_code));
pam_code = pam_open_session(handle, flags);
if (pam_code != PAM_SUCCESS)
goto fail;
close_session = true;
e = pam_getenvlist(handle);
if (!e) {
pam_code = PAM_BUF_ERR;
goto fail;
}
/* Block SIGTERM, so that we know that it won't get lost in the child */
assert_se(sigprocmask_many(SIG_BLOCK, &old_ss, SIGTERM, -1) >= 0);
parent_pid = getpid_cached();
r = safe_fork("(sd-pam)", 0, &pam_pid);
if (r < 0)
goto fail;
if (r == 0) {
int sig, ret = EXIT_PAM;
/* The child's job is to reset the PAM session on termination */
barrier_set_role(&barrier, BARRIER_CHILD);
/* Make sure we don't keep open the passed fds in this child. We assume that otherwise only
* those fds are open here that have been opened by PAM. */
(void) close_many(fds, n_fds);
/* Drop privileges - we don't need any to pam_close_session and this will make
* PR_SET_PDEATHSIG work in most cases. If this fails, ignore the error - but expect sd-pam
* threads to fail to exit normally */
r = maybe_setgroups(0, NULL);
if (r < 0)
log_warning_errno(r, "Failed to setgroups() in sd-pam: %m");
if (setresgid(gid, gid, gid) < 0)
log_warning_errno(errno, "Failed to setresgid() in sd-pam: %m");
if (setresuid(uid, uid, uid) < 0)
log_warning_errno(errno, "Failed to setresuid() in sd-pam: %m");
(void) ignore_signals(SIGPIPE);
/* Wait until our parent died. This will only work if the above setresuid() succeeds,
* otherwise the kernel will not allow unprivileged parents kill their privileged children
* this way. We rely on the control groups kill logic to do the rest for us. */
if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
goto child_finish;
/* Tell the parent that our setup is done. This is especially important regarding dropping
* privileges. Otherwise, unit setup might race against our setresuid(2) call.
*
* If the parent aborted, we'll detect this below, hence ignore return failure here. */
(void) barrier_place(&barrier);
/* Check if our parent process might already have died? */
if (getppid() == parent_pid) {
sigset_t ss;
assert_se(sigemptyset(&ss) >= 0);
assert_se(sigaddset(&ss, SIGTERM) >= 0);
for (;;) {
if (sigwait(&ss, &sig) < 0) {
if (errno == EINTR)
continue;
goto child_finish;
}
assert(sig == SIGTERM);
break;
}
}
pam_code = pam_setcred(handle, PAM_DELETE_CRED | flags);
if (pam_code != PAM_SUCCESS)
goto child_finish;
/* If our parent died we'll end the session */
if (getppid() != parent_pid) {
pam_code = pam_close_session(handle, flags);
if (pam_code != PAM_SUCCESS)
goto child_finish;
}
ret = 0;
child_finish:
/* NB: pam_end() when called in child processes should set PAM_DATA_SILENT to let the module
* know about this. See pam_end(3) */
(void) pam_end(handle, pam_code | flags | PAM_DATA_SILENT);
_exit(ret);
}
barrier_set_role(&barrier, BARRIER_PARENT);
/* If the child was forked off successfully it will do all the cleanups, so forget about the handle
* here. */
handle = NULL;
/* Unblock SIGTERM again in the parent */
assert_se(sigprocmask(SIG_SETMASK, &old_ss, NULL) >= 0);
/* We close the log explicitly here, since the PAM modules might have opened it, but we don't want
* this fd around. */
closelog();
/* Synchronously wait for the child to initialize. We don't care for errors as we cannot
* recover. However, warn loudly if it happens. */
if (!barrier_place_and_sync(&barrier))
log_error("PAM initialization failed");
return strv_free_and_replace(*env, e);
fail:
if (pam_code != PAM_SUCCESS) {
log_error("PAM failed: %s", pam_strerror(handle, pam_code));
r = -EPERM; /* PAM errors do not map to errno */
} else
log_error_errno(r, "PAM failed: %m");
if (handle) {
if (close_session)
pam_code = pam_close_session(handle, flags);
(void) pam_end(handle, pam_code | flags);
}
closelog();
return r;
#else
return 0;
#endif
}
static void rename_process_from_path(const char *path) {
_cleanup_free_ char *buf = NULL;
const char *p;
assert(path);
/* This resulting string must fit in 10 chars (i.e. the length of "/sbin/init") to look pretty in
* /bin/ps */
if (path_extract_filename(path, &buf) < 0) {
rename_process("(...)");
return;
}
size_t l = strlen(buf);
if (l > 8) {
/* The end of the process name is usually more interesting, since the first bit might just be
* "systemd-" */
p = buf + l - 8;
l = 8;
} else
p = buf;
char process_name[11];
process_name[0] = '(';
memcpy(process_name+1, p, l);
process_name[1+l] = ')';
process_name[1+l+1] = 0;
rename_process(process_name);
}
static bool context_has_address_families(const ExecContext *c) {
assert(c);
return c->address_families_allow_list ||
!set_isempty(c->address_families);
}
static bool context_has_syscall_filters(const ExecContext *c) {
assert(c);
return c->syscall_allow_list ||
!hashmap_isempty(c->syscall_filter);
}
static bool context_has_syscall_logs(const ExecContext *c) {
assert(c);
return c->syscall_log_allow_list ||
!hashmap_isempty(c->syscall_log);
}
static bool context_has_no_new_privileges(const ExecContext *c) {
assert(c);
if (c->no_new_privileges)
return true;
if (have_effective_cap(CAP_SYS_ADMIN) > 0) /* if we are privileged, we don't need NNP */
return false;
/* We need NNP if we have any form of seccomp and are unprivileged */
return c->lock_personality ||
c->memory_deny_write_execute ||
c->private_devices ||
c->protect_clock ||
c->protect_hostname ||
c->protect_kernel_tunables ||
c->protect_kernel_modules ||
c->protect_kernel_logs ||
context_has_address_families(c) ||
exec_context_restrict_namespaces_set(c) ||
c->restrict_realtime ||
c->restrict_suid_sgid ||
!set_isempty(c->syscall_archs) ||
context_has_syscall_filters(c) ||
context_has_syscall_logs(c);
}
#if HAVE_SECCOMP
static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {
if (is_seccomp_available())
return false;
log_unit_debug(u, "SECCOMP features not detected in the kernel, skipping %s", msg);
return true;
}
static int apply_syscall_filter(const Unit* u, const ExecContext *c, bool needs_ambient_hack) {
uint32_t negative_action, default_action, action;
int r;
assert(u);
assert(c);
if (!context_has_syscall_filters(c))
return 0;
if (skip_seccomp_unavailable(u, "SystemCallFilter="))
return 0;
negative_action = c->syscall_errno == SECCOMP_ERROR_NUMBER_KILL ? scmp_act_kill_process() : SCMP_ACT_ERRNO(c->syscall_errno);
if (c->syscall_allow_list) {
default_action = negative_action;
action = SCMP_ACT_ALLOW;
} else {
default_action = SCMP_ACT_ALLOW;
action = negative_action;
}
if (needs_ambient_hack) {
r = seccomp_filter_set_add(c->syscall_filter, c->syscall_allow_list, syscall_filter_sets + SYSCALL_FILTER_SET_SETUID);
if (r < 0)
return r;
}
return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_filter, action, false);
}
static int apply_syscall_log(const Unit* u, const ExecContext *c) {
#ifdef SCMP_ACT_LOG
uint32_t default_action, action;
#endif
assert(u);
assert(c);
if (!context_has_syscall_logs(c))
return 0;
#ifdef SCMP_ACT_LOG
if (skip_seccomp_unavailable(u, "SystemCallLog="))
return 0;
if (c->syscall_log_allow_list) {
/* Log nothing but the ones listed */
default_action = SCMP_ACT_ALLOW;
action = SCMP_ACT_LOG;
} else {
/* Log everything but the ones listed */
default_action = SCMP_ACT_LOG;
action = SCMP_ACT_ALLOW;
}
return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_log, action, false);
#else
/* old libseccomp */
log_unit_debug(u, "SECCOMP feature SCMP_ACT_LOG not available, skipping SystemCallLog=");
return 0;
#endif
}
static int apply_syscall_archs(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
if (set_isempty(c->syscall_archs))
return 0;
if (skip_seccomp_unavailable(u, "SystemCallArchitectures="))
return 0;
return seccomp_restrict_archs(c->syscall_archs);
}
static int apply_address_families(const Unit* u, const ExecContext *c) {
assert(u);
assert(c);
if (!context_has_address_families(c))
return 0;
if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))
return 0;
return seccomp_restrict_address_families(c->address_families, c->address_families_allow_list);
}
static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) {
int r;
assert(u);
assert(c);
if (!c->memory_deny_write_execute)
return 0;
/* use prctl() if kernel supports it (6.3) */
r = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 0, 0, 0);
if (r == 0) {
log_unit_debug(u, "Enabled MemoryDenyWriteExecute= with PR_SET_MDWE");
return 0;
}
if (r < 0 && errno != EINVAL)
return log_unit_debug_errno(u, errno, "Failed to enable MemoryDenyWriteExecute= with PR_SET_MDWE: %m");
/* else use seccomp */
log_unit_debug(u, "Kernel doesn't support PR_SET_MDWE: falling back to seccomp");
if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))
return 0;
return seccomp_memory_deny_write_execute();
}
static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
assert(u);
assert(c);
if (!c->restrict_realtime)
return 0;
if (skip_seccomp_unavailable(u, "RestrictRealtime="))
return 0;
return seccomp_restrict_realtime();
}
static int apply_restrict_suid_sgid(const Unit* u, const ExecContext *c) {
assert(u);
assert(c);
if (!c->restrict_suid_sgid)
return 0;
if (skip_seccomp_unavailable(u, "RestrictSUIDSGID="))
return 0;
return seccomp_restrict_suid_sgid();
}
static int apply_protect_sysctl(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
/* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
* let's protect even those systems where this is left on in the kernel. */
if (!c->protect_kernel_tunables)
return 0;
if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))
return 0;
return seccomp_protect_sysctl();
}
static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
/* Turn off module syscalls on ProtectKernelModules=yes */
if (!c->protect_kernel_modules)
return 0;
if (skip_seccomp_unavailable(u, "ProtectKernelModules="))
return 0;
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM), false);
}
static int apply_protect_kernel_logs(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
if (!c->protect_kernel_logs)
return 0;
if (skip_seccomp_unavailable(u, "ProtectKernelLogs="))
return 0;
return seccomp_protect_syslog();
}
static int apply_protect_clock(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
if (!c->protect_clock)
return 0;
if (skip_seccomp_unavailable(u, "ProtectClock="))
return 0;
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_CLOCK, SCMP_ACT_ERRNO(EPERM), false);
}
static int apply_private_devices(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
/* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
if (!c->private_devices)
return 0;
if (skip_seccomp_unavailable(u, "PrivateDevices="))
return 0;
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM), false);
}
static int apply_restrict_namespaces(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
if (!exec_context_restrict_namespaces_set(c))
return 0;
if (skip_seccomp_unavailable(u, "RestrictNamespaces="))
return 0;
return seccomp_restrict_namespaces(c->restrict_namespaces);
}
static int apply_lock_personality(const Unit* u, const ExecContext *c) {
unsigned long personality;
int r;
assert(u);
assert(c);
if (!c->lock_personality)
return 0;
if (skip_seccomp_unavailable(u, "LockPersonality="))
return 0;
personality = c->personality;
/* If personality is not specified, use either PER_LINUX or PER_LINUX32 depending on what is currently set. */
if (personality == PERSONALITY_INVALID) {
r = opinionated_personality(&personality);
if (r < 0)
return r;
}
return seccomp_lock_personality(personality);
}
#endif
#if HAVE_LIBBPF
static int apply_restrict_filesystems(Unit *u, const ExecContext *c) {
assert(u);
assert(c);
if (!exec_context_restrict_filesystems_set(c))
return 0;
if (!u->manager->restrict_fs) {
/* LSM BPF is unsupported or lsm_bpf_setup failed */
log_unit_debug(u, "LSM BPF not supported, skipping RestrictFileSystems=");
return 0;
}
return lsm_bpf_unit_restrict_filesystems(u, c->restrict_filesystems, c->restrict_filesystems_allow_list);
}
#endif
static int apply_protect_hostname(const Unit *u, const ExecContext *c, int *ret_exit_status) {
assert(u);
assert(c);
if (!c->protect_hostname)
return 0;
if (ns_type_supported(NAMESPACE_UTS)) {
if (unshare(CLONE_NEWUTS) < 0) {
if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno)) {
*ret_exit_status = EXIT_NAMESPACE;
return log_unit_error_errno(u, errno, "Failed to set up UTS namespacing: %m");
}
log_unit_warning(u, "ProtectHostname=yes is configured, but UTS namespace setup is prohibited (container manager?), ignoring namespace setup.");
}
} else
log_unit_warning(u, "ProtectHostname=yes is configured, but the kernel does not support UTS namespaces, ignoring namespace setup.");
#if HAVE_SECCOMP
int r;
if (skip_seccomp_unavailable(u, "ProtectHostname="))
return 0;
r = seccomp_protect_hostname();
if (r < 0) {
*ret_exit_status = EXIT_SECCOMP;
return log_unit_error_errno(u, r, "Failed to apply hostname restrictions: %m");
}
#endif
return 0;
}
static void do_idle_pipe_dance(int idle_pipe[static 4]) {
assert(idle_pipe);
idle_pipe[1] = safe_close(idle_pipe[1]);
idle_pipe[2] = safe_close(idle_pipe[2]);
if (idle_pipe[0] >= 0) {
int r;
r = fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT_USEC);
if (idle_pipe[3] >= 0 && r == 0 /* timeout */) {
ssize_t n;
/* Signal systemd that we are bored and want to continue. */
n = write(idle_pipe[3], "x", 1);
if (n > 0)
/* Wait for systemd to react to the signal above. */
(void) fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT2_USEC);
}
idle_pipe[0] = safe_close(idle_pipe[0]);
}
idle_pipe[3] = safe_close(idle_pipe[3]);
}
static const char *exec_directory_env_name_to_string(ExecDirectoryType t);
static int build_environment(
const Unit *u,
const ExecContext *c,
const ExecParameters *p,
const CGroupContext *cgroup_context,
size_t n_fds,
char **fdnames,
const char *home,
const char *username,
const char *shell,
dev_t journal_stream_dev,
ino_t journal_stream_ino,
const char *memory_pressure_path,
char ***ret) {
_cleanup_strv_free_ char **our_env = NULL;
size_t n_env = 0;
char *x;
int r;
assert(u);
assert(c);
assert(p);
assert(ret);
#define N_ENV_VARS 19
our_env = new0(char*, N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX);
if (!our_env)
return -ENOMEM;
if (n_fds > 0) {
_cleanup_free_ char *joined = NULL;
if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
if (asprintf(&x, "LISTEN_FDS=%zu", n_fds) < 0)
return -ENOMEM;
our_env[n_env++] = x;
joined = strv_join(fdnames, ":");
if (!joined)
return -ENOMEM;
x = strjoin("LISTEN_FDNAMES=", joined);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
if (asprintf(&x, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
/* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use blocking
* Varlink calls back to us for look up dynamic users in PID 1. Break the deadlock between D-Bus and
* PID 1 by disabling use of PID1' NSS interface for looking up dynamic users. */
if (p->flags & EXEC_NSS_DYNAMIC_BYPASS) {
x = strdup("SYSTEMD_NSS_DYNAMIC_BYPASS=1");
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
/* We query "root" if this is a system unit and User= is not specified. $USER is always set. $HOME
* could cause problem for e.g. getty, since login doesn't override $HOME, and $LOGNAME and $SHELL don't
* really make much sense since we're not logged in. Hence we conditionalize the three based on
* SetLoginEnvironment= switch. */
if (!c->user && !c->dynamic_user && p->runtime_scope == RUNTIME_SCOPE_SYSTEM) {
r = get_fixed_user("root", &username, NULL, NULL, &home, &shell);
if (r < 0)
return log_unit_error_errno(u, r, "Failed to determine user credentials for root: %m");
}
bool set_user_login_env = c->set_login_environment >= 0 ? c->set_login_environment : (c->user || c->dynamic_user);
if (username) {
x = strjoin("USER=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
if (set_user_login_env) {
x = strjoin("LOGNAME=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
}
if (home && set_user_login_env) {
x = strjoin("HOME=", home);
if (!x)
return -ENOMEM;
path_simplify(x + 5);
our_env[n_env++] = x;
}
if (shell && set_user_login_env) {
x = strjoin("SHELL=", shell);
if (!x)
return -ENOMEM;
path_simplify(x + 6);
our_env[n_env++] = x;
}
if (!sd_id128_is_null(u->invocation_id)) {
if (asprintf(&x, "INVOCATION_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(u->invocation_id)) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
if (exec_context_needs_term(c)) {
_cleanup_free_ char *cmdline = NULL;
const char *tty_path, *term = NULL;
tty_path = exec_context_tty_path(c);
/* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try
* to inherit the $TERM set for PID 1. This is useful for containers so that the $TERM the
* container manager passes to PID 1 ends up all the way in the console login shown. */
if (path_equal_ptr(tty_path, "/dev/console") && getppid() == 1)
term = getenv("TERM");
else if (tty_path && in_charset(skip_dev_prefix(tty_path), ALPHANUMERICAL)) {
_cleanup_free_ char *key = NULL;
key = strjoin("systemd.tty.term.", skip_dev_prefix(tty_path));
if (!key)
return -ENOMEM;
r = proc_cmdline_get_key(key, 0, &cmdline);
if (r < 0)
log_debug_errno(r, "Failed to read %s from kernel cmdline, ignoring: %m", key);
else if (r > 0)
term = cmdline;
}
if (!term)
term = default_term_for_tty(tty_path);
x = strjoin("TERM=", term);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (journal_stream_dev != 0 && journal_stream_ino != 0) {
if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
if (c->log_namespace) {
x = strjoin("LOG_NAMESPACE=", c->log_namespace);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
_cleanup_free_ char *joined = NULL;
const char *n;
if (!p->prefix[t])
continue;
if (c->directories[t].n_items == 0)
continue;
n = exec_directory_env_name_to_string(t);
if (!n)
continue;
for (size_t i = 0; i < c->directories[t].n_items; i++) {
_cleanup_free_ char *prefixed = NULL;
prefixed = path_join(p->prefix[t], c->directories[t].items[i].path);
if (!prefixed)
return -ENOMEM;
if (!strextend_with_separator(&joined, ":", prefixed))
return -ENOMEM;
}
x = strjoin(n, "=", joined);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
_cleanup_free_ char *creds_dir = NULL;
r = exec_context_get_credential_directory(c, p, u->id, &creds_dir);
if (r < 0)
return r;
if (r > 0) {
x = strjoin("CREDENTIALS_DIRECTORY=", creds_dir);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (asprintf(&x, "SYSTEMD_EXEC_PID=" PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
if (memory_pressure_path) {
x = strjoin("MEMORY_PRESSURE_WATCH=", memory_pressure_path);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
if (cgroup_context && !path_equal(memory_pressure_path, "/dev/null")) {
_cleanup_free_ char *b = NULL, *e = NULL;
if (asprintf(&b, "%s " USEC_FMT " " USEC_FMT,
MEMORY_PRESSURE_DEFAULT_TYPE,
cgroup_context->memory_pressure_threshold_usec == USEC_INFINITY ? MEMORY_PRESSURE_DEFAULT_THRESHOLD_USEC :
CLAMP(cgroup_context->memory_pressure_threshold_usec, 1U, MEMORY_PRESSURE_DEFAULT_WINDOW_USEC),
MEMORY_PRESSURE_DEFAULT_WINDOW_USEC) < 0)
return -ENOMEM;
if (base64mem(b, strlen(b) + 1, &e) < 0)
return -ENOMEM;
x = strjoin("MEMORY_PRESSURE_WRITE=", e);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
}
assert(n_env < N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX);
#undef N_ENV_VARS
*ret = TAKE_PTR(our_env);
return 0;
}
static int build_pass_environment(const ExecContext *c, char ***ret) {
_cleanup_strv_free_ char **pass_env = NULL;
size_t n_env = 0;
STRV_FOREACH(i, c->pass_environment) {
_cleanup_free_ char *x = NULL;
char *v;
v = getenv(*i);
if (!v)
continue;
x = strjoin(*i, "=", v);
if (!x)
return -ENOMEM;
if (!GREEDY_REALLOC(pass_env, n_env + 2))
return -ENOMEM;
pass_env[n_env++] = TAKE_PTR(x);
pass_env[n_env] = NULL;
}
*ret = TAKE_PTR(pass_env);
return 0;
}
bool exec_needs_network_namespace(const ExecContext *context) {
assert(context);
return context->private_network || context->network_namespace_path;
}
static bool exec_needs_ephemeral(const ExecContext *context) {
return (context->root_image || context->root_directory) && context->root_ephemeral;
}
static bool exec_needs_ipc_namespace(const ExecContext *context) {
assert(context);
return context->private_ipc || context->ipc_namespace_path;
}
bool exec_needs_mount_namespace(
const ExecContext *context,
const ExecParameters *params,
const ExecRuntime *runtime) {
assert(context);
if (context->root_image)
return true;
if (!strv_isempty(context->read_write_paths) ||
!strv_isempty(context->read_only_paths) ||
!strv_isempty(context->inaccessible_paths) ||
!strv_isempty(context->exec_paths) ||
!strv_isempty(context->no_exec_paths))
return true;
if (context->n_bind_mounts > 0)
return true;
if (context->n_temporary_filesystems > 0)
return true;
if (context->n_mount_images > 0)
return true;
if (context->n_extension_images > 0)
return true;
if (!strv_isempty(context->extension_directories))
return true;
if (!IN_SET(context->mount_propagation_flag, 0, MS_SHARED))
return true;
if (context->private_tmp && runtime && runtime->shared && (runtime->shared->tmp_dir || runtime->shared->var_tmp_dir))
return true;
if (context->private_devices ||
context->private_mounts > 0 ||
(context->private_mounts < 0 && exec_needs_network_namespace(context)) ||
context->protect_system != PROTECT_SYSTEM_NO ||
context->protect_home != PROTECT_HOME_NO ||
context->protect_kernel_tunables ||
context->protect_kernel_modules ||
context->protect_kernel_logs ||
context->protect_control_groups ||
context->protect_proc != PROTECT_PROC_DEFAULT ||
context->proc_subset != PROC_SUBSET_ALL ||
exec_needs_ipc_namespace(context))
return true;
if (context->root_directory) {
if (exec_context_get_effective_mount_apivfs(context))
return true;
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (params && !params->prefix[t])
continue;
if (context->directories[t].n_items > 0)
return true;
}
}
if (context->dynamic_user &&
(context->directories[EXEC_DIRECTORY_STATE].n_items > 0 ||
context->directories[EXEC_DIRECTORY_CACHE].n_items > 0 ||
context->directories[EXEC_DIRECTORY_LOGS].n_items > 0))
return true;
if (context->log_namespace)
return true;
return false;
}
static int setup_private_users(uid_t ouid, gid_t ogid, uid_t uid, gid_t gid) {
_cleanup_free_ char *uid_map = NULL, *gid_map = NULL;
_cleanup_close_pair_ int errno_pipe[2] = PIPE_EBADF;
_cleanup_close_ int unshare_ready_fd = -EBADF;
_cleanup_(sigkill_waitp) pid_t pid = 0;
uint64_t c = 1;
ssize_t n;
int r;
/* Set up a user namespace and map the original UID/GID (IDs from before any user or group changes, i.e.
* the IDs from the user or system manager(s)) to itself, the selected UID/GID to itself, and everything else to
* nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which
* we however lack after opening the user namespace. To work around this we fork() a temporary child process,
* which waits for the parent to create the new user namespace while staying in the original namespace. The
* child then writes the UID mapping, under full privileges. The parent waits for the child to finish and
* continues execution normally.
* For unprivileged users (i.e. without capabilities), the root to root mapping is excluded. As such, it
* does not need CAP_SETUID to write the single line mapping to itself. */
/* Can only set up multiple mappings with CAP_SETUID. */
if (have_effective_cap(CAP_SETUID) > 0 && uid != ouid && uid_is_valid(uid))
r = asprintf(&uid_map,
UID_FMT " " UID_FMT " 1\n" /* Map $OUID → $OUID */
UID_FMT " " UID_FMT " 1\n", /* Map $UID → $UID */
ouid, ouid, uid, uid);
else
r = asprintf(&uid_map,
UID_FMT " " UID_FMT " 1\n", /* Map $OUID → $OUID */
ouid, ouid);
if (r < 0)
return -ENOMEM;
/* Can only set up multiple mappings with CAP_SETGID. */
if (have_effective_cap(CAP_SETGID) > 0 && gid != ogid && gid_is_valid(gid))
r = asprintf(&gid_map,
GID_FMT " " GID_FMT " 1\n" /* Map $OGID → $OGID */
GID_FMT " " GID_FMT " 1\n", /* Map $GID → $GID */
ogid, ogid, gid, gid);
else
r = asprintf(&gid_map,
GID_FMT " " GID_FMT " 1\n", /* Map $OGID -> $OGID */
ogid, ogid);
if (r < 0)
return -ENOMEM;
/* Create a communication channel so that the parent can tell the child when it finished creating the user
* namespace. */
unshare_ready_fd = eventfd(0, EFD_CLOEXEC);
if (unshare_ready_fd < 0)
return -errno;
/* Create a communication channel so that the child can tell the parent a proper error code in case it
* failed. */
if (pipe2(errno_pipe, O_CLOEXEC) < 0)
return -errno;
r = safe_fork("(sd-userns)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid);
if (r < 0)
return r;
if (r == 0) {
_cleanup_close_ int fd = -EBADF;
const char *a;
pid_t ppid;
/* Child process, running in the original user namespace. Let's update the parent's UID/GID map from
* here, after the parent opened its own user namespace. */
ppid = getppid();
errno_pipe[0] = safe_close(errno_pipe[0]);
/* Wait until the parent unshared the user namespace */
if (read(unshare_ready_fd, &c, sizeof(c)) < 0) {
r = -errno;
goto child_fail;
}
/* Disable the setgroups() system call in the child user namespace, for good. */
a = procfs_file_alloca(ppid, "setgroups");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
if (errno != ENOENT) {
r = -errno;
goto child_fail;
}
/* If the file is missing the kernel is too old, let's continue anyway. */
} else {
if (write(fd, "deny\n", 5) < 0) {
r = -errno;
goto child_fail;
}
fd = safe_close(fd);
}
/* First write the GID map */
a = procfs_file_alloca(ppid, "gid_map");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
r = -errno;
goto child_fail;
}
if (write(fd, gid_map, strlen(gid_map)) < 0) {
r = -errno;
goto child_fail;
}
fd = safe_close(fd);
/* The write the UID map */
a = procfs_file_alloca(ppid, "uid_map");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
r = -errno;
goto child_fail;
}
if (write(fd, uid_map, strlen(uid_map)) < 0) {
r = -errno;
goto child_fail;
}
_exit(EXIT_SUCCESS);
child_fail:
(void) write(errno_pipe[1], &r, sizeof(r));
_exit(EXIT_FAILURE);
}
errno_pipe[1] = safe_close(errno_pipe[1]);
if (unshare(CLONE_NEWUSER) < 0)
return -errno;
/* Let the child know that the namespace is ready now */
if (write(unshare_ready_fd, &c, sizeof(c)) < 0)
return -errno;
/* Try to read an error code from the child */
n = read(errno_pipe[0], &r, sizeof(r));
if (n < 0)
return -errno;
if (n == sizeof(r)) { /* an error code was sent to us */
if (r < 0)
return r;
return -EIO;
}
if (n != 0) /* on success we should have read 0 bytes */
return -EIO;
r = wait_for_terminate_and_check("(sd-userns)", TAKE_PID(pid), 0);
if (r < 0)
return r;
if (r != EXIT_SUCCESS) /* If something strange happened with the child, let's consider this fatal, too */
return -EIO;
return 0;
}
static bool exec_directory_is_private(const ExecContext *context, ExecDirectoryType type) {
assert(context);
if (!context->dynamic_user)
return false;
if (type == EXEC_DIRECTORY_CONFIGURATION)
return false;
if (type == EXEC_DIRECTORY_RUNTIME && context->runtime_directory_preserve_mode == EXEC_PRESERVE_NO)
return false;
return true;
}
static int create_many_symlinks(const char *root, const char *source, char **symlinks) {
_cleanup_free_ char *src_abs = NULL;
int r;
assert(source);
src_abs = path_join(root, source);
if (!src_abs)
return -ENOMEM;
STRV_FOREACH(dst, symlinks) {
_cleanup_free_ char *dst_abs = NULL;
dst_abs = path_join(root, *dst);
if (!dst_abs)
return -ENOMEM;
r = mkdir_parents_label(dst_abs, 0755);
if (r < 0)
return r;
r = symlink_idempotent(src_abs, dst_abs, true);
if (r < 0)
return r;
}
return 0;
}
static int setup_exec_directory(
Unit *u,
const ExecContext *context,
const ExecParameters *params,
uid_t uid,
gid_t gid,
ExecDirectoryType type,
bool needs_mount_namespace,
int *exit_status) {
static const int exit_status_table[_EXEC_DIRECTORY_TYPE_MAX] = {
[EXEC_DIRECTORY_RUNTIME] = EXIT_RUNTIME_DIRECTORY,
[EXEC_DIRECTORY_STATE] = EXIT_STATE_DIRECTORY,
[EXEC_DIRECTORY_CACHE] = EXIT_CACHE_DIRECTORY,
[EXEC_DIRECTORY_LOGS] = EXIT_LOGS_DIRECTORY,
[EXEC_DIRECTORY_CONFIGURATION] = EXIT_CONFIGURATION_DIRECTORY,
};
int r;
assert(context);
assert(params);
assert(type >= 0 && type < _EXEC_DIRECTORY_TYPE_MAX);
assert(exit_status);
if (!params->prefix[type])
return 0;
if (params->flags & EXEC_CHOWN_DIRECTORIES) {
if (!uid_is_valid(uid))
uid = 0;
if (!gid_is_valid(gid))
gid = 0;
}
for (size_t i = 0; i < context->directories[type].n_items; i++) {
_cleanup_free_ char *p = NULL, *pp = NULL;
p = path_join(params->prefix[type], context->directories[type].items[i].path);
if (!p) {
r = -ENOMEM;
goto fail;
}
r = mkdir_parents_label(p, 0755);
if (r < 0)
goto fail;
if (IN_SET(type, EXEC_DIRECTORY_STATE, EXEC_DIRECTORY_LOGS) && params->runtime_scope == RUNTIME_SCOPE_USER) {
/* If we are in user mode, and a configuration directory exists but a state directory
* doesn't exist, then we likely are upgrading from an older systemd version that
* didn't know the more recent addition to the xdg-basedir spec: the $XDG_STATE_HOME
* directory. In older systemd versions EXEC_DIRECTORY_STATE was aliased to
* EXEC_DIRECTORY_CONFIGURATION, with the advent of $XDG_STATE_HOME is is now
* separated. If a service has both dirs configured but only the configuration dir
* exists and the state dir does not, we assume we are looking at an update
* situation. Hence, create a compatibility symlink, so that all expectations are
* met.
*
* (We also do something similar with the log directory, which still doesn't exist in
* the xdg basedir spec. We'll make it a subdir of the state dir.) */
/* this assumes the state dir is always created before the configuration dir */
assert_cc(EXEC_DIRECTORY_STATE < EXEC_DIRECTORY_LOGS);
assert_cc(EXEC_DIRECTORY_LOGS < EXEC_DIRECTORY_CONFIGURATION);
r = laccess(p, F_OK);
if (r == -ENOENT) {
_cleanup_free_ char *q = NULL;
/* OK, we know that the state dir does not exist. Let's see if the dir exists
* under the configuration hierarchy. */
if (type == EXEC_DIRECTORY_STATE)
q = path_join(params->prefix[EXEC_DIRECTORY_CONFIGURATION], context->directories[type].items[i].path);
else if (type == EXEC_DIRECTORY_LOGS)
q = path_join(params->prefix[EXEC_DIRECTORY_CONFIGURATION], "log", context->directories[type].items[i].path);
else
assert_not_reached();
if (!q) {
r = -ENOMEM;
goto fail;
}
r = laccess(q, F_OK);
if (r >= 0) {
/* It does exist! This hence looks like an update. Symlink the
* configuration directory into the state directory. */
r = symlink_idempotent(q, p, /* make_relative= */ true);
if (r < 0)
goto fail;
log_unit_notice(u, "Unit state directory %s missing but matching configuration directory %s exists, assuming update from systemd 253 or older, creating compatibility symlink.", p, q);
continue;
} else if (r != -ENOENT)
log_unit_warning_errno(u, r, "Unable to detect whether unit configuration directory '%s' exists, assuming not: %m", q);
} else if (r < 0)
log_unit_warning_errno(u, r, "Unable to detect whether unit state directory '%s' is missing, assuming it is: %m", p);
}
if (exec_directory_is_private(context, type)) {
/* So, here's one extra complication when dealing with DynamicUser=1 units. In that
* case we want to avoid leaving a directory around fully accessible that is owned by
* a dynamic user whose UID is later on reused. To lock this down we use the same
* trick used by container managers to prohibit host users to get access to files of
* the same UID in containers: we place everything inside a directory that has an
* access mode of 0700 and is owned root:root, so that it acts as security boundary
* for unprivileged host code. We then use fs namespacing to make this directory
* permeable for the service itself.
*
* Specifically: for a service which wants a special directory "foo/" we first create
* a directory "private/" with access mode 0700 owned by root:root. Then we place
* "foo" inside of that directory (i.e. "private/foo/"), and make "foo" a symlink to
* "private/foo". This way, privileged host users can access "foo/" as usual, but
* unprivileged host users can't look into it. Inside of the namespace of the unit
* "private/" is replaced by a more liberally accessible tmpfs, into which the host's
* "private/foo/" is mounted under the same name, thus disabling the access boundary
* for the service and making sure it only gets access to the dirs it needs but no
* others. Tricky? Yes, absolutely, but it works!
*
* Note that we don't do this for EXEC_DIRECTORY_CONFIGURATION as that's assumed not
* to be owned by the service itself.
*
* Also, note that we don't do this for EXEC_DIRECTORY_RUNTIME as that's often used
* for sharing files or sockets with other services. */
pp = path_join(params->prefix[type], "private");
if (!pp) {
r = -ENOMEM;
goto fail;
}
/* First set up private root if it doesn't exist yet, with access mode 0700 and owned by root:root */
r = mkdir_safe_label(pp, 0700, 0, 0, MKDIR_WARN_MODE);
if (r < 0)
goto fail;
if (!path_extend(&pp, context->directories[type].items[i].path)) {
r = -ENOMEM;
goto fail;
}
/* Create all directories between the configured directory and this private root, and mark them 0755 */
r = mkdir_parents_label(pp, 0755);
if (r < 0)
goto fail;
if (is_dir(p, false) > 0 &&
(laccess(pp, F_OK) == -ENOENT)) {
/* Hmm, the private directory doesn't exist yet, but the normal one exists? If so, move
* it over. Most likely the service has been upgraded from one that didn't use
* DynamicUser=1, to one that does. */
log_unit_info(u, "Found pre-existing public %s= directory %s, migrating to %s.\n"
"Apparently, service previously had DynamicUser= turned off, and has now turned it on.",
exec_directory_type_to_string(type), p, pp);
r = RET_NERRNO(rename(p, pp));
if (r < 0)
goto fail;
} else {
/* Otherwise, create the actual directory for the service */
r = mkdir_label(pp, context->directories[type].mode);
if (r < 0 && r != -EEXIST)
goto fail;
}
if (!context->directories[type].items[i].only_create) {
/* And link it up from the original place.
* Notes
* 1) If a mount namespace is going to be used, then this symlink remains on
* the host, and a new one for the child namespace will be created later.
* 2) It is not necessary to create this symlink when one of its parent
* directories is specified and already created. E.g.
* StateDirectory=foo foo/bar
* In that case, the inode points to pp and p for "foo/bar" are the same:
* pp = "/var/lib/private/foo/bar"
* p = "/var/lib/foo/bar"
* and, /var/lib/foo is a symlink to /var/lib/private/foo. So, not only
* we do not need to create the symlink, but we cannot create the symlink.
* See issue #24783. */
r = symlink_idempotent(pp, p, true);
if (r < 0)
goto fail;
}
} else {
_cleanup_free_ char *target = NULL;
if (type != EXEC_DIRECTORY_CONFIGURATION &&
readlink_and_make_absolute(p, &target) >= 0) {
_cleanup_free_ char *q = NULL, *q_resolved = NULL, *target_resolved = NULL;
/* This already exists and is a symlink? Interesting. Maybe it's one created
* by DynamicUser=1 (see above)?
*
* We do this for all directory types except for ConfigurationDirectory=,
* since they all support the private/ symlink logic at least in some
* configurations, see above. */
r = chase(target, NULL, 0, &target_resolved, NULL);
if (r < 0)
goto fail;
q = path_join(params->prefix[type], "private", context->directories[type].items[i].path);
if (!q) {
r = -ENOMEM;
goto fail;
}
/* /var/lib or friends may be symlinks. So, let's chase them also. */
r = chase(q, NULL, CHASE_NONEXISTENT, &q_resolved, NULL);
if (r < 0)
goto fail;
if (path_equal(q_resolved, target_resolved)) {
/* Hmm, apparently DynamicUser= was once turned on for this service,
* but is no longer. Let's move the directory back up. */
log_unit_info(u, "Found pre-existing private %s= directory %s, migrating to %s.\n"
"Apparently, service previously had DynamicUser= turned on, and has now turned it off.",
exec_directory_type_to_string(type), q, p);
r = RET_NERRNO(unlink(p));
if (r < 0)
goto fail;
r = RET_NERRNO(rename(q, p));
if (r < 0)
goto fail;
}
}
r = mkdir_label(p, context->directories[type].mode);
if (r < 0) {
if (r != -EEXIST)
goto fail;
if (type == EXEC_DIRECTORY_CONFIGURATION) {
struct stat st;
/* Don't change the owner/access mode of the configuration directory,
* as in the common case it is not written to by a service, and shall
* not be writable. */
r = RET_NERRNO(stat(p, &st));
if (r < 0)
goto fail;
/* Still complain if the access mode doesn't match */
if (((st.st_mode ^ context->directories[type].mode) & 07777) != 0)
log_unit_warning(u, "%s \'%s\' already exists but the mode is different. "
"(File system: %o %sMode: %o)",
exec_directory_type_to_string(type), context->directories[type].items[i].path,
st.st_mode & 07777, exec_directory_type_to_string(type), context->directories[type].mode & 07777);
continue;
}
}
}
/* Lock down the access mode (we use chmod_and_chown() to make this idempotent. We don't
* specify UID/GID here, so that path_chown_recursive() can optimize things depending on the
* current UID/GID ownership.) */
r = chmod_and_chown(pp ?: p, context->directories[type].mode, UID_INVALID, GID_INVALID);
if (r < 0)
goto fail;
/* Skip the rest (which deals with ownership) in user mode, since ownership changes are not
* available to user code anyway */
if (params->runtime_scope != RUNTIME_SCOPE_SYSTEM)
continue;
/* Then, change the ownership of the whole tree, if necessary. When dynamic users are used we
* drop the suid/sgid bits, since we really don't want SUID/SGID files for dynamic UID/GID
* assignments to exist. */
r = path_chown_recursive(pp ?: p, uid, gid, context->dynamic_user ? 01777 : 07777, AT_SYMLINK_FOLLOW);
if (r < 0)
goto fail;
}
/* If we are not going to run in a namespace, set up the symlinks - otherwise
* they are set up later, to allow configuring empty var/run/etc. */
if (!needs_mount_namespace)
for (size_t i = 0; i < context->directories[type].n_items; i++) {
r = create_many_symlinks(params->prefix[type],
context->directories[type].items[i].path,
context->directories[type].items[i].symlinks);
if (r < 0)
goto fail;
}
return 0;
fail:
*exit_status = exit_status_table[type];
return r;
}
#if ENABLE_SMACK
static int setup_smack(
const Manager *manager,
const ExecContext *context,
int executable_fd) {
int r;
assert(context);
assert(executable_fd >= 0);
if (context->smack_process_label) {
r = mac_smack_apply_pid(0, context->smack_process_label);
if (r < 0)
return r;
} else if (manager->defaults.smack_process_label) {
_cleanup_free_ char *exec_label = NULL;
r = mac_smack_read_fd(executable_fd, SMACK_ATTR_EXEC, &exec_label);
if (r < 0 && !ERRNO_IS_XATTR_ABSENT(r))
return r;
r = mac_smack_apply_pid(0, exec_label ?: manager->defaults.smack_process_label);
if (r < 0)
return r;
}
return 0;
}
#endif
static int compile_bind_mounts(
const ExecContext *context,
const ExecParameters *params,
BindMount **ret_bind_mounts,
size_t *ret_n_bind_mounts,
char ***ret_empty_directories) {
_cleanup_strv_free_ char **empty_directories = NULL;
BindMount *bind_mounts = NULL;
size_t n, h = 0;
int r;
assert(context);
assert(params);
assert(ret_bind_mounts);
assert(ret_n_bind_mounts);
assert(ret_empty_directories);
CLEANUP_ARRAY(bind_mounts, h, bind_mount_free_many);
n = context->n_bind_mounts;
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (!params->prefix[t])
continue;
for (size_t i = 0; i < context->directories[t].n_items; i++)
n += !context->directories[t].items[i].only_create;
}
if (n <= 0) {
*ret_bind_mounts = NULL;
*ret_n_bind_mounts = 0;
*ret_empty_directories = NULL;
return 0;
}
bind_mounts = new(BindMount, n);
if (!bind_mounts)
return -ENOMEM;
for (size_t i = 0; i < context->n_bind_mounts; i++) {
BindMount *item = context->bind_mounts + i;
_cleanup_free_ char *s = NULL, *d = NULL;
s = strdup(item->source);
if (!s)
return -ENOMEM;
d = strdup(item->destination);
if (!d)
return -ENOMEM;
bind_mounts[h++] = (BindMount) {
.source = TAKE_PTR(s),
.destination = TAKE_PTR(d),
.read_only = item->read_only,
.recursive = item->recursive,
.ignore_enoent = item->ignore_enoent,
};
}
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (!params->prefix[t])
continue;
if (context->directories[t].n_items == 0)
continue;
if (exec_directory_is_private(context, t) &&
!exec_context_with_rootfs(context)) {
char *private_root;
/* So this is for a dynamic user, and we need to make sure the process can access its own
* directory. For that we overmount the usually inaccessible "private" subdirectory with a
* tmpfs that makes it accessible and is empty except for the submounts we do this for. */
private_root = path_join(params->prefix[t], "private");
if (!private_root)
return -ENOMEM;
r = strv_consume(&empty_directories, private_root);
if (r < 0)
return r;
}
for (size_t i = 0; i < context->directories[t].n_items; i++) {
_cleanup_free_ char *s = NULL, *d = NULL;
/* When one of the parent directories is in the list, we cannot create the symlink
* for the child directory. See also the comments in setup_exec_directory(). */
if (context->directories[t].items[i].only_create)
continue;
if (exec_directory_is_private(context, t))
s = path_join(params->prefix[t], "private", context->directories[t].items[i].path);
else
s = path_join(params->prefix[t], context->directories[t].items[i].path);
if (!s)
return -ENOMEM;
if (exec_directory_is_private(context, t) &&
exec_context_with_rootfs(context))
/* When RootDirectory= or RootImage= are set, then the symbolic link to the private
* directory is not created on the root directory. So, let's bind-mount the directory
* on the 'non-private' place. */
d = path_join(params->prefix[t], context->directories[t].items[i].path);
else
d = strdup(s);
if (!d)
return -ENOMEM;
bind_mounts[h++] = (BindMount) {
.source = TAKE_PTR(s),
.destination = TAKE_PTR(d),
.read_only = false,
.nosuid = context->dynamic_user, /* don't allow suid/sgid when DynamicUser= is on */
.recursive = true,
.ignore_enoent = false,
};
}
}
assert(h == n);
*ret_bind_mounts = TAKE_PTR(bind_mounts);
*ret_n_bind_mounts = n;
*ret_empty_directories = TAKE_PTR(empty_directories);
return (int) n;
}
/* ret_symlinks will contain a list of pairs src:dest that describes
* the symlinks to create later on. For example, the symlinks needed
* to safely give private directories to DynamicUser=1 users. */
static int compile_symlinks(
const ExecContext *context,
const ExecParameters *params,
bool setup_os_release_symlink,
char ***ret_symlinks) {
_cleanup_strv_free_ char **symlinks = NULL;
int r;
assert(context);
assert(params);
assert(ret_symlinks);
for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) {
for (size_t i = 0; i < context->directories[dt].n_items; i++) {
_cleanup_free_ char *private_path = NULL, *path = NULL;
STRV_FOREACH(symlink, context->directories[dt].items[i].symlinks) {
_cleanup_free_ char *src_abs = NULL, *dst_abs = NULL;
src_abs = path_join(params->prefix[dt], context->directories[dt].items[i].path);
dst_abs = path_join(params->prefix[dt], *symlink);
if (!src_abs || !dst_abs)
return -ENOMEM;
r = strv_consume_pair(&symlinks, TAKE_PTR(src_abs), TAKE_PTR(dst_abs));
if (r < 0)
return r;
}
if (!exec_directory_is_private(context, dt) ||
exec_context_with_rootfs(context) ||
context->directories[dt].items[i].only_create)
continue;
private_path = path_join(params->prefix[dt], "private", context->directories[dt].items[i].path);
if (!private_path)
return -ENOMEM;
path = path_join(params->prefix[dt], context->directories[dt].items[i].path);
if (!path)
return -ENOMEM;
r = strv_consume_pair(&symlinks, TAKE_PTR(private_path), TAKE_PTR(path));
if (r < 0)
return r;
}
}
/* We make the host's os-release available via a symlink, so that we can copy it atomically
* and readers will never get a half-written version. Note that, while the paths specified here are
* absolute, when they are processed in namespace.c they will be made relative automatically, i.e.:
* 'os-release -> .os-release-stage/os-release' is what will be created. */
if (setup_os_release_symlink) {
r = strv_extend(&symlinks, "/run/host/.os-release-stage/os-release");
if (r < 0)
return r;
r = strv_extend(&symlinks, "/run/host/os-release");
if (r < 0)
return r;
}
*ret_symlinks = TAKE_PTR(symlinks);
return 0;
}
static bool insist_on_sandboxing(
const ExecContext *context,
const char *root_dir,
const char *root_image,
const BindMount *bind_mounts,
size_t n_bind_mounts) {
assert(context);
assert(n_bind_mounts == 0 || bind_mounts);
/* Checks whether we need to insist on fs namespacing. i.e. whether we have settings configured that
* would alter the view on the file system beyond making things read-only or invisible, i.e. would
* rearrange stuff in a way we cannot ignore gracefully. */
if (context->n_temporary_filesystems > 0)
return true;
if (root_dir || root_image)
return true;
if (context->n_mount_images > 0)
return true;
if (context->dynamic_user)
return true;
if (context->n_extension_images > 0 || !strv_isempty(context->extension_directories))
return true;
/* If there are any bind mounts set that don't map back onto themselves, fs namespacing becomes
* essential. */
for (size_t i = 0; i < n_bind_mounts; i++)
if (!path_equal(bind_mounts[i].source, bind_mounts[i].destination))
return true;
if (context->log_namespace)
return true;
return false;
}
static int setup_ephemeral(const ExecContext *context, ExecRuntime *runtime) {
_cleanup_close_ int fd = -EBADF;
int r;
if (!runtime || !runtime->ephemeral_copy)
return 0;
r = posix_lock(runtime->ephemeral_storage_socket[0], LOCK_EX);
if (r < 0)
return log_debug_errno(r, "Failed to lock ephemeral storage socket: %m");
CLEANUP_POSIX_UNLOCK(runtime->ephemeral_storage_socket[0]);
fd = receive_one_fd(runtime->ephemeral_storage_socket[0], MSG_PEEK|MSG_DONTWAIT);
if (fd >= 0)
/* We got an fd! That means ephemeral has already been set up, so nothing to do here. */
return 0;
if (fd != -EAGAIN)
return log_debug_errno(fd, "Failed to receive file descriptor queued on ephemeral storage socket: %m");
log_debug("Making ephemeral snapshot of %s to %s",
context->root_image ?: context->root_directory, runtime->ephemeral_copy);
if (context->root_image)
fd = copy_file(context->root_image, runtime->ephemeral_copy, O_EXCL, 0600,
COPY_LOCK_BSD|COPY_REFLINK|COPY_CRTIME);
else
fd = btrfs_subvol_snapshot_at(AT_FDCWD, context->root_directory,
AT_FDCWD, runtime->ephemeral_copy,
BTRFS_SNAPSHOT_FALLBACK_COPY |
BTRFS_SNAPSHOT_FALLBACK_DIRECTORY |
BTRFS_SNAPSHOT_RECURSIVE |
BTRFS_SNAPSHOT_LOCK_BSD);
if (fd < 0)
return log_debug_errno(fd, "Failed to snapshot %s to %s: %m",
context->root_image ?: context->root_directory, runtime->ephemeral_copy);
if (context->root_image) {
/* A root image might be subject to lots of random writes so let's try to disable COW on it
* which tends to not perform well in combination with lots of random writes.
*
* Note: btrfs actually isn't impressed by us setting the flag after making the reflink'ed
* copy, but we at least want to make the intention clear.
*/
r = chattr_fd(fd, FS_NOCOW_FL, FS_NOCOW_FL, NULL);
if (r < 0)
log_debug_errno(fd, "Failed to disable copy-on-write for %s, ignoring: %m", runtime->ephemeral_copy);
}
r = send_one_fd(runtime->ephemeral_storage_socket[1], fd, MSG_DONTWAIT);
if (r < 0)
return log_debug_errno(r, "Failed to queue file descriptor on ephemeral storage socket: %m");
return 1;
}
static int verity_settings_prepare(
VeritySettings *verity,
const char *root_image,
const void *root_hash,
size_t root_hash_size,
const char *root_hash_path,
const void *root_hash_sig,
size_t root_hash_sig_size,
const char *root_hash_sig_path,
const char *verity_data_path) {
int r;
assert(verity);
if (root_hash) {
void *d;
d = memdup(root_hash, root_hash_size);
if (!d)
return -ENOMEM;
free_and_replace(verity->root_hash, d);
verity->root_hash_size = root_hash_size;
verity->designator = PARTITION_ROOT;
}
if (root_hash_sig) {
void *d;
d = memdup(root_hash_sig, root_hash_sig_size);
if (!d)
return -ENOMEM;
free_and_replace(verity->root_hash_sig, d);
verity->root_hash_sig_size = root_hash_sig_size;
verity->designator = PARTITION_ROOT;
}
if (verity_data_path) {
r = free_and_strdup(&verity->data_path, verity_data_path);
if (r < 0)
return r;
}
r = verity_settings_load(
verity,
root_image,
root_hash_path,
root_hash_sig_path);
if (r < 0)
return log_debug_errno(r, "Failed to load root hash: %m");
return 0;
}
static int apply_mount_namespace(
const Unit *u,
ExecCommandFlags command_flags,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
const char *memory_pressure_path,
char **error_path) {
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
_cleanup_strv_free_ char **empty_directories = NULL, **symlinks = NULL,
**read_write_paths_cleanup = NULL;
_cleanup_free_ char *creds_path = NULL, *incoming_dir = NULL, *propagate_dir = NULL,
*extension_dir = NULL, *host_os_release_stage = NULL;
const char *root_dir = NULL, *root_image = NULL, *tmp_dir = NULL, *var_tmp_dir = NULL;
char **read_write_paths;
bool needs_sandboxing, setup_os_release_symlink;
BindMount *bind_mounts = NULL;
size_t n_bind_mounts = 0;
int r;
assert(context);
CLEANUP_ARRAY(bind_mounts, n_bind_mounts, bind_mount_free_many);
if (params->flags & EXEC_APPLY_CHROOT) {
r = setup_ephemeral(context, runtime);
if (r < 0)
return r;
if (context->root_image)
root_image = (runtime ? runtime->ephemeral_copy : NULL) ?: context->root_image;
else
root_dir = (runtime ? runtime->ephemeral_copy : NULL) ?: context->root_directory;
}
r = compile_bind_mounts(context, params, &bind_mounts, &n_bind_mounts, &empty_directories);
if (r < 0)
return r;
/* We need to make the pressure path writable even if /sys/fs/cgroups is made read-only, as the
* service will need to write to it in order to start the notifications. */
if (context->protect_control_groups && memory_pressure_path && !streq(memory_pressure_path, "/dev/null")) {
read_write_paths_cleanup = strv_copy(context->read_write_paths);
if (!read_write_paths_cleanup)
return -ENOMEM;
r = strv_extend(&read_write_paths_cleanup, memory_pressure_path);
if (r < 0)
return r;
read_write_paths = read_write_paths_cleanup;
} else
read_write_paths = context->read_write_paths;
needs_sandboxing = (params->flags & EXEC_APPLY_SANDBOXING) && !(command_flags & EXEC_COMMAND_FULLY_PRIVILEGED);
if (needs_sandboxing) {
/* The runtime struct only contains the parent of the private /tmp, which is non-accessible
* to world users. Inside of it there's a /tmp that is sticky, and that's the one we want to
* use here. This does not apply when we are using /run/systemd/empty as fallback. */
if (context->private_tmp && runtime && runtime->shared) {
if (streq_ptr(runtime->shared->tmp_dir, RUN_SYSTEMD_EMPTY))
tmp_dir = runtime->shared->tmp_dir;
else if (runtime->shared->tmp_dir)
tmp_dir = strjoina(runtime->shared->tmp_dir, "/tmp");
if (streq_ptr(runtime->shared->var_tmp_dir, RUN_SYSTEMD_EMPTY))
var_tmp_dir = runtime->shared->var_tmp_dir;
else if (runtime->shared->var_tmp_dir)
var_tmp_dir = strjoina(runtime->shared->var_tmp_dir, "/tmp");
}
}
/* Symlinks (exec dirs, os-release) are set up after other mounts, before they are made read-only. */
setup_os_release_symlink = needs_sandboxing && exec_context_get_effective_mount_apivfs(context) && (root_dir || root_image);
r = compile_symlinks(context, params, setup_os_release_symlink, &symlinks);
if (r < 0)
return r;
if (context->mount_propagation_flag == MS_SHARED)
log_unit_debug(u, "shared mount propagation hidden by other fs namespacing unit settings: ignoring");
if (FLAGS_SET(params->flags, EXEC_WRITE_CREDENTIALS)) {
r = exec_context_get_credential_directory(context, params, u->id, &creds_path);
if (r < 0)
return r;
}
if (params->runtime_scope == RUNTIME_SCOPE_SYSTEM) {
propagate_dir = path_join("/run/systemd/propagate/", u->id);
if (!propagate_dir)
return -ENOMEM;
incoming_dir = strdup("/run/systemd/incoming");
if (!incoming_dir)
return -ENOMEM;
extension_dir = strdup("/run/systemd/unit-extensions");
if (!extension_dir)
return -ENOMEM;
/* If running under a different root filesystem, propagate the host's os-release. We make a
* copy rather than just bind mounting it, so that it can be updated on soft-reboot. */
if (setup_os_release_symlink) {
host_os_release_stage = strdup("/run/systemd/propagate/.os-release-stage");
if (!host_os_release_stage)
return -ENOMEM;
}
} else {
assert(params->runtime_scope == RUNTIME_SCOPE_USER);
if (asprintf(&extension_dir, "/run/user/" UID_FMT "/systemd/unit-extensions", geteuid()) < 0)
return -ENOMEM;
if (setup_os_release_symlink) {
if (asprintf(&host_os_release_stage,
"/run/user/" UID_FMT "/systemd/propagate/.os-release-stage",
geteuid()) < 0)
return -ENOMEM;
}
}
if (root_image) {
r = verity_settings_prepare(
&verity,
root_image,
context->root_hash, context->root_hash_size, context->root_hash_path,
context->root_hash_sig, context->root_hash_sig_size, context->root_hash_sig_path,
context->root_verity);
if (r < 0)
return r;
}
NamespaceParameters parameters = {
.runtime_scope = params->runtime_scope,
.root_directory = root_dir,
.root_image = root_image,
.root_image_options = context->root_image_options,
.root_image_policy = context->root_image_policy ?: &image_policy_service,
.read_write_paths = read_write_paths,
.read_only_paths = needs_sandboxing ? context->read_only_paths : NULL,
.inaccessible_paths = needs_sandboxing ? context->inaccessible_paths : NULL,
.exec_paths = needs_sandboxing ? context->exec_paths : NULL,
.no_exec_paths = needs_sandboxing ? context->no_exec_paths : NULL,
.empty_directories = empty_directories,
.symlinks = symlinks,
.bind_mounts = bind_mounts,
.n_bind_mounts = n_bind_mounts,
.temporary_filesystems = context->temporary_filesystems,
.n_temporary_filesystems = context->n_temporary_filesystems,
.mount_images = context->mount_images,
.n_mount_images = context->n_mount_images,
.mount_image_policy = context->mount_image_policy ?: &image_policy_service,
.tmp_dir = tmp_dir,
.var_tmp_dir = var_tmp_dir,
.creds_path = creds_path,
.log_namespace = context->log_namespace,
.mount_propagation_flag = context->mount_propagation_flag,
.verity = &verity,
.extension_images = context->extension_images,
.n_extension_images = context->n_extension_images,
.extension_image_policy = context->extension_image_policy ?: &image_policy_sysext,
.extension_directories = context->extension_directories,
.propagate_dir = propagate_dir,
.incoming_dir = incoming_dir,
.extension_dir = extension_dir,
.notify_socket = root_dir || root_image ? params->notify_socket : NULL,
.host_os_release_stage = host_os_release_stage,
/* If DynamicUser=no and RootDirectory= is set then lets pass a relaxed sandbox info,
* otherwise enforce it, don't ignore protected paths and fail if we are enable to apply the
* sandbox inside the mount namespace. */
.ignore_protect_paths = !needs_sandboxing && !context->dynamic_user && root_dir,
.protect_control_groups = needs_sandboxing && context->protect_control_groups,
.protect_kernel_tunables = needs_sandboxing && context->protect_kernel_tunables,
.protect_kernel_modules = needs_sandboxing && context->protect_kernel_modules,
.protect_kernel_logs = needs_sandboxing && context->protect_kernel_logs,
.protect_hostname = needs_sandboxing && context->protect_hostname,
.private_dev = needs_sandboxing && context->private_devices,
.private_network = needs_sandboxing && exec_needs_network_namespace(context),
.private_ipc = needs_sandboxing && exec_needs_ipc_namespace(context),
.mount_apivfs = needs_sandboxing && exec_context_get_effective_mount_apivfs(context),
/* If NNP is on, we can turn on MS_NOSUID, since it won't have any effect anymore. */
.mount_nosuid = needs_sandboxing && context->no_new_privileges && !mac_selinux_use(),
.protect_home = needs_sandboxing && context->protect_home,
.protect_system = needs_sandboxing && context->protect_system,
.protect_proc = needs_sandboxing && context->protect_proc,
.proc_subset = needs_sandboxing && context->proc_subset,
};
r = setup_namespace(&parameters, error_path);
/* If we couldn't set up the namespace this is probably due to a missing capability. setup_namespace() reports
* that with a special, recognizable error ENOANO. In this case, silently proceed, but only if exclusively
* sandboxing options were used, i.e. nothing such as RootDirectory= or BindMount= that would result in a
* completely different execution environment. */
if (r == -ENOANO) {
if (insist_on_sandboxing(
context,
root_dir, root_image,
bind_mounts,
n_bind_mounts))
return log_unit_debug_errno(u,
SYNTHETIC_ERRNO(EOPNOTSUPP),
"Failed to set up namespace, and refusing to continue since "
"the selected namespacing options alter mount environment non-trivially.\n"
"Bind mounts: %zu, temporary filesystems: %zu, root directory: %s, root image: %s, dynamic user: %s",
n_bind_mounts,
context->n_temporary_filesystems,
yes_no(root_dir),
yes_no(root_image),
yes_no(context->dynamic_user));
log_unit_debug(u, "Failed to set up namespace, assuming containerized execution and ignoring.");
return 0;
}
return r;
}
static int apply_working_directory(
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
const char *home,
int *exit_status) {
const char *d, *wd;
assert(context);
assert(exit_status);
if (context->working_directory_home) {
if (!home) {
*exit_status = EXIT_CHDIR;
return -ENXIO;
}
wd = home;
} else
wd = empty_to_root(context->working_directory);
if (params->flags & EXEC_APPLY_CHROOT)
d = wd;
else
d = prefix_roota((runtime ? runtime->ephemeral_copy : NULL) ?: context->root_directory, wd);
if (chdir(d) < 0 && !context->working_directory_missing_ok) {
*exit_status = EXIT_CHDIR;
return -errno;
}
return 0;
}
static int apply_root_directory(
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
const bool needs_mount_ns,
int *exit_status) {
assert(context);
assert(exit_status);
if (params->flags & EXEC_APPLY_CHROOT)
if (!needs_mount_ns && context->root_directory)
if (chroot((runtime ? runtime->ephemeral_copy : NULL) ?: context->root_directory) < 0) {
*exit_status = EXIT_CHROOT;
return -errno;
}
return 0;
}
static int setup_keyring(
const Unit *u,
const ExecContext *context,
const ExecParameters *p,
uid_t uid, gid_t gid) {
key_serial_t keyring;
int r = 0;
uid_t saved_uid;
gid_t saved_gid;
assert(u);
assert(context);
assert(p);
/* Let's set up a new per-service "session" kernel keyring for each system service. This has the benefit that
* each service runs with its own keyring shared among all processes of the service, but with no hook-up beyond
* that scope, and in particular no link to the per-UID keyring. If we don't do this the keyring will be
* automatically created on-demand and then linked to the per-UID keyring, by the kernel. The kernel's built-in
* on-demand behaviour is very appropriate for login users, but probably not so much for system services, where
* UIDs are not necessarily specific to a service but reused (at least in the case of UID 0). */
if (context->keyring_mode == EXEC_KEYRING_INHERIT)
return 0;
/* Acquiring a reference to the user keyring is nasty. We briefly change identity in order to get things set up
* properly by the kernel. If we don't do that then we can't create it atomically, and that sucks for parallel
* execution. This mimics what pam_keyinit does, too. Setting up session keyring, to be owned by the right user
* & group is just as nasty as acquiring a reference to the user keyring. */
saved_uid = getuid();
saved_gid = getgid();
if (gid_is_valid(gid) && gid != saved_gid) {
if (setregid(gid, -1) < 0)
return log_unit_error_errno(u, errno, "Failed to change GID for user keyring: %m");
}
if (uid_is_valid(uid) && uid != saved_uid) {
if (setreuid(uid, -1) < 0) {
r = log_unit_error_errno(u, errno, "Failed to change UID for user keyring: %m");
goto out;
}
}
keyring = keyctl(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
if (keyring == -1) {
if (errno == ENOSYS)
log_unit_debug_errno(u, errno, "Kernel keyring not supported, ignoring.");
else if (ERRNO_IS_PRIVILEGE(errno))
log_unit_debug_errno(u, errno, "Kernel keyring access prohibited, ignoring.");
else if (errno == EDQUOT)
log_unit_debug_errno(u, errno, "Out of kernel keyrings to allocate, ignoring.");
else
r = log_unit_error_errno(u, errno, "Setting up kernel keyring failed: %m");
goto out;
}
/* When requested link the user keyring into the session keyring. */
if (context->keyring_mode == EXEC_KEYRING_SHARED) {
if (keyctl(KEYCTL_LINK,
KEY_SPEC_USER_KEYRING,
KEY_SPEC_SESSION_KEYRING, 0, 0) < 0) {
r = log_unit_error_errno(u, errno, "Failed to link user keyring into session keyring: %m");
goto out;
}
}
/* Restore uid/gid back */
if (uid_is_valid(uid) && uid != saved_uid) {
if (setreuid(saved_uid, -1) < 0) {
r = log_unit_error_errno(u, errno, "Failed to change UID back for user keyring: %m");
goto out;
}
}
if (gid_is_valid(gid) && gid != saved_gid) {
if (setregid(saved_gid, -1) < 0)
return log_unit_error_errno(u, errno, "Failed to change GID back for user keyring: %m");
}
/* Populate they keyring with the invocation ID by default, as original saved_uid. */
if (!sd_id128_is_null(u->invocation_id)) {
key_serial_t key;
key = add_key("user", "invocation_id", &u->invocation_id, sizeof(u->invocation_id), KEY_SPEC_SESSION_KEYRING);
if (key == -1)
log_unit_debug_errno(u, errno, "Failed to add invocation ID to keyring, ignoring: %m");
else {
if (keyctl(KEYCTL_SETPERM, key,
KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH|
KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH, 0, 0) < 0)
r = log_unit_error_errno(u, errno, "Failed to restrict invocation ID permission: %m");
}
}
out:
/* Revert back uid & gid for the last time, and exit */
/* no extra logging, as only the first already reported error matters */
if (getuid() != saved_uid)
(void) setreuid(saved_uid, -1);
if (getgid() != saved_gid)
(void) setregid(saved_gid, -1);
return r;
}
static void append_socket_pair(int *array, size_t *n, const int pair[static 2]) {
assert(array);
assert(n);
assert(pair);
if (pair[0] >= 0)
array[(*n)++] = pair[0];
if (pair[1] >= 0)
array[(*n)++] = pair[1];
}
static int close_remaining_fds(
const ExecParameters *params,
const ExecRuntime *runtime,
int user_lookup_fd,
int socket_fd,
const int *fds, size_t n_fds) {
size_t n_dont_close = 0;
int dont_close[n_fds + 14];
assert(params);
if (params->stdin_fd >= 0)
dont_close[n_dont_close++] = params->stdin_fd;
if (params->stdout_fd >= 0)
dont_close[n_dont_close++] = params->stdout_fd;
if (params->stderr_fd >= 0)
dont_close[n_dont_close++] = params->stderr_fd;
if (socket_fd >= 0)
dont_close[n_dont_close++] = socket_fd;
if (n_fds > 0) {
memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
n_dont_close += n_fds;
}
if (runtime)
append_socket_pair(dont_close, &n_dont_close, runtime->ephemeral_storage_socket);
if (runtime && runtime->shared) {
append_socket_pair(dont_close, &n_dont_close, runtime->shared->netns_storage_socket);
append_socket_pair(dont_close, &n_dont_close, runtime->shared->ipcns_storage_socket);
}
if (runtime && runtime->dynamic_creds) {
if (runtime->dynamic_creds->user)
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->user->storage_socket);
if (runtime->dynamic_creds->group)
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->group->storage_socket);
}
if (user_lookup_fd >= 0)
dont_close[n_dont_close++] = user_lookup_fd;
return close_all_fds(dont_close, n_dont_close);
}
static int send_user_lookup(
Unit *unit,
int user_lookup_fd,
uid_t uid,
gid_t gid) {
assert(unit);
/* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID
* data as well as the unit name. Note that we suppress sending this if no user/group to resolve was
* specified. */
if (user_lookup_fd < 0)
return 0;
if (!uid_is_valid(uid) && !gid_is_valid(gid))
return 0;
if (writev(user_lookup_fd,
(struct iovec[]) {
IOVEC_MAKE(&uid, sizeof(uid)),
IOVEC_MAKE(&gid, sizeof(gid)),
IOVEC_MAKE_STRING(unit->id) }, 3) < 0)
return -errno;
return 0;
}
static int acquire_home(const ExecContext *c, uid_t uid, const char** home, char **buf) {
int r;
assert(c);
assert(home);
assert(buf);
/* If WorkingDirectory=~ is set, try to acquire a usable home directory. */
if (*home)
return 0;
if (!c->working_directory_home)
return 0;
r = get_home_dir(buf);
if (r < 0)
return r;
*home = *buf;
return 1;
}
static int compile_suggested_paths(const ExecContext *c, const ExecParameters *p, char ***ret) {
_cleanup_strv_free_ char ** list = NULL;
int r;
assert(c);
assert(p);
assert(ret);
assert(c->dynamic_user);
/* Compile a list of paths that it might make sense to read the owning UID from to use as initial candidate for
* dynamic UID allocation, in order to save us from doing costly recursive chown()s of the special
* directories. */
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (t == EXEC_DIRECTORY_CONFIGURATION)
continue;
if (!p->prefix[t])
continue;
for (size_t i = 0; i < c->directories[t].n_items; i++) {
char *e;
if (exec_directory_is_private(c, t))
e = path_join(p->prefix[t], "private", c->directories[t].items[i].path);
else
e = path_join(p->prefix[t], c->directories[t].items[i].path);
if (!e)
return -ENOMEM;
r = strv_consume(&list, e);
if (r < 0)
return r;
}
}
*ret = TAKE_PTR(list);
return 0;
}
static int exec_parameters_get_cgroup_path(
const ExecParameters *params,
const CGroupContext *c,
char **ret) {
const char *subgroup = NULL;
char *p;
assert(params);
assert(ret);
if (!params->cgroup_path)
return -EINVAL;
/* If we are called for a unit where cgroup delegation is on, and the payload created its own populated
* subcgroup (which we expect it to do, after all it asked for delegation), then we cannot place the control
* processes started after the main unit's process in the unit's main cgroup because it is now an inner one,
* and inner cgroups may not contain processes. Hence, if delegation is on, and this is a control process,
* let's use ".control" as subcgroup instead. Note that we do so only for ExecStartPost=, ExecReload=,
* ExecStop=, ExecStopPost=, i.e. for the commands where the main process is already forked. For ExecStartPre=
* this is not necessary, the cgroup is still empty. We distinguish these cases with the EXEC_CONTROL_CGROUP
* flag, which is only passed for the former statements, not for the latter. */
if (FLAGS_SET(params->flags, EXEC_CGROUP_DELEGATE) && (FLAGS_SET(params->flags, EXEC_CONTROL_CGROUP) || c->delegate_subgroup)) {
if (FLAGS_SET(params->flags, EXEC_IS_CONTROL))
subgroup = ".control";
else
subgroup = c->delegate_subgroup;
}
if (subgroup)
p = path_join(params->cgroup_path, subgroup);
else
p = strdup(params->cgroup_path);
if (!p)
return -ENOMEM;
*ret = p;
return !!subgroup;
}
static int exec_context_cpu_affinity_from_numa(const ExecContext *c, CPUSet *ret) {
_cleanup_(cpu_set_reset) CPUSet s = {};
int r;
assert(c);
assert(ret);
if (!c->numa_policy.nodes.set) {
log_debug("Can't derive CPU affinity mask from NUMA mask because NUMA mask is not set, ignoring");
return 0;
}
r = numa_to_cpu_set(&c->numa_policy, &s);
if (r < 0)
return r;
cpu_set_reset(ret);
return cpu_set_add_all(ret, &s);
}
bool exec_context_get_cpu_affinity_from_numa(const ExecContext *c) {
assert(c);
return c->cpu_affinity_from_numa;
}
static int add_shifted_fd(int *fds, size_t fds_size, size_t *n_fds, int fd, int *ret_fd) {
int r;
assert(fds);
assert(n_fds);
assert(*n_fds < fds_size);
assert(ret_fd);
if (fd < 0) {
*ret_fd = -EBADF;
return 0;
}
if (fd < 3 + (int) *n_fds) {
/* Let's move the fd up, so that it's outside of the fd range we will use to store
* the fds we pass to the process (or which are closed only during execve). */
r = fcntl(fd, F_DUPFD_CLOEXEC, 3 + (int) *n_fds);
if (r < 0)
return -errno;
close_and_replace(fd, r);
}
*ret_fd = fds[*n_fds] = fd;
(*n_fds) ++;
return 1;
}
static int connect_unix_harder(Unit *u, const OpenFile *of, int ofd) {
union sockaddr_union addr = {
.un.sun_family = AF_UNIX,
};
socklen_t sa_len;
static const int socket_types[] = { SOCK_DGRAM, SOCK_STREAM, SOCK_SEQPACKET };
int r;
assert(u);
assert(of);
assert(ofd >= 0);
r = sockaddr_un_set_path(&addr.un, FORMAT_PROC_FD_PATH(ofd));
if (r < 0)
return log_unit_error_errno(u, r, "Failed to set sockaddr for %s: %m", of->path);
sa_len = r;
for (size_t i = 0; i < ELEMENTSOF(socket_types); i++) {
_cleanup_close_ int fd = -EBADF;
fd = socket(AF_UNIX, socket_types[i] | SOCK_CLOEXEC, 0);
if (fd < 0)
return log_unit_error_errno(u, errno, "Failed to create socket for %s: %m", of->path);
r = RET_NERRNO(connect(fd, &addr.sa, sa_len));
if (r == -EPROTOTYPE)
continue;
if (r < 0)
return log_unit_error_errno(u, r, "Failed to connect socket for %s: %m", of->path);
return TAKE_FD(fd);
}
return log_unit_error_errno(u, SYNTHETIC_ERRNO(EPROTOTYPE), "Failed to connect socket for \"%s\".", of->path);
}
static int get_open_file_fd(Unit *u, const OpenFile *of) {
struct stat st;
_cleanup_close_ int fd = -EBADF, ofd = -EBADF;
assert(u);
assert(of);
ofd = open(of->path, O_PATH | O_CLOEXEC);
if (ofd < 0)
return log_unit_error_errno(u, errno, "Could not open \"%s\": %m", of->path);
if (fstat(ofd, &st) < 0)
return log_unit_error_errno(u, errno, "Failed to stat %s: %m", of->path);
if (S_ISSOCK(st.st_mode)) {
fd = connect_unix_harder(u, of, ofd);
if (fd < 0)
return fd;
if (FLAGS_SET(of->flags, OPENFILE_READ_ONLY) && shutdown(fd, SHUT_WR) < 0)
return log_unit_error_errno(u, errno, "Failed to shutdown send for socket %s: %m",
of->path);
log_unit_debug(u, "socket %s opened (fd=%d)", of->path, fd);
} else {
int flags = FLAGS_SET(of->flags, OPENFILE_READ_ONLY) ? O_RDONLY : O_RDWR;
if (FLAGS_SET(of->flags, OPENFILE_APPEND))
flags |= O_APPEND;
else if (FLAGS_SET(of->flags, OPENFILE_TRUNCATE))
flags |= O_TRUNC;
fd = fd_reopen(ofd, flags | O_CLOEXEC);
if (fd < 0)
return log_unit_error_errno(u, fd, "Failed to open file %s: %m", of->path);
log_unit_debug(u, "file %s opened (fd=%d)", of->path, fd);
}
return TAKE_FD(fd);
}
static int collect_open_file_fds(
Unit *u,
OpenFile* open_files,
int **fds,
char ***fdnames,
size_t *n_fds) {
int r;
assert(u);
assert(fds);
assert(fdnames);
assert(n_fds);
LIST_FOREACH(open_files, of, open_files) {
_cleanup_close_ int fd = -EBADF;
fd = get_open_file_fd(u, of);
if (fd < 0) {
if (FLAGS_SET(of->flags, OPENFILE_GRACEFUL)) {
log_unit_debug_errno(u, fd, "Failed to get OpenFile= file descriptor for %s, ignoring: %m", of->path);
continue;
}
return fd;
}
if (!GREEDY_REALLOC(*fds, *n_fds + 1))
return -ENOMEM;
r = strv_extend(fdnames, of->fdname);
if (r < 0)
return r;
(*fds)[*n_fds] = TAKE_FD(fd);
(*n_fds)++;
}
return 0;
}
static void log_command_line(Unit *unit, const char *msg, const char *executable, char **argv) {
assert(unit);
assert(msg);
assert(executable);
if (!DEBUG_LOGGING)
return;
_cleanup_free_ char *cmdline = quote_command_line(argv, SHELL_ESCAPE_EMPTY);
log_unit_struct(unit, LOG_DEBUG,
"EXECUTABLE=%s", executable,
LOG_UNIT_MESSAGE(unit, "%s: %s", msg, strnull(cmdline)),
LOG_UNIT_INVOCATION_ID(unit));
}
static bool exec_context_need_unprivileged_private_users(
const ExecContext *context,
const ExecParameters *params) {
assert(context);
assert(params);
/* These options require PrivateUsers= when used in user units, as we need to be in a user namespace
* to have permission to enable them when not running as root. If we have effective CAP_SYS_ADMIN
* (system manager) then we have privileges and don't need this. */
if (params->runtime_scope != RUNTIME_SCOPE_USER)
return false;
return context->private_users ||
context->private_tmp ||
context->private_devices ||
context->private_network ||
context->network_namespace_path ||
context->private_ipc ||
context->ipc_namespace_path ||
context->private_mounts > 0 ||
context->mount_apivfs ||
context->n_bind_mounts > 0 ||
context->n_temporary_filesystems > 0 ||
context->root_directory ||
!strv_isempty(context->extension_directories) ||
context->protect_system != PROTECT_SYSTEM_NO ||
context->protect_home != PROTECT_HOME_NO ||
context->protect_kernel_tunables ||
context->protect_kernel_modules ||
context->protect_kernel_logs ||
context->protect_control_groups ||
context->protect_clock ||
context->protect_hostname ||
!strv_isempty(context->read_write_paths) ||
!strv_isempty(context->read_only_paths) ||
!strv_isempty(context->inaccessible_paths) ||
!strv_isempty(context->exec_paths) ||
!strv_isempty(context->no_exec_paths);
}
static int exec_child(
Unit *unit,
const ExecCommand *command,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
const CGroupContext *cgroup_context,
int socket_fd,
const int named_iofds[static 3],
int *params_fds,
size_t n_socket_fds,
size_t n_storage_fds,
char **files_env,
int user_lookup_fd,
int *exit_status) {
_cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **joined_exec_search_path = NULL, **accum_env = NULL, **replaced_argv = NULL;
int r, ngids = 0, exec_fd;
_cleanup_free_ gid_t *supplementary_gids = NULL;
const char *username = NULL, *groupname = NULL;
_cleanup_free_ char *home_buffer = NULL, *memory_pressure_path = NULL;
const char *home = NULL, *shell = NULL;
char **final_argv = NULL;
dev_t journal_stream_dev = 0;
ino_t journal_stream_ino = 0;
bool userns_set_up = false;
bool needs_sandboxing, /* Do we need to set up full sandboxing? (i.e. all namespacing, all MAC stuff, caps, yadda yadda */
needs_setuid, /* Do we need to do the actual setresuid()/setresgid() calls? */
needs_mount_namespace, /* Do we need to set up a mount namespace for this kernel? */
needs_ambient_hack; /* Do we need to apply the ambient capabilities hack? */
#if HAVE_SELINUX
_cleanup_free_ char *mac_selinux_context_net = NULL;
bool use_selinux = false;
#endif
#if ENABLE_SMACK
bool use_smack = false;
#endif
#if HAVE_APPARMOR
bool use_apparmor = false;
#endif
uid_t saved_uid = getuid();
gid_t saved_gid = getgid();
uid_t uid = UID_INVALID;
gid_t gid = GID_INVALID;
size_t n_fds = n_socket_fds + n_storage_fds, /* fds to pass to the child */
n_keep_fds; /* total number of fds not to close */
int secure_bits;
_cleanup_free_ gid_t *gids_after_pam = NULL;
int ngids_after_pam = 0;
_cleanup_free_ int *fds = NULL;
_cleanup_strv_free_ char **fdnames = NULL;
assert(unit);
assert(command);
assert(context);
assert(params);
assert(exit_status);
/* Explicitly test for CVE-2021-4034 inspired invocations */
assert(command->path);
assert(!strv_isempty(command->argv));
rename_process_from_path(command->path);
/* We reset exactly these signals, since they are the only ones we set to SIG_IGN in the main
* daemon. All others we leave untouched because we set them to SIG_DFL or a valid handler initially,
* both of which will be demoted to SIG_DFL. */
(void) default_signals(SIGNALS_CRASH_HANDLER,
SIGNALS_IGNORE);
if (context->ignore_sigpipe)
(void) ignore_signals(SIGPIPE);
r = reset_signal_mask();
if (r < 0) {
*exit_status = EXIT_SIGNAL_MASK;
return log_unit_error_errno(unit, r, "Failed to set process signal mask: %m");
}
if (params->idle_pipe)
do_idle_pipe_dance(params->idle_pipe);
/* Close fds we don't need very early to make sure we don't block init reexecution because it cannot bind its
* sockets. Among the fds we close are the logging fds, and we want to keep them closed, so that we don't have
* any fds open we don't really want open during the transition. In order to make logging work, we switch the
* log subsystem into open_when_needed mode, so that it reopens the logs on every single log call. */
log_forget_fds();
log_set_open_when_needed(true);
log_settle_target();
/* In case anything used libc syslog(), close this here, too */
closelog();
fds = newdup(int, params_fds, n_fds);
if (!fds) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
fdnames = strv_copy((char**) params->fd_names);
if (!fdnames) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = collect_open_file_fds(unit, params->open_files, &fds, &fdnames, &n_fds);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to get OpenFile= file descriptors: %m");
}
int keep_fds[n_fds + 3];
memcpy_safe(keep_fds, fds, n_fds * sizeof(int));
n_keep_fds = n_fds;
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, params->exec_fd, &exec_fd);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m");
}
#if HAVE_LIBBPF
if (unit->manager->restrict_fs) {
int bpf_map_fd = lsm_bpf_map_restrict_fs_fd(unit);
if (bpf_map_fd < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, bpf_map_fd, "Failed to get restrict filesystems BPF map fd: %m");
}
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, bpf_map_fd, &bpf_map_fd);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m");
}
}
#endif
r = close_remaining_fds(params, runtime, user_lookup_fd, socket_fd, keep_fds, n_keep_fds);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to close unwanted file descriptors: %m");
}
if (!context->same_pgrp &&
setsid() < 0) {
*exit_status = EXIT_SETSID;
return log_unit_error_errno(unit, errno, "Failed to create new process session: %m");
}
exec_context_tty_reset(context, params);
if (unit_shall_confirm_spawn(unit)) {
_cleanup_free_ char *cmdline = NULL;
cmdline = quote_command_line(command->argv, SHELL_ESCAPE_EMPTY);
if (!cmdline) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = ask_for_confirmation(context, params->confirm_spawn, unit, cmdline);
if (r != CONFIRM_EXECUTE) {
if (r == CONFIRM_PRETEND_SUCCESS) {
*exit_status = EXIT_SUCCESS;
return 0;
}
*exit_status = EXIT_CONFIRM;
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ECANCELED),
"Execution cancelled by the user");
}
}
/* We are about to invoke NSS and PAM modules. Let's tell them what we are doing here, maybe they care. This is
* used by nss-resolve to disable itself when we are about to start systemd-resolved, to avoid deadlocks. Note
* that these env vars do not survive the execve(), which means they really only apply to the PAM and NSS
* invocations themselves. Also note that while we'll only invoke NSS modules involved in user management they
* might internally call into other NSS modules that are involved in hostname resolution, we never know. */
if (setenv("SYSTEMD_ACTIVATION_UNIT", unit->id, true) != 0 ||
setenv("SYSTEMD_ACTIVATION_SCOPE", runtime_scope_to_string(params->runtime_scope), true) != 0) {
*exit_status = EXIT_MEMORY;
return log_unit_error_errno(unit, errno, "Failed to update environment: %m");
}
if (context->dynamic_user && runtime && runtime->dynamic_creds) {
_cleanup_strv_free_ char **suggested_paths = NULL;
/* On top of that, make sure we bypass our own NSS module nss-systemd comprehensively for any NSS
* checks, if DynamicUser=1 is used, as we shouldn't create a feedback loop with ourselves here. */
if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, errno, "Failed to update environment: %m");
}
r = compile_suggested_paths(context, params, &suggested_paths);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = dynamic_creds_realize(runtime->dynamic_creds, suggested_paths, &uid, &gid);
if (r < 0) {
*exit_status = EXIT_USER;
if (r == -EILSEQ)
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP),
"Failed to update dynamic user credentials: User or group with specified name already exists.");
return log_unit_error_errno(unit, r, "Failed to update dynamic user credentials: %m");
}
if (!uid_is_valid(uid)) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ESRCH), "UID validation failed for \""UID_FMT"\"", uid);
}
if (!gid_is_valid(gid)) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ESRCH), "GID validation failed for \""GID_FMT"\"", gid);
}
if (runtime->dynamic_creds->user)
username = runtime->dynamic_creds->user->name;
} else {
if (context->user) {
r = get_fixed_user(context->user, &username, &uid, &gid, &home, &shell);
if (r < 0) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, r, "Failed to determine user credentials: %m");
}
}
if (context->group) {
r = get_fixed_group(context->group, &groupname, &gid);
if (r < 0) {
*exit_status = EXIT_GROUP;
return log_unit_error_errno(unit, r, "Failed to determine group credentials: %m");
}
}
}
/* Initialize user supplementary groups and get SupplementaryGroups= ones */
r = get_supplementary_groups(context, username, groupname, gid,
&supplementary_gids, &ngids);
if (r < 0) {
*exit_status = EXIT_GROUP;
return log_unit_error_errno(unit, r, "Failed to determine supplementary groups: %m");
}
r = send_user_lookup(unit, user_lookup_fd, uid, gid);
if (r < 0) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, r, "Failed to send user credentials to PID1: %m");
}
user_lookup_fd = safe_close(user_lookup_fd);
r = acquire_home(context, uid, &home, &home_buffer);
if (r < 0) {
*exit_status = EXIT_CHDIR;
return log_unit_error_errno(unit, r, "Failed to determine $HOME for user: %m");
}
/* If a socket is connected to STDIN/STDOUT/STDERR, we must drop O_NONBLOCK */
if (socket_fd >= 0)
(void) fd_nonblock(socket_fd, false);
/* Journald will try to look-up our cgroup in order to populate _SYSTEMD_CGROUP and _SYSTEMD_UNIT fields.
* Hence we need to migrate to the target cgroup from init.scope before connecting to journald */
if (params->cgroup_path) {
_cleanup_free_ char *p = NULL;
r = exec_parameters_get_cgroup_path(params, cgroup_context, &p);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to acquire cgroup path: %m");
}
r = cg_attach_everywhere(params->cgroup_supported, p, 0, NULL, NULL);
if (r == -EUCLEAN) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to attach process to cgroup %s "
"because the cgroup or one of its parents or "
"siblings is in the threaded mode: %m", p);
}
if (r < 0) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to attach to cgroup %s: %m", p);
}
}
if (context->network_namespace_path && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) {
r = open_shareable_ns_path(runtime->shared->netns_storage_socket, context->network_namespace_path, CLONE_NEWNET);
if (r < 0) {
*exit_status = EXIT_NETWORK;
return log_unit_error_errno(unit, r, "Failed to open network namespace path %s: %m", context->network_namespace_path);
}
}
if (context->ipc_namespace_path && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) {
r = open_shareable_ns_path(runtime->shared->ipcns_storage_socket, context->ipc_namespace_path, CLONE_NEWIPC);
if (r < 0) {
*exit_status = EXIT_NAMESPACE;
return log_unit_error_errno(unit, r, "Failed to open IPC namespace path %s: %m", context->ipc_namespace_path);
}
}
r = setup_input(context, params, socket_fd, named_iofds);
if (r < 0) {
*exit_status = EXIT_STDIN;
return log_unit_error_errno(unit, r, "Failed to set up standard input: %m");
}
r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDOUT;
return log_unit_error_errno(unit, r, "Failed to set up standard output: %m");
}
r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDERR;
return log_unit_error_errno(unit, r, "Failed to set up standard error output: %m");
}
if (context->oom_score_adjust_set) {
/* When we can't make this change due to EPERM, then let's silently skip over it. User
* namespaces prohibit write access to this file, and we shouldn't trip up over that. */
r = set_oom_score_adjust(context->oom_score_adjust);
if (ERRNO_IS_NEG_PRIVILEGE(r))
log_unit_debug_errno(unit, r,
"Failed to adjust OOM setting, assuming containerized execution, ignoring: %m");
else if (r < 0) {
*exit_status = EXIT_OOM_ADJUST;
return log_unit_error_errno(unit, r, "Failed to adjust OOM setting: %m");
}
}
if (context->coredump_filter_set) {
r = set_coredump_filter(context->coredump_filter);
if (ERRNO_IS_NEG_PRIVILEGE(r))
log_unit_debug_errno(unit, r, "Failed to adjust coredump_filter, ignoring: %m");
else if (r < 0) {
*exit_status = EXIT_LIMITS;
return log_unit_error_errno(unit, r, "Failed to adjust coredump_filter: %m");
}
}
if (context->nice_set) {
r = setpriority_closest(context->nice);
if (r < 0) {
*exit_status = EXIT_NICE;
return log_unit_error_errno(unit, r, "Failed to set up process scheduling priority (nice level): %m");
}
}
if (context->cpu_sched_set) {
struct sched_param param = {
.sched_priority = context->cpu_sched_priority,
};
r = sched_setscheduler(0,
context->cpu_sched_policy |
(context->cpu_sched_reset_on_fork ?
SCHED_RESET_ON_FORK : 0),
&param);
if (r < 0) {
*exit_status = EXIT_SETSCHEDULER;
return log_unit_error_errno(unit, errno, "Failed to set up CPU scheduling: %m");
}
}
if (context->cpu_affinity_from_numa || context->cpu_set.set) {
_cleanup_(cpu_set_reset) CPUSet converted_cpu_set = {};
const CPUSet *cpu_set;
if (context->cpu_affinity_from_numa) {
r = exec_context_cpu_affinity_from_numa(context, &converted_cpu_set);
if (r < 0) {
*exit_status = EXIT_CPUAFFINITY;
return log_unit_error_errno(unit, r, "Failed to derive CPU affinity mask from NUMA mask: %m");
}
cpu_set = &converted_cpu_set;
} else
cpu_set = &context->cpu_set;
if (sched_setaffinity(0, cpu_set->allocated, cpu_set->set) < 0) {
*exit_status = EXIT_CPUAFFINITY;
return log_unit_error_errno(unit, errno, "Failed to set up CPU affinity: %m");
}
}
if (mpol_is_valid(numa_policy_get_type(&context->numa_policy))) {
r = apply_numa_policy(&context->numa_policy);
if (ERRNO_IS_NEG_NOT_SUPPORTED(r))
log_unit_debug_errno(unit, r, "NUMA support not available, ignoring.");
else if (r < 0) {
*exit_status = EXIT_NUMA_POLICY;
return log_unit_error_errno(unit, r, "Failed to set NUMA memory policy: %m");
}
}
if (context->ioprio_set)
if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
*exit_status = EXIT_IOPRIO;
return log_unit_error_errno(unit, errno, "Failed to set up IO scheduling priority: %m");
}
if (context->timer_slack_nsec != NSEC_INFINITY)
if (prctl(PR_SET_TIMERSLACK, context->timer_slack_nsec) < 0) {
*exit_status = EXIT_TIMERSLACK;
return log_unit_error_errno(unit, errno, "Failed to set up timer slack: %m");
}
if (context->personality != PERSONALITY_INVALID) {
r = safe_personality(context->personality);
if (r < 0) {
*exit_status = EXIT_PERSONALITY;
return log_unit_error_errno(unit, r, "Failed to set up execution domain (personality): %m");
}
}
if (context->utmp_id) {
const char *line = context->tty_path ?
(path_startswith(context->tty_path, "/dev/") ?: context->tty_path) :
NULL;
utmp_put_init_process(context->utmp_id, getpid_cached(), getsid(0),
line,
context->utmp_mode == EXEC_UTMP_INIT ? INIT_PROCESS :
context->utmp_mode == EXEC_UTMP_LOGIN ? LOGIN_PROCESS :
USER_PROCESS,
username);
}
if (uid_is_valid(uid)) {
r = chown_terminal(STDIN_FILENO, uid);
if (r < 0) {
*exit_status = EXIT_STDIN;
return log_unit_error_errno(unit, r, "Failed to change ownership of terminal: %m");
}
}
if (params->cgroup_path) {
/* If delegation is enabled we'll pass ownership of the cgroup to the user of the new process. On cgroup v1
* this is only about systemd's own hierarchy, i.e. not the controller hierarchies, simply because that's not
* safe. On cgroup v2 there's only one hierarchy anyway, and delegation is safe there, hence in that case only
* touch a single hierarchy too. */
if (params->flags & EXEC_CGROUP_DELEGATE) {
_cleanup_free_ char *p = NULL;
r = cg_set_access(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, uid, gid);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to adjust control group access: %m");
}
r = exec_parameters_get_cgroup_path(params, cgroup_context, &p);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to acquire cgroup path: %m");
}
if (r > 0) {
r = cg_set_access_recursive(SYSTEMD_CGROUP_CONTROLLER, p, uid, gid);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return log_unit_error_errno(unit, r, "Failed to adjust control subgroup access: %m");
}
}
}
if (cgroup_context && cg_unified() > 0 && is_pressure_supported() > 0) {
if (cgroup_context_want_memory_pressure(cgroup_context)) {
r = cg_get_path("memory", params->cgroup_path, "memory.pressure", &memory_pressure_path);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = chmod_and_chown(memory_pressure_path, 0644, uid, gid);
if (r < 0) {
log_unit_full_errno(unit, r == -ENOENT || ERRNO_IS_PRIVILEGE(r) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to adjust ownership of '%s', ignoring: %m", memory_pressure_path);
memory_pressure_path = mfree(memory_pressure_path);
}
} else if (cgroup_context->memory_pressure_watch == CGROUP_PRESSURE_WATCH_OFF) {
memory_pressure_path = strdup("/dev/null"); /* /dev/null is explicit indicator for turning of memory pressure watch */
if (!memory_pressure_path) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
}
}
}
needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime);
for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) {
r = setup_exec_directory(unit, context, params, uid, gid, dt, needs_mount_namespace, exit_status);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to set up special execution directory in %s: %m", params->prefix[dt]);
}
if (FLAGS_SET(params->flags, EXEC_WRITE_CREDENTIALS)) {
r = exec_setup_credentials(context, params, unit->id, uid, gid);
if (r < 0) {
*exit_status = EXIT_CREDENTIALS;
return log_unit_error_errno(unit, r, "Failed to set up credentials: %m");
}
}
r = build_environment(
unit,
context,
params,
cgroup_context,
n_fds,
fdnames,
home,
username,
shell,
journal_stream_dev,
journal_stream_ino,
memory_pressure_path,
&our_env);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = build_pass_environment(context, &pass_env);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
/* The $PATH variable is set to the default path in params->environment. However, this is overridden
* if user-specified fields have $PATH set. The intention is to also override $PATH if the unit does
* not specify PATH but the unit has ExecSearchPath. */
if (!strv_isempty(context->exec_search_path)) {
_cleanup_free_ char *joined = NULL;
joined = strv_join(context->exec_search_path, ":");
if (!joined) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
r = strv_env_assign(&joined_exec_search_path, "PATH", joined);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
}
accum_env = strv_env_merge(params->environment,
our_env,
joined_exec_search_path,
pass_env,
context->environment,
files_env);
if (!accum_env) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
accum_env = strv_env_clean(accum_env);
(void) umask(context->umask);
r = setup_keyring(unit, context, params, uid, gid);
if (r < 0) {
*exit_status = EXIT_KEYRING;
return log_unit_error_errno(unit, r, "Failed to set up kernel keyring: %m");
}
/* We need sandboxing if the caller asked us to apply it and the command isn't explicitly excepted
* from it. */
needs_sandboxing = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & EXEC_COMMAND_FULLY_PRIVILEGED);
/* We need the ambient capability hack, if the caller asked us to apply it and the command is marked
* for it, and the kernel doesn't actually support ambient caps. */
needs_ambient_hack = (params->flags & EXEC_APPLY_SANDBOXING) && (command->flags & EXEC_COMMAND_AMBIENT_MAGIC) && !ambient_capabilities_supported();
/* We need setresuid() if the caller asked us to apply sandboxing and the command isn't explicitly
* excepted from either whole sandboxing or just setresuid() itself, and the ambient hack is not
* desired. */
if (needs_ambient_hack)
needs_setuid = false;
else
needs_setuid = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & (EXEC_COMMAND_FULLY_PRIVILEGED|EXEC_COMMAND_NO_SETUID));
uint64_t capability_ambient_set = context->capability_ambient_set;
if (needs_sandboxing) {
/* MAC enablement checks need to be done before a new mount ns is created, as they rely on
* /sys being present. The actual MAC context application will happen later, as late as
* possible, to avoid impacting our own code paths. */
#if HAVE_SELINUX
use_selinux = mac_selinux_use();
#endif
#if ENABLE_SMACK
use_smack = mac_smack_use();
#endif
#if HAVE_APPARMOR
use_apparmor = mac_apparmor_use();
#endif
}
if (needs_sandboxing) {
int which_failed;
/* Let's set the resource limits before we call into PAM, so that pam_limits wins over what
* is set here. (See below.) */
r = setrlimit_closest_all((const struct rlimit* const *) context->rlimit, &which_failed);
if (r < 0) {
*exit_status = EXIT_LIMITS;
return log_unit_error_errno(unit, r, "Failed to adjust resource limit RLIMIT_%s: %m", rlimit_to_string(which_failed));
}
}
if (needs_setuid && context->pam_name && username) {
/* Let's call into PAM after we set up our own idea of resource limits to that pam_limits
* wins here. (See above.) */
/* All fds passed in the fds array will be closed in the pam child process. */
r = setup_pam(context->pam_name, username, uid, gid, context->tty_path, &accum_env, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_PAM;
return log_unit_error_errno(unit, r, "Failed to set up PAM session: %m");
}
if (ambient_capabilities_supported()) {
uint64_t ambient_after_pam;
/* PAM modules might have set some ambient caps. Query them here and merge them into
* the caps we want to set in the end, so that we don't end up unsetting them. */
r = capability_get_ambient(&ambient_after_pam);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return log_unit_error_errno(unit, r, "Failed to query ambient caps: %m");
}
capability_ambient_set |= ambient_after_pam;
}
ngids_after_pam = getgroups_alloc(&gids_after_pam);
if (ngids_after_pam < 0) {
*exit_status = EXIT_MEMORY;
return log_unit_error_errno(unit, ngids_after_pam, "Failed to obtain groups after setting up PAM: %m");
}
}
if (needs_sandboxing && exec_context_need_unprivileged_private_users(context, params)) {
/* If we're unprivileged, set up the user namespace first to enable use of the other namespaces.
* Users with CAP_SYS_ADMIN can set up user namespaces last because they will be able to
* set up the all of the other namespaces (i.e. network, mount, UTS) without a user namespace. */
r = setup_private_users(saved_uid, saved_gid, uid, gid);
/* If it was requested explicitly and we can't set it up, fail early. Otherwise, continue and let
* the actual requested operations fail (or silently continue). */
if (r < 0 && context->private_users) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, r, "Failed to set up user namespacing for unprivileged user: %m");
}
if (r < 0)
log_unit_info_errno(unit, r, "Failed to set up user namespacing for unprivileged user, ignoring: %m");
else
userns_set_up = true;
}
if (exec_needs_network_namespace(context) && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) {
/* Try to enable network namespacing if network namespacing is available and we have
* CAP_NET_ADMIN. We need CAP_NET_ADMIN to be able to configure the loopback device in the
* new network namespace. And if we don't have that, then we could only create a network
* namespace without the ability to set up "lo". Hence gracefully skip things then. */
if (ns_type_supported(NAMESPACE_NET) && have_effective_cap(CAP_NET_ADMIN) > 0) {
r = setup_shareable_ns(runtime->shared->netns_storage_socket, CLONE_NEWNET);
if (ERRNO_IS_NEG_PRIVILEGE(r))
log_unit_notice_errno(unit, r,
"PrivateNetwork=yes is configured, but network namespace setup not permitted, proceeding without: %m");
else if (r < 0) {
*exit_status = EXIT_NETWORK;
return log_unit_error_errno(unit, r, "Failed to set up network namespacing: %m");
}
} else if (context->network_namespace_path) {
*exit_status = EXIT_NETWORK;
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP),
"NetworkNamespacePath= is not supported, refusing.");
} else
log_unit_notice(unit, "PrivateNetwork=yes is configured, but the kernel does not support or we lack privileges for network namespace, proceeding without.");
}
if (exec_needs_ipc_namespace(context) && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) {
if (ns_type_supported(NAMESPACE_IPC)) {
r = setup_shareable_ns(runtime->shared->ipcns_storage_socket, CLONE_NEWIPC);
if (r == -EPERM)
log_unit_warning_errno(unit, r,
"PrivateIPC=yes is configured, but IPC namespace setup failed, ignoring: %m");
else if (r < 0) {
*exit_status = EXIT_NAMESPACE;
return log_unit_error_errno(unit, r, "Failed to set up IPC namespacing: %m");
}
} else if (context->ipc_namespace_path) {
*exit_status = EXIT_NAMESPACE;
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP),
"IPCNamespacePath= is not supported, refusing.");
} else
log_unit_warning(unit, "PrivateIPC=yes is configured, but the kernel does not support IPC namespaces, ignoring.");
}
if (needs_mount_namespace) {
_cleanup_free_ char *error_path = NULL;
r = apply_mount_namespace(unit, command->flags, context, params, runtime, memory_pressure_path, &error_path);
if (r < 0) {
*exit_status = EXIT_NAMESPACE;
return log_unit_error_errno(unit, r, "Failed to set up mount namespacing%s%s: %m",
error_path ? ": " : "", strempty(error_path));
}
}
if (needs_sandboxing) {
r = apply_protect_hostname(unit, context, exit_status);
if (r < 0)
return r;
}
if (context->memory_ksm >= 0)
if (prctl(PR_SET_MEMORY_MERGE, context->memory_ksm) < 0) {
if (ERRNO_IS_NOT_SUPPORTED(errno))
log_unit_debug_errno(unit, errno, "KSM support not available, ignoring.");
else {
*exit_status = EXIT_KSM;
return log_unit_error_errno(unit, errno, "Failed to set KSM: %m");
}
}
/* Drop groups as early as possible.
* This needs to be done after PrivateDevices=y setup as device nodes should be owned by the host's root.
* For non-root in a userns, devices will be owned by the user/group before the group change, and nobody. */
if (needs_setuid) {
_cleanup_free_ gid_t *gids_to_enforce = NULL;
int ngids_to_enforce = 0;
ngids_to_enforce = merge_gid_lists(supplementary_gids,
ngids,
gids_after_pam,
ngids_after_pam,
&gids_to_enforce);
if (ngids_to_enforce < 0) {
*exit_status = EXIT_MEMORY;
return log_unit_error_errno(unit,
ngids_to_enforce,
"Failed to merge group lists. Group membership might be incorrect: %m");
}
r = enforce_groups(gid, gids_to_enforce, ngids_to_enforce);
if (r < 0) {
*exit_status = EXIT_GROUP;
return log_unit_error_errno(unit, r, "Changing group credentials failed: %m");
}
}
/* If the user namespace was not set up above, try to do it now.
* It's preferred to set up the user namespace later (after all other namespaces) so as not to be
* restricted by rules pertaining to combining user namespaces with other namespaces (e.g. in the
* case of mount namespaces being less privileged when the mount point list is copied from a
* different user namespace). */
if (needs_sandboxing && context->private_users && !userns_set_up) {
r = setup_private_users(saved_uid, saved_gid, uid, gid);
if (r < 0) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, r, "Failed to set up user namespacing: %m");
}
}
/* Now that the mount namespace has been set up and privileges adjusted, let's look for the thing we
* shall execute. */
_cleanup_free_ char *executable = NULL;
_cleanup_close_ int executable_fd = -EBADF;
r = find_executable_full(command->path, /* root= */ NULL, context->exec_search_path, false, &executable, &executable_fd);
if (r < 0) {
if (r != -ENOMEM && (command->flags & EXEC_COMMAND_IGNORE_FAILURE)) {
log_unit_struct_errno(unit, LOG_INFO, r,
"MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR,
LOG_UNIT_INVOCATION_ID(unit),
LOG_UNIT_MESSAGE(unit, "Executable %s missing, skipping: %m",
command->path),
"EXECUTABLE=%s", command->path);
*exit_status = EXIT_SUCCESS;
return 0;
}
*exit_status = EXIT_EXEC;
return log_unit_struct_errno(unit, LOG_INFO, r,
"MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR,
LOG_UNIT_INVOCATION_ID(unit),
LOG_UNIT_MESSAGE(unit, "Failed to locate executable %s: %m",
command->path),
"EXECUTABLE=%s", command->path);
}
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, executable_fd, &executable_fd);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m");
}
#if HAVE_SELINUX
if (needs_sandboxing && use_selinux && params->selinux_context_net) {
int fd = -EBADF;
if (socket_fd >= 0)
fd = socket_fd;
else if (params->n_socket_fds == 1)
/* If stdin is not connected to a socket but we are triggered by exactly one socket unit then we
* use context from that fd to compute the label. */
fd = params->fds[0];
if (fd >= 0) {
r = mac_selinux_get_child_mls_label(fd, executable, context->selinux_context, &mac_selinux_context_net);
if (r < 0) {
if (!context->selinux_context_ignore) {
*exit_status = EXIT_SELINUX_CONTEXT;
return log_unit_error_errno(unit, r, "Failed to determine SELinux context: %m");
}
log_unit_debug_errno(unit, r, "Failed to determine SELinux context, ignoring: %m");
}
}
}
#endif
/* We repeat the fd closing here, to make sure that nothing is leaked from the PAM modules. Note that
* we are more aggressive this time, since we don't need socket_fd and the netns and ipcns fds any
* more. We do keep exec_fd however, if we have it, since we need to keep it open until the final
* execve(). */
r = close_all_fds(keep_fds, n_keep_fds);
if (r >= 0)
r = shift_fds(fds, n_fds);
if (r >= 0)
r = flags_fds(fds, n_socket_fds, n_fds, context->non_blocking);
if (r < 0) {
*exit_status = EXIT_FDS;
return log_unit_error_errno(unit, r, "Failed to adjust passed file descriptors: %m");
}
/* At this point, the fds we want to pass to the program are all ready and set up, with O_CLOEXEC turned off
* and at the right fd numbers. The are no other fds open, with one exception: the exec_fd if it is defined,
* and it has O_CLOEXEC set, after all we want it to be closed by the execve(), so that our parent knows we
* came this far. */
secure_bits = context->secure_bits;
if (needs_sandboxing) {
uint64_t bset;
/* Set the RTPRIO resource limit to 0, but only if nothing else was explicitly requested.
* (Note this is placed after the general resource limit initialization, see above, in order
* to take precedence.) */
if (context->restrict_realtime && !context->rlimit[RLIMIT_RTPRIO]) {
if (setrlimit(RLIMIT_RTPRIO, &RLIMIT_MAKE_CONST(0)) < 0) {
*exit_status = EXIT_LIMITS;
return log_unit_error_errno(unit, errno, "Failed to adjust RLIMIT_RTPRIO resource limit: %m");
}
}
#if ENABLE_SMACK
/* LSM Smack needs the capability CAP_MAC_ADMIN to change the current execution security context of the
* process. This is the latest place before dropping capabilities. Other MAC context are set later. */
if (use_smack) {
r = setup_smack(unit->manager, context, executable_fd);
if (r < 0 && !context->smack_process_label_ignore) {
*exit_status = EXIT_SMACK_PROCESS_LABEL;
return log_unit_error_errno(unit, r, "Failed to set SMACK process label: %m");
}
}
#endif
bset = context->capability_bounding_set;
/* If the ambient caps hack is enabled (which means the kernel can't do them, and the user asked for
* our magic fallback), then let's add some extra caps, so that the service can drop privs of its own,
* instead of us doing that */
if (needs_ambient_hack)
bset |= (UINT64_C(1) << CAP_SETPCAP) |
(UINT64_C(1) << CAP_SETUID) |
(UINT64_C(1) << CAP_SETGID);
if (!cap_test_all(bset)) {
r = capability_bounding_set_drop(bset, /* right_now= */ false);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return log_unit_error_errno(unit, r, "Failed to drop capabilities: %m");
}
}
/* Ambient capabilities are cleared during setresuid() (in enforce_user()) even with
* keep-caps set.
*
* To be able to raise the ambient capabilities after setresuid() they have to be added to
* the inherited set and keep caps has to be set (done in enforce_user()). After setresuid()
* the ambient capabilities can be raised as they are present in the permitted and
* inhertiable set. However it is possible that someone wants to set ambient capabilities
* without changing the user, so we also set the ambient capabilities here.
*
* The requested ambient capabilities are raised in the inheritable set if the second
* argument is true. */
if (!needs_ambient_hack) {
r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ true);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return log_unit_error_errno(unit, r, "Failed to apply ambient capabilities (before UID change): %m");
}
}
}
/* chroot to root directory first, before we lose the ability to chroot */
r = apply_root_directory(context, params, runtime, needs_mount_namespace, exit_status);
if (r < 0)
return log_unit_error_errno(unit, r, "Chrooting to the requested root directory failed: %m");
if (needs_setuid) {
if (uid_is_valid(uid)) {
r = enforce_user(context, uid, capability_ambient_set);
if (r < 0) {
*exit_status = EXIT_USER;
return log_unit_error_errno(unit, r, "Failed to change UID to " UID_FMT ": %m", uid);
}
if (!needs_ambient_hack && capability_ambient_set != 0) {
/* Raise the ambient capabilities after user change. */
r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ false);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return log_unit_error_errno(unit, r, "Failed to apply ambient capabilities (after UID change): %m");
}
}
}
}
/* Apply working directory here, because the working directory might be on NFS and only the user running
* this service might have the correct privilege to change to the working directory */
r = apply_working_directory(context, params, runtime, home, exit_status);
if (r < 0)
return log_unit_error_errno(unit, r, "Changing to the requested working directory failed: %m");
if (needs_sandboxing) {
/* Apply other MAC contexts late, but before seccomp syscall filtering, as those should really be last to
* influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires
* syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls
* are restricted. */
#if HAVE_SELINUX
if (use_selinux) {
char *exec_context = mac_selinux_context_net ?: context->selinux_context;
if (exec_context) {
r = setexeccon(exec_context);
if (r < 0) {
if (!context->selinux_context_ignore) {
*exit_status = EXIT_SELINUX_CONTEXT;
return log_unit_error_errno(unit, r, "Failed to change SELinux context to %s: %m", exec_context);
}
log_unit_debug_errno(unit, r, "Failed to change SELinux context to %s, ignoring: %m", exec_context);
}
}
}
#endif
#if HAVE_APPARMOR
if (use_apparmor && context->apparmor_profile) {
r = aa_change_onexec(context->apparmor_profile);
if (r < 0 && !context->apparmor_profile_ignore) {
*exit_status = EXIT_APPARMOR_PROFILE;
return log_unit_error_errno(unit, errno, "Failed to prepare AppArmor profile change to %s: %m", context->apparmor_profile);
}
}
#endif
/* PR_GET_SECUREBITS is not privileged, while PR_SET_SECUREBITS is. So to suppress potential
* EPERMs we'll try not to call PR_SET_SECUREBITS unless necessary. Setting securebits
* requires CAP_SETPCAP. */
if (prctl(PR_GET_SECUREBITS) != secure_bits) {
/* CAP_SETPCAP is required to set securebits. This capability is raised into the
* effective set here.
*
* The effective set is overwritten during execve() with the following values:
*
* - ambient set (for non-root processes)
*
* - (inheritable | bounding) set for root processes)
*
* Hence there is no security impact to raise it in the effective set before execve
*/
r = capability_gain_cap_setpcap(/* return_caps= */ NULL);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return log_unit_error_errno(unit, r, "Failed to gain CAP_SETPCAP for setting secure bits");
}
if (prctl(PR_SET_SECUREBITS, secure_bits) < 0) {
*exit_status = EXIT_SECUREBITS;
return log_unit_error_errno(unit, errno, "Failed to set process secure bits: %m");
}
}
if (context_has_no_new_privileges(context))
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
*exit_status = EXIT_NO_NEW_PRIVILEGES;
return log_unit_error_errno(unit, errno, "Failed to disable new privileges: %m");
}
#if HAVE_SECCOMP
r = apply_address_families(unit, context);
if (r < 0) {
*exit_status = EXIT_ADDRESS_FAMILIES;
return log_unit_error_errno(unit, r, "Failed to restrict address families: %m");
}
r = apply_memory_deny_write_execute(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to disable writing to executable memory: %m");
}
r = apply_restrict_realtime(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply realtime restrictions: %m");
}
r = apply_restrict_suid_sgid(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply SUID/SGID restrictions: %m");
}
r = apply_restrict_namespaces(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply namespace restrictions: %m");
}
r = apply_protect_sysctl(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply sysctl restrictions: %m");
}
r = apply_protect_kernel_modules(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply module loading restrictions: %m");
}
r = apply_protect_kernel_logs(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply kernel log restrictions: %m");
}
r = apply_protect_clock(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply clock restrictions: %m");
}
r = apply_private_devices(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to set up private devices: %m");
}
r = apply_syscall_archs(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply syscall architecture restrictions: %m");
}
r = apply_lock_personality(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to lock personalities: %m");
}
r = apply_syscall_log(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply system call log filters: %m");
}
/* This really should remain the last step before the execve(), to make sure our own code is unaffected
* by the filter as little as possible. */
r = apply_syscall_filter(unit, context, needs_ambient_hack);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return log_unit_error_errno(unit, r, "Failed to apply system call filters: %m");
}
#endif
#if HAVE_LIBBPF
r = apply_restrict_filesystems(unit, context);
if (r < 0) {
*exit_status = EXIT_BPF;
return log_unit_error_errno(unit, r, "Failed to restrict filesystems: %m");
}
#endif
}
if (!strv_isempty(context->unset_environment)) {
char **ee = NULL;
ee = strv_env_delete(accum_env, 1, context->unset_environment);
if (!ee) {
*exit_status = EXIT_MEMORY;
return log_oom();
}
strv_free_and_replace(accum_env, ee);
}
if (!FLAGS_SET(command->flags, EXEC_COMMAND_NO_ENV_EXPAND)) {
_cleanup_strv_free_ char **unset_variables = NULL, **bad_variables = NULL;
r = replace_env_argv(command->argv, accum_env, &replaced_argv, &unset_variables, &bad_variables);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return log_unit_error_errno(unit, r, "Failed to replace environment variables: %m");
}
final_argv = replaced_argv;
if (!strv_isempty(unset_variables)) {
_cleanup_free_ char *ju = strv_join(unset_variables, ", ");
log_unit_warning(unit, "Referenced but unset environment variable evaluates to an empty string: %s", strna(ju));
}
if (!strv_isempty(bad_variables)) {
_cleanup_free_ char *jb = strv_join(bad_variables, ", ");
log_unit_warning(unit, "Invalid environment variable name evaluates to an empty string: %s", strna(jb));;
}
} else
final_argv = command->argv;
log_command_line(unit, "Executing", executable, final_argv);
if (exec_fd >= 0) {
uint8_t hot = 1;
/* We have finished with all our initializations. Let's now let the manager know that. From this point
* on, if the manager sees POLLHUP on the exec_fd, then execve() was successful. */
if (write(exec_fd, &hot, sizeof(hot)) < 0) {
*exit_status = EXIT_EXEC;
return log_unit_error_errno(unit, errno, "Failed to enable exec_fd: %m");
}
}
r = fexecve_or_execve(executable_fd, executable, final_argv, accum_env);
if (exec_fd >= 0) {
uint8_t hot = 0;
/* The execve() failed. This means the exec_fd is still open. Which means we need to tell the manager
* that POLLHUP on it no longer means execve() succeeded. */
if (write(exec_fd, &hot, sizeof(hot)) < 0) {
*exit_status = EXIT_EXEC;
return log_unit_error_errno(unit, errno, "Failed to disable exec_fd: %m");
}
}
*exit_status = EXIT_EXEC;
return log_unit_error_errno(unit, r, "Failed to execute %s: %m", executable);
}
static int exec_context_load_environment(const Unit *unit, const ExecContext *c, char ***l);
static int exec_context_named_iofds(const ExecContext *c, const ExecParameters *p, int named_iofds[static 3]);
int exec_spawn(Unit *unit,
ExecCommand *command,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
const CGroupContext *cgroup_context,
pid_t *ret) {
int socket_fd, r, named_iofds[3] = { -1, -1, -1 }, *fds = NULL;
_cleanup_free_ char *subcgroup_path = NULL;
_cleanup_strv_free_ char **files_env = NULL;
size_t n_storage_fds = 0, n_socket_fds = 0;
pid_t pid;
assert(unit);
assert(command);
assert(context);
assert(ret);
assert(params);
assert(params->fds || (params->n_socket_fds + params->n_storage_fds <= 0));
LOG_CONTEXT_PUSH_UNIT(unit);
if (context->std_input == EXEC_INPUT_SOCKET ||
context->std_output == EXEC_OUTPUT_SOCKET ||
context->std_error == EXEC_OUTPUT_SOCKET) {
if (params->n_socket_fds > 1)
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EINVAL), "Got more than one socket.");
if (params->n_socket_fds == 0)
return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EINVAL), "Got no socket.");
socket_fd = params->fds[0];
} else {
socket_fd = -EBADF;
fds = params->fds;
n_socket_fds = params->n_socket_fds;
n_storage_fds = params->n_storage_fds;
}
r = exec_context_named_iofds(context, params, named_iofds);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to load a named file descriptor: %m");
r = exec_context_load_environment(unit, context, &files_env);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to load environment files: %m");
/* Fork with up-to-date SELinux label database, so the child inherits the up-to-date db
and, until the next SELinux policy changes, we save further reloads in future children. */
mac_selinux_maybe_reload();
/* We won't know the real executable path until we create the mount namespace in the child, but we
want to log from the parent, so we use the possibly inaccurate path here. */
log_command_line(unit, "About to execute", command->path, command->argv);
if (params->cgroup_path) {
r = exec_parameters_get_cgroup_path(params, cgroup_context, &subcgroup_path);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to acquire subcgroup path: %m");
if (r > 0) {
/* If there's a subcgroup, then let's create it here now (the main cgroup was already
* realized by the unit logic) */
r = cg_create(SYSTEMD_CGROUP_CONTROLLER, subcgroup_path);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to create subcgroup '%s': %m", subcgroup_path);
}
}
pid = fork();
if (pid < 0)
return log_unit_error_errno(unit, errno, "Failed to fork: %m");
if (pid == 0) {
int exit_status;
r = exec_child(unit,
command,
context,
params,
runtime,
cgroup_context,
socket_fd,
named_iofds,
fds,
n_socket_fds,
n_storage_fds,
files_env,
unit->manager->user_lookup_fds[1],
&exit_status);
if (r < 0) {
const char *status = ASSERT_PTR(
exit_status_to_string(exit_status, EXIT_STATUS_LIBC | EXIT_STATUS_SYSTEMD));
log_unit_struct_errno(unit, LOG_ERR, r,
"MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR,
LOG_UNIT_INVOCATION_ID(unit),
LOG_UNIT_MESSAGE(unit, "Failed at step %s spawning %s: %m",
status, command->path),
"EXECUTABLE=%s", command->path);
} else
assert(exit_status == EXIT_SUCCESS);
_exit(exit_status);
}
log_unit_debug(unit, "Forked %s as "PID_FMT, command->path, pid);
/* We add the new process to the cgroup both in the child (so that we can be sure that no user code is ever
* executed outside of the cgroup) and in the parent (so that we can be sure that when we kill the cgroup the
* process will be killed too). */
if (subcgroup_path)
(void) cg_attach(SYSTEMD_CGROUP_CONTROLLER, subcgroup_path, pid);
exec_status_start(&command->exec_status, pid);
*ret = pid;
return 0;
}
void exec_context_init(ExecContext *c) {
assert(c);
*c = (ExecContext) {
.umask = 0022,
.ioprio = IOPRIO_DEFAULT_CLASS_AND_PRIO,
.cpu_sched_policy = SCHED_OTHER,
.syslog_priority = LOG_DAEMON|LOG_INFO,
.syslog_level_prefix = true,
.ignore_sigpipe = true,
.timer_slack_nsec = NSEC_INFINITY,
.personality = PERSONALITY_INVALID,
.timeout_clean_usec = USEC_INFINITY,
.capability_bounding_set = CAP_MASK_UNSET,
.restrict_namespaces = NAMESPACE_FLAGS_INITIAL,
.log_level_max = -1,
#if HAVE_SECCOMP
.syscall_errno = SECCOMP_ERROR_NUMBER_KILL,
#endif
.tty_rows = UINT_MAX,
.tty_cols = UINT_MAX,
.private_mounts = -1,
.memory_ksm = -1,
.set_login_environment = -1,
};
FOREACH_ARRAY(d, c->directories, _EXEC_DIRECTORY_TYPE_MAX)
d->mode = 0755;
numa_policy_reset(&c->numa_policy);
assert_cc(NAMESPACE_FLAGS_INITIAL != NAMESPACE_FLAGS_ALL);
}
void exec_context_done(ExecContext *c) {
assert(c);
c->environment = strv_free(c->environment);
c->environment_files = strv_free(c->environment_files);
c->pass_environment = strv_free(c->pass_environment);
c->unset_environment = strv_free(c->unset_environment);
rlimit_free_all(c->rlimit);
for (size_t l = 0; l < 3; l++) {
c->stdio_fdname[l] = mfree(c->stdio_fdname[l]);
c->stdio_file[l] = mfree(c->stdio_file[l]);
}
c->working_directory = mfree(c->working_directory);
c->root_directory = mfree(c->root_directory);
c->root_image = mfree(c->root_image);
c->root_image_options = mount_options_free_all(c->root_image_options);
c->root_hash = mfree(c->root_hash);
c->root_hash_size = 0;
c->root_hash_path = mfree(c->root_hash_path);
c->root_hash_sig = mfree(c->root_hash_sig);
c->root_hash_sig_size = 0;
c->root_hash_sig_path = mfree(c->root_hash_sig_path);
c->root_verity = mfree(c->root_verity);
c->extension_images = mount_image_free_many(c->extension_images, &c->n_extension_images);
c->extension_directories = strv_free(c->extension_directories);
c->tty_path = mfree(c->tty_path);
c->syslog_identifier = mfree(c->syslog_identifier);
c->user = mfree(c->user);
c->group = mfree(c->group);
c->supplementary_groups = strv_free(c->supplementary_groups);
c->pam_name = mfree(c->pam_name);
c->read_only_paths = strv_free(c->read_only_paths);
c->read_write_paths = strv_free(c->read_write_paths);
c->inaccessible_paths = strv_free(c->inaccessible_paths);
c->exec_paths = strv_free(c->exec_paths);
c->no_exec_paths = strv_free(c->no_exec_paths);
c->exec_search_path = strv_free(c->exec_search_path);
bind_mount_free_many(c->bind_mounts, c->n_bind_mounts);
c->bind_mounts = NULL;
c->n_bind_mounts = 0;
temporary_filesystem_free_many(c->temporary_filesystems, c->n_temporary_filesystems);
c->temporary_filesystems = NULL;
c->n_temporary_filesystems = 0;
c->mount_images = mount_image_free_many(c->mount_images, &c->n_mount_images);
cpu_set_reset(&c->cpu_set);
numa_policy_reset(&c->numa_policy);
c->utmp_id = mfree(c->utmp_id);
c->selinux_context = mfree(c->selinux_context);
c->apparmor_profile = mfree(c->apparmor_profile);
c->smack_process_label = mfree(c->smack_process_label);
c->restrict_filesystems = set_free_free(c->restrict_filesystems);
c->syscall_filter = hashmap_free(c->syscall_filter);
c->syscall_archs = set_free(c->syscall_archs);
c->address_families = set_free(c->address_families);
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++)
exec_directory_done(&c->directories[t]);
c->log_level_max = -1;
exec_context_free_log_extra_fields(c);
c->log_filter_allowed_patterns = set_free_free(c->log_filter_allowed_patterns);
c->log_filter_denied_patterns = set_free_free(c->log_filter_denied_patterns);
c->log_ratelimit_interval_usec = 0;
c->log_ratelimit_burst = 0;
c->stdin_data = mfree(c->stdin_data);
c->stdin_data_size = 0;
c->network_namespace_path = mfree(c->network_namespace_path);
c->ipc_namespace_path = mfree(c->ipc_namespace_path);
c->log_namespace = mfree(c->log_namespace);
c->load_credentials = hashmap_free(c->load_credentials);
c->set_credentials = hashmap_free(c->set_credentials);
c->import_credentials = set_free_free(c->import_credentials);
c->root_image_policy = image_policy_free(c->root_image_policy);
c->mount_image_policy = image_policy_free(c->mount_image_policy);
c->extension_image_policy = image_policy_free(c->extension_image_policy);
}
int exec_context_destroy_runtime_directory(const ExecContext *c, const char *runtime_prefix) {
assert(c);
if (!runtime_prefix)
return 0;
for (size_t i = 0; i < c->directories[EXEC_DIRECTORY_RUNTIME].n_items; i++) {
_cleanup_free_ char *p = NULL;
if (exec_directory_is_private(c, EXEC_DIRECTORY_RUNTIME))
p = path_join(runtime_prefix, "private", c->directories[EXEC_DIRECTORY_RUNTIME].items[i].path);
else
p = path_join(runtime_prefix, c->directories[EXEC_DIRECTORY_RUNTIME].items[i].path);
if (!p)
return -ENOMEM;
/* We execute this synchronously, since we need to be sure this is gone when we start the
* service next. */
(void) rm_rf(p, REMOVE_ROOT);
STRV_FOREACH(symlink, c->directories[EXEC_DIRECTORY_RUNTIME].items[i].symlinks) {
_cleanup_free_ char *symlink_abs = NULL;
if (exec_directory_is_private(c, EXEC_DIRECTORY_RUNTIME))
symlink_abs = path_join(runtime_prefix, "private", *symlink);
else
symlink_abs = path_join(runtime_prefix, *symlink);
if (!symlink_abs)
return -ENOMEM;
(void) unlink(symlink_abs);
}
}
return 0;
}
int exec_context_destroy_mount_ns_dir(Unit *u) {
_cleanup_free_ char *p = NULL;
if (!u || !MANAGER_IS_SYSTEM(u->manager))
return 0;
p = path_join("/run/systemd/propagate/", u->id);
if (!p)
return -ENOMEM;
/* This is only filled transiently (see mount_in_namespace()), should be empty or even non-existent*/
if (rmdir(p) < 0 && errno != ENOENT)
log_unit_debug_errno(u, errno, "Unable to remove propagation dir '%s', ignoring: %m", p);
return 0;
}
static void exec_command_done(ExecCommand *c) {
assert(c);
c->path = mfree(c->path);
c->argv = strv_free(c->argv);
}
void exec_command_done_array(ExecCommand *c, size_t n) {
for (size_t i = 0; i < n; i++)
exec_command_done(c+i);
}
ExecCommand* exec_command_free_list(ExecCommand *c) {
ExecCommand *i;
while ((i = LIST_POP(command, c))) {
exec_command_done(i);
free(i);
}
return NULL;
}
void exec_command_free_array(ExecCommand **c, size_t n) {
for (size_t i = 0; i < n; i++)
c[i] = exec_command_free_list(c[i]);
}
void exec_command_reset_status_array(ExecCommand *c, size_t n) {
for (size_t i = 0; i < n; i++)
exec_status_reset(&c[i].exec_status);
}
void exec_command_reset_status_list_array(ExecCommand **c, size_t n) {
for (size_t i = 0; i < n; i++)
LIST_FOREACH(command, z, c[i])
exec_status_reset(&z->exec_status);
}
typedef struct InvalidEnvInfo {
const Unit *unit;
const char *path;
} InvalidEnvInfo;
static void invalid_env(const char *p, void *userdata) {
InvalidEnvInfo *info = userdata;
log_unit_error(info->unit, "Ignoring invalid environment assignment '%s': %s", p, info->path);
}
const char* exec_context_fdname(const ExecContext *c, int fd_index) {
assert(c);
switch (fd_index) {
case STDIN_FILENO:
if (c->std_input != EXEC_INPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDIN_FILENO] ?: "stdin";
case STDOUT_FILENO:
if (c->std_output != EXEC_OUTPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDOUT_FILENO] ?: "stdout";
case STDERR_FILENO:
if (c->std_error != EXEC_OUTPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDERR_FILENO] ?: "stderr";
default:
return NULL;
}
}
static int exec_context_named_iofds(
const ExecContext *c,
const ExecParameters *p,
int named_iofds[static 3]) {
size_t targets;
const char* stdio_fdname[3];
size_t n_fds;
assert(c);
assert(p);
assert(named_iofds);
targets = (c->std_input == EXEC_INPUT_NAMED_FD) +
(c->std_output == EXEC_OUTPUT_NAMED_FD) +
(c->std_error == EXEC_OUTPUT_NAMED_FD);
for (size_t i = 0; i < 3; i++)
stdio_fdname[i] = exec_context_fdname(c, i);
n_fds = p->n_storage_fds + p->n_socket_fds;
for (size_t i = 0; i < n_fds && targets > 0; i++)
if (named_iofds[STDIN_FILENO] < 0 &&
c->std_input == EXEC_INPUT_NAMED_FD &&
stdio_fdname[STDIN_FILENO] &&
streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) {
named_iofds[STDIN_FILENO] = p->fds[i];
targets--;
} else if (named_iofds[STDOUT_FILENO] < 0 &&
c->std_output == EXEC_OUTPUT_NAMED_FD &&
stdio_fdname[STDOUT_FILENO] &&
streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
named_iofds[STDOUT_FILENO] = p->fds[i];
targets--;
} else if (named_iofds[STDERR_FILENO] < 0 &&
c->std_error == EXEC_OUTPUT_NAMED_FD &&
stdio_fdname[STDERR_FILENO] &&
streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
named_iofds[STDERR_FILENO] = p->fds[i];
targets--;
}
return targets == 0 ? 0 : -ENOENT;
}
static int exec_context_load_environment(const Unit *unit, const ExecContext *c, char ***ret) {
_cleanup_strv_free_ char **v = NULL;
int r;
assert(c);
assert(ret);
STRV_FOREACH(i, c->environment_files) {
_cleanup_globfree_ glob_t pglob = {};
bool ignore = false;
char *fn = *i;
if (fn[0] == '-') {
ignore = true;
fn++;
}
if (!path_is_absolute(fn)) {
if (ignore)
continue;
return -EINVAL;
}
/* Filename supports globbing, take all matching files */
r = safe_glob(fn, 0, &pglob);
if (r < 0) {
if (ignore)
continue;
return r;
}
/* When we don't match anything, -ENOENT should be returned */
assert(pglob.gl_pathc > 0);
for (size_t n = 0; n < pglob.gl_pathc; n++) {
_cleanup_strv_free_ char **p = NULL;
r = load_env_file(NULL, pglob.gl_pathv[n], &p);
if (r < 0) {
if (ignore)
continue;
return r;
}
/* Log invalid environment variables with filename */
if (p) {
InvalidEnvInfo info = {
.unit = unit,
.path = pglob.gl_pathv[n]
};
p = strv_env_clean_with_callback(p, invalid_env, &info);
}
if (!v)
v = TAKE_PTR(p);
else {
char **m = strv_env_merge(v, p);
if (!m)
return -ENOMEM;
strv_free_and_replace(v, m);
}
}
}
*ret = TAKE_PTR(v);
return 0;
}
static bool tty_may_match_dev_console(const char *tty) {
_cleanup_free_ char *resolved = NULL;
if (!tty)
return true;
tty = skip_dev_prefix(tty);
/* trivial identity? */
if (streq(tty, "console"))
return true;
if (resolve_dev_console(&resolved) < 0)
return true; /* if we could not resolve, assume it may */
/* "tty0" means the active VC, so it may be the same sometimes */
return path_equal(resolved, tty) || (streq(resolved, "tty0") && tty_is_vc(tty));
}
static bool exec_context_may_touch_tty(const ExecContext *ec) {
assert(ec);
return ec->tty_reset ||
ec->tty_vhangup ||
ec->tty_vt_disallocate ||
is_terminal_input(ec->std_input) ||
is_terminal_output(ec->std_output) ||
is_terminal_output(ec->std_error);
}
bool exec_context_may_touch_console(const ExecContext *ec) {
return exec_context_may_touch_tty(ec) &&
tty_may_match_dev_console(exec_context_tty_path(ec));
}
static void strv_fprintf(FILE *f, char **l) {
assert(f);
STRV_FOREACH(g, l)
fprintf(f, " %s", *g);
}
static void strv_dump(FILE* f, const char *prefix, const char *name, char **strv) {
assert(f);
assert(prefix);
assert(name);
if (!strv_isempty(strv)) {
fprintf(f, "%s%s:", prefix, name);
strv_fprintf(f, strv);
fputs("\n", f);
}
}
void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix) {
int r;
assert(c);
assert(f);
prefix = strempty(prefix);
fprintf(f,
"%sUMask: %04o\n"
"%sWorkingDirectory: %s\n"
"%sRootDirectory: %s\n"
"%sRootEphemeral: %s\n"
"%sNonBlocking: %s\n"
"%sPrivateTmp: %s\n"
"%sPrivateDevices: %s\n"
"%sProtectKernelTunables: %s\n"
"%sProtectKernelModules: %s\n"
"%sProtectKernelLogs: %s\n"
"%sProtectClock: %s\n"
"%sProtectControlGroups: %s\n"
"%sPrivateNetwork: %s\n"
"%sPrivateUsers: %s\n"
"%sProtectHome: %s\n"
"%sProtectSystem: %s\n"
"%sMountAPIVFS: %s\n"
"%sIgnoreSIGPIPE: %s\n"
"%sMemoryDenyWriteExecute: %s\n"
"%sRestrictRealtime: %s\n"
"%sRestrictSUIDSGID: %s\n"
"%sKeyringMode: %s\n"
"%sProtectHostname: %s\n"
"%sProtectProc: %s\n"
"%sProcSubset: %s\n",
prefix, c->umask,
prefix, empty_to_root(c->working_directory),
prefix, empty_to_root(c->root_directory),
prefix, yes_no(c->root_ephemeral),
prefix, yes_no(c->non_blocking),
prefix, yes_no(c->private_tmp),
prefix, yes_no(c->private_devices),
prefix, yes_no(c->protect_kernel_tunables),
prefix, yes_no(c->protect_kernel_modules),
prefix, yes_no(c->protect_kernel_logs),
prefix, yes_no(c->protect_clock),
prefix, yes_no(c->protect_control_groups),
prefix, yes_no(c->private_network),
prefix, yes_no(c->private_users),
prefix, protect_home_to_string(c->protect_home),
prefix, protect_system_to_string(c->protect_system),
prefix, yes_no(exec_context_get_effective_mount_apivfs(c)),
prefix, yes_no(c->ignore_sigpipe),
prefix, yes_no(c->memory_deny_write_execute),
prefix, yes_no(c->restrict_realtime),
prefix, yes_no(c->restrict_suid_sgid),
prefix, exec_keyring_mode_to_string(c->keyring_mode),
prefix, yes_no(c->protect_hostname),
prefix, protect_proc_to_string(c->protect_proc),
prefix, proc_subset_to_string(c->proc_subset));
if (c->root_image)
fprintf(f, "%sRootImage: %s\n", prefix, c->root_image);
if (c->root_image_options) {
fprintf(f, "%sRootImageOptions:", prefix);
LIST_FOREACH(mount_options, o, c->root_image_options)
if (!isempty(o->options))
fprintf(f, " %s:%s",
partition_designator_to_string(o->partition_designator),
o->options);
fprintf(f, "\n");
}
if (c->root_hash) {
_cleanup_free_ char *encoded = NULL;
encoded = hexmem(c->root_hash, c->root_hash_size);
if (encoded)
fprintf(f, "%sRootHash: %s\n", prefix, encoded);
}
if (c->root_hash_path)
fprintf(f, "%sRootHash: %s\n", prefix, c->root_hash_path);
if (c->root_hash_sig) {
_cleanup_free_ char *encoded = NULL;
ssize_t len;
len = base64mem(c->root_hash_sig, c->root_hash_sig_size, &encoded);
if (len)
fprintf(f, "%sRootHashSignature: base64:%s\n", prefix, encoded);
}
if (c->root_hash_sig_path)
fprintf(f, "%sRootHashSignature: %s\n", prefix, c->root_hash_sig_path);
if (c->root_verity)
fprintf(f, "%sRootVerity: %s\n", prefix, c->root_verity);
STRV_FOREACH(e, c->environment)
fprintf(f, "%sEnvironment: %s\n", prefix, *e);
STRV_FOREACH(e, c->environment_files)
fprintf(f, "%sEnvironmentFile: %s\n", prefix, *e);
STRV_FOREACH(e, c->pass_environment)
fprintf(f, "%sPassEnvironment: %s\n", prefix, *e);
STRV_FOREACH(e, c->unset_environment)
fprintf(f, "%sUnsetEnvironment: %s\n", prefix, *e);
fprintf(f, "%sRuntimeDirectoryPreserve: %s\n", prefix, exec_preserve_mode_to_string(c->runtime_directory_preserve_mode));
for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) {
fprintf(f, "%s%sMode: %04o\n", prefix, exec_directory_type_to_string(dt), c->directories[dt].mode);
for (size_t i = 0; i < c->directories[dt].n_items; i++) {
fprintf(f, "%s%s: %s\n", prefix, exec_directory_type_to_string(dt), c->directories[dt].items[i].path);
STRV_FOREACH(d, c->directories[dt].items[i].symlinks)
fprintf(f, "%s%s: %s:%s\n", prefix, exec_directory_type_symlink_to_string(dt), c->directories[dt].items[i].path, *d);
}
}
fprintf(f, "%sTimeoutCleanSec: %s\n", prefix, FORMAT_TIMESPAN(c->timeout_clean_usec, USEC_PER_SEC));
if (c->nice_set)
fprintf(f, "%sNice: %i\n", prefix, c->nice);
if (c->oom_score_adjust_set)
fprintf(f, "%sOOMScoreAdjust: %i\n", prefix, c->oom_score_adjust);
if (c->coredump_filter_set)
fprintf(f, "%sCoredumpFilter: 0x%"PRIx64"\n", prefix, c->coredump_filter);
for (unsigned i = 0; i < RLIM_NLIMITS; i++)
if (c->rlimit[i]) {
fprintf(f, "%sLimit%s: " RLIM_FMT "\n",
prefix, rlimit_to_string(i), c->rlimit[i]->rlim_max);
fprintf(f, "%sLimit%sSoft: " RLIM_FMT "\n",
prefix, rlimit_to_string(i), c->rlimit[i]->rlim_cur);
}
if (c->ioprio_set) {
_cleanup_free_ char *class_str = NULL;
r = ioprio_class_to_string_alloc(ioprio_prio_class(c->ioprio), &class_str);
if (r >= 0)
fprintf(f, "%sIOSchedulingClass: %s\n", prefix, class_str);
fprintf(f, "%sIOPriority: %d\n", prefix, ioprio_prio_data(c->ioprio));
}
if (c->cpu_sched_set) {
_cleanup_free_ char *policy_str = NULL;
r = sched_policy_to_string_alloc(c->cpu_sched_policy, &policy_str);
if (r >= 0)
fprintf(f, "%sCPUSchedulingPolicy: %s\n", prefix, policy_str);
fprintf(f,
"%sCPUSchedulingPriority: %i\n"
"%sCPUSchedulingResetOnFork: %s\n",
prefix, c->cpu_sched_priority,
prefix, yes_no(c->cpu_sched_reset_on_fork));
}
if (c->cpu_set.set) {
_cleanup_free_ char *affinity = NULL;
affinity = cpu_set_to_range_string(&c->cpu_set);
fprintf(f, "%sCPUAffinity: %s\n", prefix, affinity);
}
if (mpol_is_valid(numa_policy_get_type(&c->numa_policy))) {
_cleanup_free_ char *nodes = NULL;
nodes = cpu_set_to_range_string(&c->numa_policy.nodes);
fprintf(f, "%sNUMAPolicy: %s\n", prefix, mpol_to_string(numa_policy_get_type(&c->numa_policy)));
fprintf(f, "%sNUMAMask: %s\n", prefix, strnull(nodes));
}
if (c->timer_slack_nsec != NSEC_INFINITY)
fprintf(f, "%sTimerSlackNSec: "NSEC_FMT "\n", prefix, c->timer_slack_nsec);
fprintf(f,
"%sStandardInput: %s\n"
"%sStandardOutput: %s\n"
"%sStandardError: %s\n",
prefix, exec_input_to_string(c->std_input),
prefix, exec_output_to_string(c->std_output),
prefix, exec_output_to_string(c->std_error));
if (c->std_input == EXEC_INPUT_NAMED_FD)
fprintf(f, "%sStandardInputFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDIN_FILENO]);
if (c->std_output == EXEC_OUTPUT_NAMED_FD)
fprintf(f, "%sStandardOutputFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDOUT_FILENO]);
if (c->std_error == EXEC_OUTPUT_NAMED_FD)
fprintf(f, "%sStandardErrorFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDERR_FILENO]);
if (c->std_input == EXEC_INPUT_FILE)
fprintf(f, "%sStandardInputFile: %s\n", prefix, c->stdio_file[STDIN_FILENO]);
if (c->std_output == EXEC_OUTPUT_FILE)
fprintf(f, "%sStandardOutputFile: %s\n", prefix, c->stdio_file[STDOUT_FILENO]);
if (c->std_output == EXEC_OUTPUT_FILE_APPEND)
fprintf(f, "%sStandardOutputFileToAppend: %s\n", prefix, c->stdio_file[STDOUT_FILENO]);
if (c->std_output == EXEC_OUTPUT_FILE_TRUNCATE)
fprintf(f, "%sStandardOutputFileToTruncate: %s\n", prefix, c->stdio_file[STDOUT_FILENO]);
if (c->std_error == EXEC_OUTPUT_FILE)
fprintf(f, "%sStandardErrorFile: %s\n", prefix, c->stdio_file[STDERR_FILENO]);
if (c->std_error == EXEC_OUTPUT_FILE_APPEND)
fprintf(f, "%sStandardErrorFileToAppend: %s\n", prefix, c->stdio_file[STDERR_FILENO]);
if (c->std_error == EXEC_OUTPUT_FILE_TRUNCATE)
fprintf(f, "%sStandardErrorFileToTruncate: %s\n", prefix, c->stdio_file[STDERR_FILENO]);
if (c->tty_path)
fprintf(f,
"%sTTYPath: %s\n"
"%sTTYReset: %s\n"
"%sTTYVHangup: %s\n"
"%sTTYVTDisallocate: %s\n"
"%sTTYRows: %u\n"
"%sTTYColumns: %u\n",
prefix, c->tty_path,
prefix, yes_no(c->tty_reset),
prefix, yes_no(c->tty_vhangup),
prefix, yes_no(c->tty_vt_disallocate),
prefix, c->tty_rows,
prefix, c->tty_cols);
if (IN_SET(c->std_output,
EXEC_OUTPUT_KMSG,
EXEC_OUTPUT_JOURNAL,
EXEC_OUTPUT_KMSG_AND_CONSOLE,
EXEC_OUTPUT_JOURNAL_AND_CONSOLE) ||
IN_SET(c->std_error,
EXEC_OUTPUT_KMSG,
EXEC_OUTPUT_JOURNAL,
EXEC_OUTPUT_KMSG_AND_CONSOLE,
EXEC_OUTPUT_JOURNAL_AND_CONSOLE)) {
_cleanup_free_ char *fac_str = NULL, *lvl_str = NULL;
r = log_facility_unshifted_to_string_alloc(c->syslog_priority >> 3, &fac_str);
if (r >= 0)
fprintf(f, "%sSyslogFacility: %s\n", prefix, fac_str);
r = log_level_to_string_alloc(LOG_PRI(c->syslog_priority), &lvl_str);
if (r >= 0)
fprintf(f, "%sSyslogLevel: %s\n", prefix, lvl_str);
}
if (c->log_level_max >= 0) {
_cleanup_free_ char *t = NULL;
(void) log_level_to_string_alloc(c->log_level_max, &t);
fprintf(f, "%sLogLevelMax: %s\n", prefix, strna(t));
}
if (c->log_ratelimit_interval_usec > 0)
fprintf(f,
"%sLogRateLimitIntervalSec: %s\n",
prefix, FORMAT_TIMESPAN(c->log_ratelimit_interval_usec, USEC_PER_SEC));
if (c->log_ratelimit_burst > 0)
fprintf(f, "%sLogRateLimitBurst: %u\n", prefix, c->log_ratelimit_burst);
if (!set_isempty(c->log_filter_allowed_patterns) || !set_isempty(c->log_filter_denied_patterns)) {
fprintf(f, "%sLogFilterPatterns:", prefix);
char *pattern;
SET_FOREACH(pattern, c->log_filter_allowed_patterns)
fprintf(f, " %s", pattern);
SET_FOREACH(pattern, c->log_filter_denied_patterns)
fprintf(f, " ~%s", pattern);
fputc('\n', f);
}
for (size_t j = 0; j < c->n_log_extra_fields; j++) {
fprintf(f, "%sLogExtraFields: ", prefix);
fwrite(c->log_extra_fields[j].iov_base,
1, c->log_extra_fields[j].iov_len,
f);
fputc('\n', f);
}
if (c->log_namespace)
fprintf(f, "%sLogNamespace: %s\n", prefix, c->log_namespace);
if (c->secure_bits) {
_cleanup_free_ char *str = NULL;
r = secure_bits_to_string_alloc(c->secure_bits, &str);
if (r >= 0)
fprintf(f, "%sSecure Bits: %s\n", prefix, str);
}
if (c->capability_bounding_set != CAP_MASK_UNSET) {
_cleanup_free_ char *str = NULL;
r = capability_set_to_string(c->capability_bounding_set, &str);
if (r >= 0)
fprintf(f, "%sCapabilityBoundingSet: %s\n", prefix, str);
}
if (c->capability_ambient_set != 0) {
_cleanup_free_ char *str = NULL;
r = capability_set_to_string(c->capability_ambient_set, &str);
if (r >= 0)
fprintf(f, "%sAmbientCapabilities: %s\n", prefix, str);
}
if (c->user)
fprintf(f, "%sUser: %s\n", prefix, c->user);
if (c->group)
fprintf(f, "%sGroup: %s\n", prefix, c->group);
fprintf(f, "%sDynamicUser: %s\n", prefix, yes_no(c->dynamic_user));
strv_dump(f, prefix, "SupplementaryGroups", c->supplementary_groups);
if (c->pam_name)
fprintf(f, "%sPAMName: %s\n", prefix, c->pam_name);
strv_dump(f, prefix, "ReadWritePaths", c->read_write_paths);
strv_dump(f, prefix, "ReadOnlyPaths", c->read_only_paths);
strv_dump(f, prefix, "InaccessiblePaths", c->inaccessible_paths);
strv_dump(f, prefix, "ExecPaths", c->exec_paths);
strv_dump(f, prefix, "NoExecPaths", c->no_exec_paths);
strv_dump(f, prefix, "ExecSearchPath", c->exec_search_path);
for (size_t i = 0; i < c->n_bind_mounts; i++)
fprintf(f, "%s%s: %s%s:%s:%s\n", prefix,
c->bind_mounts[i].read_only ? "BindReadOnlyPaths" : "BindPaths",
c->bind_mounts[i].ignore_enoent ? "-": "",
c->bind_mounts[i].source,
c->bind_mounts[i].destination,
c->bind_mounts[i].recursive ? "rbind" : "norbind");
for (size_t i = 0; i < c->n_temporary_filesystems; i++) {
const TemporaryFileSystem *t = c->temporary_filesystems + i;
fprintf(f, "%sTemporaryFileSystem: %s%s%s\n", prefix,
t->path,
isempty(t->options) ? "" : ":",
strempty(t->options));
}
if (c->utmp_id)
fprintf(f,
"%sUtmpIdentifier: %s\n",
prefix, c->utmp_id);
if (c->selinux_context)
fprintf(f,
"%sSELinuxContext: %s%s\n",
prefix, c->selinux_context_ignore ? "-" : "", c->selinux_context);
if (c->apparmor_profile)
fprintf(f,
"%sAppArmorProfile: %s%s\n",
prefix, c->apparmor_profile_ignore ? "-" : "", c->apparmor_profile);
if (c->smack_process_label)
fprintf(f,
"%sSmackProcessLabel: %s%s\n",
prefix, c->smack_process_label_ignore ? "-" : "", c->smack_process_label);
if (c->personality != PERSONALITY_INVALID)
fprintf(f,
"%sPersonality: %s\n",
prefix, strna(personality_to_string(c->personality)));
fprintf(f,
"%sLockPersonality: %s\n",
prefix, yes_no(c->lock_personality));
if (c->syscall_filter) {
fprintf(f,
"%sSystemCallFilter: ",
prefix);
if (!c->syscall_allow_list)
fputc('~', f);
#if HAVE_SECCOMP
void *id, *val;
bool first = true;
HASHMAP_FOREACH_KEY(val, id, c->syscall_filter) {
_cleanup_free_ char *name = NULL;
const char *errno_name = NULL;
int num = PTR_TO_INT(val);
if (first)
first = false;
else
fputc(' ', f);
name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
fputs(strna(name), f);
if (num >= 0) {
errno_name = seccomp_errno_or_action_to_string(num);
if (errno_name)
fprintf(f, ":%s", errno_name);
else
fprintf(f, ":%d", num);
}
}
#endif
fputc('\n', f);
}
if (c->syscall_archs) {
fprintf(f,
"%sSystemCallArchitectures:",
prefix);
#if HAVE_SECCOMP
void *id;
SET_FOREACH(id, c->syscall_archs)
fprintf(f, " %s", strna(seccomp_arch_to_string(PTR_TO_UINT32(id) - 1)));
#endif
fputc('\n', f);
}
if (exec_context_restrict_namespaces_set(c)) {
_cleanup_free_ char *s = NULL;
r = namespace_flags_to_string(c->restrict_namespaces, &s);
if (r >= 0)
fprintf(f, "%sRestrictNamespaces: %s\n",
prefix, strna(s));
}
#if HAVE_LIBBPF
if (exec_context_restrict_filesystems_set(c)) {
char *fs;
SET_FOREACH(fs, c->restrict_filesystems)
fprintf(f, "%sRestrictFileSystems: %s\n", prefix, fs);
}
#endif
if (c->network_namespace_path)
fprintf(f,
"%sNetworkNamespacePath: %s\n",
prefix, c->network_namespace_path);
if (c->syscall_errno > 0) {
fprintf(f, "%sSystemCallErrorNumber: ", prefix);
#if HAVE_SECCOMP
const char *errno_name = seccomp_errno_or_action_to_string(c->syscall_errno);
if (errno_name)
fputs(errno_name, f);
else
fprintf(f, "%d", c->syscall_errno);
#endif
fputc('\n', f);
}
for (size_t i = 0; i < c->n_mount_images; i++) {
fprintf(f, "%sMountImages: %s%s:%s", prefix,
c->mount_images[i].ignore_enoent ? "-": "",
c->mount_images[i].source,
c->mount_images[i].destination);
LIST_FOREACH(mount_options, o, c->mount_images[i].mount_options)
fprintf(f, ":%s:%s",
partition_designator_to_string(o->partition_designator),
strempty(o->options));
fprintf(f, "\n");
}
for (size_t i = 0; i < c->n_extension_images; i++) {
fprintf(f, "%sExtensionImages: %s%s", prefix,
c->extension_images[i].ignore_enoent ? "-": "",
c->extension_images[i].source);
LIST_FOREACH(mount_options, o, c->extension_images[i].mount_options)
fprintf(f, ":%s:%s",
partition_designator_to_string(o->partition_designator),
strempty(o->options));
fprintf(f, "\n");
}
strv_dump(f, prefix, "ExtensionDirectories", c->extension_directories);
}
bool exec_context_maintains_privileges(const ExecContext *c) {
assert(c);
/* Returns true if the process forked off would run under
* an unchanged UID or as root. */
if (!c->user)
return true;
if (streq(c->user, "root") || streq(c->user, "0"))
return true;
return false;
}
int exec_context_get_effective_ioprio(const ExecContext *c) {
int p;
assert(c);
if (c->ioprio_set)
return c->ioprio;
p = ioprio_get(IOPRIO_WHO_PROCESS, 0);
if (p < 0)
return IOPRIO_DEFAULT_CLASS_AND_PRIO;
return ioprio_normalize(p);
}
bool exec_context_get_effective_mount_apivfs(const ExecContext *c) {
assert(c);
/* Explicit setting wins */
if (c->mount_apivfs_set)
return c->mount_apivfs;
/* Default to "yes" if root directory or image are specified */
if (exec_context_with_rootfs(c))
return true;
return false;
}
void exec_context_free_log_extra_fields(ExecContext *c) {
assert(c);
for (size_t l = 0; l < c->n_log_extra_fields; l++)
free(c->log_extra_fields[l].iov_base);
c->log_extra_fields = mfree(c->log_extra_fields);
c->n_log_extra_fields = 0;
}
void exec_context_revert_tty(ExecContext *c) {
_cleanup_close_ int fd = -EBADF;
const char *path;
struct stat st;
int r;
assert(c);
/* First, reset the TTY (possibly kicking everybody else from the TTY) */
exec_context_tty_reset(c, NULL);
/* And then undo what chown_terminal() did earlier. Note that we only do this if we have a path
* configured. If the TTY was passed to us as file descriptor we assume the TTY is opened and managed
* by whoever passed it to us and thus knows better when and how to chmod()/chown() it back. */
if (!exec_context_may_touch_tty(c))
return;
path = exec_context_tty_path(c);
if (!path)
return;
fd = open(path, O_PATH|O_CLOEXEC);
if (fd < 0)
return (void) log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno,
"Failed to open TTY inode of '%s' to adjust ownership/access mode, ignoring: %m",
path);
if (fstat(fd, &st) < 0)
return (void) log_warning_errno(errno, "Failed to stat TTY '%s', ignoring: %m", path);
/* Let's add a superficial check that we only do this for stuff that looks like a TTY. We only check
* if things are a character device, since a proper check either means we'd have to open the TTY and
* use isatty(), but we'd rather not do that since opening TTYs comes with all kinds of side-effects
* and is slow. Or we'd have to hardcode dev_t major information, which we'd rather avoid. Why bother
* with this at all? → https://github.com/systemd/systemd/issues/19213 */
if (!S_ISCHR(st.st_mode))
return log_warning("Configured TTY '%s' is not actually a character device, ignoring.", path);
r = fchmod_and_chown(fd, TTY_MODE, 0, TTY_GID);
if (r < 0)
log_warning_errno(r, "Failed to reset TTY ownership/access mode of %s, ignoring: %m", path);
}
int exec_context_get_clean_directories(
ExecContext *c,
char **prefix,
ExecCleanMask mask,
char ***ret) {
_cleanup_strv_free_ char **l = NULL;
int r;
assert(c);
assert(prefix);
assert(ret);
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
if (!FLAGS_SET(mask, 1U << t))
continue;
if (!prefix[t])
continue;
for (size_t i = 0; i < c->directories[t].n_items; i++) {
char *j;
j = path_join(prefix[t], c->directories[t].items[i].path);
if (!j)
return -ENOMEM;
r = strv_consume(&l, j);
if (r < 0)
return r;
/* Also remove private directories unconditionally. */
if (t != EXEC_DIRECTORY_CONFIGURATION) {
j = path_join(prefix[t], "private", c->directories[t].items[i].path);
if (!j)
return -ENOMEM;
r = strv_consume(&l, j);
if (r < 0)
return r;
}
STRV_FOREACH(symlink, c->directories[t].items[i].symlinks) {
j = path_join(prefix[t], *symlink);
if (!j)
return -ENOMEM;
r = strv_consume(&l, j);
if (r < 0)
return r;
}
}
}
*ret = TAKE_PTR(l);
return 0;
}
int exec_context_get_clean_mask(ExecContext *c, ExecCleanMask *ret) {
ExecCleanMask mask = 0;
assert(c);
assert(ret);
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++)
if (c->directories[t].n_items > 0)
mask |= 1U << t;
*ret = mask;
return 0;
}
void exec_status_start(ExecStatus *s, pid_t pid) {
assert(s);
*s = (ExecStatus) {
.pid = pid,
};
dual_timestamp_get(&s->start_timestamp);
}
void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status) {
assert(s);
if (s->pid != pid)
*s = (ExecStatus) {
.pid = pid,
};
dual_timestamp_get(&s->exit_timestamp);
s->code = code;
s->status = status;
if (context && context->utmp_id)
(void) utmp_put_dead_process(context->utmp_id, pid, code, status);
}
void exec_status_reset(ExecStatus *s) {
assert(s);
*s = (ExecStatus) {};
}
void exec_status_dump(const ExecStatus *s, FILE *f, const char *prefix) {
assert(s);
assert(f);
if (s->pid <= 0)
return;
prefix = strempty(prefix);
fprintf(f,
"%sPID: "PID_FMT"\n",
prefix, s->pid);
if (dual_timestamp_is_set(&s->start_timestamp))
fprintf(f,
"%sStart Timestamp: %s\n",
prefix, FORMAT_TIMESTAMP(s->start_timestamp.realtime));
if (dual_timestamp_is_set(&s->exit_timestamp))
fprintf(f,
"%sExit Timestamp: %s\n"
"%sExit Code: %s\n"
"%sExit Status: %i\n",
prefix, FORMAT_TIMESTAMP(s->exit_timestamp.realtime),
prefix, sigchld_code_to_string(s->code),
prefix, s->status);
}
static void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) {
_cleanup_free_ char *cmd = NULL;
const char *prefix2;
assert(c);
assert(f);
prefix = strempty(prefix);
prefix2 = strjoina(prefix, "\t");
cmd = quote_command_line(c->argv, SHELL_ESCAPE_EMPTY);
fprintf(f,
"%sCommand Line: %s\n",
prefix, strnull(cmd));
exec_status_dump(&c->exec_status, f, prefix2);
}
void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
assert(f);
prefix = strempty(prefix);
LIST_FOREACH(command, i, c)
exec_command_dump(i, f, prefix);
}
void exec_command_append_list(ExecCommand **l, ExecCommand *e) {
ExecCommand *end;
assert(l);
assert(e);
if (*l) {
/* It's kind of important, that we keep the order here */
end = LIST_FIND_TAIL(command, *l);
LIST_INSERT_AFTER(command, *l, end, e);
} else
*l = e;
}
int exec_command_set(ExecCommand *c, const char *path, ...) {
va_list ap;
char **l, *p;
assert(c);
assert(path);
va_start(ap, path);
l = strv_new_ap(path, ap);
va_end(ap);
if (!l)
return -ENOMEM;
p = strdup(path);
if (!p) {
strv_free(l);
return -ENOMEM;
}
free_and_replace(c->path, p);
return strv_free_and_replace(c->argv, l);
}
int exec_command_append(ExecCommand *c, const char *path, ...) {
_cleanup_strv_free_ char **l = NULL;
va_list ap;
int r;
assert(c);
assert(path);
va_start(ap, path);
l = strv_new_ap(path, ap);
va_end(ap);
if (!l)
return -ENOMEM;
r = strv_extend_strv(&c->argv, l, false);
if (r < 0)
return r;
return 0;
}
static char *destroy_tree(char *path) {
if (!path)
return NULL;
if (!path_equal(path, RUN_SYSTEMD_EMPTY)) {
log_debug("Spawning process to nuke '%s'", path);
(void) asynchronous_rm_rf(path, REMOVE_ROOT|REMOVE_SUBVOLUME|REMOVE_PHYSICAL);
}
return mfree(path);
}
static ExecSharedRuntime* exec_shared_runtime_free(ExecSharedRuntime *rt) {
if (!rt)
return NULL;
if (rt->manager)
(void) hashmap_remove(rt->manager->exec_shared_runtime_by_id, rt->id);
rt->id = mfree(rt->id);
rt->tmp_dir = mfree(rt->tmp_dir);
rt->var_tmp_dir = mfree(rt->var_tmp_dir);
safe_close_pair(rt->netns_storage_socket);
safe_close_pair(rt->ipcns_storage_socket);
return mfree(rt);
}
DEFINE_TRIVIAL_UNREF_FUNC(ExecSharedRuntime, exec_shared_runtime, exec_shared_runtime_free);
DEFINE_TRIVIAL_CLEANUP_FUNC(ExecSharedRuntime*, exec_shared_runtime_free);
ExecSharedRuntime* exec_shared_runtime_destroy(ExecSharedRuntime *rt) {
if (!rt)
return NULL;
assert(rt->n_ref > 0);
rt->n_ref--;
if (rt->n_ref > 0)
return NULL;
rt->tmp_dir = destroy_tree(rt->tmp_dir);
rt->var_tmp_dir = destroy_tree(rt->var_tmp_dir);
return exec_shared_runtime_free(rt);
}
static int exec_shared_runtime_allocate(ExecSharedRuntime **ret, const char *id) {
_cleanup_free_ char *id_copy = NULL;
ExecSharedRuntime *n;
assert(ret);
id_copy = strdup(id);
if (!id_copy)
return -ENOMEM;
n = new(ExecSharedRuntime, 1);
if (!n)
return -ENOMEM;
*n = (ExecSharedRuntime) {
.id = TAKE_PTR(id_copy),
.netns_storage_socket = PIPE_EBADF,
.ipcns_storage_socket = PIPE_EBADF,
};
*ret = n;
return 0;
}
static int exec_shared_runtime_add(
Manager *m,
const char *id,
char **tmp_dir,
char **var_tmp_dir,
int netns_storage_socket[2],
int ipcns_storage_socket[2],
ExecSharedRuntime **ret) {
_cleanup_(exec_shared_runtime_freep) ExecSharedRuntime *rt = NULL;
int r;
assert(m);
assert(id);
/* tmp_dir, var_tmp_dir, {net,ipc}ns_storage_socket fds are donated on success */
r = exec_shared_runtime_allocate(&rt, id);
if (r < 0)
return r;
r = hashmap_ensure_put(&m->exec_shared_runtime_by_id, &string_hash_ops, rt->id, rt);
if (r < 0)
return r;
assert(!!rt->tmp_dir == !!rt->var_tmp_dir); /* We require both to be set together */
rt->tmp_dir = TAKE_PTR(*tmp_dir);
rt->var_tmp_dir = TAKE_PTR(*var_tmp_dir);
if (netns_storage_socket) {
rt->netns_storage_socket[0] = TAKE_FD(netns_storage_socket[0]);
rt->netns_storage_socket[1] = TAKE_FD(netns_storage_socket[1]);
}
if (ipcns_storage_socket) {
rt->ipcns_storage_socket[0] = TAKE_FD(ipcns_storage_socket[0]);
rt->ipcns_storage_socket[1] = TAKE_FD(ipcns_storage_socket[1]);
}
rt->manager = m;
if (ret)
*ret = rt;
/* do not remove created ExecSharedRuntime object when the operation succeeds. */
TAKE_PTR(rt);
return 0;
}
static int exec_shared_runtime_make(
Manager *m,
const ExecContext *c,
const char *id,
ExecSharedRuntime **ret) {
_cleanup_(namespace_cleanup_tmpdirp) char *tmp_dir = NULL, *var_tmp_dir = NULL;
_cleanup_close_pair_ int netns_storage_socket[2] = PIPE_EBADF, ipcns_storage_socket[2] = PIPE_EBADF;
int r;
assert(m);
assert(c);
assert(id);
/* It is not necessary to create ExecSharedRuntime object. */
if (!exec_needs_network_namespace(c) && !exec_needs_ipc_namespace(c) && !c->private_tmp) {
*ret = NULL;
return 0;
}
if (c->private_tmp &&
!(prefixed_path_strv_contains(c->inaccessible_paths, "/tmp") &&
(prefixed_path_strv_contains(c->inaccessible_paths, "/var/tmp") ||
prefixed_path_strv_contains(c->inaccessible_paths, "/var")))) {
r = setup_tmp_dirs(id, &tmp_dir, &var_tmp_dir);
if (r < 0)
return r;
}
if (exec_needs_network_namespace(c)) {
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, netns_storage_socket) < 0)
return -errno;
}
if (exec_needs_ipc_namespace(c)) {
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, ipcns_storage_socket) < 0)
return -errno;
}
r = exec_shared_runtime_add(m, id, &tmp_dir, &var_tmp_dir, netns_storage_socket, ipcns_storage_socket, ret);
if (r < 0)
return r;
return 1;
}
int exec_shared_runtime_acquire(Manager *m, const ExecContext *c, const char *id, bool create, ExecSharedRuntime **ret) {
ExecSharedRuntime *rt;
int r;
assert(m);
assert(id);
assert(ret);
rt = hashmap_get(m->exec_shared_runtime_by_id, id);
if (rt)
/* We already have an ExecSharedRuntime object, let's increase the ref count and reuse it */
goto ref;
if (!create) {
*ret = NULL;
return 0;
}
/* If not found, then create a new object. */
r = exec_shared_runtime_make(m, c, id, &rt);
if (r < 0)
return r;
if (r == 0) {
/* When r == 0, it is not necessary to create ExecSharedRuntime object. */
*ret = NULL;
return 0;
}
ref:
/* increment reference counter. */
rt->n_ref++;
*ret = rt;
return 1;
}
int exec_shared_runtime_serialize(const Manager *m, FILE *f, FDSet *fds) {
ExecSharedRuntime *rt;
assert(m);
assert(f);
assert(fds);
HASHMAP_FOREACH(rt, m->exec_shared_runtime_by_id) {
fprintf(f, "exec-runtime=%s", rt->id);
if (rt->tmp_dir)
fprintf(f, " tmp-dir=%s", rt->tmp_dir);
if (rt->var_tmp_dir)
fprintf(f, " var-tmp-dir=%s", rt->var_tmp_dir);
if (rt->netns_storage_socket[0] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->netns_storage_socket[0]);
if (copy < 0)
return copy;
fprintf(f, " netns-socket-0=%i", copy);
}
if (rt->netns_storage_socket[1] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->netns_storage_socket[1]);
if (copy < 0)
return copy;
fprintf(f, " netns-socket-1=%i", copy);
}
if (rt->ipcns_storage_socket[0] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->ipcns_storage_socket[0]);
if (copy < 0)
return copy;
fprintf(f, " ipcns-socket-0=%i", copy);
}
if (rt->ipcns_storage_socket[1] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->ipcns_storage_socket[1]);
if (copy < 0)
return copy;
fprintf(f, " ipcns-socket-1=%i", copy);
}
fputc('\n', f);
}
return 0;
}
int exec_shared_runtime_deserialize_compat(Unit *u, const char *key, const char *value, FDSet *fds) {
_cleanup_(exec_shared_runtime_freep) ExecSharedRuntime *rt_create = NULL;
ExecSharedRuntime *rt;
int r;
/* This is for the migration from old (v237 or earlier) deserialization text.
* Due to the bug #7790, this may not work with the units that use JoinsNamespaceOf=.
* Even if the ExecSharedRuntime object originally created by the other unit, we cannot judge
* so or not from the serialized text, then we always creates a new object owned by this. */
assert(u);
assert(key);
assert(value);
/* Manager manages ExecSharedRuntime objects by the unit id.
* So, we omit the serialized text when the unit does not have id (yet?)... */
if (isempty(u->id)) {
log_unit_debug(u, "Invocation ID not found. Dropping runtime parameter.");
return 0;
}
if (hashmap_ensure_allocated(&u->manager->exec_shared_runtime_by_id, &string_hash_ops) < 0)
return log_oom();
rt = hashmap_get(u->manager->exec_shared_runtime_by_id, u->id);
if (!rt) {
if (exec_shared_runtime_allocate(&rt_create, u->id) < 0)
return log_oom();
rt = rt_create;
}
if (streq(key, "tmp-dir")) {
if (free_and_strdup_warn(&rt->tmp_dir, value) < 0)
return -ENOMEM;
} else if (streq(key, "var-tmp-dir")) {
if (free_and_strdup_warn(&rt->var_tmp_dir, value) < 0)
return -ENOMEM;
} else if (streq(key, "netns-socket-0")) {
int fd;
if ((fd = parse_fd(value)) < 0 || !fdset_contains(fds, fd)) {
log_unit_debug(u, "Failed to parse netns socket value: %s", value);
return 0;
}
safe_close(rt->netns_storage_socket[0]);
rt->netns_storage_socket[0] = fdset_remove(fds, fd);
} else if (streq(key, "netns-socket-1")) {
int fd;
if ((fd = parse_fd(value)) < 0 || !fdset_contains(fds, fd)) {
log_unit_debug(u, "Failed to parse netns socket value: %s", value);
return 0;
}
safe_close(rt->netns_storage_socket[1]);
rt->netns_storage_socket[1] = fdset_remove(fds, fd);
} else
return 0;
/* If the object is newly created, then put it to the hashmap which manages ExecSharedRuntime objects. */
if (rt_create) {
r = hashmap_put(u->manager->exec_shared_runtime_by_id, rt_create->id, rt_create);
if (r < 0) {
log_unit_debug_errno(u, r, "Failed to put runtime parameter to manager's storage: %m");
return 0;
}
rt_create->manager = u->manager;
/* Avoid cleanup */
TAKE_PTR(rt_create);
}
return 1;
}
int exec_shared_runtime_deserialize_one(Manager *m, const char *value, FDSet *fds) {
_cleanup_free_ char *tmp_dir = NULL, *var_tmp_dir = NULL;
char *id = NULL;
int r, netns_fdpair[] = {-1, -1}, ipcns_fdpair[] = {-1, -1};
const char *p, *v = ASSERT_PTR(value);
size_t n;
assert(m);
assert(fds);
n = strcspn(v, " ");
id = strndupa_safe(v, n);
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
v = startswith(p, "tmp-dir=");
if (v) {
n = strcspn(v, " ");
tmp_dir = strndup(v, n);
if (!tmp_dir)
return log_oom();
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
}
v = startswith(p, "var-tmp-dir=");
if (v) {
n = strcspn(v, " ");
var_tmp_dir = strndup(v, n);
if (!var_tmp_dir)
return log_oom();
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
}
v = startswith(p, "netns-socket-0=");
if (v) {
char *buf;
n = strcspn(v, " ");
buf = strndupa_safe(v, n);
netns_fdpair[0] = parse_fd(buf);
if (netns_fdpair[0] < 0)
return log_debug_errno(netns_fdpair[0], "Unable to parse exec-runtime specification netns-socket-0=%s: %m", buf);
if (!fdset_contains(fds, netns_fdpair[0]))
return log_debug_errno(SYNTHETIC_ERRNO(EBADF),
"exec-runtime specification netns-socket-0= refers to unknown fd %d: %m", netns_fdpair[0]);
netns_fdpair[0] = fdset_remove(fds, netns_fdpair[0]);
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
}
v = startswith(p, "netns-socket-1=");
if (v) {
char *buf;
n = strcspn(v, " ");
buf = strndupa_safe(v, n);
netns_fdpair[1] = parse_fd(buf);
if (netns_fdpair[1] < 0)
return log_debug_errno(netns_fdpair[1], "Unable to parse exec-runtime specification netns-socket-1=%s: %m", buf);
if (!fdset_contains(fds, netns_fdpair[1]))
return log_debug_errno(SYNTHETIC_ERRNO(EBADF),
"exec-runtime specification netns-socket-1= refers to unknown fd %d: %m", netns_fdpair[1]);
netns_fdpair[1] = fdset_remove(fds, netns_fdpair[1]);
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
}
v = startswith(p, "ipcns-socket-0=");
if (v) {
char *buf;
n = strcspn(v, " ");
buf = strndupa_safe(v, n);
ipcns_fdpair[0] = parse_fd(buf);
if (ipcns_fdpair[0] < 0)
return log_debug_errno(ipcns_fdpair[0], "Unable to parse exec-runtime specification ipcns-socket-0=%s: %m", buf);
if (!fdset_contains(fds, ipcns_fdpair[0]))
return log_debug_errno(SYNTHETIC_ERRNO(EBADF),
"exec-runtime specification ipcns-socket-0= refers to unknown fd %d: %m", ipcns_fdpair[0]);
ipcns_fdpair[0] = fdset_remove(fds, ipcns_fdpair[0]);
if (v[n] != ' ')
goto finalize;
p = v + n + 1;
}
v = startswith(p, "ipcns-socket-1=");
if (v) {
char *buf;
n = strcspn(v, " ");
buf = strndupa_safe(v, n);
ipcns_fdpair[1] = parse_fd(buf);
if (ipcns_fdpair[1] < 0)
return log_debug_errno(ipcns_fdpair[1], "Unable to parse exec-runtime specification ipcns-socket-1=%s: %m", buf);
if (!fdset_contains(fds, ipcns_fdpair[1]))
return log_debug_errno(SYNTHETIC_ERRNO(EBADF),
"exec-runtime specification ipcns-socket-1= refers to unknown fd %d: %m", ipcns_fdpair[1]);
ipcns_fdpair[1] = fdset_remove(fds, ipcns_fdpair[1]);
}
finalize:
r = exec_shared_runtime_add(m, id, &tmp_dir, &var_tmp_dir, netns_fdpair, ipcns_fdpair, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to add exec-runtime: %m");
return 0;
}
void exec_shared_runtime_vacuum(Manager *m) {
ExecSharedRuntime *rt;
assert(m);
/* Free unreferenced ExecSharedRuntime objects. This is used after manager deserialization process. */
HASHMAP_FOREACH(rt, m->exec_shared_runtime_by_id) {
if (rt->n_ref > 0)
continue;
(void) exec_shared_runtime_free(rt);
}
}
int exec_runtime_make(
const Unit *unit,
const ExecContext *context,
ExecSharedRuntime *shared,
DynamicCreds *creds,
ExecRuntime **ret) {
_cleanup_close_pair_ int ephemeral_storage_socket[2] = PIPE_EBADF;
_cleanup_free_ char *ephemeral = NULL;
_cleanup_(exec_runtime_freep) ExecRuntime *rt = NULL;
int r;
assert(unit);
assert(context);
assert(ret);
if (!shared && !creds && !exec_needs_ephemeral(context)) {
*ret = NULL;
return 0;
}
if (exec_needs_ephemeral(context)) {
r = mkdir_p("/var/lib/systemd/ephemeral-trees", 0755);
if (r < 0)
return r;
r = tempfn_random_child("/var/lib/systemd/ephemeral-trees", unit->id, &ephemeral);
if (r < 0)
return r;
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, ephemeral_storage_socket) < 0)
return -errno;
}
rt = new(ExecRuntime, 1);
if (!rt)
return -ENOMEM;
*rt = (ExecRuntime) {
.shared = shared,
.dynamic_creds = creds,
.ephemeral_copy = TAKE_PTR(ephemeral),
.ephemeral_storage_socket[0] = TAKE_FD(ephemeral_storage_socket[0]),
.ephemeral_storage_socket[1] = TAKE_FD(ephemeral_storage_socket[1]),
};
*ret = TAKE_PTR(rt);
return 1;
}
ExecRuntime* exec_runtime_free(ExecRuntime *rt) {
if (!rt)
return NULL;
exec_shared_runtime_unref(rt->shared);
dynamic_creds_unref(rt->dynamic_creds);
rt->ephemeral_copy = destroy_tree(rt->ephemeral_copy);
safe_close_pair(rt->ephemeral_storage_socket);
return mfree(rt);
}
ExecRuntime* exec_runtime_destroy(ExecRuntime *rt) {
if (!rt)
return NULL;
rt->shared = exec_shared_runtime_destroy(rt->shared);
rt->dynamic_creds = dynamic_creds_destroy(rt->dynamic_creds);
return exec_runtime_free(rt);
}
void exec_params_clear(ExecParameters *p) {
if (!p)
return;
p->environment = strv_free(p->environment);
p->fd_names = strv_free(p->fd_names);
p->fds = mfree(p->fds);
p->exec_fd = safe_close(p->exec_fd);
}
void exec_directory_done(ExecDirectory *d) {
if (!d)
return;
for (size_t i = 0; i < d->n_items; i++) {
free(d->items[i].path);
strv_free(d->items[i].symlinks);
}
d->items = mfree(d->items);
d->n_items = 0;
d->mode = 0755;
}
static ExecDirectoryItem *exec_directory_find(ExecDirectory *d, const char *path) {
assert(d);
assert(path);
for (size_t i = 0; i < d->n_items; i++)
if (path_equal(d->items[i].path, path))
return &d->items[i];
return NULL;
}
int exec_directory_add(ExecDirectory *d, const char *path, const char *symlink) {
_cleanup_strv_free_ char **s = NULL;
_cleanup_free_ char *p = NULL;
ExecDirectoryItem *existing;
int r;
assert(d);
assert(path);
existing = exec_directory_find(d, path);
if (existing) {
r = strv_extend(&existing->symlinks, symlink);
if (r < 0)
return r;
return 0; /* existing item is updated */
}
p = strdup(path);
if (!p)
return -ENOMEM;
if (symlink) {
s = strv_new(symlink);
if (!s)
return -ENOMEM;
}
if (!GREEDY_REALLOC(d->items, d->n_items + 1))
return -ENOMEM;
d->items[d->n_items++] = (ExecDirectoryItem) {
.path = TAKE_PTR(p),
.symlinks = TAKE_PTR(s),
};
return 1; /* new item is added */
}
static int exec_directory_item_compare_func(const ExecDirectoryItem *a, const ExecDirectoryItem *b) {
assert(a);
assert(b);
return path_compare(a->path, b->path);
}
void exec_directory_sort(ExecDirectory *d) {
assert(d);
/* Sort the exec directories to make always parent directories processed at first in
* setup_exec_directory(), e.g., even if StateDirectory=foo/bar foo, we need to create foo at first,
* then foo/bar. Also, set .only_create flag if one of the parent directories is contained in the
* list. See also comments in setup_exec_directory() and issue #24783. */
if (d->n_items <= 1)
return;
typesafe_qsort(d->items, d->n_items, exec_directory_item_compare_func);
for (size_t i = 1; i < d->n_items; i++)
for (size_t j = 0; j < i; j++)
if (path_startswith(d->items[i].path, d->items[j].path)) {
d->items[i].only_create = true;
break;
}
}
ExecCleanMask exec_clean_mask_from_string(const char *s) {
ExecDirectoryType t;
assert(s);
if (streq(s, "all"))
return EXEC_CLEAN_ALL;
if (streq(s, "fdstore"))
return EXEC_CLEAN_FDSTORE;
t = exec_resource_type_from_string(s);
if (t < 0)
return (ExecCleanMask) t;
return 1U << t;
}
static const char* const exec_input_table[_EXEC_INPUT_MAX] = {
[EXEC_INPUT_NULL] = "null",
[EXEC_INPUT_TTY] = "tty",
[EXEC_INPUT_TTY_FORCE] = "tty-force",
[EXEC_INPUT_TTY_FAIL] = "tty-fail",
[EXEC_INPUT_SOCKET] = "socket",
[EXEC_INPUT_NAMED_FD] = "fd",
[EXEC_INPUT_DATA] = "data",
[EXEC_INPUT_FILE] = "file",
};
DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);
static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
[EXEC_OUTPUT_INHERIT] = "inherit",
[EXEC_OUTPUT_NULL] = "null",
[EXEC_OUTPUT_TTY] = "tty",
[EXEC_OUTPUT_KMSG] = "kmsg",
[EXEC_OUTPUT_KMSG_AND_CONSOLE] = "kmsg+console",
[EXEC_OUTPUT_JOURNAL] = "journal",
[EXEC_OUTPUT_JOURNAL_AND_CONSOLE] = "journal+console",
[EXEC_OUTPUT_SOCKET] = "socket",
[EXEC_OUTPUT_NAMED_FD] = "fd",
[EXEC_OUTPUT_FILE] = "file",
[EXEC_OUTPUT_FILE_APPEND] = "append",
[EXEC_OUTPUT_FILE_TRUNCATE] = "truncate",
};
DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
static const char* const exec_utmp_mode_table[_EXEC_UTMP_MODE_MAX] = {
[EXEC_UTMP_INIT] = "init",
[EXEC_UTMP_LOGIN] = "login",
[EXEC_UTMP_USER] = "user",
};
DEFINE_STRING_TABLE_LOOKUP(exec_utmp_mode, ExecUtmpMode);
static const char* const exec_preserve_mode_table[_EXEC_PRESERVE_MODE_MAX] = {
[EXEC_PRESERVE_NO] = "no",
[EXEC_PRESERVE_YES] = "yes",
[EXEC_PRESERVE_RESTART] = "restart",
};
DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(exec_preserve_mode, ExecPreserveMode, EXEC_PRESERVE_YES);
/* This table maps ExecDirectoryType to the setting it is configured with in the unit */
static const char* const exec_directory_type_table[_EXEC_DIRECTORY_TYPE_MAX] = {
[EXEC_DIRECTORY_RUNTIME] = "RuntimeDirectory",
[EXEC_DIRECTORY_STATE] = "StateDirectory",
[EXEC_DIRECTORY_CACHE] = "CacheDirectory",
[EXEC_DIRECTORY_LOGS] = "LogsDirectory",
[EXEC_DIRECTORY_CONFIGURATION] = "ConfigurationDirectory",
};
DEFINE_STRING_TABLE_LOOKUP(exec_directory_type, ExecDirectoryType);
/* This table maps ExecDirectoryType to the symlink setting it is configured with in the unit */
static const char* const exec_directory_type_symlink_table[_EXEC_DIRECTORY_TYPE_MAX] = {
[EXEC_DIRECTORY_RUNTIME] = "RuntimeDirectorySymlink",
[EXEC_DIRECTORY_STATE] = "StateDirectorySymlink",
[EXEC_DIRECTORY_CACHE] = "CacheDirectorySymlink",
[EXEC_DIRECTORY_LOGS] = "LogsDirectorySymlink",
[EXEC_DIRECTORY_CONFIGURATION] = "ConfigurationDirectorySymlink",
};
DEFINE_STRING_TABLE_LOOKUP(exec_directory_type_symlink, ExecDirectoryType);
/* And this table maps ExecDirectoryType too, but to a generic term identifying the type of resource. This
* one is supposed to be generic enough to be used for unit types that don't use ExecContext and per-unit
* directories, specifically .timer units with their timestamp touch file. */
static const char* const exec_resource_type_table[_EXEC_DIRECTORY_TYPE_MAX] = {
[EXEC_DIRECTORY_RUNTIME] = "runtime",
[EXEC_DIRECTORY_STATE] = "state",
[EXEC_DIRECTORY_CACHE] = "cache",
[EXEC_DIRECTORY_LOGS] = "logs",
[EXEC_DIRECTORY_CONFIGURATION] = "configuration",
};
DEFINE_STRING_TABLE_LOOKUP(exec_resource_type, ExecDirectoryType);
/* And this table also maps ExecDirectoryType, to the environment variable we pass the selected directory to
* the service payload in. */
static const char* const exec_directory_env_name_table[_EXEC_DIRECTORY_TYPE_MAX] = {
[EXEC_DIRECTORY_RUNTIME] = "RUNTIME_DIRECTORY",
[EXEC_DIRECTORY_STATE] = "STATE_DIRECTORY",
[EXEC_DIRECTORY_CACHE] = "CACHE_DIRECTORY",
[EXEC_DIRECTORY_LOGS] = "LOGS_DIRECTORY",
[EXEC_DIRECTORY_CONFIGURATION] = "CONFIGURATION_DIRECTORY",
};
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(exec_directory_env_name, ExecDirectoryType);
static const char* const exec_keyring_mode_table[_EXEC_KEYRING_MODE_MAX] = {
[EXEC_KEYRING_INHERIT] = "inherit",
[EXEC_KEYRING_PRIVATE] = "private",
[EXEC_KEYRING_SHARED] = "shared",
};
DEFINE_STRING_TABLE_LOOKUP(exec_keyring_mode, ExecKeyringMode);
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