Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.
As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.
Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Commit 1fde6f21d9 ("proc: fix /proc/net/* after setns(2)") only forced
revalidation of regular files under /proc/net/
However, /proc/net/ is unusual in the sense of /proc/net/foo handlers
take netns pointer from parent directory which is old netns.
Steps to reproduce:
(void)open("/proc/net/sctp/snmp", O_RDONLY);
unshare(CLONE_NEWNET);
int fd = open("/proc/net/sctp/snmp", O_RDONLY);
read(fd, &c, 1);
Read will read wrong data from original netns.
Patch forces lookup on every directory under /proc/net .
Link: https://lkml.kernel.org/r/20201205160916.GA109739@localhost.localdomain
Fixes: 1da4d377f9 ("proc: revalidate misc dentries")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: "Rantala, Tommi T. (Nokia - FI/Espoo)" <tommi.t.rantala@nokia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement ->read_iter for all proc "single files" so that more bionic
tests cases can pass when they call splice() on other fun files like
/proc/version
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kmemleak reported some memory leak on reading proc files. After adding
some debug lines, find that proc_seq_fops is using seq_release as
release handler, which won't handle the free of 'private' field of
seq_file, while in fact the open handler proc_seq_open could create
the private data with __seq_open_private when state_size is greater
than zero. So after reading files created with proc_create_seq_private,
such as /proc/timer_list and /proc/vmallocinfo, the private mem of a
seq_file is not freed. Fix it by adding the paired proc_seq_release
as the default release handler of proc_seq_ops instead of seq_release.
Fixes: 44414d82cf ("proc: introduce proc_create_seq_private")
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull AFS updates from Al Viro:
"Assorted AFS stuff - ended up in vfs.git since most of that consists
of David's AFS-related followups to Christoph's procfs series"
* 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
afs: Optimise callback breaking by not repeating volume lookup
afs: Display manually added cells in dynamic root mount
afs: Enable IPv6 DNS lookups
afs: Show all of a server's addresses in /proc/fs/afs/servers
afs: Handle CONFIG_PROC_FS=n
proc: Make inline name size calculation automatic
afs: Implement network namespacing
afs: Mark afs_net::ws_cell as __rcu and set using rcu functions
afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus()
proc: Add a way to make network proc files writable
afs: Rearrange fs/afs/proc.c to remove remaining predeclarations.
afs: Rearrange fs/afs/proc.c to move the show routines up
afs: Rearrange fs/afs/proc.c by moving fops and open functions down
afs: Move /proc management functions to the end of the file
Make calculation of the size of the inline name in struct proc_dir_entry
automatic, rather than having to manually encode the numbers and failing to
allow for lockdep.
Require a minimum inline name size of 33+1 to allow for names that look
like two hex numbers with a dash between.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull dcache lookup cleanups from Al Viro:
"Cleaning ->lookup() instances up - mostly d_splice_alias() conversions"
* 'work.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (29 commits)
switch the rest of procfs lookups to d_splice_alias()
procfs: switch instantiate_t to d_splice_alias()
don't bother with tid_fd_revalidate() in lookups
proc_lookupfd_common(): don't bother with instantiate unless the file is open
procfs: get rid of ancient BS in pid_revalidate() uses
cifs_lookup(): switch to d_splice_alias()
cifs_lookup(): cifs_get_inode_...() never returns 0 with *inode left NULL
9p: unify paths in v9fs_vfs_lookup()
ncp_lookup(): use d_splice_alias()
hfsplus: switch to d_splice_alias()
hfs: don't allow mounting over .../rsrc
hfs: use d_splice_alias()
omfs_lookup(): report IO errors, use d_splice_alias()
orangefs_lookup: simplify
openpromfs: switch to d_splice_alias()
xfs_vn_lookup: simplify a bit
adfs_lookup: do not fail with ENOENT on negatives, use d_splice_alias()
adfs_lookup_byname: .. *is* taken care of in fs/namei.c
romfs_lookup: switch to d_splice_alias()
qnx6_lookup: switch to d_splice_alias()
...
Provide two extra functions, proc_create_net_data_write() and
proc_create_net_single_write() that act like their non-write versions but
also set a write method in the proc_dir_entry struct.
An internal simple write function is provided that will copy its buffer and
hand it to the pde->write() method if available (or give an error if not).
The buffer may be modified by the write method.
Signed-off-by: David Howells <dhowells@redhat.com>
Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Variant of proc_create_data that directly take a struct seq_operations
argument + a private state size and drastically reduces the boilerplate
code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
