The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
NETFILTER_CFG record generation was inconsistent for x_tables and
ebtables configuration changes. The call was needlessly messy and there
were supporting records missing at times while they were produced when
not requested. Simplify the logging call into a new audit_log_nfcfg
call. Honour the audit_enabled setting while more consistently
recording information including supporting records by tidying up dummy
checks.
Add an op= field that indicates the operation being performed (register
or replace).
Here is the enhanced sample record:
type=NETFILTER_CFG msg=audit(1580905834.919:82970): table=filter family=2 entries=83 op=replace
Generate audit NETFILTER_CFG records on ebtables table registration.
Previously this was being done for x_tables registration and replacement
operations and ebtables table replacement only.
See: https://github.com/linux-audit/audit-kernel/issues/25
See: https://github.com/linux-audit/audit-kernel/issues/35
See: https://github.com/linux-audit/audit-kernel/issues/43
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This renames the very specific audit_log_link_denied() to
audit_log_path_denied() and adds the AUDIT_* type as an argument. This
allows for the creation of the new AUDIT_ANOM_CREAT that can be used to
report the fifo/regular file creation restrictions that were introduced
in commit 30aba6656f ("namei: allow restricted O_CREAT of FIFOs and
regular files").
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The former has no users left; the latter was only to get LOOKUP_...
values to remapper in audit_inode() and that's an ex-parrot now.
All places that use symbols from namei.h include it either directly
or (in a few cases) via a local header, like fs/autofs/autofs_i.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
don't bother with remapping LOOKUP_... values - all callers pass
constants and we can just as well pass the right ones from the
very beginning.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull audit updates from Paul Moore:
"This pull request is a bit early, but with some vacation time coming
up I wanted to send this out now just in case the remote Internet Gods
decide not to smile on me once the merge window opens. The patchset
for v5.3 is pretty minor this time, the highlights include:
- When the audit daemon is sent a signal, ensure we deliver
information about the sender even when syscall auditing is not
enabled/supported.
- Add the ability to filter audit records based on network address
family.
- Tighten the audit field filtering restrictions on string based
fields.
- Cleanup the audit field filtering verification code.
- Remove a few BUG() calls from the audit code"
* tag 'audit-pr-20190702' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: remove the BUG() calls in the audit rule comparison functions
audit: enforce op for string fields
audit: add saddr_fam filter field
audit: re-structure audit field valid checks
audit: deliver signal_info regarless of syscall
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1334 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a process signals the audit daemon (shutdown, rotate, resume,
reconfig) but syscall auditing is not enabled, we still want to know the
identity of the process sending the signal to the audit daemon.
Move audit_signal_info() out of syscall auditing to general auditing but
create a new function audit_signal_info_syscall() to take care of the
syscall dependent parts for when syscall auditing is enabled.
Please see the github kernel audit issue
https://github.com/linux-audit/audit-kernel/issues/111
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Emit an audit record every time selected NTP parameters are modified
from userspace (via adjtimex(2) or clock_adjtime(2)). These parameters
may be used to indirectly change system clock, and thus their
modifications should be audited.
Such events will now generate records of type AUDIT_TIME_ADJNTPVAL
containing the following fields:
- op -- which value was adjusted:
- offset -- corresponding to the time_offset variable
- freq -- corresponding to the time_freq variable
- status -- corresponding to the time_status variable
- adjust -- corresponding to the time_adjust variable
- tick -- corresponding to the tick_usec variable
- tai -- corresponding to the timekeeping's TAI offset
- old -- the old value
- new -- the new value
Example records:
type=TIME_ADJNTPVAL msg=audit(1530616044.507:7): op=status old=64 new=8256
type=TIME_ADJNTPVAL msg=audit(1530616044.511:11): op=freq old=0 new=49180377088000
The records of this type will be associated with the corresponding
syscall records.
An overview of parameter changes that can be done via do_adjtimex()
(based on information from Miroslav Lichvar) and whether they are
audited:
__timekeeping_set_tai_offset() -- sets the offset from the
International Atomic Time
(AUDITED)
NTP variables:
time_offset -- can adjust the clock by up to 0.5 seconds per call
and also speed it up or slow down by up to about
0.05% (43 seconds per day) (AUDITED)
time_freq -- can speed up or slow down by up to about 0.05%
(AUDITED)
time_status -- can insert/delete leap seconds and it also enables/
disables synchronization of the hardware real-time
clock (AUDITED)
time_maxerror, time_esterror -- change error estimates used to
inform userspace applications
(NOT AUDITED)
time_constant -- controls the speed of the clock adjustments that
are made when time_offset is set (NOT AUDITED)
time_adjust -- can temporarily speed up or slow down the clock by up
to 0.05% (AUDITED)
tick_usec -- a more extreme version of time_freq; can speed up or
slow down the clock by up to 10% (AUDITED)
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Emit an audit record whenever the system clock is changed (i.e. shifted
by a non-zero offset) by a syscall from userspace. The syscalls than can
(at the time of writing) trigger such record are:
- settimeofday(2), stime(2), clock_settime(2) -- via
do_settimeofday64()
- adjtimex(2), clock_adjtime(2) -- via do_adjtimex()
The new records have type AUDIT_TIME_INJOFFSET and contain the following
fields:
- sec -- the 'seconds' part of the offset
- nsec -- the 'nanoseconds' part of the offset
Example record (time was shifted backwards by ~15.875 seconds):
type=TIME_INJOFFSET msg=audit(1530616049.652:13): sec=-16 nsec=124887145
The records of this type will be associated with the corresponding
syscall records.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
[PM: fixed a line width problem in __audit_tk_injoffset()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
auditsc_get_stamp() and audit_serial() are internal audit functions so
move their prototypes from include/linux/audit.h to kernel/audit.h
so they are not visible to the rest of the kernel.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Don't fetch fcaps when umount2 is called to avoid a process hang while
it waits for the missing resource to (possibly never) re-appear.
Note the comment above user_path_mountpoint_at():
* A umount is a special case for path walking. We're not actually interested
* in the inode in this situation, and ESTALE errors can be a problem. We
* simply want track down the dentry and vfsmount attached at the mountpoint
* and avoid revalidating the last component.
This can happen on ceph, cifs, 9p, lustre, fuse (gluster) or NFS.
Please see the github issue tracker
https://github.com/linux-audit/audit-kernel/issues/100
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in audit_log_fcaps()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
loginuid and sessionid (and audit_log_session_info) should be part of
CONFIG_AUDIT scope and not CONFIG_AUDITSYSCALL since it is used in
CONFIG_CHANGE, ANOM_LINK, FEATURE_CHANGE (and INTEGRITY_RULE), none of
which are otherwise dependent on AUDITSYSCALL.
Please see github issue
https://github.com/linux-audit/audit-kernel/issues/104
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: tweaked subject line for better grep'ing]
Signed-off-by: Paul Moore <paul@paul-moore.com>
There are many places, notably audit_log_task_info() and
audit_log_exit(), that take task_struct pointers but in reality they
are always working on the current task. This patch eliminates the
task_struct arguments and uses current directly which allows a number
of cleanups as well.
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The audit_log_session_info() function is only used in kernel/audit*, so
move its prototype to kernel/audit.h
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Recognizing that the audit context is an internal audit value, use an
access function to set the audit context pointer for the task
rather than reaching directly into the task struct to set it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in audit.h]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Recognizing that the audit context is an internal audit value, use an
access function to retrieve the audit context pointer for the task
rather than reaching directly into the task struct to get it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in auditsc.c and selinuxfs.c, checkpatch.pl fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use a macro, "AUDIT_SID_UNSET", to replace each instance of
initialization and comparison to an audit session ID.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Seccomp logging for "handled" actions such as RET_TRAP, RET_TRACE, or
RET_ERRNO can be very noisy for processes that are being audited. This
patch modifies the seccomp logging behavior to treat processes that are
being inspected via the audit subsystem the same as processes that
aren't under inspection. Handled actions will no longer be logged just
because the process is being inspected. Since v4.14, applications have
the ability to request logging of handled actions by using the
SECCOMP_FILTER_FLAG_LOG flag when loading seccomp filters.
With this patch, the logic for deciding if an action will be logged is:
if action == RET_ALLOW:
do not log
else if action not in actions_logged:
do not log
else if action == RET_KILL:
log
else if action == RET_LOG:
log
else if filter-requests-logging:
log
else:
do not log
Reported-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The decision to log a seccomp action will always be subject to the
value of the kernel.seccomp.actions_logged sysctl, even for processes
that are being inspected via the audit subsystem, in an upcoming patch.
Therefore, we need to emit an audit record on attempts at writing to the
actions_logged sysctl when auditing is enabled.
This patch updates the write handler for the actions_logged sysctl to
emit an audit record on attempts to write to the sysctl. Successful
writes to the sysctl will result in a record that includes a normalized
list of logged actions in the "actions" field and a "res" field equal to
1. Unsuccessful writes to the sysctl will result in a record that
doesn't include the "actions" field and has a "res" field equal to 0.
Not all unsuccessful writes to the sysctl are audited. For example, an
audit record will not be emitted if an unprivileged process attempts to
open the sysctl file for reading since that access control check is not
part of the sysctl's write handler.
Below are some example audit records when writing various strings to the
actions_logged sysctl.
Writing "not-a-real-action", when the kernel.seccomp.actions_logged
sysctl previously was "kill_process kill_thread trap errno trace log",
emits this audit record:
type=CONFIG_CHANGE msg=audit(1525392371.454:120): op=seccomp-logging
actions=? old-actions=kill_process,kill_thread,trap,errno,trace,log
res=0
If you then write "kill_process kill_thread errno trace log", this audit
record is emitted:
type=CONFIG_CHANGE msg=audit(1525392401.645:126): op=seccomp-logging
actions=kill_process,kill_thread,errno,trace,log
old-actions=kill_process,kill_thread,trap,errno,trace,log res=1
If you then write "log log errno trace kill_process kill_thread", which
is unordered and contains the log action twice, it results in the same
actions value as the previous record:
type=CONFIG_CHANGE msg=audit(1525392436.354:132): op=seccomp-logging
actions=kill_process,kill_thread,errno,trace,log
old-actions=kill_process,kill_thread,errno,trace,log res=1
If you then write an empty string to the sysctl, this audit record is
emitted:
type=CONFIG_CHANGE msg=audit(1525392494.413:138): op=seccomp-logging
actions=(none) old-actions=kill_process,kill_thread,errno,trace,log
res=1
No audit records are generated when reading the actions_logged sysctl.
Suggested-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In commit 45b578fe4c
("audit: link denied should not directly generate PATH record")
the need for the struct path *link parameter was removed.
Remove the now useless struct path argument.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"Another relatively small pull request for audit, nine patches total.
The only real new bit of functionality is the patch from Richard which
adds the ability to filter records based on the filesystem type.
The remainder are bug fixes and cleanups; the bug fix highlights
include:
- ensuring that we properly audit init/PID-1 (me)
- allowing the audit daemon to shutdown the kernel/auditd connection
cleanly by setting the audit PID to zero (Steve)"
* tag 'audit-pr-20171113' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: filter PATH records keyed on filesystem magic
Audit: remove unused audit_log_secctx function
audit: Allow auditd to set pid to 0 to end auditing
audit: Add new syscalls to the perm=w filter
audit: use audit_set_enabled() in audit_enable()
audit: convert audit_ever_enabled to a boolean
audit: don't use simple_strtol() anymore
audit: initialize the audit subsystem as early as possible
audit: ensure that 'audit=1' actually enables audit for PID 1
The function audit_log_secctx() is unused in the upstream kernel.
All it does is wrap another function that doesn't need wrapping.
It claims to give you the SELinux context, but that is not true if
you are using a different security module.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Gustavo A. R. Silva
Richard Guy Briggs
Kees Cook
Al Viro
Linus Torvalds
Thomas Gleixner
Ondrej Mosnacek
Paul Moore
Tyler Hicks
Casey Schaufler