Use str_enabled_disabled() helper instead of open
coding the same.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In a few audit records, PIDs were being recorded with task_pid_nr()
instead of task_tgid_nr().
$ grep "task_pid_nr" kernel/audit*.c
audit.c: task_pid_nr(current),
auditfilter.c: pid = task_pid_nr(current);
auditsc.c: audit_log_format(ab, " pid=%u", task_pid_nr(current));
For single-thread applications, the process id (pid) and the thread
group id (tgid) are the same. However, on multi-thread applications,
task_pid_nr() returns the current thread id (user-space's TID), while
task_tgid_nr() returns the main thread id (user-space's PID). Since
the users are more interested in the process id (pid), rather than the
thread id (tid), this patch converts these callers to the correct method.
Link: https://github.com/linux-audit/audit-kernel/issues/126
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the new KMEM_CACHE() macro instead of direct kmem_cache_create
to simplify the creation of SLAB caches.
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
When auditd_set sets the auditd_conn pointer, audit messages can
immediately be put on the socket by other kernel threads. If the backlog
is large or the rate is high, this can immediately fill the socket
buffer. If the audit daemon requested an ACK for this operation, a full
socket buffer causes the ACK to get dropped, also setting ENOBUFS on the
socket.
To avoid this race and ensure ACKs get through, fast-track the ACK in
this specific case to ensure it is sent before auditd_conn is set.
Signed-off-by: Chris Riches <chris.riches@nutanix.com>
[PM: fix some tab vs space damage]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Fixes following checkpatch.pl issue:
ERROR: trailing statements should be on next line
Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The ifdef-else logic is already in the header file, so include it
unconditionally, no functional changes here.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: fixed misspelling in the subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently nobody use is_audit_feature_set() outside this file, so make
it static.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
data_len is already getting checked if it's less than 2 earlier in this
function.
Signed-off-by: Shreenidhi Shedi <sshedi@vmware.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
When an admin enables audit at early boot via the "audit=1" kernel
command line the audit queue behavior is slightly different; the
audit subsystem goes to greater lengths to avoid dropping records,
which unfortunately can result in problems when the audit daemon is
forcibly stopped for an extended period of time.
This patch makes a number of changes designed to improve the audit
queuing behavior so that leaving the audit daemon in a stopped state
for an extended period does not cause a significant impact to the
system.
- kauditd_send_queue() is now limited to looping through the
passed queue only once per call. This not only prevents the
function from looping indefinitely when records are returned
to the current queue, it also allows any recovery handling in
kauditd_thread() to take place when kauditd_send_queue()
returns.
- Transient netlink send errors seen as -EAGAIN now cause the
record to be returned to the retry queue instead of going to
the hold queue. The intention of the hold queue is to store,
perhaps for an extended period of time, the events which led
up to the audit daemon going offline. The retry queue remains
a temporary queue intended to protect against transient issues
between the kernel and the audit daemon.
- The retry queue is now limited by the audit_backlog_limit
setting, the same as the other queues. This allows admins
to bound the size of all of the audit queues on the system.
- kauditd_rehold_skb() now returns records to the end of the
hold queue to ensure ordering is preserved in the face of
recent changes to kauditd_send_queue().
Cc: stable@vger.kernel.org
Fixes: 5b52330bbf ("audit: fix auditd/kernel connection state tracking")
Fixes: f4b3ee3c85 ("audit: improve robustness of the audit queue handling")
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"Four audit patches for v5.17:
- Harden the code through additional use of the struct_size() macro
and zero-length arrays to flexible-array conversions.
- Ensure that processes which generate userspace audit records are
not exempt from the kernel's audit throttling when the audit queues
are being overrun"
* tag 'audit-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: replace zero-length array with flexible-array member
audit: use struct_size() helper in audit_[send|make]_reply()
audit: ensure userspace is penalized the same as the kernel when under pressure
audit: use struct_size() helper in kmalloc()
Pull selinux updates from Paul Moore:
"Nothing too significant, but five SELinux patches for v5.17 that do
the following:
- Harden the code through additional use of the struct_size() macro
- Plug some memory leaks
- Clean up the code via removal of the security_add_mnt_opt() LSM
hook and minor tweaks to selinux_add_opt()
- Rename security_task_getsecid_subj() to better reflect its actual
behavior/use - now called security_current_getsecid_subj()"
* tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: minor tweaks to selinux_add_opt()
selinux: fix potential memleak in selinux_add_opt()
security,selinux: remove security_add_mnt_opt()
selinux: Use struct_size() helper in kmalloc()
lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
If the audit daemon were ever to get stuck in a stopped state the
kernel's kauditd_thread() could get blocked attempting to send audit
records to the userspace audit daemon. With the kernel thread
blocked it is possible that the audit queue could grow unbounded as
certain audit record generating events must be exempt from the queue
limits else the system enter a deadlock state.
This patch resolves this problem by lowering the kernel thread's
socket sending timeout from MAX_SCHEDULE_TIMEOUT to HZ/10 and tweaks
the kauditd_send_queue() function to better manage the various audit
queues when connection problems occur between the kernel and the
audit daemon. With this patch, the backlog may temporarily grow
beyond the defined limits when the audit daemon is stopped and the
system is under heavy audit pressure, but kauditd_thread() will
continue to make progress and drain the queues as it would for other
connection problems. For example, with the audit daemon put into a
stopped state and the system configured to audit every syscall it
was still possible to shutdown the system without a kernel panic,
deadlock, etc.; granted, the system was slow to shutdown but that is
to be expected given the extreme pressure of recording every syscall.
The timeout value of HZ/10 was chosen primarily through
experimentation and this developer's "gut feeling". There is likely
no one perfect value, but as this scenario is limited in scope (root
privileges would be needed to send SIGSTOP to the audit daemon), it
is likely not worth exposing this as a tunable at present. This can
always be done at a later date if it proves necessary.
Cc: stable@vger.kernel.org
Fixes: 5b52330bbf ("audit: fix auditd/kernel connection state tracking")
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Due to the audit control mutex necessary for serializing audit
userspace messages we haven't been able to block/penalize userspace
processes that attempt to send audit records while the system is
under audit pressure. The result is that privileged userspace
applications have a priority boost with respect to audit as they are
not bound by the same audit queue throttling as the other tasks on
the system.
This patch attempts to restore some balance to the system when under
audit pressure by blocking these privileged userspace tasks after
they have finished their audit processing, and dropped the audit
control mutex, but before they return to userspace.
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The security_task_getsecid_subj() LSM hook invites misuse by allowing
callers to specify a task even though the hook is only safe when the
current task is referenced. Fix this by removing the task_struct
argument to the hook, requiring LSM implementations to use the
current task. While we are changing the hook declaration we also
rename the function to security_current_getsecid_subj() in an effort
to reinforce that the hook captures the subjective credentials of the
current task and not an arbitrary task on the system.
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials. This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.
This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.
void security_task_getsecid_subj(struct task_struct *p,
u32 *secid);
void security_task_getsecid_obj(struct task_struct *p,
u32 *secid);
While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks. The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.
Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This was replaced with a kauditd_wait kthread long ago,
back in:
b7d1125817 (AUDIT: Send netlink messages from a separate kernel thread)
Update the stale comment.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Some unused macros could cause gcc warning:
kernel/audit.c:68:0: warning: macro "AUDIT_UNINITIALIZED" is not used
[-Wunused-macros]
kernel/auditsc.c:104:0: warning: macro "AUDIT_AUX_IPCPERM" is not used
[-Wunused-macros]
kernel/auditsc.c:82:0: warning: macro "AUDITSC_INVALID" is not used
[-Wunused-macros]
AUDIT_UNINITIALIZED and AUDITSC_INVALID are still meaningful and should
be in incorporated.
Just remove AUDIT_AUX_IPCPERM.
Thanks comments from Richard Guy Briggs and Paul Moore.
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Moore <paul@paul-moore.com>
When there are no audit rules registered, mandatory records (config,
etc.) are missing their accompanying records (syscall, proctitle, etc.).
This is due to audit context dummy set on syscall entry based on absence
of rules that signals that no other records are to be printed. Clear the dummy
bit if any record is generated, open coding this in audit_log_start().
The proctitle context and dummy checks are pointless since the
proctitle record will not be printed if no syscall records are printed.
The fds array is reset to -1 after the first syscall to indicate it
isn't valid any more, but was never set to -1 when the context was
allocated to indicate it wasn't yet valid.
Check ctx->pwd in audit_log_name().
The audit_inode* functions can be called without going through
getname_flags() or getname_kernel() that sets audit_names and cwd, so
set the cwd in audit_alloc_name() if it has not already been done so due to
audit_names being valid and purge all other audit_getcwd() calls.
Revert the LSM dump_common_audit_data() LSM_AUDIT_DATA_* cases from the
ghak96 patch since they are no longer necessary due to cwd coverage in
audit_alloc_name().
Thanks to bauen1 <j2468h@googlemail.com> for reporting LSM situations in
which context->cwd is not valid, inadvertantly fixed by the ghak96 patch.
Please see upstream github issue
https://github.com/linux-audit/audit-kernel/issues/120
This is also related to upstream github issue
https://github.com/linux-audit/audit-kernel/issues/96
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Because kfree_skb already checked NULL skb parameter,
so the additional check is unnecessary, just remove it.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Paul Moore <paul@paul-moore.com>
