BMC/Intel-BMC/linux.git/kernel/auditsc.c, branch dev-4.10

audit: fix auditd/kernel connection state tracking

2017-03-30T07:44:06+00:00

commit 5b52330bbfe63b3305765354d6046c9f7f89c011 upstream. What started as a rather straightforward race condition reported by Dmitry using the syzkaller fuzzer ended up revealing some major problems with how the audit subsystem managed its netlink sockets and its connection with the userspace audit daemon. Fixing this properly had quite the cascading effect and what we are left with is this rather large and complicated patch. My initial goal was to try and decompose this patch into multiple smaller patches, but the way these changes are intertwined makes it difficult to split these changes into meaningful pieces that don't break or somehow make things worse for the intermediate states. The patch makes a number of changes, but the most significant are highlighted below: * The auditd tracking variables, e.g. audit_sock, are now gone and replaced by a RCU/spin_lock protected variable auditd_conn which is a structure containing all of the auditd tracking information. * We no longer track the auditd sock directly, instead we track it via the network namespace in which it resides and we use the audit socket associated with that namespace. In spirit, this is what the code was trying to do prior to this patch (at least I think that is what the original authors intended), but it was done rather poorly and added a layer of obfuscation that only masked the underlying problems. * Big backlog queue cleanup, again. In v4.10 we made some pretty big changes to how the audit backlog queues work, here we haven't changed the queue design so much as cleaned up the implementation. Brought about by the locking changes, we've simplified kauditd_thread() quite a bit by consolidating the queue handling into a new helper function, kauditd_send_queue(), which allows us to eliminate a lot of very similar code and makes the looping logic in kauditd_thread() clearer. * All netlink messages sent to auditd are now sent via auditd_send_unicast_skb(). Other than just making sense, this makes the lock handling easier. * Change the audit_log_start() sleep behavior so that we never sleep on auditd events (unchanged) or if the caller is holding the audit_cmd_mutex (changed). Previously we didn't sleep if the caller was auditd or if the message type fell between a certain range; the type check was a poor effort of doing what the cmd_mutex check now does. Richard Guy Briggs originally proposed not sleeping the cmd_mutex owner several years ago but his patch wasn't acceptable at the time. At least the idea lives on here. * A problem with the lost record counter has been resolved. Steve Grubb and I both happened to notice this problem and according to some quick testing by Steve, this problem goes back quite some time. It's largely a harmless problem, although it may have left some careful sysadmins quite puzzled. Reported-by: Dmitry Vyukov Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit

2016-12-14T22:06:40+00:00

Pull audit updates from Paul Moore: "After the small number of patches for v4.9, we've got a much bigger pile for v4.10. The bulk of these patches involve a rework of the audit backlog queue to enable us to move the netlink multicasting out of the task/thread that generates the audit record and into the kernel thread that emits the record (just like we do for the audit unicast to auditd). While we were playing with the backlog queue(s) we fixed a number of other little problems with the code, and from all the testing so far things look to be in much better shape now. Doing this also allowed us to re-enable disabling IRQs for some netns operations ("netns: avoid disabling irq for netns id"). The remaining patches fix some small problems that are well documented in the commit descriptions, as well as adding session ID filtering support" * 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit: audit: use proper refcount locking on audit_sock netns: avoid disabling irq for netns id audit: don't ever sleep on a command record/message audit: handle a clean auditd shutdown with grace audit: wake up kauditd_thread after auditd registers audit: rework audit_log_start() audit: rework the audit queue handling audit: rename the queues and kauditd related functions audit: queue netlink multicast sends just like we do for unicast sends audit: fixup audit_init() audit: move kaudit thread start from auditd registration to kaudit init (#2) audit: add support for session ID user filter audit: fix formatting of AUDIT_CONFIG_CHANGE events audit: skip sessionid sentinel value when auto-incrementing audit: tame initialization warning len_abuf in audit_log_execve_info audit: less stack usage for /proc/*/loginuid

audit: add support for session ID user filter

2016-11-29T20:10:12+00:00

Define AUDIT_SESSIONID in the uapi and add support for specifying user filters based on the session ID. Also add the new session ID filter to the feature bitmap so userspace knows it is available. https://github.com/linux-audit/audit-kernel/issues/4 RFE: add a session ID filter to the kernel's user filter Signed-off-by: Richard Guy Briggs [PM: combine multiple patches from Richard into this one] Signed-off-by: Paul Moore

audit: skip sessionid sentinel value when auto-incrementing

2016-11-20T20:28:22+00:00

The value (unsigned int)-1 is used as a sentinel to indicate the sessionID is unset. Skip this value when the session_id value wraps. Signed-off-by: Richard Guy Briggs Signed-off-by: Paul Moore

audit: tame initialization warning len_abuf in audit_log_execve_info

2016-11-14T20:18:48+00:00

Tame initialization warning of len_abuf in audit_log_execve_info even though there isn't presently a bug introduced by commit 43761473c254 ("audit: fix a double fetch in audit_log_single_execve_arg()"). Using UNINITIALIZED_VAR instead may mask future bugs. Signed-off-by: Richard Guy Briggs Signed-off-by: Paul Moore

Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit

2016-10-04T21:21:41+00:00

Pull audit updates from Paul Moore: "Another relatively small pull request for v4.9 with just two patches. The patch from Richard updates the list of features we support and report back to userspace; this should have been sent earlier with the rest of the v4.8 patches but it got lost in my inbox. The second patch fixes a problem reported by our Android friends where we weren't very consistent in recording PIDs" * 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit: audit: add exclude filter extension to feature bitmap audit: consistently record PIDs with task_tgid_nr()

audit: consistently record PIDs with task_tgid_nr()

2016-08-30T21:19:13+00:00

Unfortunately we record PIDs in audit records using a variety of methods despite the correct way being the use of task_tgid_nr(). This patch converts all of these callers, except for the case of AUDIT_SET in audit_receive_msg() (see the comment in the code). Reported-by: Jeff Vander Stoep Signed-off-by: Paul Moore

Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit

2016-07-30T00:54:17+00:00

Pull audit updates from Paul Moore: "Six audit patches for 4.8. There are a couple of style and minor whitespace tweaks for the logs, as well as a minor fixup to catch errors on user filter rules, however the major improvements are a fix to the s390 syscall argument masking code (reviewed by the nice s390 folks), some consolidation around the exclude filtering (less code, always a win), and a double-fetch fix for recording the execve arguments" * 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit: audit: fix a double fetch in audit_log_single_execve_arg() audit: fix whitespace in CWD record audit: add fields to exclude filter by reusing user filter s390: ensure that syscall arguments are properly masked on s390 audit: fix some horrible switch statement style crimes audit: fixup: log on errors from filter user rules

audit: fix a double fetch in audit_log_single_execve_arg()

2016-07-20T18:15:46+00:00

There is a double fetch problem in audit_log_single_execve_arg() where we first check the execve(2) argumnets for any "bad" characters which would require hex encoding and then re-fetch the arguments for logging in the audit record[1]. Of course this leaves a window of opportunity for an unsavory application to munge with the data. This patch reworks things by only fetching the argument data once[2] into a buffer where it is scanned and logged into the audit records(s). In addition to fixing the double fetch, this patch improves on the original code in a few other ways: better handling of large arguments which require encoding, stricter record length checking, and some performance improvements (completely unverified, but we got rid of some strlen() calls, that's got to be a good thing). As part of the development of this patch, I've also created a basic regression test for the audit-testsuite, the test can be tracked on GitHub at the following link: * https://github.com/linux-audit/audit-testsuite/issues/25 [1] If you pay careful attention, there is actually a triple fetch problem due to a strnlen_user() call at the top of the function. [2] This is a tiny white lie, we do make a call to strnlen_user() prior to fetching the argument data. I don't like it, but due to the way the audit record is structured we really have no choice unless we copy the entire argument at once (which would require a rather wasteful allocation). The good news is that with this patch the kernel no longer relies on this strnlen_user() value for anything beyond recording it in the log, we also update it with a trustworthy value whenever possible. Reported-by: Pengfei Wang Cc: Signed-off-by: Paul Moore

audit: fix whitespace in CWD record

2016-07-14T21:47:43+00:00

Fix the whitespace in the CWD record Signed-off-by: Steve Grubb [PM: fixed subject line] Signed-off-by: Paul Moore