svn commit: r355155 - head/contrib/openbsm/bin/auditd

[Conrad Meyer]

Author: cem
Date: Thu Nov 28 00:46:03 2019
New Revision: 355155
URL: https://svnweb.freebsd.org/changeset/base/355155

Log:
  auditd(8): fix long-standing uninitialized memory use bug
  
  The bogus use could lead to an infinite loop depending on how fast the
  audit_warn script to execute.
  
  By fixing read(2) interruptibility, d060887 (r335899) revealed another bug
  in auditd_wait_for_events.  When read is interrupted by SIGCHLD,
  auditd_reap_children will always return with errno set to ECHILD.  But
  auditd_wait_for_events checks errno after that point, expecting it to be
  unchanged since read.  As a result, it calls auditd_handle_trigger with bogus
  stack garbage.  The result is the error message "Got unknown trigger 48."  Fix
  by simply ignoring errno at that point; there's only one value it could've
  possibly had, thanks to the check up above.
  
  The best part is we've had a fix for this for like 18 months and just never
  merged it.  Merge it now.
  
  PR:		234209
  Reported by:	Marie Helene Kvello-Aune <freebsd AT mhka.no> (2018-12)
  Submitted by:	asomers (2018-07)
  Reviewed by:	me (in OpenBSM)
  Obtained from:	OpenBSM
  X-MFC-With:	r335899
  Security:	¯\_(ツ)_/¯
  Differential Revision:	https://github.com/openbsm/openbsm/pull/45

Modified:
  head/contrib/openbsm/bin/auditd/auditd_fbsd.c

Modified: head/contrib/openbsm/bin/auditd/auditd_fbsd.c
==============================================================================
--- head/contrib/openbsm/bin/auditd/auditd_fbsd.c	Thu Nov 28 00:42:55 2019	(r355154)
+++ head/contrib/openbsm/bin/auditd/auditd_fbsd.c	Thu Nov 28 00:46:03 2019	(r355155)
@@ -241,7 +241,7 @@ auditd_wait_for_events(void)
 			auditd_config_controls();
 		}
 
-		if ((num == -1) && (errno == EINTR))
+		if (num == -1)
 			continue;
 		if (num == 0) {
 			auditd_log_err("%s: read EOF", __FUNCTION__);