svn commit: r277236 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Fri Jan 16 07:06:58 2015
New Revision: 277236
URL: https://svnweb.freebsd.org/changeset/base/277236

Log:
  For sigaction(2), ignore possible garbage in sa_flags for sa_handler
  == SIG_DFL or SIG_IGN.  Sloppy code does not fully initialize struct
  sigaction for such cases, and being too demanding in the case of
  default handler does not catch anything.
  
  Reported and tested by:	Alex Tutubalin <lexa at lexa.ru>
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/kern_sig.c

Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c	Fri Jan 16 06:19:52 2015	(r277235)
+++ head/sys/kern/kern_sig.c	Fri Jan 16 07:06:58 2015	(r277236)
@@ -653,9 +653,10 @@ kern_sigaction(td, sig, act, oact, flags
 
 	if (!_SIG_VALID(sig))
 		return (EINVAL);
-	if (act != NULL && (act->sa_flags & ~(SA_ONSTACK | SA_RESTART |
-	    SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | SA_NOCLDWAIT |
-	    SA_SIGINFO)) != 0)
+	if (act != NULL && act->sa_handler != SIG_DFL &&
+	    act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
+	    SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
+	    SA_NOCLDWAIT | SA_SIGINFO)) != 0)
 		return (EINVAL);
 
 	PROC_LOCK(p);