From 2d864174107380d9c7d2b8c783410a484b925bff Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Fri, 22 Aug 2014 07:52:47 +0000
Subject: [PATCH] Check the validity of struct sigaction sa_flags value, reject
 unknown flags.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
---
 sys/kern/kern_sig.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 561ea0a125b7..31070f5e48ed 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -639,6 +639,10 @@ 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)
+		return (EINVAL);
 
 	PROC_LOCK(p);
 	ps = p->p_sigacts;