svn commit: r224044 - head/sys/net

[Mark Peek]

Author: mp
Date: Thu Jul 14 21:06:22 2011
New Revision: 224044
URL: http://svn.freebsd.org/changeset/base/224044

Log:
  Clear the filter memory area before using it. Leaving it uninitialized may
  leak previous kernel stack contents through a malicioius BPF filter.
  
  PR:		kern/158880
  Submitted by:	Guy Harris
  Obtained from:	OpenBSD
  MFC after:	1 week

Modified:
  head/sys/net/bpf_filter.c

Modified: head/sys/net/bpf_filter.c
==============================================================================
--- head/sys/net/bpf_filter.c	Thu Jul 14 21:02:15 2011	(r224043)
+++ head/sys/net/bpf_filter.c	Thu Jul 14 21:06:22 2011	(r224044)
@@ -177,6 +177,8 @@ bpf_filter(const struct bpf_insn *pc, u_
 	bpf_u_int32 k;
 	u_int32_t mem[BPF_MEMWORDS];
 
+	bzero(mem, sizeof(mem));
+
 	if (pc == NULL)
 		/*
 		 * No filter means accept all.