From: Vasiliy Kulikov <segoon@openwall.com>
Date: Mon, 14 Feb 2011 15:49:23 +0000 (+0100)
Subject: bridge: netfilter: fix information leak
X-Git-Tag: v2.6.35.13~84
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ce0f98ea90a8171cdaf249c0c623b455931d69ec;p=thirdparty%2Fkernel%2Fstable.git

bridge: netfilter: fix information leak

commit d846f71195d57b0bbb143382647c2c6638b04c5a upstream.

Struct tmp is copied from userspace.  It is not checked whether the "name"
field is NULL terminated.  This may lead to buffer overflow and passing
contents of kernel stack as a module name to try_then_request_module() and,
consequently, to modprobe commandline.  It would be seen by all userspace
processes.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 59ca00e40dec2..62675dc51179b 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1098,6 +1098,8 @@ static int do_replace(struct net *net, const void __user *user,
 	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
 		return -ENOMEM;
 
+	tmp.name[sizeof(tmp.name) - 1] = 0;
+
 	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
 	newinfo = vmalloc(sizeof(*newinfo) + countersize);
 	if (!newinfo)