From: Xi Wang <xi.wang@gmail.com>
Date: Thu, 28 Feb 2013 01:05:21 +0000 (-0800)
Subject: sysctl: fix null checking in bin_dn_node_address()
X-Git-Tag: v3.2.40~39
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0ba15a927d8cf09cab753066736c87831a735987;p=thirdparty%2Fkernel%2Fstable.git

sysctl: fix null checking in bin_dn_node_address()

commit df1778be1a33edffa51d094eeda87c858ded6560 upstream.

The null check of `strchr() + 1' is broken, which is always non-null,
leading to OOB read.  Instead, check the result of strchr().

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index a650694883a18..9f9aa32059738 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1194,9 +1194,10 @@ static ssize_t bin_dn_node_address(struct file *file,
 
 		/* Convert the decnet address to binary */
 		result = -EIO;
-		nodep = strchr(buf, '.') + 1;
+		nodep = strchr(buf, '.');
 		if (!nodep)
 			goto out;
+		++nodep;
 
 		area = simple_strtoul(buf, NULL, 10);
 		node = simple_strtoul(nodep, NULL, 10);