ipv4: check optlen for IP_MULTICAST_IF option

Due to man page of setsockopt, if optlen is not valid, kernel should return -EINVAL. But a simple testcase as following, errno is 0, which means setsockopt is successful. addr.s_addr = inet_addr("192.1.2.3"); setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &addr, 1); printf("errno is %d\n", errno); Xiaotian Feng([email protected]) caught the bug. We fix it firstly checking the availability of optlen and then dealing with the logic like other options. Reported-by: Xiaotian Feng <[email protected]> Signed-off-by: Shan Wei <[email protected]> Acked-by: Alexey Kuznetsov <[email protected]> Signed-off-by: David S. Miller <[email protected]>
kyagi · Sep 24, 2009 · 0915921 · 0915921
1 parent 8b3f6af
commit 0915921
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
@@ -611,6 +611,9 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 		 *	Check the arguments are allowable
 		 */
 
+		if (optlen < sizeof(struct in_addr))
+			goto e_inval;
+
 		err = -EFAULT;
 		if (optlen >= sizeof(struct ip_mreqn)) {
 			if (copy_from_user(&mreq, optval, sizeof(mreq)))