ipv4: check optlen for IP_MULTICAST_IF option
authorShan Wei <shanwei@cn.fujitsu.com>
Tue, 22 Sep 2009 15:41:10 +0000 (15:41 +0000)
committerDavid S. Miller <davem@davemloft.net>
Thu, 24 Sep 2009 22:38:44 +0000 (15:38 -0700)
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(dfeng@redhat.com) 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 <dfeng@redhat.com>
Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/ip_sockglue.c

index fc7993e9061fd855d1cb34b42fa491c49dcd669d..5a0693576e821c628edfb3f436243a0f8b107d4a 100644 (file)
@@ -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)))