Commit 0915921b authored Sep 22, 2009 by Shan Wei Committed by David S. Miller Sep 24, 2009

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(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>

parent 8b3f6af8

net/ipv4/ip_sockglue.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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)))

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