Commit 0915921b authored by Shan Wei's avatar Shan Wei Committed by David S. Miller

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: default avatarXiaotian Feng <dfeng@redhat.com>
Signed-off-by: default avatarShan Wei <shanwei@cn.fujitsu.com>
Acked-by: default avatarAlexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8b3f6af8
...@@ -611,6 +611,9 @@ static int do_ip_setsockopt(struct sock *sk, int level, ...@@ -611,6 +611,9 @@ static int do_ip_setsockopt(struct sock *sk, int level,
* Check the arguments are allowable * Check the arguments are allowable
*/ */
if (optlen < sizeof(struct in_addr))
goto e_inval;
err = -EFAULT; err = -EFAULT;
if (optlen >= sizeof(struct ip_mreqn)) { if (optlen >= sizeof(struct ip_mreqn)) {
if (copy_from_user(&mreq, optval, sizeof(mreq))) if (copy_from_user(&mreq, optval, sizeof(mreq)))
......
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