ip6mr: Add sizeof verification to MRT6_ASSERT and MT6_PIM

Verify the length of the user-space arguments.

Signed-off-by: Joe Perches <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv6/ip6mr.c

···
 	case MRT6_ASSERT:
 	{
 		int v;
+
+		if (optlen != sizeof(v))
+			return -EINVAL;
 		if (get_user(v, (int __user *)optval))
 			return -EFAULT;
 		mrt->mroute_do_assert = v;
···
 	case MRT6_PIM:
 	{
 		int v;
+
+		if (optlen != sizeof(v))
+			return -EINVAL;
 		if (get_user(v, (int __user *)optval))
 			return -EFAULT;
 		v = !!v;