[NET]: Do not leak MSG_CMSG_COMPAT into userspace.

Noticed by Sridhar Samudrala.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/socket.c b/net/socket.c
index c699e93..f926447 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -1862,7 +1862,8 @@ asmlinkage long sys_recvmsg(int fd, struct msghdr __user *msg, unsigned int flag
                if (err < 0)
                        goto out_freeiov;
        }
-       err = __put_user(msg_sys.msg_flags, COMPAT_FLAGS(msg));
+       err = __put_user((msg_sys.msg_flags & ~MSG_CMSG_COMPAT),
+                        COMPAT_FLAGS(msg));
        if (err)
                goto out_freeiov;
        if (MSG_CMSG_COMPAT & flags)