net: recvmmsg: Strip MSG_WAITFORONE when calling recvmsg

recvmmsg fails on a raw socket with EINVAL. The reason for this is
packet_recvmsg checks the incoming flags:

        err = -EINVAL;
        if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT|MSG_ERRQUEUE))
                goto out;

This patch strips out MSG_WAITFORONE when calling recvmmsg which
fixes the issue.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: stable@kernel.org [2.6.34+]
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/socket.c

@@ -2122,14 +2122,16 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 		 */
 		if (MSG_CMSG_COMPAT & flags) {
 			err = __sys_recvmsg(sock, (struct msghdr __user *)compat_entry,
-					    &msg_sys, flags, datagrams);
+					    &msg_sys, flags & ~MSG_WAITFORONE,
+					    datagrams);
 			if (err < 0)
 				break;
 			err = __put_user(err, &compat_entry->msg_len);
 			++compat_entry;
 		} else {
 			err = __sys_recvmsg(sock, (struct msghdr __user *)entry,
-					    &msg_sys, flags, datagrams);
+					    &msg_sys, flags & ~MSG_WAITFORONE,
+					    datagrams);
 			if (err < 0)
 				break;
 			err = put_user(err, &entry->msg_len);