llc: Fix missing msg_namelen update in llc_ui_recvmsg()

For stream sockets the code misses to update the msg_namelen member to 0 and therefore makes net/socket.c leak the local, uninitialized sockaddr_storage variable to userland -- 128 bytes of kernel stack memory. The msg_namelen update is also missing for datagram sockets in case the socket is shutting down during receive. Fix both issues by setting msg_namelen to 0 early. It will be updated later if we're going to fill the msg_name member. Cc: Arnaldo Carvalho de Melo <[email protected]> Signed-off-by: Mathias Krause <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Apr 7, 2013 · c77a4b9 · c77a4b9
1 parent b860d3c
commit c77a4b9
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
@@ -720,6 +720,8 @@ static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
 	int target;	/* Read at least this many bytes */
 	long timeo;
 
+	msg->msg_namelen = 0;
+
 	lock_sock(sk);
 	copied = -ENOTCONN;
 	if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))