[105/118] llc: Fix missing msg_namelen update in llc_ui_recvmsg()

Ben Hutchings
2013-05-10T14:48:38Z

From: Mathias Krause <minipli@googlemail.com>

[ Upstream commit c77a4b9cffb6215a15196ec499490d116dfad181 ]

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 <acme@ghostprotocols.net>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/llc/af_llc.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -720,6 +720,8 @@ static int llc_ui_recvmsg(struct kiocb *
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))