[PATCH 034/118] irda: Fix missing msg_namelen update in irda_recvmsg_dgram()

[Luis Henriques]

3.5.7.12 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli at googlemail.com>

commit 5ae94c0d2f0bed41d6718be743985d61b7f5c47d upstream.

The current code does not fill the msg_name member in case it is set.
It also does not set 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.

Fix that by simply setting msg_namelen to 0 as obviously nobody cared
about irda_recvmsg_dgram() not filling the msg_name in case it was
set.

Cc: Samuel Ortiz <samuel at sortiz.org>
Signed-off-by: Mathias Krause <minipli at googlemail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/irda/af_irda.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index d6c291c..bd25678 100644
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1386,6 +1386,8 @@ static int irda_recvmsg_dgram(struct kiocb *iocb, struct socket *sock,
 
 	IRDA_DEBUG(4, "%s()\n", __func__);
 
+	msg->msg_namelen = 0;
+
 	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 				flags & MSG_DONTWAIT, &err);
 	if (!skb)
-- 
1.8.1.2