irda: Fix missing msg_namelen update in irda_recvmsg_dgram()

[ Upstream commit 5ae94c0d2f0bed41d6718be743985d61b7f5c47d ]

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@sortiz.org>
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>

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index f4b49c5..91821e9 100644 (file)
--- 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)