From: Mathias Krause <minipli@googlemail.com>
Date: Sun, 7 Apr 2013 01:51:49 +0000 (+0000)
Subject: Bluetooth: fix possible info leak in bt_sock_recvmsg()
X-Git-Tag: v2.6.34.15~81
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6dffe152f694412b91577145f7bbdf2dc5dd2be4;p=thirdparty%2Fkernel%2Fstable.git

Bluetooth: fix possible info leak in bt_sock_recvmsg()

commit 4683f42fde3977bdb4e8a09622788cc8b5313778 upstream.

In case the socket is already shutting down, bt_sock_recvmsg() returns
with 0 without updating msg_namelen leading to net/socket.c leaking the
local, uninitialized sockaddr_storage variable to userland -- 128 bytes
of kernel stack memory.

Fix this by moving the msg_namelen assignment in front of the shutdown
test.

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---

diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 404a8500fd031..0891857b7ca22 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -240,14 +240,14 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 	if (flags & (MSG_OOB))
 		return -EOPNOTSUPP;
 
+	msg->msg_namelen = 0;
+
 	if (!(skb = skb_recv_datagram(sk, flags, noblock, &err))) {
 		if (sk->sk_shutdown & RCV_SHUTDOWN)
 			return 0;
 		return err;
 	}
 
-	msg->msg_namelen = 0;
-
 	copied = skb->len;
 	if (len < copied) {
 		msg->msg_flags |= MSG_TRUNC;