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Bluetooth: fix possible info leak in bt_sock_recvmsg()

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>
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1 parent ef3313e commit 4683f42fde3977bdb4e8a09622788cc8b5313778 @minipli minipli committed with davem330 Apr 7, 2013
Showing with 2 additions and 2 deletions.
  1. +2 −2 net/bluetooth/af_bluetooth.c
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4 net/bluetooth/af_bluetooth.c
@@ -230,15 +230,15 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
if (flags & (MSG_OOB))
return -EOPNOTSUPP;
+ msg->msg_namelen = 0;
+
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (!skb) {
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;

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