[PATCH 3.2 85/94] Bluetooth: cmtp: cmtp_add_connection() should verify that it's dealing with l2cap socket

[Ben Hutchings]

3.2.97-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 96c26653ce65bf84f3212f8b00d4316c1efcbf4c upstream.

... rather than relying on ciptool(8) never passing it anything else.  Give
it e.g. an AF_UNIX connected socket (from socketpair(2)) and it'll oops,
trying to evaluate &l2cap_pi(sock->sk)->chan->dst...

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/bluetooth/cmtp/core.c | 3 +++
 1 file changed, 3 insertions(+)

--- a/net/bluetooth/cmtp/core.c
+++ b/net/bluetooth/cmtp/core.c
@@ -336,6 +336,9 @@ int cmtp_add_connection(struct cmtp_conn
 
 	BT_DBG("");
 
+	if (!l2cap_is_socket(sock))
+		return -EBADFD;
+
 	session = kzalloc(sizeof(struct cmtp_session), GFP_KERNEL);
 	if (!session)
 		return -ENOMEM;