Kernel supports SMP Security Request so don't block increasing security
when we are slave.

Signed-off-by: Marcin Kraglak <marcin.kraglak@tieto.com>
Acked-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org

-[0x01 Introduction

We have found a programming error causing a deadlock in Bluetooth subsystem
of Linux kernel. The problem is caused by missing release_sock() call when
L2CAP connection creation fails due full accept queue.

The issue can be reproduced with 3.15-rc5 kernel and is also present in
earlier kernels.

-[0x02 Details

The problem occurs when multiple L2CAP connections are created to a PSM which
contains listening socket (like SDP) and left pending, for example,
configuration (the underlying ACL link is not disconnected between
connections).

When L2CAP connection request is received and listening socket is found the
l2cap_sock_new_connection_cb() function (net/bluetooth/l2cap_sock.c) is called.
This function locks the 'parent' socket and then checks if the accept queue
is full.

1178         lock_sock(parent);
1179
1180         /* Check for backlog size */
1181         if (sk_acceptq_is_full(parent)) {
1182                 BT_DBG("backlog full %d", parent->sk_ack_backlog);
1183                 return NULL;
1184         }

If case the accept queue is full NULL is returned, but the 'parent' socket
is not released. Thus when next L2CAP connection request is received the code
blocks on lock_sock() since the parent is still locked.

Also note that for connections already established and waiting for
configuration to complete a timeout will occur and l2cap_chan_timeout()
(net/bluetooth/l2cap_core.c) will be called. All threads calling this
function will also be blocked waiting for the channel mutex since the thread
which is waiting on lock_sock() alread holds the channel mutex.

We were able to reproduce this by sending continuously L2CAP connection
request followed by disconnection request containing invalid CID. This left
the created connections pending configuration.

After the deadlock occurs it is impossible to kill bluetoothd, btmon will not
get any more data etc. requiring reboot to recover.

-[0x03 Fix

Releasing the 'parent' socket when l2cap_sock_new_connection_cb() returns NULL
seems to fix the issue.

Signed-off-by: Jukka Taimisto <jtt@codenomicon.com>
Reported-by: Tommi Mäkilä <tmakila@codenomicon.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Cc: stable@vger.kernel.org

Several spots in the kernel perform a sequence like:

	skb_queue_tail(&sk->s_receive_queue, skb);
	sk->sk_data_ready(sk, skb->len);

But at the moment we place the SKB onto the socket receive queue it
can be consumed and freed up.  So this skb->len access is potentially
to freed up memory.

Furthermore, the skb->len can be modified by the consumer so it is
possible that the value isn't accurate.

And finally, no actual implementation of this callback actually uses
the length argument.  And since nobody actually cared about it's
value, lots of call sites pass arbitrary values in such as '0' and
even '1'.

So just remove the length argument from the callback, that way there
is no confusion whatsoever and all of these use-after-free cases get
fixed as a side effect.

Based upon a patch by Eric Dumazet and his suggestion to audit this
issue tree-wide.

Signed-off-by: David S. Miller <davem@davemloft.net>

We should let user space request the peer address also in the pending
connect states, i.e. BT_CONNECT and BT_CONNECT2. There is existing user
space code that tries to do this and will fail without extending the set
of allowed states for the peer address information.

This patch adds the two states to the allowed ones in the L2CAP and
RFCOMM sock_getname functions, thereby preventing ENOTCONN from being
returned.

Reported-by: Andrzej Kaczmarek <andrzej.kaczmarek@tieto.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Tested-by: Andrzej Kaczmarek <andrzej.kaczmarek@tieto.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

The use of __constant_<foo> has been unnecessary for quite awhile now.

Make these uses consistent with the rest of the kernel.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Now that the LE L2CAP Connection Oriented Channel support has undergone a
decent amount of testing we can make it officially supported. This patch
removes the enable_lecoc module parameter which was previously needed to
enable support for LE L2CAP CoC.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

The l2cap_chan->psm value is always set to a valid value for a
connection oriented channel. The l2cap_chan->sport is used for tracking
local PSM allocations but will not always have a proper value, such as
with connected sockets derived from a listening socket. This patch fixes
the sock_getname callback to always use chan->psm when returning address
information.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

When we're not connected the peer address information is undefined. This
patch fixes the remote address getting to return a proper error in case
the state is anything else than BT_CONNECTED.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Fixed channels have the same source and destination CID. Ensure that the
values get properly initialized when receiving incoming connections and
deriving values from the parent socket.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>