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Commit eb622495 authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann
Browse files

Bluetooth: Fix ATT socket backwards compatibility with user space 



Old user space versions bind the Attribute Protocol socket to
BDADDR_BREDR when they should be using BDADDR_LE_PUBLIC or
BDADDR_LE_RANDOM. The kernel recently introduced stricter checks on the
socket parameters but we need to punch this hole for old user space
versions to keep them working.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 2bfa3531

net/bluetooth/l2cap_sock.c

+25 −2
Original line number Diff line number Diff line
@@ -159,9 +159,32 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, 
	if (!bdaddr_type_is_valid(la.l2_bdaddr_type))

		return -EINVAL;



	if (chan->src_type == BDADDR_BREDR && la.l2_bdaddr_type != BDADDR_BREDR)

	/* Check that the socket wasn't bound to something that

	 * conflicts with the address given to connect(). If chan->src

	 * is BDADDR_ANY it means bind() was never used, in which case

	 * chan->src_type and la.l2_bdaddr_type do not need to match.

	 */

	if (chan->src_type == BDADDR_BREDR && bacmp(&chan->src, BDADDR_ANY) &&

	    bdaddr_type_is_le(la.l2_bdaddr_type)) {

		/* Old user space versions will try to incorrectly bind

		 * the ATT socket using BDADDR_BREDR. We need to accept

		 * this and fix up the source address type only when

		 * both the source CID and destination CID indicate

		 * ATT. Anything else is an invalid combination.

		 */

		if (chan->scid != L2CAP_CID_ATT ||

		    la.l2_cid != __constant_cpu_to_le16(L2CAP_CID_ATT))

			return -EINVAL;



		/* We don't have the hdev available here to make a

		 * better decision on random vs public, but since all

		 * user space versions that exhibit this issue anyway do

		 * not support random local addresses assuming public

		 * here is good enough.

		 */

		chan->src_type = BDADDR_LE_PUBLIC;

	}



	if (chan->src_type != BDADDR_BREDR && la.l2_bdaddr_type == BDADDR_BREDR)

		return -EINVAL;