Commit a8d1d73c authored by Luiz Augusto von Dentz's avatar Luiz Augusto von Dentz
Browse files

Bluetooth: L2CAP: Fix not checking output MTU is acceptable on L2CAP_ECRED_CONN_REQ 

Upon receiving L2CAP_ECRED_CONN_REQ the given MTU shall be checked
against the suggested MTU of the listening socket as that is required
by the likes of PTS L2CAP/ECFC/BV-27-C test which expects
L2CAP_CR_LE_UNACCEPT_PARAMS if the MTU is lowers than socket omtu.

In order to be able to set chan->omtu the code now allows setting
setsockopt(BT_SNDMTU), but it is only allowed when connection has not
been stablished since there is no procedure to reconfigure the output
MTU.

Link: https://github.com/bluez/bluez/issues/1895


Fixes: 15f02b91 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 7cff9a40

net/bluetooth/l2cap_core.c

+8 −0
Original line number Diff line number Diff line
@@ -5117,6 +5117,14 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn, 
		goto unlock;

	}



	/* Check if the listening channel has set an output MTU then the

	 * requested MTU shall be less than or equal to that value.

	 */

	if (pchan->omtu && mtu < pchan->omtu) {

		result = L2CAP_CR_LE_UNACCEPT_PARAMS;

		goto unlock;

	}



	result = L2CAP_CR_LE_SUCCESS;



	for (i = 0; i < num_scid; i++) {

net/bluetooth/l2cap_sock.c

+11 −4
Original line number Diff line number Diff line
@@ -1029,10 +1029,17 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, 
			break;

		}



		/* Setting is not supported as it's the remote side that

		 * decides this.

		 */

		err = -EPERM;

		/* Only allow setting output MTU when not connected */

		if (sk->sk_state == BT_CONNECTED) {

			err = -EISCONN;

			break;

		}



		err = copy_safe_from_sockptr(&mtu, sizeof(mtu), optval, optlen);

		if (err)

			break;



		chan->omtu = mtu;

		break;



	case BT_RCVMTU: