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Commit 26000089 authored by Gustavo Padovan's avatar Gustavo Padovan Committed by Marcel Holtmann
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Bluetooth: Check packet FCS earlier 



This way, if FCS is enabled and the packet is corrupted, we just drop it
without read it len, which could be corrupted.

Signed-off-by: default avatarGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 45d65c46

net/bluetooth/l2cap.c

+11 −11
Original line number Diff line number Diff line
@@ -4166,25 +4166,25 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk 
		skb_pull(skb, 2);

		len = skb->len;



		/*

		 * We can just drop the corrupted I-frame here.

		 * Receiver will miss it and start proper recovery

		 * procedures and ask retransmission.

		 */

		if (l2cap_check_fcs(pi, skb))

			goto drop;



		if (__is_sar_start(control) && __is_iframe(control))

			len -= 2;



		if (pi->fcs == L2CAP_FCS_CRC16)

			len -= 2;



		/*

		 * We can just drop the corrupted I-frame here.

		 * Receiver will miss it and start proper recovery

		 * procedures and ask retransmission.

		 */

		if (len > pi->mps) {

			l2cap_send_disconn_req(pi->conn, sk);

			goto drop;

		}



		if (l2cap_check_fcs(pi, skb))

			goto drop;



		req_seq = __get_reqseq(control);

		req_seq_offset = (req_seq - pi->expected_ack_seq) % 64;

		if (req_seq_offset < 0)
@@ -4224,6 +4224,9 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk 
		skb_pull(skb, 2);

		len = skb->len;



		if (l2cap_check_fcs(pi, skb))

			goto drop;



		if (__is_sar_start(control))

			len -= 2;
@@ -4233,9 +4236,6 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk 
		if (len > pi->mps || len < 0 || __is_sframe(control))

			goto drop;



		if (l2cap_check_fcs(pi, skb))

			goto drop;



		tx_seq = __get_txseq(control);



		if (pi->expected_tx_seq == tx_seq)