From 260000896750690b774d4343294ae5cbff1423e5 Mon Sep 17 00:00:00 2001
From: "Gustavo F. Padovan" <padovan@profusion.mobi>
Date: Tue, 11 May 2010 22:02:00 -0300
Subject: 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: Gustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
---
 net/bluetooth/l2cap.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

(limited to 'net')

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 6094870..8c9f577 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -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)
-- 
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