netdev - [PATCH 10/13] Bluetooth: Fix L2CAP control bit field corruption

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Date:	Thu,  8 Jul 2010 16:59:59 -0300
From:	Marcel Holtmann <marcel@...tmann.org>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: [PATCH 10/13] Bluetooth: Fix L2CAP control bit field corruption

From: Gustavo F. Padovan <padovan@...fusion.mobi>

When resending an I-frame, ERTM was reusing the control bits from the last
time it was sent, that was causing a corruption in the new control field
due to it dirty fields.

This patches extracts only the SAR bits from the old field and reuse it to
resend the packet, the others bits should be reset and receive the
updated value.

Signed-off-by: Gustavo F. Padovan <padovan@...fusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
---
 net/bluetooth/l2cap.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 41c9887..6785e52 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1422,6 +1422,8 @@ static void l2cap_retransmit_one_frame(struct sock *sk, u8 tx_seq)
 	tx_skb = skb_clone(skb, GFP_ATOMIC);
 	bt_cb(skb)->retries++;
 	control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+	control &= L2CAP_CTRL_SAR;
+
 	control |= (pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT)
 			| (tx_seq << L2CAP_CTRL_TXSEQ_SHIFT);
 	put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
@@ -1457,6 +1459,8 @@ static int l2cap_ertm_send(struct sock *sk)
 		bt_cb(skb)->retries++;
 
 		control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+		control &= L2CAP_CTRL_SAR;
+
 		if (pi->conn_state & L2CAP_CONN_SEND_FBIT) {
 			control |= L2CAP_CTRL_FINAL;
 			pi->conn_state &= ~L2CAP_CONN_SEND_FBIT;
-- 
1.7.1.1

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