netdev - [PATCH 56/64] Bluetooth: Prevents buffer overflow on l2cap_ertm_reassembly

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Message-Id: <4178ba462a3e8ab5094e69606f01d9e95f2d5ea6.1273484098.git.marcel@holtmann.org>
Date:	Mon, 10 May 2010 11:37:46 +0200
From:	Marcel Holtmann <marcel@...tmann.org>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: [PATCH 56/64] Bluetooth: Prevents buffer overflow on l2cap_ertm_reassembly_sdu()

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

The checks should be done before the the memcpy to avoid buffer
overflow.

Reported-by: João Paulo Rechi Vita <jprvita@...fusion.mobi>
Signed-off-by: Gustavo F. Padovan <padovan@...fusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
---
 net/bluetooth/l2cap.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index fe663e9..9ef01c3 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3470,12 +3470,12 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 		if (!pi->sdu)
 			goto disconnect;
 
-		memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
-
 		pi->partial_sdu_len += skb->len;
 		if (pi->partial_sdu_len > pi->sdu_len)
 			goto drop;
 
+		memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
+
 		break;
 
 	case L2CAP_SDU_END:
@@ -3486,8 +3486,6 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 			goto disconnect;
 
 		if (!(pi->conn_state & L2CAP_CONN_SAR_RETRY)) {
-			memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
-
 			pi->partial_sdu_len += skb->len;
 
 			if (pi->partial_sdu_len > pi->imtu)
@@ -3495,6 +3493,8 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 
 			if (pi->partial_sdu_len != pi->sdu_len)
 				goto drop;
+
+			memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
 		}
 
 		_skb = skb_clone(pi->sdu, GFP_ATOMIC);
-- 
1.6.6.1

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