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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 121/215] Bluetooth: L2CAP: Fix invalid access if ECRED Reconfigure fails
Date:   Thu, 15 Jul 2021 20:38:13 +0200
Message-Id: <20210715182620.884335160@linuxfoundation.org>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 1fa20d7d4aad02206e84b74915819fbe9f81dab3 ]

The use of l2cap_chan_del is not safe under a loop using
list_for_each_entry.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bluetooth/l2cap_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index cdc386337173..17520133093a 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6237,7 +6237,7 @@ static inline int l2cap_ecred_reconf_rsp(struct l2cap_conn *conn,
 					 struct l2cap_cmd_hdr *cmd, u16 cmd_len,
 					 u8 *data)
 {
-	struct l2cap_chan *chan;
+	struct l2cap_chan *chan, *tmp;
 	struct l2cap_ecred_conn_rsp *rsp = (void *) data;
 	u16 result;
 
@@ -6251,7 +6251,7 @@ static inline int l2cap_ecred_reconf_rsp(struct l2cap_conn *conn,
 	if (!result)
 		return 0;
 
-	list_for_each_entry(chan, &conn->chan_l, list) {
+	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
 		if (chan->ident != cmd->ident)
 			continue;
 
-- 
2.30.2