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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,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 122/215] Bluetooth: L2CAP: Fix invalid access on ECRED Connection response
Date:   Thu, 15 Jul 2021 20:38:14 +0200
Message-Id: <20210715182621.054893225@linuxfoundation.org>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit de895b43932cb47e69480540be7eca289af24f23 ]

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

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 17520133093a..0ddbc415ce15 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6055,7 +6055,7 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn,
 	struct l2cap_ecred_conn_rsp *rsp = (void *) data;
 	struct hci_conn *hcon = conn->hcon;
 	u16 mtu, mps, credits, result;
-	struct l2cap_chan *chan;
+	struct l2cap_chan *chan, *tmp;
 	int err = 0, sec_level;
 	int i = 0;
 
@@ -6074,7 +6074,7 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn,
 
 	cmd_len -= sizeof(*rsp);
 
-	list_for_each_entry(chan, &conn->chan_l, list) {
+	list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) {
 		u16 dcid;
 
 		if (chan->ident != cmd->ident ||
-- 
2.30.2