From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com,
Marcel Holtmann <marcel@holtmann.org>,
Sasha Levin <sashal@kernel.org>,
linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 32/74] Bluetooth: skip invalid hci_sync_conn_complete_evt
Date: Thu, 9 Sep 2021 07:56:44 -0400 [thread overview]
Message-ID: <20210909115726.149004-32-sashal@kernel.org> (raw)
In-Reply-To: <20210909115726.149004-1-sashal@kernel.org>
From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
[ Upstream commit 92fe24a7db751b80925214ede43f8d2be792ea7b ]
Syzbot reported a corrupted list in kobject_add_internal [1]. This
happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
status 0 are sent for the same HCI connection. This causes us to
register the device more than once which corrupts the kset list.
As this is forbidden behavior, we add a check for whether we're
trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
times for one connection. If that's the case, the event is invalid, so
we report an error that the device is misbehaving, and ignore the
packet.
Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/hci_event.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 45cc864cf2b3..714a45355610 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4083,6 +4083,21 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
switch (ev->status) {
case 0x00:
+ /* The synchronous connection complete event should only be
+ * sent once per new connection. Receiving a successful
+ * complete event when the connection status is already
+ * BT_CONNECTED means that the device is misbehaving and sent
+ * multiple complete event packets for the same new connection.
+ *
+ * Registering the device more than once can corrupt kernel
+ * memory, hence upon detecting this invalid event, we report
+ * an error and ignore the packet.
+ */
+ if (conn->state == BT_CONNECTED) {
+ bt_dev_err(hdev, "Ignoring connect complete event for existing connection");
+ goto unlock;
+ }
+
conn->handle = __le16_to_cpu(ev->handle);
conn->state = BT_CONNECTED;
conn->type = ev->link_type;
--
2.30.2
next parent reply other threads:[~2021-09-09 13:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210909115726.149004-1-sashal@kernel.org>
2021-09-09 11:56 ` Sasha Levin [this message]
2021-09-09 11:56 ` [PATCH AUTOSEL 4.19 44/74] Bluetooth: schedule SCO timeouts with delayed_work Sasha Levin
2021-09-09 11:56 ` [PATCH AUTOSEL 4.19 45/74] Bluetooth: avoid circular locks in sco_sock_connect Sasha Levin
2021-09-09 11:57 ` [PATCH AUTOSEL 4.19 49/74] Bluetooth: Fix handling of LE Enhanced Connection Complete Sasha Levin
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