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authorDesmond Cheong Zhi Xi <desmondcheongzx@gmail.com>2021-07-28 15:51:04 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-09-22 11:41:25 +0200
commit470f7a682dbd120b9a7b92715d0e57c9b98cc7cc (patch)
tree835cc8043e67d0cd46de2a020c9c1b0cffc17fff
parent614bf36bd5bcd9413c1332608b4b9063b96a4a56 (diff)
Bluetooth: skip invalid hci_sync_conn_complete_evt
[ 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>
-rw-r--r--net/bluetooth/hci_event.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 7ed3c7df271a..6528ecc3a3bc 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3747,6 +3747,21 @@ 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;