| Message ID | 20210728075105.415214-1-desmondcheongzx@gmail.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] Bluetooth: skip invalid hci_sync_conn_complete_evt | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | success | CCed 7 of 7 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 22 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
Hi Desmond, > 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> > --- > > v1 -> v2: > - Added more comments to explain the reasoning behind the new check, and > a bt_dev_err message upon detecting the invalid event. As suggested by > Marcel Holtmann. > > net/bluetooth/hci_event.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) I shortened the error message and then applied your patch to bluetooth-next tree. Regards Marcel
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 016b2999f219..a6df4f9d2c23 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4373,6 +4373,22 @@ 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, + "received multiple HCI_EV_SYNC_CONN_COMPLETE events with status 0 for conn %p", + conn); + goto unlock; + } conn->handle = __le16_to_cpu(ev->handle); conn->state = BT_CONNECTED; conn->type = ev->link_type;