| Message ID | 20210721101710.82974-1-desmondcheongzx@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Bluetooth: skip invalid hci_sync_conn_complete_evt | expand |
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. and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving. > To fix this, in hci_sync_conn_complete_evt, we check 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 skip further processing and exit. > > 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> > --- > net/bluetooth/hci_event.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index 016b2999f219..091a92338492 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, > > switch (ev->status) { > case 0x00: > + if (conn->state == BT_CONNECTED) > + goto unlock; /* Already connected, event not valid */ The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well. > conn->handle = __le16_to_cpu(ev->handle); > conn->state = BT_CONNECTED; > conn->type = ev->link_type; Regards Marcel
On 22/7/21 10:39 pm, Marcel Holtmann wrote: > 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. > > and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving. > >> To fix this, in hci_sync_conn_complete_evt, we check 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 skip further processing and exit. >> >> 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> >> --- >> net/bluetooth/hci_event.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c >> index 016b2999f219..091a92338492 100644 >> --- a/net/bluetooth/hci_event.c >> +++ b/net/bluetooth/hci_event.c >> @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, >> >> switch (ev->status) { >> case 0x00: >> + if (conn->state == BT_CONNECTED) >> + goto unlock; /* Already connected, event not valid */ > > The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well. > Hi Marcel, Apologies for the delayed response. Thanks for the feedback, I'll add more elaboration for the new check and add a bt_dev_err in a v2 patch. >> conn->handle = __le16_to_cpu(ev->handle); >> conn->state = BT_CONNECTED; >> conn->type = ev->link_type; > > Regards > > Marcel >
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 016b2999f219..091a92338492 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, switch (ev->status) { case 0x00: + if (conn->state == BT_CONNECTED) + goto unlock; /* Already connected, event not valid */ conn->handle = __le16_to_cpu(ev->handle); conn->state = BT_CONNECTED; conn->type = ev->link_type;