Re: [PATCH BlueZ 1/5] gatt: Fix invalid read when disconnecting

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

On Mon, Nov 19, 2018 at 5:43 PM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>
> In case there is a client of AcquireNotify and a disconnect happens the
> code not only have to free the client object but also destroy the io
> associated with it, for this reason the client object cannot be freed
> until the io is destroyed otherwise it may lead to the following error:
>
> Invalid read of size 4
>    at 0x63920: notify_io_destroy (gatt-client.c:1461)
>    by 0x63EDB: pipe_io_destroy (gatt-client.c:1082)
>    by 0x6405B: characteristic_free (gatt-client.c:1663)
>    by 0x81F33: remove_interface (object.c:667)
>    by 0x826CB: g_dbus_unregister_interface (object.c:1391)
>    by 0x85D2B: queue_remove_all (queue.c:354)
>    by 0x635F7: unregister_service (gatt-client.c:1893)
>    by 0x85CF7: queue_remove_all (queue.c:339)
>    by 0x661DF: btd_gatt_client_service_removed (gatt-client.c:2199)
>    by 0x695CB: gatt_service_removed (device.c:3747)
>    by 0x85B17: queue_foreach (queue.c:220)
>    by 0x91283: notify_service_changed (gatt-db.c:280)
>    by 0x91283: gatt_db_service_destroy (gatt-db.c:291)
>  Address 0x515ed48 is 0 bytes inside a block of size 20 free'd
>    at 0x483EAD0: free (vg_replace_malloc.c:530)
>    by 0x85D2B: queue_remove_all (queue.c:354)
>    by 0x636D3: unregister_characteristic (gatt-client.c:1741)
>    by 0x85D2B: queue_remove_all (queue.c:354)
>    by 0x635F7: unregister_service (gatt-client.c:1893)
>    by 0x85CF7: queue_remove_all (queue.c:339)
>    by 0x661DF: btd_gatt_client_service_removed (gatt-client.c:2199)
>    by 0x695CB: gatt_service_removed (device.c:3747)
>    by 0x85B17: queue_foreach (queue.c:220)
>    by 0x91283: notify_service_changed (gatt-db.c:280)
>    by 0x91283: gatt_db_service_destroy (gatt-db.c:291)
>    by 0x85D2B: queue_remove_all (queue.c:354)
>    by 0x91387: gatt_db_clear_range (gatt-db.c:475)
> ---
>  src/gatt-client.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/src/gatt-client.c b/src/gatt-client.c
> index 234f46ed7..55aa5e423 100644
> --- a/src/gatt-client.c
> +++ b/src/gatt-client.c
> @@ -1645,13 +1645,22 @@ static const GDBusMethodTable characteristic_methods[] = {
>         { }
>  };
>
> +static void remove_client(void *data)
> +{
> +       struct notify_client *ntfy_client = data;
> +       struct btd_gatt_client *client = ntfy_client->chrc->service->client;
> +
> +       queue_remove(client->all_notify_clients, ntfy_client);
> +
> +       notify_client_unref(ntfy_client);
> +}
> +
>  static void characteristic_free(void *data)
>  {
>         struct characteristic *chrc = data;
>
>         /* List should be empty here */
>         queue_destroy(chrc->descs, NULL);
> -       queue_destroy(chrc->notify_clients, NULL);
>
>         if (chrc->write_io) {
>                 queue_remove(chrc->service->client->ios, chrc->write_io->io);
> @@ -1663,6 +1672,8 @@ static void characteristic_free(void *data)
>                 pipe_io_destroy(chrc->notify_io);
>         }
>
> +       queue_destroy(chrc->notify_clients, remove_client);
> +
>         g_free(chrc->path);
>         free(chrc);
>  }
> @@ -1715,16 +1726,6 @@ static struct characteristic *characteristic_create(
>         return chrc;
>  }
>
> -static void remove_client(void *data)
> -{
> -       struct notify_client *ntfy_client = data;
> -       struct btd_gatt_client *client = ntfy_client->chrc->service->client;
> -
> -       queue_remove(client->all_notify_clients, ntfy_client);
> -
> -       notify_client_unref(ntfy_client);
> -}
> -
>  static void unregister_characteristic(void *data)
>  {
>         struct characteristic *chrc = data;
> @@ -1738,7 +1739,6 @@ static void unregister_characteristic(void *data)
>         if (chrc->write_op)
>                 bt_gatt_client_cancel(gatt, chrc->write_op->id);
>
> -       queue_remove_all(chrc->notify_clients, NULL, NULL, remove_client);
>         queue_remove_all(chrc->descs, NULL, NULL, unregister_descriptor);
>
>         g_dbus_unregister_interface(btd_get_dbus_connection(), chrc->path,
> --
> 2.17.2

Can you try with this set to see it does work properly.

--
Luiz Augusto von Dentz