[PATCH] spmi: mediatek: Fix UAF on device remove

[Fei Shao]

On Mon, Jul 17, 2023 at 5:41 PM Yu-Che Cheng <giver at chromium.org> wrote:
>
> The pmif driver data that contains the clocks is allocated along with
> spmi_controller.
> On device remove, spmi_controller will be freed first, and then devres
> , including the clocks, will be cleanup.
> This leads to UAF because putting the clocks will access the clocks in
> the pmif driver data, which is already freed along with spmi_controller.
>
> This can be reproduced by enabling DEBUG_TEST_DRIVER_REMOVE and
> building the kernel with KASAN.
>
> Fix the UAF issue by using unmanaged clk_bulk_get() and putting the
> clocks before freeing spmi_controller.
>
> Reported-by: Fei Shao <fshao at chromium.org>
> Signed-off-by: Yu-Che Cheng <giver at chromium.org>

Reviewed-by: Fei Shao <fshao at chromium.org>
Tested-by: Fei Shao <fshao at chromium.org>