Re: [PATCH 2/2] Fix a stack buffer overflow bug in check_input_term

Hi Hui,

On Fri, Aug 30, 2019 at 05:47:29PM -0400, Hui Peng wrote:

`check_input_term` recursively calls itself with input from device side (e.g., uac_input_terminal_descriptor.bCSourceID) as argument (id). In `check_input_term`, if `check_input_term` is called with the same `id` argument as the caller, it triggers endless recursive call, resulting kernel space stack overflow.

This patch fixes the bug by adding a bitmap to `struct mixer_build` to keep track of the checked ids and stop the execution if some id has been checked (similar to how parse_audio_unit handles unitid argument).

CVE: CVE-2018-15118

Similar to the previous one, this should be CVE-2019-15118 as far I can tell.

Regards, Salvatore