Re: [RESEND PATCH] Input: elantech - Fix stack out of bound access in elantech_change_report_id()

From: Andrea Righi
Date: Tue Nov 16 2021 - 04:53:21 EST

On Tue, Nov 16, 2021 at 09:32:34AM +0100, Wolfram Sang wrote:
> On Tue, Nov 16, 2021 at 08:22:23AM +0100, Andrea Righi wrote:
> > The array param[] in elantech_change_report_id() must be at least 3
> > bytes, because elantech_read_reg_params() is calling ps2_command() with
> > PSMOUSE_CMD_GETINFO, that is going to access 3 bytes from param[], but
> > it's defined in the stack as an array of 2 bytes, therefore we have a
> > potential stack out-of-bounds access here, also confirmed by KASAN:
> I think a comment in the code why the array size is 3 when only 2 values
> are defined would be helpful. Like a short summary of the above.

Good idea, I like it, I'll send a v2 adding such comment.