linux-kernel - Re: [PATCH] platform/chrome: cros_typec

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Y9iPzvfJkxii390K@google.com>
Date:   Tue, 31 Jan 2023 11:49:34 +0800
From:   Tzung-Bi Shih <tzungbi@...nel.org>
To:     Prashant Malani <pmalani@...omium.org>
Cc:     linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev,
        bleung@...omium.org
Subject: Re: [PATCH] platform/chrome: cros_typec_vdm: Fix VDO copy

On Fri, Jan 13, 2023 at 06:26:26PM +0000, Prashant Malani wrote:
> The usage of memcpy() affects the representation of the VDOs as they are
> copied to the EC Host Command buffer. Specifically, all higher order
> bits get dropped (for example: a VDO of 0x406 just gets copied as 0x6).

memcpy() is byte-oriented; however, `vdo` is a pointer to u32.

> Avoid this by explicitly copying each VDO in the array. The number of
> VDOs generated by alternate mode drivers in their VDMs is almost always
> just 1 (apart from the header) so this doesn't affect performance in a
> meaningful way).

Although the patch has applied, I am wondering if the following would be a
better way to fix the issue:

memcpy(&vdm_req.vdm_data[1], vdo, (cnt - 1) * sizeof(*vdo));