linux-kernel - Re: [PATCH v5 06/11] i2c: rtl9300: remove SMBus Quick operation support

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: <3644932.iIbC2pHGDl@sven-desktop>
Date: Sun, 10 Aug 2025 09:13:07 +0200
From: Sven Eckelmann <sven@...fation.org>
To: Chris Packham <chris.packham@...iedtelesis.co.nz>,
 Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Jonas Jelonek <jelonek.jonas@...il.com>
Cc: linux-i2c@...r.kernel.org, Conor Dooley <conor+dt@...nel.org>,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 Markus Stockhausen <markus.stockhausen@....de>,
 Harshal Gohel <hg@...onwunderlich.de>,
 Jonas Jelonek <jelonek.jonas@...il.com>
Subject:
 Re: [PATCH v5 06/11] i2c: rtl9300: remove SMBus Quick operation support

On Sunday, 10 August 2025 00:07:07 CEST Jonas Jelonek wrote:
[...]
> The current implementation of SMBus Quick operation passes a length of
> 0 (which is actually invalid). Before the fix of a bug in a previous
> commit, this led to a read operation of 16 bytes from any register (the
> one of a former transaction or any other value.
> 
> Although there are currently no reports of actual issues this caused.
> However, as an example, i2cdetect by default uses Quick Write operation
> to probe the bus and this may already write anything to some register
> of a device, causing unintended behaviour. This could be the cause of a
> recent brick of one of my DAC cables where there was a checksum mismatch
> of the EEPROM after having run 'i2cdetect -l' before.
[...]

Nice find. I've actually observed odd behavior after/during probing and 
attributed it only to the other problems (especially the low timeout + missing 
check) we found and never did a deep dive to figure out what happened on the 
bus during the probe. Possible that this could be related.

Reviewed-by: Sven Eckelmann <sven@...fation.org>

Kind regards,
	Sven
Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)