Re: [PATCH v2] ASoC: Intel: avs: Fix potential buffer overflow by snprintf()

From: Cezary Rojewski

Date: Thu Nov 13 2025 - 03:46:29 EST


On 2025-11-12 8:20 PM, Greg KH wrote:
On Wed, Nov 12, 2025 at 11:48:51PM +0530, hariconscious@xxxxxxxxx wrote:
From: HariKrishna Sagala <hariconscious@xxxxxxxxx>

snprintf() returns the would-be-filled size when the string overflows
the given buffer size, hence using this value may result in a buffer
overflow (although it's unrealistic).

unrealistic == impossible

So why make this change at all?

The problem will never occur in production-scenario given the AudioDSP firmware limitation - max ~10 probe-point entries so, the built string will be far away from 4K_SZ bytes.

If the verdict is: ignore the recommendation as the problem is unrealistic, I'm OK with that. Typically though I'd prefer to stick to the recommendations.


This patch replaces it with a safer version, scnprintf() for papering
over such a potential issue.

Don't "paper over", actually fix real things.


Link: https://github.com/KSPP/linux/issues/105
'Fixes: 5a565ba23abe ("ASoC: Intel: avs: Probing and firmware tracing
over debugfs")'

No, this is not a "fix".

The patch isn't worded well, that's clear.
While the patch is an outcome of static-analysis, isn't it good to have 'Fixes:' to point out the offending commit regardless?