CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

The 'sprintf' call in 'add_tuning_control' may exceed the 44-byte
buffer if either string argument is too long. This triggers a compiler
warning.
Replaced 'sprintf' with 'snprintf' to limit string lengths to prevent
overflow.

The Linux kernel CVE team has assigned CVE-2025-39751 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.4.297 with commit 04fa6f5e94034654da3505d9e908dd9090f0e83c
	Fixed in 5.10.241 with commit fb8116c38d67d6e23f3b5e34bbc8d9f8c12e81e5
	Fixed in 5.15.190 with commit c2dacfe495b72699a9480c95f8eef2285042e474
	Fixed in 6.1.149 with commit 86a024a5a521da362fb67a3a6a84f54331503326
	Fixed in 6.6.103 with commit 0de69bc9b3661e16c4b08b34949529553906f5e1
	Fixed in 6.12.43 with commit 417407cdf587e3ae41a0e728daa562ee88fc1bd6
	Fixed in 6.15.11 with commit 195e4cec1007c34ddeb0ce61ef14ce9ab312544f
	Fixed in 6.16.2 with commit cf494138b9d7f78bcb510b9ea5f5faa6e882a7a3
	Fixed in 6.17-rc1 with commit a409c60111e6bb98fcabab2aeaa069daa9434ca0

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-39751
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	sound/pci/hda/patch_ca0132.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/04fa6f5e94034654da3505d9e908dd9090f0e83c
	https://git.kernel.org/stable/c/fb8116c38d67d6e23f3b5e34bbc8d9f8c12e81e5
	https://git.kernel.org/stable/c/c2dacfe495b72699a9480c95f8eef2285042e474
	https://git.kernel.org/stable/c/86a024a5a521da362fb67a3a6a84f54331503326
	https://git.kernel.org/stable/c/0de69bc9b3661e16c4b08b34949529553906f5e1
	https://git.kernel.org/stable/c/417407cdf587e3ae41a0e728daa562ee88fc1bd6
	https://git.kernel.org/stable/c/195e4cec1007c34ddeb0ce61ef14ce9ab312544f
	https://git.kernel.org/stable/c/cf494138b9d7f78bcb510b9ea5f5faa6e882a7a3
	https://git.kernel.org/stable/c/a409c60111e6bb98fcabab2aeaa069daa9434ca0

Re: CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

[Siddh Raman Pant]

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On Thu, 11 Sep 2025 18:52:52 +0200, Greg Kroah-Hartman wrote:
> ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control
> 
> The 'sprintf' call in 'add_tuning_control' may exceed the 44-byte
> buffer if either string argument is too long. This triggers a compiler
> warning.
> Replaced 'sprintf' with 'snprintf' to limit string lengths to prevent
> overflow.
> 
> The Linux kernel CVE team has assigned CVE-2025-39751 to this issue.

While the change is good for defensive reasons, there isn't actually
any buffer overflow as it is to "fix".

The largest string possible is "Wedge Angle Playback Volume", whose
length is less than 44.

Thanks,
Siddh

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Re: CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

[gregkh]

On Mon, Oct 06, 2025 at 07:07:00AM +0000, Siddh Raman Pant wrote:
> On Thu, 11 Sep 2025 18:52:52 +0200, Greg Kroah-Hartman wrote:
> > ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control
> > 
> > The 'sprintf' call in 'add_tuning_control' may exceed the 44-byte
> > buffer if either string argument is too long. This triggers a compiler
> > warning.
> > Replaced 'sprintf' with 'snprintf' to limit string lengths to prevent
> > overflow.
> > 
> > The Linux kernel CVE team has assigned CVE-2025-39751 to this issue.
> 
> While the change is good for defensive reasons, there isn't actually
> any buffer overflow as it is to "fix".
> 
> The largest string possible is "Wedge Angle Playback Volume", whose
> length is less than 44.

Thanks for the info.  What was the compiler warning about then if it
could detect just how big the string would always be as these are static
values?

Should this CVE be rejected?

thanks,

greg k-h

Re: CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

[Siddh Raman Pant]

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On Mon, Oct 06 2025 at 13:44:23 +0530, gregkh@linuxfoundation.org
wrote:
> On Mon, Oct 06, 2025 at 07:07:00AM +0000, Siddh Raman Pant wrote:
> > On Thu, 11 Sep 2025 18:52:52 +0200, Greg Kroah-Hartman wrote:
> > > ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control
> > > 
> > > The 'sprintf' call in 'add_tuning_control' may exceed the 44-byte
> > > buffer if either string argument is too long. This triggers a compiler
> > > warning.
> > > Replaced 'sprintf' with 'snprintf' to limit string lengths to prevent
> > > overflow.
> > > 
> > > The Linux kernel CVE team has assigned CVE-2025-39751 to this issue.
> > 
> > While the change is good for defensive reasons, there isn't actually
> > any buffer overflow as it is to "fix".
> > 
> > The largest string possible is "Wedge Angle Playback Volume", whose
> > length is less than 44.
> 
> Thanks for the info.  What was the compiler warning about then if it
> could detect just how big the string would always be as these are static
> values?

Probably a false positive.

GCC docs does say:

	-Wformat-overflow
	-Wformat-overflow=level

	    Warn about calls to formatted input/output functions such 
	    as sprintf and vsprintf that might overflow the
destination
	    buffer. When the exact number of bytes written by a format
	    directive cannot be determined at compile-time it is
	    estimated based on heuristics that depend on the level
	    argument and on optimization. While enabling optimization 
	    will in most cases improve the accuracy of the warning, it
	    may also result in false positives.


> Should this CVE be rejected?

Yes.

Thanks,
Siddh

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Re: CVE-2025-39751: ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control

[gregkh]

On Mon, Oct 06, 2025 at 09:19:42AM +0000, Siddh Raman Pant wrote:
> On Mon, Oct 06 2025 at 13:44:23 +0530, gregkh@linuxfoundation.org
> wrote:
> > On Mon, Oct 06, 2025 at 07:07:00AM +0000, Siddh Raman Pant wrote:
> > > On Thu, 11 Sep 2025 18:52:52 +0200, Greg Kroah-Hartman wrote:
> > > > ALSA: hda/ca0132: Fix buffer overflow in add_tuning_control
> > > > 
> > > > The 'sprintf' call in 'add_tuning_control' may exceed the 44-byte
> > > > buffer if either string argument is too long. This triggers a compiler
> > > > warning.
> > > > Replaced 'sprintf' with 'snprintf' to limit string lengths to prevent
> > > > overflow.
> > > > 
> > > > The Linux kernel CVE team has assigned CVE-2025-39751 to this issue.
> > > 
> > > While the change is good for defensive reasons, there isn't actually
> > > any buffer overflow as it is to "fix".
> > > 
> > > The largest string possible is "Wedge Angle Playback Volume", whose
> > > length is less than 44.
> > 
> > Thanks for the info.  What was the compiler warning about then if it
> > could detect just how big the string would always be as these are static
> > values?
> 
> Probably a false positive.
> 
> GCC docs does say:
> 
> 	-Wformat-overflow
> 	-Wformat-overflow=level
> 
> 	    Warn about calls to formatted input/output functions such 
> 	    as sprintf and vsprintf that might overflow the
> destination
> 	    buffer. When the exact number of bytes written by a format
> 	    directive cannot be determined at compile-time it is
> 	    estimated based on heuristics that depend on the level
> 	    argument and on optimization. While enabling optimization 
> 	    will in most cases improve the accuracy of the warning, it
> 	    may also result in false positives.

I can't seem to duplicate this warning on a newer version of gcc than
the original test used:
	https://lore.kernel.org/oe-kbuild-all/202506100642.95jpuMY1-lkp@intel.com/

But that value of "767" is very specific, which feels odd to me.

> > Should this CVE be rejected?
> 
> Yes.

Ok, will do, but this still seems odd, you should patch your kernel just
to be safe :)

thanks,

greg k-h