linux-cve-announce - CVE-2025-39923: dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees

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>] [day] [month] [year] [list]

Message-ID: <2025100122-CVE-2025-39923-6775@gregkh>
Date: Wed,  1 Oct 2025 10:07:23 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39923: dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees

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

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

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

dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees

When we don't have a clock specified in the device tree, we have no way to
ensure the BAM is on. This is often the case for remotely-controlled or
remotely-powered BAM instances. In this case, we need to read num-channels
from the DT to have all the necessary information to complete probing.

However, at the moment invalid device trees without clock and without
num-channels still continue probing, because the error handling is missing
return statements. The driver will then later try to read the number of
channels from the registers. This is unsafe, because it relies on boot
firmware and lucky timing to succeed. Unfortunately, the lack of proper
error handling here has been abused for several Qualcomm SoCs upstream,
causing early boot crashes in several situations [1, 2].

Avoid these early crashes by erroring out when any of the required DT
properties are missing. Note that this will break some of the existing DTs
upstream (mainly BAM instances related to the crypto engine). However,
clearly these DTs have never been tested properly, since the error in the
kernel log was just ignored. It's safer to disable the crypto engine for
these broken DTBs.

[1]: https://lore.kernel.org/r/CY01EKQVWE36.B9X5TDXAREPF@fairphone.com/
[2]: https://lore.kernel.org/r/20230626145959.646747-1-krzysztof.kozlowski@linaro.org/

The Linux kernel CVE team has assigned CVE-2025-39923 to this issue.

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

	Issue introduced in 4.17 with commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 and fixed in 6.1.153 with commit 555bd16351a35c79efb029a196975a5a27f7fbc4
	Issue introduced in 4.17 with commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 and fixed in 6.6.107 with commit ebf6c7c908e5999531c3517289598f187776124f
	Issue introduced in 4.17 with commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 and fixed in 6.12.48 with commit 1fc14731f0be4885e60702b9596d14d9a79cf053
	Issue introduced in 4.17 with commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 and fixed in 6.16.8 with commit 0ff9df758af7022d749718fb6b8385cc5693acf3
	Issue introduced in 4.17 with commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 and fixed in 6.17 with commit 5068b5254812433e841a40886e695633148d362d
	Issue introduced in 4.9.104 with commit cecf8a69042b3a54cb843223756c10ee8a8665e3
	Issue introduced in 4.14.45 with commit 909474cd384cb206f33461fbd18089cf170533f8
	Issue introduced in 4.16.13 with commit 5e0986f7caf17d7b1acd2092975360bf8e88a57d

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-2025-39923
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:
	drivers/dma/qcom/bam_dma.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/555bd16351a35c79efb029a196975a5a27f7fbc4
	https://git.kernel.org/stable/c/ebf6c7c908e5999531c3517289598f187776124f
	https://git.kernel.org/stable/c/1fc14731f0be4885e60702b9596d14d9a79cf053
	https://git.kernel.org/stable/c/0ff9df758af7022d749718fb6b8385cc5693acf3
	https://git.kernel.org/stable/c/5068b5254812433e841a40886e695633148d362d