CVE-2025-39923
dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees
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/[email protected]/ [2]: https://lore.kernel.org/r/[email protected]/
INFO
Published Date :
Oct. 1, 2025, 8:15 a.m.
Last Modified :
Oct. 2, 2025, 7:12 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Apply the kernel patch for dmaengine: qcom: bam_dma.
- Ensure clock and num-channels are in the device tree.
- Update device tree bindings if necessary.
- Disable crypto engine for broken device trees.
Public PoC/Exploit Available at Github
CVE-2025-39923 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
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CVE-2025-39923.
CWE - Common Weakness Enumeration
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
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weaknesses.
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 02, 2025
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/1d98ba204d8a6db0d986c7f1aefaa0dcd1c007a2 Added Reference https://git.kernel.org/stable/c/2e257a6125c63350f00dc42b9674f20fd3cf4a9f Added Reference https://git.kernel.org/stable/c/6ac1599d0e78036d9d08efc2f58c2d91f0a3ee4c -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 01, 2025
Action Type Old Value New Value Added 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/[email protected]/ [2]: https://lore.kernel.org/r/[email protected]/ Added Reference https://git.kernel.org/stable/c/0ff9df758af7022d749718fb6b8385cc5693acf3 Added Reference https://git.kernel.org/stable/c/1fc14731f0be4885e60702b9596d14d9a79cf053 Added Reference https://git.kernel.org/stable/c/5068b5254812433e841a40886e695633148d362d Added Reference https://git.kernel.org/stable/c/555bd16351a35c79efb029a196975a5a27f7fbc4 Added Reference https://git.kernel.org/stable/c/ebf6c7c908e5999531c3517289598f187776124f