CVE-2024-57800

What it actually does

The vulnerability stems from ALSA memalloc code performing explicit address checks instead of calling dma_mapping_error() to validate DMA mappings, allowing invalid device addresses to be used under CONFIG_DMA_API_DEBUG.

Why it matters to the business

Systems running affected Linux kernels with audio subsystems may encounter debug warnings, potential DMA-related memory handling issues, and reduced stability for multimedia workloads; low exploitability but still requires patching per published fixed versions.

How an attack unfolds

An attacker with local access triggers ALSA PCM operations that perform DMA mappings returning error addresses such as 0xffff0000; the missing dma_mapping_error() check allows subsequent use of the invalid mapping in snd_dma_wc_free paths without detection.

How to fix it

Upgrade affected packages to the listed fixed versions (chromium-browser 58.0.3029.81-0ubuntu0.14.04.1172 on Ubuntu 14.04 LTS where applicable) and ensure kernel builds enable proper use of dma_mapping_error() helper as recommended in dma-api documentation.

How to confirm the fix worked

Rebuild or boot with CONFIG_DMA_API_DEBUG enabled, exercise snd_pcm ioctls, and confirm absence of the 'failed to check map error' WARNING in kernel logs; verify updated packages report the fixed version strings.

Typical attack path

1. Obtain local access to a system with vulnerable ALSA snd_pcm and snd_hda_intel drivers
2. Trigger audio buffer allocation and free sequences via user-space audio clients
3. Force DMA mappings that return invalid addresses under debug configuration
4. Observe or leverage the unchecked mapping error state during unmap operations

How to detect it

Search kernel logs for 'device driver failed to check map error' and 'check_unmap' stack traces involving snd_dma_wc_free or snd_pcm_lib_free_pages; review dmesg and audit logs around wireplumber or audio client activity for DMA debug warnings.

• DMA-API: .* device driver failed to check map error
• WARNING: .* at kernel/dma/debug.c.*check_unmap
• snd_dma_wc_free+0x85/0x130
• snd_pcm_lib_free_pages+0x1e3/0x440

What your security team should do

• Apply kernel and ALSA updates immediately on all Linux systems using audio drivers
• Audit custom drivers for explicit DMA address checks and replace with dma_mapping_error()
• Monitor EPSS and KEV updates given the 638 days since publication
• Test audio workloads in debug-enabled kernels before production deployment