CVE-2023-53607

An assertion failure was found in the Linux kernel's Yamaha YMF sound card driver during buffer validation. The probe function includes a BUG_ON assertion that compares DMA buffer sizes without accounting for alignment, causing the assertion to fail when the aligned buffer size doesn't exactly match the requested size. This triggers a kernel warning and can lead to driver initialization failure and denial of service.

The YMF PCI sound driver allocates DMA buffers for audio operations during device probe. Recent changes to the DMA buffer allocation code made the bytes field reflect the aligned buffer size rather than the exact requested size—this ensures proper memory alignment for DMA operations. However, the snd_ymfpci_create function contains a snd_BUG_ON check that asserts the allocated size exactly matches the requested size. With the new alignment behavior, buffers are typically rounded up to page or cache-line boundaries, causing the sizes to differ slightly. When this happens, the assertion fires, producing kernel warnings and potentially failing driver initialization. While primarily a debug check rather than actual memory corruption, on systems with panic-on-warn enabled or depending on driver initialization behavior, this could prevent the sound card from functioning at all.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the snd_ymfpci module from being loaded. See https://access.redhat.com/solutions/41278 for instructions on blacklisting kernel modules.