Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix potential data race at PCM memory allocation helpers
The PCM memory allocation helpers have a sanity check against too many buffer allocations. However, the check is performed without a proper lock and the allocation isn’t serialized; this allows user to allocate more memories than predefined max size.
Practically seen, this isn’t really a big problem, as it’s more or less some “soft limit” as a sanity check, and it’s not possible to allocate unlimitedly. But it’s still better to address this for more consistent behavior.
The patch covers the size check in do_alloc_pages() with the card->memory_mutex, and increases the allocated size there for preventing the further overflow. When the actual allocation fails, the size is decreased accordingly.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS
- Affected packages:
- kernel @ 5.14.0 (+2 more)
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix potential data race at PCM memory allocation helpers
The PCM memory allocation helpers have a sanity check against too many buffer allocations. However, the check is performed without a proper lock and the allocation isn’t serialized; this allows user to allocate more memories than predefined max size.
Practically seen, this isn’t really a big problem, as it’s more or less some “soft limit” as a sanity check, and it’s not possible to allocate unlimitedly. But it’s still better to address this for more consistent behavior.
The patch covers the size check in do_alloc_pages() with the card->memory_mutex, and increases the allocated size there for preventing the further overflow. When the actual allocation fails, the size is decreased accordingly.