Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
dm-pcache: validate geometry fields from on-disk cache_info
cache_segs_init() iterates cache_info->n_segs times indexing cache->segments[], which is sized to the cache device geometry, and get_seg_id() takes each segment id from the on-media cache_info and the per-segment next_seg link. Both come from cache device metadata that is only CRC-protected with a fixed public seed, so whoever supplies the cache device on a table load (CAP_SYS_ADMIN) controls them: an oversized n_segs or an out-of-range id drives an out-of-bounds access of cache->segments[] and a wild CACHE_DEV_SEGMENT() pointer into the device mapping – an out-of-bounds read and write from on-disk data.
Reject an n_segs that exceeds the device segment count and a segment id that is out of range before either is used. Valid metadata is unaffected.
Details
- Affected product:
- Debian 10 ELS , Debian 11 ELS
- Affected packages:
- linux @ 5.10.259 (+1 more)