Description
In the Linux kernel, the following vulnerability has been resolved: dm cache: fix out-of-bounds access to the dirty bitset when resizing dm-cache checks the dirty bits of the cache blocks to be dropped when shrinking the fast device, but an index bug in bitset iteration causes out-of-bounds access. Reproduce steps: 1. create a cache device of 1024 cache blocks (128 bytes dirty bitset) dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. shrink the fast device to 512 cache blocks, triggering out-of-bounds access to the dirty bitset (offset 0x80) dmsetup suspend cache dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0 Read of size 8 at addr ffffc900000f3080 by task dmsetup/131 (...snip...) The buggy address belongs to the virtual mapping at [ffffc900000f3000, ffffc900000f5000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by making the index post-incremented.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
f494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < 4fa4feb873cea0e9d6ff883b37cca6f33169d8b4affectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < 8501e38dc9e0060814c4085815fc83da3e6d43bfaffectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < ee1f74925717ab36f6a091104c170639501ce818affectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < ff1dd8a04c30e8d4e2fd5c83198ca672eb6a9e7faffectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < 56507203e1b6127967ec2b51fb0b23a0d4af1334affectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < e57648ce325fa405fe6bbd0e6a618ced7c301a2daffectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < 3b02c40ff10fdf83cc545850db208de855ebe22caffectedf494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 to < 792227719725497ce10a8039803bec13f89f8910affected
Linux Linux
Default version status: affected
3.13affected0 to < 3.13unaffected4.19.324 to ≤ 4.19.*unaffected5.4.286 to ≤ 5.4.*unaffected5.10.230 to ≤ 5.10.*unaffected5.15.172 to ≤ 5.15.*unaffected6.1.117 to ≤ 6.1.*unaffected6.6.61 to ≤ 6.6.*unaffected6.11.8 to ≤ 6.11.*unaffected6.12 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/4fa4feb873cea0e9d6ff883b37cca6f33169d8b4 ↗
- https://git.kernel.org/stable/c/8501e38dc9e0060814c4085815fc83da3e6d43bf ↗
- https://git.kernel.org/stable/c/ee1f74925717ab36f6a091104c170639501ce818 ↗
- https://git.kernel.org/stable/c/ff1dd8a04c30e8d4e2fd5c83198ca672eb6a9e7f ↗
- https://git.kernel.org/stable/c/56507203e1b6127967ec2b51fb0b23a0d4af1334 ↗
- https://git.kernel.org/stable/c/e57648ce325fa405fe6bbd0e6a618ced7c301a2d ↗
- https://git.kernel.org/stable/c/3b02c40ff10fdf83cc545850db208de855ebe22c ↗
- https://git.kernel.org/stable/c/792227719725497ce10a8039803bec13f89f8910 ↗
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html ↗
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html ↗