CVE-2024-50279

dm cache: fix out-of-bounds access to the dirty bitset when resizing

HIGH

7.1

CVSS Score

Published: November 19, 2024 at 01:30 AM UTC

Updated: June 17, 2026 at 08:04 AM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.1

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

3.13 ≤ v < 4.19.3243.13 ≤ v < 5.10.2303.13 ≤ v < 5.15.1723.13 ≤ v < 5.4.2863.13 ≤ v < 6.1.1173.13 ≤ v < 6.11.83.13 ≤ v < 6.123.13 ≤ v < 6.6.614.20 ≤ v < 5.4.2865.11 ≤ v < 5.15.1725.16 ≤ v < 6.1.1175.5 ≤ v < 5.10.2306.2 ≤ v < 6.6.616.7 ≤ v < 6.11.86.12 rc1 6.12 rc2 6.12 rc3 6.12 rc4 6.12 rc5 6.12 rc6f494a9c6b1b6dd9a9f21bbb75d9210d478eeb498

Vendor states this is fixed in 3b02c40ff10fdf83cc545850db208de855ebe22c (fixed)

Vendor states this is fixed in 4fa4feb873cea0e9d6ff883b37cca6f33169d8b4 (fixed)

Vendor states this is fixed in 56507203e1b6127967ec2b51fb0b23a0d4af1334 (fixed)

Vendor states this is fixed in 792227719725497ce10a8039803bec13f89f8910 (fixed)

Vendor states this is fixed in 8501e38dc9e0060814c4085815fc83da3e6d43bf (fixed)

Vendor states this is fixed in e57648ce325fa405fe6bbd0e6a618ced7c301a2d (fixed)

Vendor states this is fixed in ee1f74925717ab36f6a091104c170639501ce818 (fixed)

Vendor states this is fixed in ff1dd8a04c30e8d4e2fd5c83198ca672eb6a9e7f (fixed)

Vendor states this is fixed in 3.13 (unaffected)

Vendor states this is fixed in 4.19.324 (unaffected)

Vendor states this is fixed in 5.10.230 (unaffected)

Vendor states this is fixed in 5.15.172 (unaffected)

Vendor states this is fixed in 5.4.286 (unaffected)

Vendor states this is fixed in 6.1.117 (unaffected)

Vendor states this is fixed in 6.11.8 (unaffected)

Vendor states this is fixed in 6.12 (unaffected)

Vendor states this is fixed in 6.6.61 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references