CVE-2024-26590 erofs: fix inconsistent per-file compression format

2024-02-2216:13:34

Linux

github.com

linux kernel

erofs

compressionalgorithmexception

syzkaller

craftedimages

nullpointerdereference

bugfix

AI Score

6.7

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

In the Linux kernel, the following vulnerability has been resolved:

erofs: fix inconsistent per-file compression format

EROFS can select compression algorithms on a per-file basis, and each
per-file compression algorithm needs to be marked in the on-disk
superblock for initialization.

However, syzkaller can generate inconsistent crafted images that use
an unsupported algorithmtype for specific inodes, e.g. use MicroLZMA
algorithmtype even it’s not set in sbi->available_compr_algs. This
can lead to an unexpected “BUG: kernel NULL pointer dereference” if
the corresponding decompressor isn’t built-in.

Fix this by checking against sbi->available_compr_algs for each
m_algorithmformat request. Incorrect !erofs_sb_has_compr_cfgs preset
bitmap is now fixed together since it was harmless previously.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "8f89926290c4",
        "lessThan": "47467e04816c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f89926290c4",
        "lessThan": "823ba1d21060",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f89926290c4",
        "lessThan": "eed24b816e50",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f89926290c4",
        "lessThan": "118a8cf504d7",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/erofs/decompressor.c",
      "fs/erofs/zmap.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.16"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.16",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "6.1.80",
        "versionType": "custom",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.14",
        "versionType": "custom",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.7.2",
        "versionType": "custom",
        "lessThanOrEqual": "6.7.*"
      },
      {
        "status": "unaffected",
        "version": "6.8",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/erofs/decompressor.c",
      "fs/erofs/zmap.c"
    ],
    "defaultStatus": "affected"
  }
]