ghsa-rhf9-9q5c-jr4g
Vulnerability from github
Published
2025-10-21 12:31
Modified
2025-10-21 12:31
Details

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

ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state

The EXT4_FC_REPLAY bit in sbi->s_mount_state is used to indicate that we are in the middle of replay the fast commit journal. This was actually a mistake, since the sbi->s_mount_info is initialized from es->s_state. Arguably s_mount_state is misleadingly named, but the name is historical --- s_mount_state and s_state dates back to ext2.

What should have been used is the ext4_{set,clear,test}mount_flag() inline functions, which sets EXT4_MF* bits in sbi->s_mount_flags.

The problem with using EXT4_FC_REPLAY is that a maliciously corrupted superblock could result in EXT4_FC_REPLAY getting set in s_mount_state. This bypasses some sanity checks, and this can trigger a BUG() in ext4_es_cache_extent(). As a easy-to-backport-fix, filter out the EXT4_FC_REPLAY bit for now. We should eventually transition away from EXT4_FC_REPLAY to something like EXT4_MF_REPLAY.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2022-49348"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:11Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state\n\nThe EXT4_FC_REPLAY bit in sbi-\u003es_mount_state is used to indicate that\nwe are in the middle of replay the fast commit journal.  This was\nactually a mistake, since the sbi-\u003es_mount_info is initialized from\nes-\u003es_state.  Arguably s_mount_state is misleadingly named, but the\nname is historical --- s_mount_state and s_state dates back to ext2.\n\nWhat should have been used is the ext4_{set,clear,test}_mount_flag()\ninline functions, which sets EXT4_MF_* bits in sbi-\u003es_mount_flags.\n\nThe problem with using EXT4_FC_REPLAY is that a maliciously corrupted\nsuperblock could result in EXT4_FC_REPLAY getting set in\ns_mount_state.  This bypasses some sanity checks, and this can trigger\na BUG() in ext4_es_cache_extent().  As a easy-to-backport-fix, filter\nout the EXT4_FC_REPLAY bit for now.  We should eventually transition\naway from EXT4_FC_REPLAY to something like EXT4_MF_REPLAY.",
  "id": "GHSA-rhf9-9q5c-jr4g",
  "modified": "2025-10-21T12:31:25Z",
  "published": "2025-10-21T12:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49348"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/55b4dbb29054a05d839562f6d635ce05669b016d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af2f1932743fb52ebcb008ad7ac500d9df0aa796"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b99fd73418350dea360da8311e87a6a7b0e15a4c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c878bea3c9d724ddfa05a813f30de3d25a0ba83f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc5b09cb6dacd4b32640537929ab4ee8fb2b9e04"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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