ghsa-8h7v-x635-x447
Vulnerability from github
Published
2024-03-13 18:31
Modified
2024-03-13 18:31
Details

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

mm: cachestat: fix folio read-after-free in cache walk

In cachestat, we access the folio from the page cache's xarray to compute its page offset, and check for its dirty and writeback flags. However, we do not hold a reference to the folio before performing these actions, which means the folio can concurrently be released and reused as another folio/page/slab.

Get around this altogether by just using xarray's existing machinery for the folio page offsets and dirty/writeback states.

This changes behavior for tmpfs files to now always report zeroes in their dirty and writeback counters. This is okay as tmpfs doesn't follow conventional writeback cache behavior: its pages get "cleaned" during swapout, after which they're no longer resident etc.

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{
  "affected": [],
  "aliases": [
    "CVE-2024-26630"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-03-13T16:15:30Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: cachestat: fix folio read-after-free in cache walk\n\nIn cachestat, we access the folio from the page cache\u0027s xarray to compute\nits page offset, and check for its dirty and writeback flags.  However, we\ndo not hold a reference to the folio before performing these actions,\nwhich means the folio can concurrently be released and reused as another\nfolio/page/slab.\n\nGet around this altogether by just using xarray\u0027s existing machinery for\nthe folio page offsets and dirty/writeback states.\n\nThis changes behavior for tmpfs files to now always report zeroes in their\ndirty and writeback counters.  This is okay as tmpfs doesn\u0027t follow\nconventional writeback cache behavior: its pages get \"cleaned\" during\nswapout, after which they\u0027re no longer resident etc.",
  "id": "GHSA-8h7v-x635-x447",
  "modified": "2024-03-13T18:31:34Z",
  "published": "2024-03-13T18:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26630"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a75cb05d53f4a6823a32deb078de1366954a804"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba60fdf75e89ea762bb617be578dc47f27655117"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe7e008e0ce728252e4ec652cceebcc62211657c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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