GHSA-HF2G-J6WM-QRRX

Vulnerability from github – Published: 2024-06-25 15:31 – Updated: 2024-11-05 18:31
VLAI
Details

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

ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()

Syzbot reports a warning as follows:

============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================

This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage.

So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2024-39276"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-06-25T15:15:13Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix mb_cache_entry\u0027s e_refcnt leak in ext4_xattr_block_cache_find()\n\nSyzbot reports a warning as follows:\n\n============================================\nWARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290\nModules linked in:\nCPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7\nRIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419\nCall Trace:\n \u003cTASK\u003e\n ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375\n generic_shutdown_super+0x136/0x2d0 fs/super.c:641\n kill_block_super+0x44/0x90 fs/super.c:1675\n ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327\n[...]\n============================================\n\nThis is because when finding an entry in ext4_xattr_block_cache_find(), if\next4_sb_bread() returns -ENOMEM, the ce\u0027s e_refcnt, which has already grown\nin the __entry_find(), won\u0027t be put away, and eventually trigger the above\nissue in mb_cache_destroy() due to reference count leakage.\n\nSo call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.",
  "id": "GHSA-hf2g-j6wm-qrrx",
  "modified": "2024-11-05T18:31:59Z",
  "published": "2024-06-25T15:31:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-39276"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9ad75e78747b5a50dc5a52f0f8e92e920a653f16"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}



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