ghsa-ccgr-xwcc-r26p
Vulnerability from github
Published
2024-10-09 15:32
Modified
2024-10-23 18:33
Details

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

fsnotify: clear PARENT_WATCHED flags lazily

In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users.

Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children.

When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2024-47660"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-10-09T14:15:07Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfsnotify: clear PARENT_WATCHED flags lazily\n\nIn some setups directories can have many (usually negative) dentries.\nHence __fsnotify_update_child_dentry_flags() function can take a\nsignificant amount of time. Since the bulk of this function happens\nunder inode-\u003ei_lock this causes a significant contention on the lock\nwhen we remove the watch from the directory as the\n__fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask()\nraces with __fsnotify_update_child_dentry_flags() calls from\n__fsnotify_parent() happening on children. This can lead upto softlockup\nreports reported by users.\n\nFix the problem by calling fsnotify_update_children_dentry_flags() to\nset PARENT_WATCHED flags only when parent starts watching children.\n\nWhen parent stops watching children, clear false positive PARENT_WATCHED\nflags lazily in __fsnotify_parent() for each accessed child.",
  "id": "GHSA-ccgr-xwcc-r26p",
  "modified": "2024-10-23T18:33:06Z",
  "published": "2024-10-09T15:32:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-47660"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/172e422ffea20a89bfdc672741c1aad6fbb5044e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f3ef1d9f66b93913ce2171120d9226b55acd41d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ef1d2e240c32b1f337a37232d037b07e3919e1a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d8c42405fc3507cc43ba7e4986a773c3fc633f6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f9a48bc3dd9099935751458a5bbbea4b7c28abc8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc1b1e135c3f72382f792e6c319fc088d5523ad5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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