ghsa-839p-pc8m-rw47
Vulnerability from github
Published
2024-10-21 12:30
Modified
2024-11-08 18:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

nilfs2: fix potential null-ptr-deref in nilfs_btree_insert()

Patch series "nilfs2: fix potential issues with empty b-tree nodes".

This series addresses three potential issues with empty b-tree nodes that can occur with corrupted filesystem images, including one recently discovered by syzbot.

This patch (of 3):

If a b-tree is broken on the device, and the b-tree height is greater than 2 (the level of the root node is greater than 1) even if the number of child nodes of the b-tree root is 0, a NULL pointer dereference occurs in nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert().

This is because, when the number of child nodes of the b-tree root is 0, nilfs_btree_do_lookup() does not set the block buffer head in any of path[x].bp_bh, leaving it as the initial value of NULL, but if the level of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(), which accesses the buffer memory of path[x].bp_bh, is called.

Fix this issue by adding a check to nilfs_btree_root_broken(), which performs sanity checks when reading the root node from the device, to detect this inconsistency.

Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause early on.

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2024-47699"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-10-21T12:15:06Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix potential null-ptr-deref in nilfs_btree_insert()\n\nPatch series \"nilfs2: fix potential issues with empty b-tree nodes\".\n\nThis series addresses three potential issues with empty b-tree nodes that\ncan occur with corrupted filesystem images, including one recently\ndiscovered by syzbot.\n\n\nThis patch (of 3):\n\nIf a b-tree is broken on the device, and the b-tree height is greater than\n2 (the level of the root node is greater than 1) even if the number of\nchild nodes of the b-tree root is 0, a NULL pointer dereference occurs in\nnilfs_btree_prepare_insert(), which is called from nilfs_btree_insert().\n\nThis is because, when the number of child nodes of the b-tree root is 0,\nnilfs_btree_do_lookup() does not set the block buffer head in any of\npath[x].bp_bh, leaving it as the initial value of NULL, but if the level\nof the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(),\nwhich accesses the buffer memory of path[x].bp_bh, is called.\n\nFix this issue by adding a check to nilfs_btree_root_broken(), which\nperforms sanity checks when reading the root node from the device, to\ndetect this inconsistency.\n\nThanks to Lizhi Xu for trying to solve the bug and clarifying the cause\nearly on.",
  "id": "GHSA-839p-pc8m-rw47",
  "modified": "2024-11-08T18:30:44Z",
  "published": "2024-10-21T12:30:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-47699"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d94dbdfbb64cc48d10dec65cc3c4fbf2497b343"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/21839b6fbc3c41b3e374ecbdb0cabbbb2c53cf34"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24bf40740a3da6b4056721da34997ae6938f3da1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b78e9df10fb7f4e9d3d7a18417dd72fbbc1dfd0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3644554d308ddf2669e459a1551a7edf60b2d62b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/73d23ecf234b7a6d47fb883f2dabe10e3230b31d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9403001ad65ae4f4c5de368bdda3a0636b51d51a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/db73500d3f0e558eb642aae1d4782e7726b4a03f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f68523e0f26faade18833fbef577a4295d8e2c94"
    }
  ],
  "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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