ghsa-xgm7-3x53-gq2c
Vulnerability from github
Published
2024-05-22 09:31
Modified
2024-07-03 18:43
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

net: batman-adv: fix error handling

Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was in wrong error handling in batadv_mesh_init().

Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case of any batadv_*_init() calls failure. This approach may work well, when there is some kind of indicator, which can tell which parts of batadv are initialized; but there isn't any.

All written above lead to cleaning up uninitialized fields. Even if we hide ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1]

To fix these bugs we can unwind batadv_init() calls one by one. It is good approach for 2 reasons: 1) It fixes bugs on error handling path 2) It improves the performance, since we won't call unneeded batadv_free() functions.

So, this patch makes all batadv_init() clean up all allocated memory before returning with an error to no call correspoing batadv_free() and open-codes batadv_mesh_free() with proper order to avoid touching uninitialized fields.

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{
   affected: [],
   aliases: [
      "CVE-2021-47482",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-544",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-05-22T09:15:10Z",
      severity: "MODERATE",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: batman-adv: fix error handling\n\nSyzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was\nin wrong error handling in batadv_mesh_init().\n\nBefore this patch batadv_mesh_init() was calling batadv_mesh_free() in case\nof any batadv_*_init() calls failure. This approach may work well, when\nthere is some kind of indicator, which can tell which parts of batadv are\ninitialized; but there isn't any.\n\nAll written above lead to cleaning up uninitialized fields. Even if we hide\nODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit\nGPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1]\n\nTo fix these bugs we can unwind batadv_*_init() calls one by one.\nIt is good approach for 2 reasons: 1) It fixes bugs on error handling\npath 2) It improves the performance, since we won't call unneeded\nbatadv_*_free() functions.\n\nSo, this patch makes all batadv_*_init() clean up all allocated memory\nbefore returning with an error to no call correspoing batadv_*_free()\nand open-codes batadv_mesh_free() with proper order to avoid touching\nuninitialized fields.",
   id: "GHSA-xgm7-3x53-gq2c",
   modified: "2024-07-03T18:43:07Z",
   published: "2024-05-22T09:31:46Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2021-47482",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/07533f1a673ce1126d0a72ef1e4b5eaaa3dd6d20",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/0c6b199f09be489c48622537a550787fc80aea73",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/6422e8471890273994fe8cc6d452b0dcd2c9483e",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/6f68cd634856f8ca93bafd623ba5357e0f648c68",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/a8f7359259dd5923adc6129284fdad12fc5db347",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/b0a2cd38553c77928ef1646ed1518486b1e70ae8",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/e50f957652190b5a88a8ebce7e5ab14ebd0d3f00",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/fbf150b16a3635634b7dfb7f229d8fcd643c6c51",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
         type: "CVSS_V3",
      },
   ],
}


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