ghsa-w6pp-p9r9-cvm4
Vulnerability from github
Published
2025-09-05 18:31
Modified
2025-09-05 18:31
Details

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

i2c: core: Fix double-free of fwnode in i2c_unregister_device()

Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct device"), i2c_unregister_device() only called fwnode_handle_put() on of_node-s in the form of calling of_node_put(client->dev.of_node).

But after this commit the i2c_client's fwnode now unconditionally gets fwnode_handle_put() on it.

When the i2c_client has no primary (ACPI / OF) fwnode but it does have a software fwnode, the software-node will be the primary node and fwnode_handle_put() will put() it.

But for the software fwnode device_remove_software_node() will also put() it leading to a double free:

[ 82.665598] ------------[ cut here ]------------ [ 82.665609] refcount_t: underflow; use-after-free. [ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11 ... [ 82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110 ... [ 82.666962] [ 82.666971] i2c_unregister_device+0x60/0x90

Fix this by not calling fwnode_handle_put() when the primary fwnode is a software-node.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-38682"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-04T16:15:35Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: core: Fix double-free of fwnode in i2c_unregister_device()\n\nBefore commit df6d7277e552 (\"i2c: core: Do not dereference fwnode in struct\ndevice\"), i2c_unregister_device() only called fwnode_handle_put() on\nof_node-s in the form of calling of_node_put(client-\u003edev.of_node).\n\nBut after this commit the i2c_client\u0027s fwnode now unconditionally gets\nfwnode_handle_put() on it.\n\nWhen the i2c_client has no primary (ACPI / OF) fwnode but it does have\na software fwnode, the software-node will be the primary node and\nfwnode_handle_put() will put() it.\n\nBut for the software fwnode device_remove_software_node() will also put()\nit leading to a double free:\n\n[   82.665598] ------------[ cut here ]------------\n[   82.665609] refcount_t: underflow; use-after-free.\n[   82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11\n...\n[   82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110\n...\n[   82.666962]  \u003cTASK\u003e\n[   82.666971]  i2c_unregister_device+0x60/0x90\n\nFix this by not calling fwnode_handle_put() when the primary fwnode is\na software-node.",
  "id": "GHSA-w6pp-p9r9-cvm4",
  "modified": "2025-09-05T18:31:15Z",
  "published": "2025-09-05T18:31:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38682"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c24e5fc0c7096e00c202a6a3e0c342c1afb47c2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ffe02f7c4e36090154646612e67d331832f92037"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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