GHSA-JRXV-VV4V-JRRH

Vulnerability from github – Published: 2025-04-16 15:34 – Updated: 2025-11-03 21:33
VLAI
Details

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

tracing: Fix use-after-free in print_graph_function_flags during tracer switching

Kairui reported a UAF issue in print_graph_function_flags() during ftrace stress testing [1]. This issue can be reproduced if puting a 'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(), and executing the following script:

$ echo function_graph > current_tracer $ cat trace > /dev/null & $ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point $ echo timerlat > current_tracer

The root cause lies in the two calls to print_graph_function_flags within print_trace_line during each s_show():

  • One through 'iter->trace->print_line()';
  • Another through 'event->funcs->trace()', which is hidden in print_trace_fmt() before print_trace_line returns.

Tracer switching only updates the former, while the latter continues to use the print_line function of the old tracer, which in the script above is print_graph_function_flags.

Moreover, when switching from the 'function_graph' tracer to the 'timerlat' tracer, s_start only calls graph_trace_close of the 'function_graph' tracer to free 'iter->private', but does not set it to NULL. This provides an opportunity for 'event->funcs->trace()' to use an invalid 'iter->private'.

To fix this issue, set 'iter->private' to NULL immediately after freeing it in graph_trace_close(), ensuring that an invalid pointer is not passed to other tracers. Additionally, clean up the unnecessary 'iter->private = NULL' during each 'cat trace' when using wakeup and irqsoff tracers.

[1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2025-22035"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-04-16T15:15:56Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free in print_graph_function_flags during tracer switching\n\nKairui reported a UAF issue in print_graph_function_flags() during\nftrace stress testing [1]. This issue can be reproduced if puting a\n\u0027mdelay(10)\u0027 after \u0027mutex_unlock(\u0026trace_types_lock)\u0027 in s_start(),\nand executing the following script:\n\n  $ echo function_graph \u003e current_tracer\n  $ cat trace \u003e /dev/null \u0026\n  $ sleep 5  # Ensure the \u0027cat\u0027 reaches the \u0027mdelay(10)\u0027 point\n  $ echo timerlat \u003e current_tracer\n\nThe root cause lies in the two calls to print_graph_function_flags\nwithin print_trace_line during each s_show():\n\n  * One through \u0027iter-\u003etrace-\u003eprint_line()\u0027;\n  * Another through \u0027event-\u003efuncs-\u003etrace()\u0027, which is hidden in\n    print_trace_fmt() before print_trace_line returns.\n\nTracer switching only updates the former, while the latter continues\nto use the print_line function of the old tracer, which in the script\nabove is print_graph_function_flags.\n\nMoreover, when switching from the \u0027function_graph\u0027 tracer to the\n\u0027timerlat\u0027 tracer, s_start only calls graph_trace_close of the\n\u0027function_graph\u0027 tracer to free \u0027iter-\u003eprivate\u0027, but does not set\nit to NULL. This provides an opportunity for \u0027event-\u003efuncs-\u003etrace()\u0027\nto use an invalid \u0027iter-\u003eprivate\u0027.\n\nTo fix this issue, set \u0027iter-\u003eprivate\u0027 to NULL immediately after\nfreeing it in graph_trace_close(), ensuring that an invalid pointer\nis not passed to other tracers. Additionally, clean up the unnecessary\n\u0027iter-\u003eprivate = NULL\u0027 during each \u0027cat trace\u0027 when using wakeup and\nirqsoff tracers.\n\n [1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/",
  "id": "GHSA-jrxv-vv4v-jrrh",
  "modified": "2025-11-03T21:33:35Z",
  "published": "2025-04-16T15:34:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-22035"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/099ef3385800828b74933a96c117574637c3fb3a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/42561fe62c3628ea3bc9623f64f047605e98857f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/70be951bc01e4a0e10d443f3510bb17426f257fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7f81f27b1093e4895e87b74143c59c055c3b1906"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81a85b12132c8ffe98f5ddbdc185481790aeaa1b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2cce54c1748216535dda02e185d07a084be837e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c85efe6e13743cac6ba4ccf144cb91f44c86231a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de7b309139f862a44379ecd96e93c9133c69f813"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f14752d66056d0c7bffe5092130409417d3baa70"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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