ghsa-qw38-ppmm-fjpw
Vulnerability from github
Published
2024-10-21 21:30
Modified
2024-10-25 21:31
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Details

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

perf: Fix perf_pending_task() UaF

Per syzbot it is possible for perf_pending_task() to run after the event is free()'d. There are two related but distinct cases:

  • the task_work was already queued before destroying the event;
  • destroying the event itself queues the task_work.

The first cannot be solved using task_work_cancel() since perf_release() itself might be called from a task_work (____fput), which means the current->task_works list is already empty and task_work_cancel() won't be able to find the perf_pending_task() entry.

The simplest alternative is extending the perf_event lifetime to cover the task_work.

The second is just silly, queueing a task_work while you know the event is going away makes no sense and is easily avoided by re-arranging how the event is marked STATE_DEAD and ensuring it goes through STATE_OFF on the way down.

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{
   affected: [],
   aliases: [
      "CVE-2022-48950",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-416",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-10-21T20:15:06Z",
      severity: "HIGH",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nperf: Fix perf_pending_task() UaF\n\nPer syzbot it is possible for perf_pending_task() to run after the\nevent is free()'d. There are two related but distinct cases:\n\n - the task_work was already queued before destroying the event;\n - destroying the event itself queues the task_work.\n\nThe first cannot be solved using task_work_cancel() since\nperf_release() itself might be called from a task_work (____fput),\nwhich means the current->task_works list is already empty and\ntask_work_cancel() won't be able to find the perf_pending_task()\nentry.\n\nThe simplest alternative is extending the perf_event lifetime to cover\nthe task_work.\n\nThe second is just silly, queueing a task_work while you know the\nevent is going away makes no sense and is easily avoided by\nre-arranging how the event is marked STATE_DEAD and ensuring it goes\nthrough STATE_OFF on the way down.",
   id: "GHSA-qw38-ppmm-fjpw",
   modified: "2024-10-25T21:31:26Z",
   published: "2024-10-21T21:30:50Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2022-48950",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/517e6a301f34613bff24a8e35b5455884f2d83d8",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/78e1317a174edbfd1182599bf76c092a2877672c",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/8bffa95ac19ff27c8261904f89d36c7fcf215d59",
      },
   ],
   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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