Use After Free Affecting perf package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.04% (6th percentile)

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  • Snyk ID SNYK-RHEL8-PERF-8283161
  • published 23 Oct 2024
  • disclosed 21 Oct 2024

How to fix?

There is no fixed version for RHEL:8 perf.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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.

CVSS Scores

version 3.1
Expand this section

NVD

7.8 high
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
Expand this section

Red Hat

5.5 medium