CVE-2024-56759

Published Jan 6, 2025

Last updated 7 months ago

CVSS high 7.8

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free when COWing tree bock and tracing is enabled When a COWing a tree block, at btrfs_cow_block(), and we have the tracepoint trace_btrfs_cow_block() enabled and preemption is also enabled (CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent buffer while inside the tracepoint code. This is because in some paths that call btrfs_cow_block(), such as btrfs_search_slot(), we are holding the last reference on the extent buffer @buf so btrfs_force_cow_block() drops the last reference on the @buf extent buffer when it calls free_extent_buffer_stale(buf), which schedules the release of the extent buffer with RCU. This means that if we are on a kernel with preemption, the current task may be preempted before calling trace_btrfs_cow_block() and the extent buffer already released by the time trace_btrfs_cow_block() is called, resulting in a use-after-free. Fix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to btrfs_force_cow_block() before the COWed extent buffer is freed. This also has a side effect of invoking the tracepoint in the tree defrag code, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is called there, but this is fine and it was actually missing there.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-416
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-416

Social media

Hype score
Not currently trending

  1. CVE-2024-56759 Use-After-Free Vulnerability Fixed in Linux btrfs COW Process In the Linux kernel, a problem has been fixed: btrfs: patch for use-after-free during COW of tree block with tracing on When doing a ... https://t.co/xQHGzSeoC6

    @VulmonFeeds

    6 Jan 2025

    16 Impressions

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  2. CVE-2024-56759 In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free when COWing tree bock and tracing is enabled When a COWing a tree bloc… https://t.co/AktqU6fzgo

    @CVEnew

    6 Jan 2025

    339 Impressions

    0 Retweets

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Configurations

Related CVEs

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References

Sources include official advisories and independent security research.