CVE-2024-46840: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: clean up our handling of refs == 0 in snapshot delete In reada we BUG_ON(refs == 0), which could be unkind since we aren't holding a lock on the extent leaf and thus could get a transient incorrect answer. In walk_down_proc we also BUG_ON(refs == 0), which could happen if we have extent tree corruption. Change that to return -EUCLEAN. In do_walk_down() we catch this case and handle it correctly, however we return -EIO, which -EUCLEAN is a more appropriate error code. Finally in walk_up_proc we have the same BUG_ON(refs == 0), so convert that to proper error handling. Also adjust the error message so we can actually do something with the information.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 4.19.322
linux	linux_kernel	4.20 — 5.4.284
linux	linux_kernel	5.5 — 5.10.226
linux	linux_kernel	5.11 — 5.15.167
linux	linux_kernel	5.16 — 6.1.110
linux	linux_kernel	6.2 — 6.6.51
linux	linux_kernel	6.7 — 6.10.10

References

Advisories & Patches

https://git.kernel.org/stable/c/03804641ec2d0da4fa088ad21c88e703d151ce16 https://git.kernel.org/stable/c/71291aa7246645ef622621934d2067400380645e https://git.kernel.org/stable/c/728d4d045b628e006b48a448f3326a7194c88d32 https://git.kernel.org/stable/c/7d1df13bf078ffebfedd361d714ff6cee1ff01b9 https://git.kernel.org/stable/c/9cc887ac24b7a0598f4042ae9af6b9a33072f75b https://git.kernel.org/stable/c/b8ccef048354074a548f108e51d0557d6adfd3a3 https://git.kernel.org/stable/c/c60676b81fab456b672796830f6d8057058f029c https://git.kernel.org/stable/c/c847b28a799733b04574060ab9d00f215970627d

Other References

https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Frequently Asked Questions

What is CVE-2024-46840? +

In the Linux kernel, the following vulnerability has been resolved: btrfs: clean up our handling of refs == 0 in snapshot delete In reada we BUG_ON(refs == 0), which could be unkind since we aren't holding a lock on the extent leaf and thus could get a transient incorrect answer. In walk_down_proc we also BUG_ON(refs == 0), which could happen if we have extent tree corruption. Change that to return -EUCLEAN. In do_walk_down() we catch this case and handle it correctly, however we return -EIO, which -EUCLEAN is a more appropriate error code. Finally in walk_up_proc we have the same BUG_ON(refs == 0), so convert that to proper error handling. Also adjust the error message so we can actually do something with the information. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2024-46840? +

CVE-2024-46840 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-46840? +

CVE-2024-46840 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-46840? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2024-46840