SecuriTricks - CVE-2024-56759

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.

Product(s) Impacted

Vendor	Product	Versions
Linux	Linux Kernel	*, 6.13

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-416

Use After Free

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
o	linux	linux_kernel	/	/	/	/	/	/	/	/
o	linux	linux_kernel	6.13	rc1	/	/	/	/	/	/
o	linux	linux_kernel	6.13	rc2	/	/	/	/	/	/
o	linux	linux_kernel	6.13	rc3	/	/	/	/	/	/
o	linux	linux_kernel	6.13	rc4	/	/	/	/	/	/

References

https://git.kernel.org/stable/c/44f52bbe96dfdbe4aca3818a2534520082a07040

https://git.kernel.org/stable/c/526ff5b27f090fb15040471f892cd2c9899ce314

https://git.kernel.org/stable/c/66376f1a73cba57fd0af2631d7888605b738e499

https://git.kernel.org/stable/c/9a466b8693b9add05de99af00c7bdff8259ecf19

https://git.kernel.org/stable/c/ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1

https://git.kernel.org/stable/c/c3a403d8ce36f5a809a492581de5ad17843e4701

CVSS Score

7.8 / 10

CVSS Data - 3.1

Attack Vector: LOCAL
Attack Complexity: LOW
Privileges Required: LOW
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: HIGH

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

View Vector String

Timeline

Published: Jan. 6, 2025, 5:15 p.m.
Last Modified: Feb. 11, 2025, 4:15 p.m.

Status : Modified

CVE has been amended by a source (CVE Primary CNA or another CNA). Analysis data supplied by the NVD may be no longer be accurate due to these changes.

More info

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVE-2024-56759