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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2022-49834 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix use-after-free bug of ns_writer on remount If a nilfs2 filesystem is downgraded to read-only due to metadata corruption on disk and is remounted read/write, or if emergency read-only remount is performed, detaching a log writer and synchronizing the filesystem can be done at the same time. In these cases, use-after-free of the log writer (hereinafter nilfs->ns_writer) can happen as shown in the scenario below: Task1 Task2 -------------------------------- ------------------------------ nilfs_construct_segment nilfs_segctor_sync init_wait init_waitqueue_entry add_wait_queue schedule nilfs_remount (R/W remount case) nilfs_attach_log_writer nilfs_detach_log_writer nilfs_segctor_destroy kfree finish_wait _raw_spin_lock_irqsave __raw_spin_lock_irqsave do_raw_spin_lock debug_spin_lock_before <-- use-after-free While Task1 is sleeping, nilfs->ns_writer is freed by Task2. After Task1 waked up, Task1 accesses nilfs->ns_writer which is already freed. This scenario diagram is based on the Shigeru Yoshida's post [1]. This patch fixes the issue by not detaching nilfs->ns_writer on remount so that this UAF race doesn't happen. Along with this change, this patch also inserts a few necessary read-only checks with superblock instance where only the ns_writer pointer was used to check if the filesystem is read-only.


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/39a3ed68270b079c6b874d4e4727a512b9b4882c kernel.org
https://git.kernel.org/stable/c/4feedde5486c07ea79787839153a71ca71329c7d kernel.org
https://git.kernel.org/stable/c/8cccf05fe857a18ee26e20d11a8455a73ffd4efd kernel.org
https://git.kernel.org/stable/c/9b162e81045266a2d5b44df9dffdf05c54de9cca kernel.org
https://git.kernel.org/stable/c/afbd1188382a75f6cfe22c0b68533f7f9664f182 kernel.org
https://git.kernel.org/stable/c/b152300d5a1ba4258dacf9916bff20e6a8c7603b kernel.org
https://git.kernel.org/stable/c/b2fbf10040216ef5ee270773755fc2f5da65b749 kernel.org
https://git.kernel.org/stable/c/b4736ab5542112fe0a40f140a0a0b072954f34da kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2022-49834
NVD Published Date:
05/01/2025
NVD Last Modified:
05/02/2025
Source:
kernel.org