CVE-2024-26685 Affecting cluster-md-kmp-default package, versions <6.4.0-150600.23.7.3


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating

    Threat Intelligence

    EPSS
    0.04% (14th percentile)

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  • Snyk ID SNYK-SLES156-CLUSTERMDKMPDEFAULT-7712798
  • published 20 Aug 2024
  • disclosed 25 Jun 2024

How to fix?

Upgrade SLES:15.6 cluster-md-kmp-default to version 6.4.0-150600.23.7.3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream cluster-md-kmp-default package and not the cluster-md-kmp-default package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

nilfs2: fix potential bug in end_buffer_async_write

According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2.

Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash.

This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel.

The use of async_write for segment summary buffers has already been removed in a previous change.

Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer.

CVSS Scores

version 3.1
Expand this section

SUSE

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

Red Hat

5.5 medium