CVE-2023-53337

/// Technical description

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

nilfs2: do not write dirty data after degenerating to read-only

According to syzbot's report, mark_buffer_dirty() called from

nilfs_segctor_do_construct() outputs a warning with some patterns after

nilfs2 detects metadata corruption and degrades to read-only mode.

After such read-only degeneration, page cache data may be cleared through

nilfs_clear_dirty_page() which may also clear the uptodate flag for their

buffer heads. However, even after the degeneration, log writes are still

performed by unmount processing etc., which causes mark_buffer_dirty() to

be called for buffer heads without the "uptodate" flag and causes the

warning.

Since any writes should not be done to a read-only file system in the

first place, this fixes the warning in mark_buffer_dirty() by letting

nilfs_segctor_do_construct() abort early if in read-only mode.

This also changes the retry check of nilfs_segctor_write_out() to avoid

unnecessary

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References