CVE-2023-53584
Description
A race condition was found in the Linux kernel's UBIFS filesystem in the page release logic. A local user can trigger this issue through concurrent file operations including writes, truncation, and cache invalidation, causing pages to become private but not dirty due to timing of dirty flag clearing and size updates. This results in hitting an assertion in ubifs_releasepage when the filesystem attempts to release pages in an unexpected state, leading to filesystem errors and denial of service.
Statement
The race occurs across three concurrent operations: Process A writes and dirties a page with UBIFS private data, then clears the dirty flag during writeback. Process B truncates the file to zero size. Process A checks the new file size, finds the page is now beyond EOF, and unlocks it without finishing writeback—leaving it private but not dirty. Process C then calls fadvise which attempts to invalidate the page, calling ubifs_releasepage on a private, non-dirty page. This state violates the driver's assumption that private pages are always dirty, triggering an assertion that switches the filesystem to read-only mode. The race window requires precise timing between write, truncate, and fadvise operations, but can occur during normal concurrent filesystem use.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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