In the Linux kernel, the following vulnerability has been resolved: btrfs: set_page_extent_mapped after read_folio in btrfs_cont_expand. While trying to get the subpage blocksize tests running, an assertion failure occurred, leading to a kernel panic. The panic is attributed to the improper handling of page mappings in certain conditions during the btrfs_cont_expand function. Specifically, if a page is read and then released before it can be safely modified, it can lead to critical errors.
This vulnerability allows for a high impact on availability, as the kernel panic can cause system instability or crashes. Organizations utilizing affected versions of the Linux kernel should prioritize remediation to avoid potential downtime.
The severity level of this vulnerability is classified as medium with a CVSS score of 5.5. The attack vector is local, requiring low privileges for exploitation, yet it can lead to significant availability issues.
Organizations should prioritize patching immediately to mitigate the risks associated with this vulnerability.
Vulnerability Details
The vulnerability arises from how the btrfs filesystem handles page mappings during certain operations. The patch modifies the order of operations to ensure that page mappings are set after reading the page, thereby preventing the potential for a kernel panic due to improper page states.
Technical Analysis
The root cause of this vulnerability is a race condition occurring in the btrfs_cont_expand function, which handles file system expansions. Specifically, the function improperly sets the page as mapped before ensuring that the data is up-to-date. This leads to scenarios where a page could be released while still being in use, resulting in a kernel panic when the page's state is later modified.
Risk & Impact Analysis
Risk to organizations includes potential downtime or data loss due to kernel panics triggered by this vulnerability. The impact is particularly concerning for systems relying on the btrfs filesystem for data storage, as the resulting instability can hinder operations and lead to significant recovery efforts.
Given the CVSS score of 5.5, organizations should address this vulnerability in their priority patch cycle to maintain operational integrity.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions prior to vendor patch, specifically: - Linux kernel versions < 6.1.42, - Linux kernel versions from 6.2 up to and excluding 6.4.7, - Version 6.5 release candidates rc1 and rc2.
Mitigation & Remediation
Organizations should apply the following patches to mitigate this vulnerability: 1. Update to Linux kernel version 6.1.42 or later. 2. If using a version between 6.2 and 6.4.7, ensure to upgrade to a patched release. 3. Apply the patch from the relevant vendor's advisory to prevent kernel panic during btrfs operations.
For further information on continuous security testing, organizations can refer to continuous penetration testing practices.
Detection Guidance
Monitoring for unusual kernel behavior or unexpected crashes during btrfs operations can be indicative of exploitation attempts. Log indicators should include kernel panic reports, unusual system resource usage, and integrity checks on filesystem states.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability reflects the persistent challenges in maintaining kernel integrity and stability. As systems evolve, the patterns of vulnerabilities indicate a need for proactive security measures.
Organizations are encouraged to adopt a comprehensive vulnerability management program to mitigate similar risks.
Additionally, ongoing education on the latest security trends, such as those detailed in our security testing best practices, will enhance organizational resilience against emerging threats.
Lastly, regular engagement with penetration testing methodologies can provide additional insights into potential vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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