Slab-Out-of-Bounds Vulnerability in Linux Kernel Package: linux
Summary
DEBIAN-CVE-2024-40955: In the Linux kernel, the following vulnerability has been resolved: ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists() We can trigger a slab-out-of-bounds with the following commands: mkfs.ext4 -F /... Affects linux versions < 6.9.7-1. Fixed in 6.9.7-1. How to fix ↓
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Background
The 'linux' package is a core component of the Debian operating system, providing the Linux kernel that manages hardware resources and enables software applications to run. It is essential for system stability and performance. This vulnerability affects versions of the Linux kernel in Debian 13 and 14, specifically related to the ext4 filesystem, which is widely used for managing disk storage.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the ext4 filesystem that can lead to a slab-out-of-bounds condition. This occurs when an oversized value is set for the 'mb_group_prealloc' parameter, allowing an out-of-bounds memory access. This can be triggered by specific commands that manipulate filesystem parameters, potentially leading to system instability or crashes. The issue arises from improper handling of memory allocation and can be exploited by a local attacker to cause denial of service or other unintended behavior.
How To Fix
Minimum fixed version
6.9.7-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, avoid setting the 'mb_group_prealloc' parameter to excessively high values. Instead, use a value within the acceptable range to prevent triggering the slab-out-of-bounds condition.
Conclusion
The slab-out-of-bounds vulnerability in the Linux kernel's ext4 filesystem poses significant risks to system stability and security. It is crucial to update the affected 'linux' package to the patched version to safeguard against potential exploits. Users should also be cautious with filesystem parameters to avoid triggering this vulnerability.
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FAQ
A slab-out-of-bounds vulnerability occurs when a program accesses memory outside the allocated bounds of a data structure, potentially leading to crashes or security issues.
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The risks include potential system crashes, data corruption, and unauthorized access to system resources, which can be exploited by local attackers.
Yes, the vulnerability can be triggered using commands such as 'mkfs.ext4 -F /dev/$disk 10G' followed by setting 'mb_group_prealloc' to an excessively high value.
If immediate updates are not possible, ensure that you do not set the 'mb_group_prealloc' parameter to high values as a temporary measure to mitigate the risk.
References
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