ext4: Fix Use-After-Free in ext4_rename_dir_prepare
Summary
GSD-2022-1004047: ext4: fix use-after-free in ext4_rename_dir_prepare. Affects Kernel versions < 1a3a15bf6f9963d755270cbdb282863b84839195. No fix is published. How to fix ↓
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Background
The ext4 package is a file system driver for the Linux Kernel. It provides support for the fourth extended file system (ext4) and is widely used in Linux distributions. The ext4 file system is known for its performance, scalability, and reliability. However, a vulnerability has been discovered in the ext4_rename_dir_prepare function, which can lead to a use-after-free condition. This vulnerability can potentially be exploited by an attacker to execute arbitrary code or cause a denial-of-service (DoS) attack.
Vulnerability Detail
The vulnerability in ext4_rename_dir_prepare arises from a use-after-free condition. This occurs when the function attempts to rename a directory and encounters an error during the process. If the error occurs after the function has already freed the memory associated with the directory, it may result in a use-after-free vulnerability. An attacker can potentially exploit this vulnerability by carefully crafting a malicious input that triggers the error condition and then manipulating the freed memory to execute arbitrary code or disrupt the normal operation of the system. The impact of this vulnerability can range from privilege escalation to system crashes or even remote code execution.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can apply patches or backports provided by their Linux distribution to address the vulnerability without updating the entire kernel. The specific steps for applying patches or backports may vary depending on the Linux distribution being used. Users are advised to consult the documentation and support channels of their Linux distribution for guidance on applying patches or backports.
Conclusion
The ext4 package in the Linux Kernel is vulnerable to a use-after-free vulnerability in the ext4_rename_dir_prepare function. This vulnerability can be exploited by an attacker to execute arbitrary code or cause a denial-of-service attack. Users are strongly recommended to update their Linux Kernel to version v4.9.318 or later to mitigate this vulnerability. Alternatively, they can apply patches or backports provided by their Linux distribution. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
ext4 is a file system driver for the Linux Kernel that provides support for the fourth extended file system (ext4). It is widely used in Linux distributions due to its performance, scalability, and reliability.
A use-after-free vulnerability occurs when a program or function continues to use a memory address after it has been freed. This can lead to memory corruption, crashes, or the execution of arbitrary code.
An attacker can exploit this vulnerability by triggering the error condition in the ext4_rename_dir_prepare function and manipulating the freed memory to execute arbitrary code or disrupt the normal operation of the system.
The impact of this vulnerability can range from privilege escalation to system crashes or even remote code execution.
To fix this vulnerability, users are advised to update their Linux Kernel to version v4.9.318 or later. Alternatively, they can apply patches or backports provided by their Linux distribution.
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