Vulnerability in Kernel: x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n
Summary
GSD-2021-1001618: x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n. Affects Kernel versions >= 3c73b81a9164d0c1b6379d6672d2772a9e95168e, < f2447f6587b8ffe42ba04d14ce67d429a1163e5e. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that acts as a bridge between the hardware and software layers. It provides essential functionalities and services to enable the proper functioning of the system. This vulnerability specifically affects the x86/entry module of the Kernel. The x86/entry module is responsible for handling system calls and interrupts on x86 architecture. It contains code that manages the transition from user mode to kernel mode and vice versa. The vulnerability arises when the CONFIG_X86_SMAP configuration option is disabled, but the X86_FEATURE_SMAP flag is not cleared properly. This can lead to potential security risks.
Vulnerability Detail
The vulnerability occurs due to a misconfiguration in the Kernel when the CONFIG_X86_SMAP option is disabled. The X86_FEATURE_SMAP flag, which is responsible for enabling Supervisor Mode Access Prevention (SMAP) on x86 processors, is not cleared properly. SMAP is a security feature that prevents the kernel from accessing user-space memory directly. By not clearing the X86_FEATURE_SMAP flag, an attacker may be able to bypass SMAP protection and gain unauthorized access to user-space memory from the kernel. This could potentially lead to information disclosure or privilege escalation attacks. The vulnerability was introduced in version v5.8 of the Linux Kernel and has been fixed in version v5.10.73.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
There is no specific workaround mentioned for this vulnerability. The recommended solution is to update the Linux Kernel to the fixed version.
Conclusion
The vulnerability in the Kernel's x86/entry module, which fails to clear the X86_FEATURE_SMAP flag when the CONFIG_X86_SMAP option is disabled, can lead to security risks. It is crucial to update the Linux Kernel to version v5.10.73 or later to fix this vulnerability. For further assistance and support in vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability can potentially allow an attacker to bypass Supervisor Mode Access Prevention (SMAP) protection and gain unauthorized access to user-space memory from the kernel. This could lead to information disclosure or privilege escalation attacks.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your system is affected by this vulnerability. Simply upload your package-lock.json file and Vulert will analyze it for any open-source vulnerabilities, including this one.
Yes, a patch has been released to fix this vulnerability. It is recommended to update the Linux Kernel to version v5.10.73 or later.
The recommended solution is to update the Linux Kernel to the fixed version. However, if updating is not feasible, it is advised to follow best security practices such as restricting access to vulnerable systems, implementing network segmentation, and monitoring for any suspicious activities.
At the time of this report, there are no known exploits for this vulnerability. However, it is important to apply the necessary updates as soon as possible to mitigate any potential risks.
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