UAF Race Condition in bpf Module of Linux Kernel
Summary
GSD-2022-1001866: bpf: Fix UAF due to race between btf_try_get_module and load_module. Affects Kernel versions >= 541c3bad8dc51b253ba8686d0cd7628e6b9b5f4c, < 51b82141fffa454abf937a8ff0b8af89e4fd0c8f. No fix is published. How to fix ↓
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Background
The bpf module is a component of the Linux Kernel that provides support for Berkeley Packet Filter (BPF) programs. BPF programs are used for various purposes, including network packet filtering and tracing. The module allows users to load and execute BPF programs within the kernel. However, a race condition exists between the btf_try_get_module and load_module functions, leading to a use-after-free vulnerability.
Vulnerability Detail
The use-after-free vulnerability in the bpf module occurs due to a race condition between the btf_try_get_module and load_module functions. This vulnerability can be exploited by an attacker to execute arbitrary code or cause a denial-of-service condition. The race condition arises when multiple threads attempt to access the same BPF module concurrently, leading to a use-after-free scenario. An attacker can trigger this race condition to corrupt memory and gain control over the affected system.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can disable the loading of BPF programs by modifying the kernel configuration. This can be achieved by setting the CONFIG_BPF option to 'n' in the kernel configuration file and recompiling the kernel. However, this workaround may impact the functionality of applications that rely on BPF programs.
Conclusion
The use-after-free vulnerability in the bpf module of the Linux Kernel can be exploited by attackers to execute arbitrary code or cause a denial-of-service condition. It is important to update the Linux Kernel to the latest version to mitigate this vulnerability. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability can be exploited by an attacker to execute arbitrary code or cause a denial-of-service condition.
You can use Vulert's 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 workaround is available by disabling the loading of BPF programs in the kernel configuration. However, this may impact the functionality of applications relying on BPF programs.
Yes, the vulnerability has been fixed in Linux Kernel version v5.15.33 by commit 51b82141fffa454abf937a8ff0b8af89e4fd0c8f.
It is recommended to update your Linux Kernel to the latest version available to ensure the vulnerability is patched. Regularly applying security updates is crucial for maintaining the security of your system.
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