Vulnerability in Kernel: UAF for rx_kref of j1939_priv
Summary
GSD-2021-1002100: can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv. Affects Kernel versions >= 9d71dd0c70099914fcd063135da3c580865e924c, < 6e8811707e2df0c6ba920f0cad3a3bca7b42132f. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that provides core functionality and facilitates communication between hardware and software. It manages system resources, including memory, processes, and device drivers. The vulnerability in question affects the j1939 module within the Kernel, which is responsible for handling the J1939 protocol used in automotive applications. This vulnerability specifically impacts the j1939_netdev_start() function, leading to a use-after-free (UAF) vulnerability in the rx_kref of j1939_priv. This vulnerability can potentially be exploited by an attacker to execute arbitrary code or cause a denial-of-service (DoS) condition.
Vulnerability Detail
The vulnerability arises due to a use-after-free issue in the j1939_netdev_start() function of the j1939 module. When a network device is started, the function fails to properly handle reference counting for the rx_kref of j1939_priv. This can result in a situation where the rx_kref is freed while still being accessed, leading to a use-after-free vulnerability. An attacker who can trigger this vulnerability may be able to manipulate the freed memory to execute arbitrary code or cause a DoS condition. The impact and attack plausibility of this vulnerability have not been proven yet.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can disable the j1939 module if it is not required for their system. This can be done by blacklisting the module or removing it from the Kernel configuration. However, this workaround may not be feasible in all cases, especially if the j1939 module is essential for the system's functionality.
Conclusion
The vulnerability in the Kernel's j1939 module poses a potential security risk due to a use-after-free vulnerability in the rx_kref of j1939_priv. It is crucial for users to update their Linux Kernel to version v5.14.15 or later to mitigate this vulnerability. Additionally, implementing network segmentation and access controls can help minimize the potential impact of an exploit. For further support and assistance in addressing this vulnerability, please contact DevNack.com.
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FAQ
The impact of this vulnerability can vary depending on the specific system and how it is configured. In some cases, an attacker may be able to execute arbitrary code with elevated privileges, potentially leading to a full compromise of the system. In other cases, the vulnerability may result in a denial-of-service condition, causing the system to become unresponsive or crash.
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 to the playground, and it will analyze the dependencies and alert you if any vulnerabilities are found.
As of now, there is no known exploit for this vulnerability. However, it is important to apply the necessary updates and patches to mitigate the risk of exploitation.
The primary mitigation for this vulnerability is to update the Linux Kernel to a version that includes the fix. Additionally, users can consider implementing network segmentation and access controls to limit the potential impact of an exploit.
The discovery of this vulnerability is credited to the Linux Kernel development community. The vulnerability was identified and fixed through the collaborative efforts of various contributors to the Kernel project.
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