The Linux kernel is an essential component of the operating system that provides low-level services to the user, such as device drivers and memory management. It plays a vital role in ensuring the efficient functioning and security of the system. Recently, a vulnerability has been discovered in the Linux kernel and has been resolved, as detailed below.

Vulnerability Details

In the Linux kernel, a vulnerability has been fixed that could lead to unintended access to uninitialized values in the hsr_get_node() function. This function is related to the High-availability Seamless Redundancy (HSR) protocol, which is used to implement fault-tolerant communication networks.

The discovery of this vulnerability was reported by KMSAN [1], which identified an uninit-value access issue in the hsr_get_node function's implementation in "net/hsr/hsr_framereg.c" (line 246):

BUG: KMSAN: uninit-value in hsr_get_node+xa2e/xa40 net/hsr/hsr_framereg.c:246

The root cause of this vulnerability was identified as an incorrect handling of packet types in the Ethernet header. If the packet type ID field in the Ethernet header is either ETH_P_PRP or ETH_P_HSR, but it is not followed by an HSR tag, the hsr_get_skb_sequence_nr() function reads an invalid value as a sequence number, resulting in the aforementioned uninit-value access issue.

Patch Details

To fix this vulnerability, the hsr_get_node() function has been patched to return NULL if the Ethernet header is not followed by an HSR tag. This ensures that only valid HSR packets are processed by the function, and no uninitialized values are accessed.

Conclusion

This vulnerability highlights the importance of thorough code reviews and testing, especially in critical components like the Linux kernel. By addressing this issue, the security and reliability of Linux-based systems are further improved.

Original References

1. KMSAN: https://github.com/google/kmsan

Exploit Details

The exploit for this vulnerability has not been publicly released. To avoid exposing systems to potential attacks, it is recommended to apply available patches and keep your Linux kernel up-to-date.

Timeline

Published on: 04/17/2024 11:15:09 UTC
Last modified on: 01/27/2025 15:05:39 UTC