Linux Kernel SMC Hash Table Re-initialization Vulnerability

A vulnerability exists in the Linux kernel's handling of Shared Memory Communication (SMC) hash tables. The issue arises because the hash table heads for both IPv4 and IPv6 are re-initialized after certain socket-related initializations. This re-initialization can inadvertently reset the hash table heads, clearing existing entries that are in use and potentially leading to a corrupted list. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability can cause corruption in the SMC hash table lists, disrupting the management of hash entries and potentially leading to erroneous behavior in applications that rely on SMC sockets.

Reproduction

The vulnerability can be reproduced by initializing the SMC netlink interface, which triggers the re-initialization of the hash table heads. This can be done by calling the SMC initialization function, which will reset the hash table heads for both IPv4 and IPv6, clearing any existing entries that are in use.

Remediation

The vulnerability has been addressed by removing the unnecessary re-initialization of the SMC hash table heads in the SMC initialization function. Users should upgrade to the latest version of the Linux kernel where this fix has been applied.