Linux Kernel RSS Key Handling Vulnerability Leading to Memory Allocation Errors

A vulnerability in the Linux kernel's handling of Receive Side Scaling (RSS) keys has been identified. When the RSS capability is not supported on certain devices, the kernel incorrectly returns a size of zero for the RSS key. This erroneous size leads to memory allocation failures. The issue arises in the 'ethtool' command when querying network interfaces that lack RSS capabilities.

Impact

The vulnerability can cause memory allocation failures, which may disrupt normal kernel operations and potentially lead to system instability.

Reproduction

The vulnerability can be reproduced by using the 'ethtool -x' command on a network interface that does not have RSS capabilities enabled. This will trigger the kernel to return an invalid size for the RSS key, leading to a memory allocation failure.