Linux Kernel Data Race Vulnerability in sock_recv_cmsgs() Function

A data race vulnerability has been identified in the Linux kernel's handling of socket timestamps within the sock_recv_cmsgs() function. This issue affects the stable group of the Linux kernel. The vulnerability arises because the read access to the socket's timestamp variable (sk->sk_stamp) is not properly synchronized, leading to potential inconsistencies. The Kernel Concurrency Sanitizer (KCSAN) reported this data race, indicating that the timestamp could be read and modified concurrently by different CPU cores, which may cause unexpected behavior in network packet processing.

Impact

The vulnerability can lead to a data race condition, where concurrent read and write operations on the socket timestamp variable can cause inconsistencies, potentially disrupting the normal processing of network packets.

Reproduction

The vulnerability can be reproduced by using the Syzkaller fuzzer, which is known to trigger such data race conditions in the Linux kernel. This can be done by running the fuzzer with a workload that exercises the packet receiving functionality, particularly in a virtualized environment that simulates multiple CPU cores.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. The specific commit that fixes this issue is available in the Linux kernel stable tree.