Linux Kernel Spectre Vulnerability in s390 Syscall Dispatch Table

A vulnerability has been addressed in the Linux kernel's handling of system calls on the s390 architecture. The issue arises because the syscall number can be manipulated by userspace, leading to potential access beyond the intended boundaries of the syscall function pointer tables. This vulnerability did not include a protective boundary to prevent such oversights, creating a risk of improper access or execution.

Impact

Exploitation of this vulnerability could allow userspace to manipulate syscall numbers and access functions beyond the intended limits, potentially leading to unauthorized actions or access within the kernel.

Reproduction

The vulnerability can be reproduced by manipulating syscall numbers from userspace on an s390 system. Without the array_index_nospec() boundary, it's possible to access functions beyond the syscall dispatch table's intended limits.

Remediation

Users can update to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for downloading the patched version are available on the official Linux kernel website.