Linux Kernel Nios2 Memory Management Vulnerability Leading to Kernel Panic

A vulnerability in the Linux kernel for the Nios2 architecture has been addressed. With the CONFIG_FLATMEM option enabled, the kernel improperly initializes the memory block limits, which can cause the maximum low page frame number (max_low_pfn) to exceed the actual physical memory limits. This misconfiguration can lead to kernel paging errors and system crashes. The issue arises because the memory block current limit is only set to allocate memory anywhere by default, allowing the low memory page frame number to incorrectly surpass the available memory range, potentially causing paging failures and kernel panics.

Impact

Exploitation of this vulnerability can cause kernel paging requests to fail, leading to a kernel panic and system crash.

Reproduction

To reproduce this vulnerability, boot a Linux kernel on a Nios2 system with the CONFIG_FLATMEM option enabled. During the boot process, the memory block current limit will be improperly set, allowing the maximum low page frame number to exceed the actual physical memory limits. This misconfiguration can be observed by monitoring the kernel messages for paging request errors, which will indicate a kernel panic has occurred.

Remediation

The vulnerability has been fixed in the Linux kernel. Users should upgrade to the latest version where this issue has been addressed.