Linux Kernel ARM Integrator Early Initialization Crash Vulnerability

A vulnerability in the Linux kernel's ARM Integrator platform has been addressed. The issue arose during early initialization when the 'intcp_init_early' function called 'syscon_regmap_lookup_by_compatible'. This sequence attempted to allocate memory before the memory management system was ready, leading to failures that either returned an error or caused a kernel crash due to a null pointer dereference. This problem was particularly reproducible with certain versions of the GCC compiler, which dereferenced the null pointer under specific conditions. The crash could be avoided, but doing so would prevent the necessary scheduling clock initialization from occurring. The vulnerability has been fixed by relocating the early initialization code to the standard machine initialization phase, ensuring that the memory management system is fully operational before any allocations are attempted.

Impact

The vulnerability could lead to a kernel crash, disrupting system operations and potentially causing a denial of service.

Reproduction

The vulnerability can be reproduced by compiling the Linux kernel with GCC versions 10.x, 11.x, or 13.x, and then booting the kernel on an ARM Integrator/CP platform. The 'intcp_init_early' function will attempt to allocate memory using 'of_syscon_register' before the memory management system is initialized, leading to a crash or an error that prevents the scheduling clock from being set up properly.

Remediation

Users can apply the latest patches from the Linux kernel stable tree to address this vulnerability. Instructions for downloading the patched version are available in the commit references.