Linux Kernel kexec IMA Handling Vulnerability in CMA Area

A vulnerability in the Linux kernel's kexec functionality can lead to improper handling of Integrity Measurement Architecture (IMA) segments when allocated in the Contiguous Memory Allocator (CMA) area. This issue arises because the kexec target address is directly allocated in the CMA to avoid copying during execution, but the current implementation expects certain pages to be available, leading to warnings and potential mismanagement of the kexec process.

Impact

This vulnerability can cause warnings during the kexec process, indicating a misalignment between expected and actual memory segment handling, which could disrupt the kexec operation.

Reproduction

To reproduce this vulnerability, reserve a CMA area in the kernel using the 'cma=' option in the kernel command line. Then, load a kexec target that is allocated in the CMA area. This will trigger the warning about the missing IND_SOURCE for the kexec segment, demonstrating the vulnerability.

Remediation

If an IMA segment is allocated in the CMA area, it is recommended to use its page_address() directly to avoid the vulnerability.