CVE-2024-26710

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

powerpc/kasan: Limit KASAN thread size increase to 32KB

KASAN is seen to increase stack usage, to the point that it was reported

to lead to stack overflow on some 32-bit machines (see link).

To avoid overflows the stack size was doubled for KASAN builds in

commit 3e8635fb2e07 ("powerpc/kasan: Force thread size increase with

KASAN").

However with a 32KB stack size to begin with, the doubling leads to a

64KB stack, which causes build errors:

arch/powerpc/kernel/switch.S:249: Error: operand out of range (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff)

Although the asm could be reworked, in practice a 32KB stack seems

sufficient even for KASAN builds - the additional usage seems to be in

the 2-3KB range for a 64-bit KASAN build.

So only increase the stack for KASAN if the stack size is < 32KB.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References