CVE-2024-56611

/// Technical description

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

mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM

We currently assume that there is at least one VMA in a MM, which isn't

true.

So we might end up having find_vma() return NULL, to then de-reference

NULL. So properly handle find_vma() returning NULL.

This fixes the report:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI

KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]

CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024

RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]

RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194

Code: ...

RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246

RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000

RDX: ff

/// 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