Use After Free Affecting kernel-default-livepatch package, versions <6.4.0-150600.23.14.2


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.03% (8th percentile)

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  • Snyk IDSNYK-SLES156-KERNELDEFAULTLIVEPATCH-7553937
  • published23 Jul 2024
  • disclosed22 Jul 2024

Introduced: 22 Jul 2024

CVE-2024-38610  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade SLES:15.6 kernel-default-livepatch to version 6.4.0-150600.23.14.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch package and not the kernel-default-livepatch package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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

drivers/virt/acrn: fix PFNMAP PTE checks in acrn_vm_ram_map()

Patch series "mm: follow_pte() improvements and acrn follow_pte() fixes".

Patch #1 fixes a bunch of issues I spotted in the acrn driver. It compiles, that's all I know. I'll appreciate some review and testing from acrn folks.

Patch #2+#3 improve follow_pte(), passing a VMA instead of the MM, adding more sanity checks, and improving the documentation. Gave it a quick test on x86-64 using VM_PAT that ends up using follow_pte().

This patch (of 3):

We currently miss handling various cases, resulting in a dangerous follow_pte() (previously follow_pfn()) usage.

(1) We're not checking PTE write permissions.

Maybe we should simply always require pte_write() like we do for pin_user_pages_fast(FOLL_WRITE)? Hard to tell, so let's check for ACRN_MEM_ACCESS_WRITE for now.

(2) We're not rejecting refcounted pages.

As we are not using MMU notifiers, messing with refcounted pages is dangerous and can result in use-after-free. Let's make sure to reject them.

(3) We are only looking at the first PTE of a bigger range.

We only lookup a single PTE, but memmap->len may span a larger area. Let's loop over all involved PTEs and make sure the PFN range is actually contiguous. Reject everything else: it couldn't have worked either way, and rather made use access PFNs we shouldn't be accessing.

CVSS Base Scores

version 3.1