In the Linux kernel, the following vulnerability has been resolved:
mm/uffd: fix pte marker when fork() without fork event
Patch series "mm: Fixes on pte markers".
Patch 1 resolves the syzkiller report from Pengfei.
Patch 2 further harden pte markers when used with the recent swapin error markers. The major case is we should persist a swapin error marker after fork(), so child shouldn't read a corrupted page.
This patch (of 2):
When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may have it and has pte marker installed. The warning is improper along with the comment. The right thing is to inherit the pte marker when needed, or keep the dst pte empty.
A vague guess is this happened by an accident when there's the prior patch to introduce src/dst vma into this helper during the uffd-wp feature got developed and I probably messed up in the rebase, since if we replace dst_vma with src_vma the warning & comment it all makes sense too.
Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the general path.
Reproducer:
https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c
Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade kernel-tools-debuginfoUpgrade perfUpgrade kernelUpgrade kernel-tools-develUpgrade kernel-headersUpgrade kernel-livepatch-6.1.12-17.42Upgrade kernel-develUpgrade perf-debuginfoUpgrade python3-perfUpgrade python3-perf-debuginfoUpgrade kernel-libbpfUpgrade kernel-libbpf-develUpgrade kernel-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-libbpf-staticUpgrade bpftool-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-x86_64Upgrade bpftool | Jun 11, 2025 | Mar 27, 2025 |
| Debian | — | Upgrade linux | Mar 31, 2025 | Mar 27, 2025 |
| Redhat_linux | — | Upgrade kernelNo solution existsUpgrade kernel-rt | Jul 9, 2025 | Mar 27, 2025 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub