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-debuginfo-common-x86_64Upgrade kernel-toolsUpgrade kernel-libbpf-staticUpgrade bpftool-debuginfoUpgrade bpftoolUpgrade kernel-libbpf-develUpgrade kernel-develUpgrade kernel-libbpfUpgrade perf-debuginfoUpgrade python3-perf-debuginfoUpgrade kernel-livepatch-6.1.12-17.42Upgrade kernel-tools-develUpgrade kernel-debuginfoUpgrade kernel-tools-debuginfoUpgrade python3-perfUpgrade kernel-debuginfo-common-aarch64Upgrade kernelUpgrade perfUpgrade kernel-headers | Jun 11, 2025 | Mar 27, 2025 |
| Debian | — | Upgrade linux | Mar 31, 2025 | Mar 27, 2025 |
| Redhat_linux | — | No solution existsUpgrade kernelUpgrade kernel-rt | Jul 9, 2025 | Mar 27, 2025 |
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