Microsoft security update for CVE-2024-50022 — azl3 kernel
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-50022. This page also shows what EchelonGraph holds for CVE-2024-50022, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products2
- azl3 kernel 6.6.56.1-5 on Azure Linux 3.0
- azl3 kernel 6.6.57.1-1 on Azure Linux 3.0
✅ Updates Microsoft lists: 1 update
1 row: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | 6.6.57.1-1 |
🧭 EchelonGraph on CVE-2024-50022
- EchelonGraph score
- 5.5 MEDIUM
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
In the Linux kernel, the following vulnerability has been resolved: device-dax: correct pgoff align in dax_set_mapping() pgoff should be aligned using ALIGN_DOWN() instead of ALIGN(). Otherwise, vmf->address not aligned to fault_size will be aligned to the next alignment, that can result in memory failure getting the wrong address. It's a subtle situation that only can be observed in page_mapped_in_vma() after the page is page fault handled by dev_dax_huge_fault. Generally, there is little chance to perform page_mapped_in_vma in dev-dax's page unless in specific error injection to the dax device to trigger an MCE - memory-failure. In that case, page_mapped_in_vma() will be triggered to determine which task is accessing the failure address and kill that task in the end. We used self-developed dax device (which is 2M aligned mapping) , to perform error injection to random address. It turned out that error injected to non-2M-aligned address was causing endless MCE until panic. Because page_mapped_in_vma() kept resulting wrong address and the task accessing the failure address was never killed properly: [ 3783.719419] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3784.049006] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3784.049190] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3784.448042] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3784.448186] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3784.792026] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3784.792179] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3785.162502] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3785.162633] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3785.461116] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3785.461247] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3785.764730] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3785.764859] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3786.042128] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3786.042259] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3786.464293] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3786.464423] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3786.818090] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3786.818217] Memory failure: 0x200c9742: recovery action for dax page: Recovered [ 3787.085297] mce: Uncorrected hardware memory error in user-access at 200c9742380 [ 3787.085424] Memory failure: 0x200c9742: recovery action for dax page: Recovered It took us several weeks to pinpoint this problem, but we eventually used bpftrace to trace the page fault and mce address and successfully identified the issue. Joao added: ; Likely we never reproduce in production because we always pin : device-dax regions in the region align they provide (Qemu does : similarly with prealloc in hugetlb/file backed memory). I think this : bug requires that we touch *unpinned* device-dax regions unaligned to : the device-dax selected alignment (page size i.e. 4K/2M/1G)
Published by kernel.org, the CVE Numbering Authority that assigned CVE-2024-50022, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).