CVE-2021-47450
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix host stage-2 PGD refcount The KVM page-table library refcounts the pages of concatenated stage-2 PGDs individually. However, when running KVM in protected mode, the host's stage-2 PGD is currently managed by EL2 as a single high-order compound page, which can cause the refcount of the tail pages to reach 0 when they shouldn't, hence corrupting the page-table. Fix this by introducing a new hyp_split_page() helper in the EL2 page allocator (matching the kernel's split_page() function), and make use of it from host_s2_zalloc_pages_exact().
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-47450
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-47450.html
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 5.15.3-1 |
| debian | bullseye | fixed | 0 |
| debian | forky | fixed | 5.15.3-1 |
| debian | sid | fixed | 5.15.3-1 |
| debian | trixie | fixed | 5.15.3-1 |
References
Verify integrity in audit chain (admin only). AS-IS.