CVE-2021-3656
Description
A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.
How to fix
- linux linux_kernel4.14.245, 4.19.205, 5.4.142, 5.10.60, 5.13.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| redhat virtualization_host | 4.0 | — |
| linux linux_kernel | 4.13 ≤ v < 4.14.245, 4.15 ≤ v < 4.19.205, 4.20 ≤ v < 5.4.142, 5.5 ≤ v < 5.10.60, 5.11 ≤ v < 5.13.12, 5.14 | 4.14.245, 4.19.205, 5.4.142, 5.10.60, 5.13.12 |
| fedoraproject fedora | 33, 34 | — |
| redhat software_collections | No range specified | — |
| redhat openstack | 13 | — |
| redhat enterprise_linux | 8.0 | — |
| redhat enterprise_linux_desktop | 7.0 | — |
| redhat enterprise_linux_eus | 8.1, 8.2, 8.4 | — |
| redhat enterprise_linux_for_ibm_z_systems | 7.0, 8.0 | — |
| redhat enterprise_linux_for_ibm_z_systems_eus | 8.1, 8.2, 8.4 | — |
| redhat enterprise_linux_for_power_big_endian | 7.0 | — |
| redhat enterprise_linux_for_power_little_endian | 7.0, 8.0 | — |
| redhat enterprise_linux_for_power_little_endian_eus | 8.1, 8.2, 8.4 | — |
| redhat enterprise_linux_for_real_time | 7, 8 | — |
| redhat enterprise_linux_for_real_time_for_nfv | 7, 8 | — |
| redhat enterprise_linux_for_real_time_for_nfv_tus | 8.2, 8.4 | — |
| redhat enterprise_linux_for_real_time_tus | 8.2, 8.4 | — |
| redhat enterprise_linux_for_scientific_computing | 7.0 | — |
| redhat enterprise_linux_server | 7.0 | — |
| redhat enterprise_linux_server_aus | 7.6, 7.7, 8.2, 8.4 | — |
| redhat enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions | 7.6, 8.1, 8.2, 8.4 | — |
| redhat enterprise_linux_server_tus | 7.6, 7.7, 8.2, 8.4 | — |
| redhat enterprise_linux_server_update_services_for_sap_solutions | 7.6, 7.7, 8.1, 8.2, 8.4 | — |
| redhat enterprise_linux_workstation | 7.0 | — |
| redhat 3scale_api_management | 2.0 | — |
| redhat codeready_linux_builder | No range specified | — |
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