- Vulnerability/
- CVE-2024-55881
CVE-2024-55881: KVM: x86: Play nice with protected guests in complete_hypercall_exit()
First published: Sat Jan 11 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Play nice with protected guests in complete_hypercall_exit() Use is_64_bit_hypercall() instead of is_64_bit_mode() to detect a 64-bit hypercall when completing said hypercall. For guests with protected state, e.g. SEV-ES and SEV-SNP, KVM must assume the hypercall was made in 64-bit mode as the vCPU state needed to detect 64-bit mode is unavailable. Hacking the sev_smoke_test selftest to generate a KVM_HC_MAP_GPA_RANGE hypercall via VMGEXIT trips the WARN: ------------[ cut here ]------------ WARNING: CPU: 273 PID: 326626 at arch/x86/kvm/x86.h:180 complete_hypercall_exit+0x44/0xe0 [kvm] Modules linked in: kvm_amd kvm ... [last unloaded: kvm] CPU: 273 UID: 0 PID: 326626 Comm: sev_smoke_test Not tainted 6.12.0-smp--392e932fa0f3-feat #470 Hardware name: Google Astoria/astoria, BIOS 0.20240617.0-0 06/17/2024 RIP: 0010:complete_hypercall_exit+0x44/0xe0 [kvm] Call Trace: <TASK> kvm_arch_vcpu_ioctl_run+0x2400/0x2720 [kvm] kvm_vcpu_ioctl+0x54f/0x630 [kvm] __se_sys_ioctl+0x6b/0xc0 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> ---[ end trace 0000000000000000 ]---
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Red Hat Kernel-devel | ||
| debian/linux | 5.10.223-1 5.10.234-1 6.1.129-1 6.1.128-1 6.12.21-1 | |
| debian/linux-6.1 | 6.1.129-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/0840d360a8909c722fb62459f42836afe32ededb
- https://git.kernel.org/stable/c/22b5c2acd65dbe949032f619d4758a35a82fffc3
- https://git.kernel.org/stable/c/3d2634ec0d1dbe8f4b511cf5261f327c6a76f4b6
- https://git.kernel.org/stable/c/7ed4db315094963de0678a8adfd43c46471b9349
- https://git.kernel.org/stable/c/9b42d1e8e4fe9dc631162c04caa69b0d1860b0f0
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-55881
- https://nvd.nist.gov/vuln/detail/CVE-2024-55881
- https://launchpad.net/bugs/cve/CVE-2024-55881
- https://security-tracker.debian.org/tracker/CVE-2024-55881
- https://ubuntu.com/security/CVE-2024-55881
- https://git.kernel.org/linus/9b42d1e8e4fe9dc631162c04caa69b0d1860b0f0
Frequently Asked Questions
What is the severity of CVE-2024-55881?
CVE-2024-55881 is considered to have a medium severity due to its impact on the Linux kernel's handling of hypercalls.
How do I fix CVE-2024-55881?
To fix CVE-2024-55881, update your Linux kernel to the latest version that contains the relevant patch.
What software is affected by CVE-2024-55881?
CVE-2024-55881 affects the Linux Kernel, particularly in interaction with protected guests.
What is the nature of the vulnerability CVE-2024-55881?
CVE-2024-55881 involves an improper check within the complete_hypercall_exit() function related to detecting 64-bit hypercalls.
What does CVE-2024-55881 affect in the virtualization context?
CVE-2024-55881 affects the KVM virtualization environment, specifically its interaction with protected guest systems.
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