KVM: SVM: Serialize accesses to the owner and mirror list with separate lock
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.1.184, 6.6.153, 6.12.105, 6.18.45, 7.1.9
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Serialize accesses to the owner and mirror list with separate lock Interaction between KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM and KVM_CAP_VM_COPY_ENC_CONTEXT_FROM can cause two separate issues: • in sev_migrate_from(), when the destination KVM is a mirror, the mirror entry is moved from the source's list to the owner's mirror_vms list, without holding the owner's lock unlike other writers of the owner's mirror list (sev_vm_copy_enc_context_from(), sev_vm_destroy()). A concurrent COPY or destroy can race with sev_migrate_from() and corrupt the list. • In sev_vm_destroy(), the owner is still active and could receive concurrently a KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM that causes sev->enc_context_owner to change. In this case the incorrect VM receives kvm_put_kvm(). The second issue needs particular care because the owner could disappear altogether (even though the race window is impossibly small) between reading it and locking it. There is thus no way to perform the checks under the owner lock without putting struct kvm under SLAB_TYPESAFE_BY_RCU (which would allow kvm_get_kvm_safe() under RCU critical section). It is much simpler to just use a global lock, since the critical sections are so small and the new lock is always a leaf lock.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in 7943ec3a6d0e7e0a2eb4943300bce089ac3e8c3e; From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in 28afde1edbd8b20058cbf4d75fb57876471ec334; From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in 328ab4fabe05af004d886659f8744076e320ddce; From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in 47976eaaf0a4eb46dade48b3246779090db9e3ec; From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in d728baba0f20e49439fc7831bf3e4e7dee82161a; From b2125513dfc0dd0ec5a9605138a3c356592cfb73 · fixed in 1d78d33275ef2a16c6d080910b291d0a97a0e613
- Linux Linux
5.18
- KernelLinux
From 5.18.0 · fixed in 6.1.184; From 6.2.0 · fixed in 6.6.153; From 6.7.0 · fixed in 6.12.105; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.1.9