CVE-2021-47389

Summary

In the Linux kernel, the following vulnerability has been resolved:

KVM: SVM: fix missing sev_decommission in sev_receive_start

DECOMMISSION the current SEV context if binding an ASID fails after RECEIVE_START. Per AMD's SEV API, RECEIVE_START generates a new guest context and thus needs to be paired with DECOMMISSION:

 The RECEIVE_START command is the only command other than the LAUNCH_START
 command that generates a new guest context and guest handle.

The missing DECOMMISSION can result in subsequent SEV launch failures, as the firmware leaks memory and might not able to allocate more SEV guest contexts in the future.

Note, LAUNCH_START suffered the same bug, but was previously fixed by commit 934002cd660b ("KVM: SVM: Call SEV Guest Decommission if ASID binding fails").

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxaf43cbbf954b50ca97d5e7bb56c2edc6ffd209ef < efd7866e114dcb44f86d151e843f8276b7efbc67affected
LinuxLinuxaf43cbbf954b50ca97d5e7bb56c2edc6ffd209ef < f1815e0aa770f2127c5df31eb5c2f0e37b60fa77affected
LinuxLinux5.13affected
LinuxLinux0 < 5.13unaffected
LinuxLinux5.14.10 <= 5.14.*unaffected
LinuxLinux5.15 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References