Linux Kernel up to 5.14.9 KVM sev_decommission memory leak

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.14.9 and classified as critical. This vulnerability affects the function sev_decommission of the component KVM. Executing a manipulation can lead to memory leak. The identification of this vulnerability is CVE-2021-47389. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.14.9. It has been declared as critical. This vulnerability affects the function sev_decommission of the component KVM. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. CVE summarizes:

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").

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2021-47389. There are known technical details, but no exploit is available.

Upgrading to version 5.14.10 eliminates this vulnerability. Applying the patch efd7866e114d/f1815e0aa770 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.14.0
• 5.14.1
• 5.14.2
• 5.14.3
• 5.14.4
• 5.14.5
• 5.14.6
• 5.14.7
• 5.14.8
• 5.14.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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