Bug 1947994 (CVE-2020-36311) - CVE-2020-36311 kernel: DoS by triggering destruction of a large SEV VM
Summary: CVE-2020-36311 kernel: DoS by triggering destruction of a large SEV VM
Keywords:
Status: NEW
Alias: CVE-2020-36311
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Nobody
QA Contact:
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Depends On: 1961037 1947996 1960868 1960869
Blocks: 1947995
TreeView+ depends on / blocked
 
Reported: 2021-04-09 17:20 UTC by Guilherme de Almeida Suckevicz
Modified: 2023-09-19 14:13 UTC (History)
36 users (show)

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A flaw was found in the Linux kernel. This flaw allows attackers to cause a denial of service (soft lockup) by triggering the destruction of a large SEV VM, which requires unregistering many encrypted regions. The highest threat from this vulnerability is to system availability.
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Description Guilherme de Almeida Suckevicz 2021-04-09 17:20:02 UTC 
An issue was discovered in the Linux kernel before 5.9. arch/x86/kvm/svm/sev.c allows attackers to cause a denial of service (soft lockup) by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions).

Reference and upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7be74942f184fdfba34ddd19a0d995deb34d4a03
Comment 1 Guilherme de Almeida Suckevicz 2021-04-09 17:21:38 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1947996]
Comment 2 Justin M. Forbes 2021-04-12 21:25:23 UTC 
This was fixed for Fedora with the 5.9 kernel rebases.
Comment 3 Mauro Matteo Cascella 2021-05-14 15:05:58 UTC 
For a general description of what a CPU soft lockup is, refer to https://access.redhat.com/articles/371803.
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