Bug 2114996 (CVE-2021-46778)

Summary: CVE-2021-46778 hw: cpu: AMD: Execution Unit Scheduler Contention Side-Channel vulnerability
Product: [Other] Security Response Reporter: Rohit Keshri <rkeshri>
Component: vulnerabilityAssignee: Nobody <nobody>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, adscvr, airlied, alciregi, aquini, bhu, brdeoliv, chwhite, crwood, dbohanno, ddepaula, debarbos, dvlasenk, hkrzesin, hpa, jarod, jarodwilson, jburrell, jfaracco, jferlan, jforbes, jglisse, jlelli, joe.lawrence, jonathan, josef, jpoimboe, jshortt, jstancek, jwboyer, jwest, jwyatt, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, llong, longman, lzampier, masami256, mchehab, mvanderw, nmurray, pmatouse, ptalbert, qzhao, rvrbovsk, scweaver, steved, vkumar, walters, williams, wmealing
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A contention-based side channel vulnerability was found in hw. Some AMD CPUs using simultaneous multithreading (SMT) may allow an attacker to measure the contention level on scheduler queues, leading to potential leakage of sensitive information.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2115011, 2115013, 2115014, 2115015, 2115017, 2115018, 2115046, 2115047, 2115048, 2115049, 2115051, 2115053, 2115054, 2115055, 2115056, 2115057, 2115058, 2115059, 2115060, 2115061, 2117012, 2210748, 2210749, 2210750, 2210751, 2210752, 2210753, 2210754, 2210755    
Bug Blocks: 2114988    

Description Rohit Keshri 2022-08-03 16:48:24 UTC 
A contention-based side-channel vulnerability on some AMD CPUs using simultaneous multithreading (SMT) may allow an attacker to measure the contention level on scheduler queues, thereby leading to the potential leakage of sensitive information.

Execution unit scheduler contention may lead to a side channel vulnerability found on AMD CPU microarchitectures codenamed “Zen 1”, “Zen 2” and “Zen 3” that use simultaneous multithreading (SMT). By measuring the contention level on scheduler queues, an attacker may potentially leak sensitive information.

References
[1] https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1039
[2] https://www.bearssl.org/constanttime.html
[3] https://www.chosenplaintext.ca/articles/beginners-guide-constant-time-cryptography.html
Comment 7 Todd Cullum 2022-08-09 18:16:15 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2117012]