Bug 1379302 (CVE-2016-6309)

Summary: CVE-2016-6309 openssl: Use After Free for large message sizes
Product: [Other] Security Response Reporter: Tomas Hoger <thoger>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: urgent Docs Contact:
Priority: urgent    
Version: unspecifiedCC: bbaranow, bmaxwell, cdewolf, csutherl, dandread, darran.lofthouse, dosoudil, erik-fedora, fnasser, gzaronik, huwang, jaeshin, jawilson, jclere, ktietz, lgao, marcandre.lureau, mbabacek, mjc, myarboro, pgier, psakar, pslavice, redhat-bugzilla, rjones, rnetuka, rsvoboda, sardella, tmraz, twalsh, vtunka, weli, yozone
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Fixed In Version: openssl 1.1.0b Doc Type: If docs needed, set a value
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Last Closed: 2016-09-26 10:36:59 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 1367347    

Description Tomas Hoger 2016-09-26 10:33:03 UTC 
Quoting form the OpenSSL upstream advisory:


Fix Use After Free for large message sizes (CVE-2016-6309)
==========================================================

Severity: Critical

This issue only affects OpenSSL 1.1.0a, released on 22nd September 2016.

The patch applied to address CVE-2016-6307 resulted in an issue where if a
message larger than approx 16k is received then the underlying buffer to store
the incoming message is reallocated and moved. Unfortunately a dangling pointer
to the old location is left which results in an attempt to write to the
previously freed location. This is likely to result in a crash, however it
could potentially lead to execution of arbitrary code.

OpenSSL 1.1.0 users should upgrade to 1.1.0b

This issue was reported to OpenSSL on 23rd September 2016 by Robert
Święcki (Google Security Team), and was found using honggfuzz. The fix
was developed by Matt Caswell of the OpenSSL development team.


External References:

https://www.openssl.org/news/secadv/20160926.txt
Comment 1 Tomas Hoger 2016-09-26 10:36:59 UTC 
The CVE-2016-6307 is tracked via bug 1378203.

Upstream commit:

https://git.openssl.org/?p=openssl.git;a=commitdiff;h=acacbfa7565c78d2273c0b2a2e5e803f44afefeb

The following commit seems to add test for this issue into upstream test suite:

https://git.openssl.org/?p=openssl.git;a=commitdiff;h=f8644220a05f75d51bbde627077cdf336e4d4592


Statement:

This issue did not affect any Red Hat product as they do not yet include OpenSSL 1.1.0.