Bug 1755523 (CVE-2019-15847)

Summary:	CVE-2019-15847 gcc: POWER9 "DARN" RNG intrinsic produces repeated output
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	ahajkova, aoliva, avi.kivity, davejohansen, dmalcolm, erik-fedora, fweimer, hannsj_uhl, jakub, jwakely, klember, ktietz, law, mcermak, mnewsome, mpolacek, msebor, nickc, ohudlick, rjones, tborcin, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-03-23 16:31:49 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1755525, 1755526, 1755527, 1760205, 1760206, 1760207, 1760208, 1760209
Bug Blocks:	1755528

Description Dhananjay Arunesh 2019-09-25 15:49:51 UTC

The POWER9 backend in GNU Compiler Collection (GCC) before version 10 could
optimize multiple calls of the __builtin_darn intrinsic into a single call, thus
reducing the entropy of the random number generator. This occurred because a
volatile operation was not specified. For example, within a single execution of
a program, the output of every __builtin_darn() call may be the same.

Reference:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481

Comment 1 Dhananjay Arunesh 2019-09-25 15:51:06 UTC

Created gcc tracking bugs for this issue:

Affects: fedora-all [bug 1755525]


Created mingw-gcc tracking bugs for this issue:

Affects: epel-all [bug 1755527]
Affects: fedora-all [bug 1755526]

Comment 3 Huzaifa S. Sidhpurwala 2019-10-10 07:22:04 UTC

Statement:

As per upstream DARN (or power9) is not supported in GCC 6 or older, therefore versions of gcc shipped with Red Hat Enterprise Linux 5, 6 and 7 are not affected by this flaw.

Comment 4 Huzaifa S. Sidhpurwala 2019-10-10 07:22:07 UTC

External References:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91481

Comment 5 errata-xmlrpc 2020-03-23 10:56:58 UTC

This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS

Via RHSA-2020:0924 https://access.redhat.com/errata/RHSA-2020:0924

Comment 6 Product Security DevOps Team 2020-03-23 16:31:49 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2019-15847

Comment 7 errata-xmlrpc 2020-04-28 16:01:17 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:1864 https://access.redhat.com/errata/RHSA-2020:1864

Comment 8 errata-xmlrpc 2020-05-26 06:07:38 UTC

This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS

Via RHSA-2020:2274 https://access.redhat.com/errata/RHSA-2020:2274