Bug 1262846 (CVE-2015-5276)

Summary:	CVE-2015-5276 gcc: Predictable randomness from std::random_device
Product:	[Other] Security Response	Reporter:	Florian Weimer <fweimer>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	cbuissar, jakub, jwakely, law, mcermak, mfranc, mnewsome, mpolacek, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-01-12 16:12:24 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:	1262852
Bug Blocks:	1262855

Description Florian Weimer 2015-09-14 13:26:24 UTC

It was discovered that the std::random_device class in libstdc++ would
not properly detect short reads and could return return predictable
values if applications used it to obtain randomness from a blocking
source such as /dev/random.

Comment 1 Florian Weimer 2015-09-14 13:31:37 UTC

External references:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65142

Comment 2 Florian Weimer 2015-09-14 13:32:02 UTC

Upstream commit:

https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=227687
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=227872

Comment 3 Florian Weimer 2015-09-14 13:32:55 UTC

Created gcc tracking bugs for this issue:

Affects: fedora-all [bug 1262852]

Comment 6 Cedric Buissart 2016-01-12 16:16:21 UTC

std::random_device is not guaranteed to be cryptographically secure and should not be used for secure cryptographic code. Thus having a low impact.

Comment 7 Jonathan Wakely 2016-01-12 16:22:43 UTC

I was intending to fix this.

std::random_device can use /dev/random in GCC's implementation (and the intent of the C++ standard is to allow, even encourage that), isn't that suitable for secure crypto?