Bug 1072180 – CVE-2014-0016 stunnel: Improper initialization of PRNG after fork()

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Bug 1072180 - (CVE-2014-0016) CVE-2014-0016 stunnel: Improper initialization of PRNG after fork()

Summary:	CVE-2014-0016 stunnel: Improper initialization of PRNG after fork()

Status:	CLOSED NOTABUG

Aliases:	CVE-2014-0016

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20140305,repor...
Keywords:	Security

Depends On:
Blocks:	1052780
	Show dependency tree / graph

Reported:	2014-03-04 00:24 EST by Huzaifa S. Sidhpurwala
Modified:	2014-03-06 11:01 EST (History)
CC List:	6 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2014-03-05 23:55:06 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
proposed patch (478 bytes, patch) 2014-03-05 01:52 EST, Huzaifa S. Sidhpurwala	no flags	Details \| Diff
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Huzaifa S. Sidhpurwala 2014-03-04 00:24:51 EST

A flaw was found in the way stunnel, a socket wrapper which can provide SSL support to ordinary applications, performed (re)initialization of PRNG after fork.  When accepting a new connection, the server forks and the child process handles the request. The RAND_bytes() function of openssl doesn't reset its state after the fork, but seeds the PRNG with the output of time(NULL). The most important consequence is that servers using EC (ECDSA) or DSA certificates may under certain conditions leak their private key.

Comment 2 Huzaifa S. Sidhpurwala 2014-03-05 01:52:47 EST

Created attachment 870826 [details]
proposed patch

Comment 3 Avesh Agarwal 2014-03-05 10:34:38 EST

stunnel and rhel7 have the same stunnel version 4.56 so would require fixing in rhel7 atleast if stunnel in fedora is fixed. Still looking into other rhel6/5 branches.

Comment 4 Avesh Agarwal 2014-03-05 11:35:43 EST

Was going through the code in stunnel 4.56 version and the code uses pthread model and USE_FORK is not used when pthread is detected in rhel and fedora.

Comment 5 Avesh Agarwal 2014-03-05 11:40:30 EST

(In reply to Avesh Agarwal from comment #4)
> Was going through the code in stunnel 4.56 version and the code uses pthread
> model and USE_FORK is not used when pthread is detected in rhel and fedora.

The same seems true for stunnel versions in rhel6 and rhel5.

Comment 6 Huzaifa S. Sidhpurwala 2014-03-05 23:54:20 EST

As mentioned in the previous comments, this flaw does not affect the version of stunnel shipped with Red Hat Enterprise Linux 5 and 6, since these versions use POSIX threads (pthreads) and no not use fork().

For the same reason this version does not affect the version of stunnel as shipped with Fedora 19 and Fedora 20.

Comment 7 Huzaifa S. Sidhpurwala 2014-03-05 23:55:06 EST

Statement:

Not vulnerable. This issue does not affect the version of stunnel package as shipped with Red Hat Enterprise Linux 5 and 6.

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