Bug 1386350

Summary:	OpenSSL incorrectly handles TLS_FALLBACK_SCSV if it is at the beginning of the cipher list in Client Hello [rhel-6]
Product:	Red Hat Enterprise Linux 6	Reporter:	Hubert Kario <hkario>
Component:	openssl	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED ERRATA	QA Contact:	Stanislav Zidek <szidek>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.8	CC:	bressers, cww, mpoole, pbajenez, qe-baseos-security, szidek, tmraz
Target Milestone:	rc	Keywords:	Reopened
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	openssl-1.0.1e-54.el6	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	1386347	Environment:
Last Closed:	2017-03-21 10:14:00 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:	1276310, 1386347
Bug Blocks:	1269194

Description Hubert Kario 2016-10-18 17:56:13 UTC

Description of problem:
When Client Hello with TLSv1.2 version and TLS_FALLBACK_SCSV at first or second position is received by the server, the server rejects the connection with a a handshake_failure alert.

Version-Release number of selected component (if applicable):
openssl-1.0.1e-48.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
  openssl req -x509 -newkey rsa:2048 -keyout localhost.key -out localhost.crt -subj /CN=localhost -nodes -batch
  openssl s_server -key localhost.key -cert localhost.crt -www

In different console:
  git clone https://github.com/tomato42/tlsfuzzer.git
  pushd tlsfuzzer
  git clone https://github.com/tomato42/tlslite-ng.git .tlslite-ng
  ln -s .tlslite-ng/tlslite tlslite
  git clone https://github.com/warner/python-ecdsa.git .python-ecdsa
  ln -s .python-ecdsa/ecdsa ecdsa
  PYTHONPATH=. python scripts/test-fallback-scsv.py

Actual results:
...
FALLBACK - record TLSv1.2 hello TLSv1.2 - pos 1 ...
Error encountered while processing node <tlsfuzzer.expect.ExpectServerHello object at 0x7efc7ff18b50> (child: <tlsfuzzer.expect.ExpectCertificate object at 0x7efc7ff18b90>) with last message being: <tlslite.messages.Message object at 0x7efc7fec9750>
Error while processing
Traceback (most recent call last):
  File "scripts/test-fallback-scsv.py", line 342, in main
    runner.run()
  File "/home/hkario/dev/tlsfuzzer/tlsfuzzer/runner.py", line 166, in run
    RecordHeader2)))
AssertionError: Unexpected message from peer: Alert(fatal, handshake_failure)
...
Test end
successful: 17
failed: 8
  'FALLBACK - hello SSL3.4 - pos 0'
  'FALLBACK - hello SSL3.4 - pos 1'
  'FALLBACK - hello TLSv1.2 - pos 0'
  'FALLBACK - hello TLSv1.2 - pos 1'
  'FALLBACK - record SSL3.4 hello SSL3.4 - pos 0'
  'FALLBACK - record SSL3.4 hello SSL3.4 - pos 1'
  'FALLBACK - record TLSv1.2 hello TLSv1.2 - pos 0'
  'FALLBACK - record TLSv1.2 hello TLSv1.2 - pos 1'

Expected results:
...
FALLBACK - record TLSv1.2 hello TLSv1.2 - pos 1 ...
OK
...

Test end
successful: 25
failed: 0


Additional info:
Issue already fixed in upstream 1.0.1 branch

Comment 13 RHEL Program Management 2016-10-26 15:47:48 UTC

Product Management has reviewed and declined this request.
You may appeal this decision by reopening this request.

Comment 19 errata-xmlrpc 2017-03-21 10:14:00 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2017-0660.html