Bug 1035695

Summary: spice-server: Use TLS 1.0 or better
Product: Red Hat Enterprise Linux 6 Reporter: David Jaša <djasa>
Component: spice-serverAssignee: Christophe Fergeau <cfergeau>
Status: CLOSED ERRATA QA Contact: Desktop QE <desktop-qa-list>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 6.5CC: cfergeau, dblechte, hkario, mkenneth, pvine, rbalakri, sdenham, thoger
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Cause: spice-server uses exclusively TLS version 1.0 for encrypted connections no matter what version(s) the client advertises. Consequence: newer versions of TLS cannot be used Fix: spice-server code was changed to allow TLS 1.0 or newer Result: clients can connect using versions of TLS newer than 1.0
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-10-14 05:04:42 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:
Embargoed:
Bug Depends On:    
Bug Blocks: 1042946, 1057564    

Description David Jaša 2013-11-28 10:10:03 UTC
Description of problem:
spice-server uses exclusively TLS version 1.0 no matter what version(s) the client advertises. This is plain wrong as TLS 1.0 shows its age and the best version supported by both parties should be used.

Version-Release number of selected component (if applicable):
spice-gtk-0.20-11.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. run spice-server:
qemu-kvm -monitor stdio -vga qxl -spice disable-ticketing,x509-dir=<dir>,tls-port=<port>
2. start wireshark capture on the port
3. connect to the port using s_client set to respective TLS versions:
openssl s_client -CAfile /path/to/ca.pem -connect <fqdn>:<port> <TLS_VERSION>
where TLS version is:
    * -tls1 for TLS 1.0
    * -tls1_1 for TLS 1.1
    * -tls1_2
4. look in the wireshark traces for ServerHello or "Client Key Exchange" messages.
If you can't see ClientHello message, right-click some captured packet, click Decode As..., go to Transport tab and select SSL.

Actual results:
TLSv1: connection is successfully established (good)
TLSv1.1: connection is terminated right after ClientHello packet
TLSv1.2: connection is terminated right after ClientHello packet

Expected results:
connection is successfully established when using any of TLS versions above

Additional info:
current version of spice-gtk is also tied to TLS 1.0 so it can't be used to test spice-server fix at the moment.

Wireshark protocol markings may be a bit misleading: there are two places where the version is specified in ClientHello message:
Secure Sockets Layer
  TLSv<misleading_version> Record Layer: Handshake Protocol: ClientHello
    ...
    Version: TLS 1.0 (0x301)  <----  set to the TLS 1.0 for TLS 1.0-1.2
    ...
    Handshake Protocol: ClientHello
      ...
      Version: TLS 1.2 (0x303)  <--- this must be set to version 1.1 or 1.2
                                     in order to verify the bug

Comment 1 David Jaša 2013-11-28 10:56:42 UTC
spice-server bug: bug 1035728

I forgot to add: when the server and client can't agree on TLS protocol version, either server sends SSL Alert message with Protocol Version message, or it just terminates connection (sends FIN packet).

Comment 4 errata-xmlrpc 2014-10-14 05:04:42 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.

http://rhn.redhat.com/errata/RHBA-2014-1435.html