Chad Loder created CXF-6143:
-------------------------------

             Summary: SSL/TLS hostname verification does not strictly follow 
HTTPS RFC2818
                 Key: CXF-6143
                 URL: https://issues.apache.org/jira/browse/CXF-6143
             Project: CXF
          Issue Type: Bug
          Components: Transports
    Affects Versions: 3.0.2
            Reporter: Chad Loder


The HTTPS specification [RFC 2818, section 
3.1|http://tools.ietf.org/html/rfc2818#section-3.1] states:

{quote}
   If a subjectAltName extension of type dNSName is present, that MUST
   be used as the identity. Otherwise, the (most specific) Common Name
   field in the Subject field of the certificate MUST be used. Although
   the use of the Common Name is existing practice, it is deprecated and
   Certification Authorities are encouraged to use the dNSName instead.
{quote}

The current 
[CertificateHostnameVerifier|https://git-wip-us.apache.org/repos/asf?p=cxf.git;a=blob;f=rt/transports/http/src/main/java/org/apache/cxf/transport/https/CertificateHostnameVerifier.java]
 implementation in CXF does not follow this logic, even in STRICT mode. 
Instead, it builds an array of both CNs and subjectAltNames and checks each of 
them sequentially, in the order returned in the certificate.

The proper approach would be to build a list of subjectAltNames having type 
dNSName. If the list is non-empty, matching should proceed against this list 
ONLY - and validation should fail if no subjectAltName. Otherwise, only if the 
subjectAltName list is empty, a list of CNs from the Subject field should be 
built, and perhaps sorted from most- to least-specific. A match should then 
proceed against this list, taking into account wildcards of course.

Likewise, the [HostnameVerifier implementation in 
not-yet-commons-ssl|http://juliusdavies.ca/svn/viewvc.cgi/not-yet-commons-ssl/trunk/src/java/org/apache/commons/ssl/HostnameVerifier.java?revision=121&pathrev=172]
 has the same issue. However, since not-yet-commons-ssl is a generic SSL/TLS 
transport library, it should not be made to follow HTTPS application layer 
rules for all TLS connections - instead a STRICT_HTTPS mode could be 
implemented for this purpose.

For more information, see http://tools.ietf.org/search/rfc6125 (for future 
reference and background on where implementations are going) and 
http://tersesystems.com/2014/03/23/fixing-hostname-verification/





--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to