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)