[HTTPCLIENT-1802] RFC violations in hostname checking

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.5.2
• Fix Version/s: 4.5.3, 5.0 Alpha2
• Component/s: HttpClient (classic)
• Assignee: Oleg Kalnichevski
• Reporter: Suphannee Sivakorn
• Created: 17/Jan/17 19:27
• Updated: 18/May/20 13:47
• Resolved: 20/Jan/17 19:22

Description

1. Matching commonName in case sensitive manner when wildcard presents
(violation of RFC 6125 and RFC 5280)
HttpClient matches certificate commonName in the case sensitive manner
when there is a wildcard presents in the certificate commonName, for
example, given commonName as "*.google.com", HttpClient matches
"foo.google.com", it however does not match "foo.Google.com". We found
that this behavior is inconsistent with section 6.4.4 of RFC 6125
specification – "If the client chooses to compare a reference
identifier of type CN-ID against that string, it MUST follow the
comparison rules for the DNS domain name portion of an identifier of
type DNS-ID, SRV-ID, or URI-ID". Note that matching DNS-ID, SRV-ID and
URI-ID all are in case insensitive manner (RFC 5280).

Testing certificate attached: s_google_com.pem
Testing hostname: foo.Google.com
Expected behavior: match

2. Attempting to match commonName when SubjectAltName identifier presents
Section 6.3 of RFC 6125 prohibits clients from attempting to match
certificate CN if the presented identifiers include a DNS-ID, SRV-ID,
URI-ID, or any application-specific identifier types supported by the
client. We found that HttpClient violates this requirement as it
attempts to match CN even when there is a subjectAltName identifier
presents e.g., IP address. However, the library does not attempt to
match certificate CN when certificate subjectAltName DNS presents.

Testing certificate attached: 1_1_1_1.pem
Testing hostname: dummy-value.com
Expected behavior: no match

Credit:
Suphannee Sivakorn
George Argyros
Kexin Pei
Prof. Suman Jana