[HTTPCLIENT-1489] Multiple, comma-separated challenges in WWW-Authenticate are not recognized

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.3.3
• Fix Version/s: 5.0 Alpha1
• Component/s: HttpClient (classic)
• Labels: authentication parsing
• Assignee: Unassigned
• Reporter: bitfire
• Created: 21/Mar/14 19:44
• Updated: 04/May/17 09:49
• Resolved: 04/Jul/15 13:46

Description

As per RFC 2616, WWW-Authenticate may contain more than one challenge:
»User agents are advised to take special care in parsing the WWW- Authenticate field value as it might contain more than one challenge, or if more than one WWW-Authenticate header field is provided, the contents of a challenge itself can contain a comma-separated list of authentication parameters.« https://tools.ietf.org/html/rfc2616#section-14.47

For instance, https://contacts.icloud.com returns such a WWW-Authenticate header:

> GET / HTTP/1.1
> Host: contacts.icloud.com
> Accept: /
>
< HTTP/1.1 401 Unauthorized
< ...
< WWW-Authenticate: X-MobileMe-AuthToken realm="Newcastle", Basic realm="Newcastle"

The X-MobileMe-AuthToken challenge is recognized by HttpClient, but the Basic challenge is not. HttpClient logs when sending a GET request to https://contacts.icloud.com:

[DEBUG] headers - http-outgoing-0 << HTTP/1.1 401 Unauthorized
[DEBUG] headers - http-outgoing-0 << Date: Fri, 21 Mar 2014 19:20:14 GMT
[DEBUG] headers - http-outgoing-0 << X-Apple-Request-UUID: d1d0aa7d-d651-4da2-be9f-595f1619db85
[DEBUG] headers - http-outgoing-0 << X-Responding-Instance: carddav:12100701:st13p21ic-quav11230703:8001:14B52:125783
[DEBUG] headers - http-outgoing-0 << WWW-Authenticate: X-MobileMe-AuthToken realm="Newcastle", Basic realm="Newcastle"
[DEBUG] headers - http-outgoing-0 << Content-Length: 0
[DEBUG] MainClientExec - Connection can be kept alive indefinitely
[DEBUG] HttpAuthenticator - Authentication required
[DEBUG] HttpAuthenticator - contacts.icloud.com:443 requested authentication
[INFO] TargetAuthenticationStrategy - GOT Auth header: X-MobileMe-AuthToken realm="Newcastle", Basic realm="Newcastle"
[DEBUG] TargetAuthenticationStrategy - Authentication schemes in the order of preference: [negotiate, Kerberos, NTLM, Digest, Basic]
[DEBUG] TargetAuthenticationStrategy - Challenge for negotiate authentication scheme not available
[DEBUG] TargetAuthenticationStrategy - Challenge for Kerberos authentication scheme not available
[DEBUG] TargetAuthenticationStrategy - Challenge for NTLM authentication scheme not available
[DEBUG] TargetAuthenticationStrategy - Challenge for Digest authentication scheme not available
[DEBUG] TargetAuthenticationStrategy - Challenge for Basic authentication scheme not available

The Basic auth challenge is NOT recognized!

Reason: org.apache.http.impl.client.AuthenticationStrategyImpl:getChallenges iterates through the WWW-Authenticate HEADERS but doesn't take account that a single header may contain multiple challenges.

How to fix:
Split and parse the WWW-Authenticate header correctly in org.apache.http.impl.client.AuthenticationStrategyImpl:getChallenges