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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef NET_HTTP_HTTP_AUTH_HANDLER_H_
6 #define NET_HTTP_HTTP_AUTH_HANDLER_H_
7 
8 #include <string>
9 
10 #include "net/base/completion_callback.h"
11 #include "net/base/net_export.h"
12 #include "net/base/net_log.h"
13 #include "net/http/http_auth.h"
14 
15 namespace net {
16 
17 class HttpAuthChallengeTokenizer;
18 struct HttpRequestInfo;
19 
20 // HttpAuthHandler is the interface for the authentication schemes
21 // (basic, digest, NTLM, Negotiate).
22 // HttpAuthHandler objects are typically created by an HttpAuthHandlerFactory.
23 class NET_EXPORT_PRIVATE HttpAuthHandler {
24  public:
25   HttpAuthHandler();
26   virtual ~HttpAuthHandler();
27 
28   // Initializes the handler using a challenge issued by a server.
29   // |challenge| must be non-NULL and have already tokenized the
30   // authentication scheme, but none of the tokens occurring after the
31   // authentication scheme. |target| and |origin| are both stored
32   // for later use, and are not part of the initial challenge.
33   bool InitFromChallenge(HttpAuthChallengeTokenizer* challenge,
34                          HttpAuth::Target target,
35                          const GURL& origin,
36                          const BoundNetLog& net_log);
37 
38   // Determines how the previous authorization attempt was received.
39   //
40   // This is called when the server/proxy responds with a 401/407 after an
41   // earlier authorization attempt. Although this normally means that the
42   // previous attempt was rejected, in multi-round schemes such as
43   // NTLM+Negotiate it may indicate that another round of challenge+response
44   // is required. For Digest authentication it may also mean that the previous
45   // attempt used a stale nonce (and nonce-count) and that a new attempt should
46   // be made with a different nonce provided in the challenge.
47   //
48   // |challenge| must be non-NULL and have already tokenized the
49   // authentication scheme, but none of the tokens occurring after the
50   // authentication scheme.
51   virtual HttpAuth::AuthorizationResult HandleAnotherChallenge(
52       HttpAuthChallengeTokenizer* challenge) = 0;
53 
54   // Generates an authentication token, potentially asynchronously.
55   //
56   // When |credentials| is NULL, the default credentials for the currently
57   // logged in user are used. |AllowsDefaultCredentials()| MUST be true in this
58   // case.
59   //
60   // |request|, |callback|, and |auth_token| must be non-NULL.
61   //
62   // The return value is a net error code.
63   //
64   // If |OK| is returned, |*auth_token| is filled in with an authentication
65   // token which can be inserted in the HTTP request.
66   //
67   // If |ERR_IO_PENDING| is returned, |*auth_token| will be filled in
68   // asynchronously and |callback| will be invoked. The lifetime of
69   // |request|, |callback|, and |auth_token| must last until |callback| is
70   // invoked, but |credentials| is only used during the initial call.
71   //
72   // All other return codes indicate that there was a problem generating a
73   // token, and the value of |*auth_token| is unspecified.
74   int GenerateAuthToken(const AuthCredentials* credentials,
75                         const HttpRequestInfo* request,
76                         const CompletionCallback& callback,
77                         std::string* auth_token);
78 
79   // The authentication scheme as an enumerated value.
auth_scheme()80   HttpAuth::Scheme auth_scheme() const {
81     return auth_scheme_;
82   }
83 
84   // The realm, encoded as UTF-8. This may be empty.
realm()85   const std::string& realm() const {
86     return realm_;
87   }
88 
89   // The challenge which was issued when creating the handler.
challenge()90   const std::string challenge() const {
91     return auth_challenge_;
92   }
93 
94   // Numeric rank based on the challenge's security level. Higher
95   // numbers are better. Used by HttpAuth::ChooseBestChallenge().
score()96   int score() const {
97     return score_;
98   }
99 
target()100   HttpAuth::Target target() const {
101     return target_;
102   }
103 
104   // Returns the proxy or server which issued the authentication challenge
105   // that this HttpAuthHandler is handling. The URL includes scheme, host, and
106   // port, but does not include path.
origin()107   const GURL& origin() const {
108     return origin_;
109   }
110 
111   // Returns true if the authentication scheme does not send the username and
112   // password in the clear.
encrypts_identity()113   bool encrypts_identity() const {
114     return (properties_ & ENCRYPTS_IDENTITY) != 0;
115   }
116 
117   // Returns true if the authentication scheme is connection-based, for
118   // example, NTLM.  A connection-based authentication scheme does not support
119   // preemptive authentication, and must use the same handler object
120   // throughout the life of an HTTP transaction.
is_connection_based()121   bool is_connection_based() const {
122     return (properties_ & IS_CONNECTION_BASED) != 0;
123   }
124 
125   // Returns true if the response to the current authentication challenge
126   // requires an identity.
127   // TODO(wtc): Find a better way to handle a multi-round challenge-response
128   // sequence used by a connection-based authentication scheme.
129   virtual bool NeedsIdentity();
130 
131   // Returns whether the default credentials may be used for the |origin| passed
132   // into |InitFromChallenge|. If true, the user does not need to be prompted
133   // for username and password to establish credentials.
134   // NOTE: SSO is a potential security risk.
135   // TODO(cbentzel): Add a pointer to Firefox documentation about risk.
136   virtual bool AllowsDefaultCredentials();
137 
138   // Returns whether explicit credentials can be used with this handler.  If
139   // true the user may be prompted for credentials if an implicit identity
140   // cannot be determined.
141   virtual bool AllowsExplicitCredentials();
142 
143  protected:
144   enum Property {
145     ENCRYPTS_IDENTITY = 1 << 0,
146     IS_CONNECTION_BASED = 1 << 1,
147   };
148 
149   // Initializes the handler using a challenge issued by a server.
150   // |challenge| must be non-NULL and have already tokenized the
151   // authentication scheme, but none of the tokens occurring after the
152   // authentication scheme.
153   // Implementations are expected to initialize the following members:
154   // scheme_, realm_, score_, properties_
155   virtual bool Init(HttpAuthChallengeTokenizer* challenge) = 0;
156 
157   // |GenerateAuthTokenImpl()} is the auth-scheme specific implementation
158   // of generating the next auth token. Callers should use |GenerateAuthToken()|
159   // which will in turn call |GenerateAuthTokenImpl()|
160   virtual int GenerateAuthTokenImpl(const AuthCredentials* credentials,
161                                     const HttpRequestInfo* request,
162                                     const CompletionCallback& callback,
163                                     std::string* auth_token) = 0;
164 
165   // The auth-scheme as an enumerated value.
166   HttpAuth::Scheme auth_scheme_;
167 
168   // The realm, encoded as UTF-8. Used by "basic" and "digest".
169   std::string realm_;
170 
171   // The auth challenge.
172   std::string auth_challenge_;
173 
174   // The {scheme, host, port} for the authentication target.  Used by "ntlm"
175   // and "negotiate" to construct the service principal name.
176   GURL origin_;
177 
178   // The score for this challenge. Higher numbers are better.
179   int score_;
180 
181   // Whether this authentication request is for a proxy server, or an
182   // origin server.
183   HttpAuth::Target target_;
184 
185   // A bitmask of the properties of the authentication scheme.
186   int properties_;
187 
188   BoundNetLog net_log_;
189 
190  private:
191   void OnGenerateAuthTokenComplete(int rv);
192   void FinishGenerateAuthToken();
193 
194   CompletionCallback callback_;
195 };
196 
197 }  // namespace net
198 
199 #endif  // NET_HTTP_HTTP_AUTH_HANDLER_H_
200