net/http/http_auth_handler_digest.cc

   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 #include "net/http/http_auth_handler_digest.h"
   6
   7 #include <string>
   8
   9 #include "base/i18n/icu_string_conversions.h"
  10 #include "base/logging.h"
  11 #include "base/md5.h"
  12 #include "base/rand_util.h"
  13 #include "base/strings/string_util.h"
  14 #include "base/strings/stringprintf.h"
  15 #include "base/strings/utf_string_conversions.h"
  16 #include "net/base/net_errors.h"
  17 #include "net/base/net_util.h"
  18 #include "net/http/http_auth.h"
  19 #include "net/http/http_request_info.h"
  20 #include "net/http/http_util.h"
  21
  22 namespace net {
  23
  24 // Digest authentication is specified in RFC 2617.
  25 // The expanded derivations are listed in the tables below.
  26
  27 //==========+==========+==========================================+
  28 //    qop   |algorithm |               response                   |
  29 //==========+==========+==========================================+
  30 //    ?     |  ?, md5, | MD5(MD5(A1):nonce:MD5(A2))               |
  31 //          | md5-sess |                                          |
  32 //--------- +----------+------------------------------------------+
  33 //   auth,  |  ?, md5, | MD5(MD5(A1):nonce:nc:cnonce:qop:MD5(A2)) |
  34 // auth-int | md5-sess |                                          |
  35 //==========+==========+==========================================+
  36 //    qop   |algorithm |                  A1                      |
  37 //==========+==========+==========================================+
  38 //          | ?, md5   | user:realm:password                      |
  39 //----------+----------+------------------------------------------+
  40 //          | md5-sess | MD5(user:realm:password):nonce:cnonce    |
  41 //==========+==========+==========================================+
  42 //    qop   |algorithm |                  A2                      |
  43 //==========+==========+==========================================+
  44 //  ?, auth |          | req-method:req-uri                       |
  45 //----------+----------+------------------------------------------+
  46 // auth-int |          | req-method:req-uri:MD5(req-entity-body)  |
  47 //=====================+==========================================+
  48
  49 HttpAuthHandlerDigest::NonceGenerator::NonceGenerator() {
  50 }
  51
  52 HttpAuthHandlerDigest::NonceGenerator::~NonceGenerator() {
  53 }
  54
  55 HttpAuthHandlerDigest::DynamicNonceGenerator::DynamicNonceGenerator() {
  56 }
  57
  58 std::string HttpAuthHandlerDigest::DynamicNonceGenerator::GenerateNonce()
  59     const {
  60   // This is how mozilla generates their cnonce -- a 16 digit hex string.
  61   static const char domain[] = "0123456789abcdef";
  62   std::string cnonce;
  63   cnonce.reserve(16);
  64   for (int i = 0; i < 16; ++i)
  65     cnonce.push_back(domain[base::RandInt(0, 15)]);
  66   return cnonce;
  67 }
  68
  69 HttpAuthHandlerDigest::FixedNonceGenerator::FixedNonceGenerator(
  70     const std::string& nonce)
  71     : nonce_(nonce) {
  72 }
  73
  74 std::string HttpAuthHandlerDigest::FixedNonceGenerator::GenerateNonce() const {
  75   return nonce_;
  76 }
  77
  78 HttpAuthHandlerDigest::Factory::Factory()
  79     : nonce_generator_(new DynamicNonceGenerator()) {
  80 }
  81
  82 HttpAuthHandlerDigest::Factory::~Factory() {
  83 }
  84
  85 void HttpAuthHandlerDigest::Factory::set_nonce_generator(
  86     const NonceGenerator* nonce_generator) {
  87   nonce_generator_.reset(nonce_generator);
  88 }
  89
  90 int HttpAuthHandlerDigest::Factory::CreateAuthHandler(
  91     HttpAuth::ChallengeTokenizer* challenge,
  92     HttpAuth::Target target,
  93     const GURL& origin,
  94     CreateReason reason,
  95     int digest_nonce_count,
  96     const BoundNetLog& net_log,
  97     scoped_ptr<HttpAuthHandler>* handler) {
  98   // TODO(cbentzel): Move towards model of parsing in the factory
  99   //                 method and only constructing when valid.
 100   scoped_ptr<HttpAuthHandler> tmp_handler(
 101       new HttpAuthHandlerDigest(digest_nonce_count, nonce_generator_.get()));
 102   if (!tmp_handler->InitFromChallenge(challenge, target, origin, net_log))
 103     return ERR_INVALID_RESPONSE;
 104   handler->swap(tmp_handler);
 105   return OK;
 106 }
 107
 108 HttpAuth::AuthorizationResult HttpAuthHandlerDigest::HandleAnotherChallenge(
 109     HttpAuth::ChallengeTokenizer* challenge) {
 110   // Even though Digest is not connection based, a "second round" is parsed
 111   // to differentiate between stale and rejected responses.
 112   // Note that the state of the current handler is not mutated - this way if
 113   // there is a rejection the realm hasn't changed.
 114   if (!LowerCaseEqualsASCII(challenge->scheme(), "digest"))
 115     return HttpAuth::AUTHORIZATION_RESULT_INVALID;
 116
 117   HttpUtil::NameValuePairsIterator parameters = challenge->param_pairs();
 118
 119   // Try to find the "stale" value, and also keep track of the realm
 120   // for the new challenge.
 121   std::string original_realm;
 122   while (parameters.GetNext()) {
 123     if (LowerCaseEqualsASCII(parameters.name(), "stale")) {
 124       if (LowerCaseEqualsASCII(parameters.value(), "true"))
 125         return HttpAuth::AUTHORIZATION_RESULT_STALE;
 126     } else if (LowerCaseEqualsASCII(parameters.name(), "realm")) {
 127       original_realm = parameters.value();
 128     }
 129   }
 130   return (original_realm_ != original_realm) ?
 131       HttpAuth::AUTHORIZATION_RESULT_DIFFERENT_REALM :
 132       HttpAuth::AUTHORIZATION_RESULT_REJECT;
 133 }
 134
 135 bool HttpAuthHandlerDigest::Init(HttpAuth::ChallengeTokenizer* challenge) {
 136   return ParseChallenge(challenge);
 137 }
 138
 139 int HttpAuthHandlerDigest::GenerateAuthTokenImpl(
 140     const AuthCredentials* credentials, const HttpRequestInfo* request,
 141     const CompletionCallback& callback, std::string* auth_token) {
 142   // Generate a random client nonce.
 143   std::string cnonce = nonce_generator_->GenerateNonce();
 144
 145   // Extract the request method and path -- the meaning of 'path' is overloaded
 146   // in certain cases, to be a hostname.
 147   std::string method;
 148   std::string path;
 149   GetRequestMethodAndPath(request, &method, &path);
 150
 151   *auth_token = AssembleCredentials(method, path, *credentials,
 152                                     cnonce, nonce_count_);
 153   return OK;
 154 }
 155
 156 HttpAuthHandlerDigest::HttpAuthHandlerDigest(
 157     int nonce_count, const NonceGenerator* nonce_generator)
 158     : stale_(false),
 159       algorithm_(ALGORITHM_UNSPECIFIED),
 160       qop_(QOP_UNSPECIFIED),
 161       nonce_count_(nonce_count),
 162       nonce_generator_(nonce_generator) {
 163   DCHECK(nonce_generator_);
 164 }
 165
 166 HttpAuthHandlerDigest::~HttpAuthHandlerDigest() {
 167 }
 168
 169 // The digest challenge header looks like:
 170 //   WWW-Authenticate: Digest
 171 //     [realm="<realm-value>"]
 172 //     nonce="<nonce-value>"
 173 //     [domain="<list-of-URIs>"]
 174 //     [opaque="<opaque-token-value>"]
 175 //     [stale="<true-or-false>"]
 176 //     [algorithm="<digest-algorithm>"]
 177 //     [qop="<list-of-qop-values>"]
 178 //     [<extension-directive>]
 179 //
 180 // Note that according to RFC 2617 (section 1.2) the realm is required.
 181 // However we allow it to be omitted, in which case it will default to the
 182 // empty string.
 183 //
 184 // This allowance is for better compatibility with webservers that fail to
 185 // send the realm (See http://crbug.com/20984 for an instance where a
 186 // webserver was not sending the realm with a BASIC challenge).
 187 bool HttpAuthHandlerDigest::ParseChallenge(
 188     HttpAuth::ChallengeTokenizer* challenge) {
 189   auth_scheme_ = HttpAuth::AUTH_SCHEME_DIGEST;
 190   score_ = 2;
 191   properties_ = ENCRYPTS_IDENTITY;
 192
 193   // Initialize to defaults.
 194   stale_ = false;
 195   algorithm_ = ALGORITHM_UNSPECIFIED;
 196   qop_ = QOP_UNSPECIFIED;
 197   realm_ = original_realm_ = nonce_ = domain_ = opaque_ = std::string();
 198
 199   // FAIL -- Couldn't match auth-scheme.
 200   if (!LowerCaseEqualsASCII(challenge->scheme(), "digest"))
 201     return false;
 202
 203   HttpUtil::NameValuePairsIterator parameters = challenge->param_pairs();
 204
 205   // Loop through all the properties.
 206   while (parameters.GetNext()) {
 207     // FAIL -- couldn't parse a property.
 208     if (!ParseChallengeProperty(parameters.name(),
 209                                 parameters.value()))
 210       return false;
 211   }
 212
 213   // Check if tokenizer failed.
 214   if (!parameters.valid())
 215     return false;
 216
 217   // Check that a minimum set of properties were provided.
 218   if (nonce_.empty())
 219     return false;
 220
 221   return true;
 222 }
 223
 224 bool HttpAuthHandlerDigest::ParseChallengeProperty(const std::string& name,
 225                                                    const std::string& value) {
 226   if (LowerCaseEqualsASCII(name, "realm")) {
 227     std::string realm;
 228     if (!base::ConvertToUtf8AndNormalize(value, base::kCodepageLatin1, &realm))
 229       return false;
 230     realm_ = realm;
 231     original_realm_ = value;
 232   } else if (LowerCaseEqualsASCII(name, "nonce")) {
 233     nonce_ = value;
 234   } else if (LowerCaseEqualsASCII(name, "domain")) {
 235     domain_ = value;
 236   } else if (LowerCaseEqualsASCII(name, "opaque")) {
 237     opaque_ = value;
 238   } else if (LowerCaseEqualsASCII(name, "stale")) {
 239     // Parse the stale boolean.
 240     stale_ = LowerCaseEqualsASCII(value, "true");
 241   } else if (LowerCaseEqualsASCII(name, "algorithm")) {
 242     // Parse the algorithm.
 243     if (LowerCaseEqualsASCII(value, "md5")) {
 244       algorithm_ = ALGORITHM_MD5;
 245     } else if (LowerCaseEqualsASCII(value, "md5-sess")) {
 246       algorithm_ = ALGORITHM_MD5_SESS;
 247     } else {
 248       DVLOG(1) << "Unknown value of algorithm";
 249       return false;  // FAIL -- unsupported value of algorithm.
 250     }
 251   } else if (LowerCaseEqualsASCII(name, "qop")) {
 252     // Parse the comma separated list of qops.
 253     // auth is the only supported qop, and all other values are ignored.
 254     HttpUtil::ValuesIterator qop_values(value.begin(), value.end(), ',');
 255     qop_ = QOP_UNSPECIFIED;
 256     while (qop_values.GetNext()) {
 257       if (LowerCaseEqualsASCII(qop_values.value(), "auth")) {
 258         qop_ = QOP_AUTH;
 259         break;
 260       }
 261     }
 262   } else {
 263     DVLOG(1) << "Skipping unrecognized digest property";
 264     // TODO(eroman): perhaps we should fail instead of silently skipping?
 265   }
 266   return true;
 267 }
 268
 269 // static
 270 std::string HttpAuthHandlerDigest::QopToString(QualityOfProtection qop) {
 271   switch (qop) {
 272     case QOP_UNSPECIFIED:
 273       return std::string();
 274     case QOP_AUTH:
 275       return "auth";
 276     default:
 277       NOTREACHED();
 278       return std::string();
 279   }
 280 }
 281
 282 // static
 283 std::string HttpAuthHandlerDigest::AlgorithmToString(
 284     DigestAlgorithm algorithm) {
 285   switch (algorithm) {
 286     case ALGORITHM_UNSPECIFIED:
 287       return std::string();
 288     case ALGORITHM_MD5:
 289       return "MD5";
 290     case ALGORITHM_MD5_SESS:
 291       return "MD5-sess";
 292     default:
 293       NOTREACHED();
 294       return std::string();
 295   }
 296 }
 297
 298 void HttpAuthHandlerDigest::GetRequestMethodAndPath(
 299     const HttpRequestInfo* request,
 300     std::string* method,
 301     std::string* path) const {
 302   DCHECK(request);
 303
 304   const GURL& url = request->url;
 305
 306   if (target_ == HttpAuth::AUTH_PROXY &&
 307       (url.SchemeIs("https") || url.SchemeIs("ws") || url.SchemeIs("wss"))) {
 308     *method = "CONNECT";
 309     *path = GetHostAndPort(url);
 310   } else {
 311     *method = request->method;
 312     *path = HttpUtil::PathForRequest(url);
 313   }
 314 }
 315
 316 std::string HttpAuthHandlerDigest::AssembleResponseDigest(
 317     const std::string& method,
 318     const std::string& path,
 319     const AuthCredentials& credentials,
 320     const std::string& cnonce,
 321     const std::string& nc) const {
 322   // ha1 = MD5(A1)
 323   // TODO(eroman): is this the right encoding?
 324   std::string ha1 = base::MD5String(UTF16ToUTF8(credentials.username()) + ":" +
 325                                     original_realm_ + ":" +
 326                                     UTF16ToUTF8(credentials.password()));
 327   if (algorithm_ == HttpAuthHandlerDigest::ALGORITHM_MD5_SESS)
 328     ha1 = base::MD5String(ha1 + ":" + nonce_ + ":" + cnonce);
 329
 330   // ha2 = MD5(A2)
 331   // TODO(eroman): need to add MD5(req-entity-body) for qop=auth-int.
 332   std::string ha2 = base::MD5String(method + ":" + path);
 333
 334   std::string nc_part;
 335   if (qop_ != HttpAuthHandlerDigest::QOP_UNSPECIFIED) {
 336     nc_part = nc + ":" + cnonce + ":" + QopToString(qop_) + ":";
 337   }
 338
 339   return base::MD5String(ha1 + ":" + nonce_ + ":" + nc_part + ha2);
 340 }
 341
 342 std::string HttpAuthHandlerDigest::AssembleCredentials(
 343     const std::string& method,
 344     const std::string& path,
 345     const AuthCredentials& credentials,
 346     const std::string& cnonce,
 347     int nonce_count) const {
 348   // the nonce-count is an 8 digit hex string.
 349   std::string nc = base::StringPrintf("%08x", nonce_count);
 350
 351   // TODO(eroman): is this the right encoding?
 352   std::string authorization = (std::string("Digest username=") +
 353                                HttpUtil::Quote(
 354                                    UTF16ToUTF8(credentials.username())));
 355   authorization += ", realm=" + HttpUtil::Quote(original_realm_);
 356   authorization += ", nonce=" + HttpUtil::Quote(nonce_);
 357   authorization += ", uri=" + HttpUtil::Quote(path);
 358
 359   if (algorithm_ != ALGORITHM_UNSPECIFIED) {
 360     authorization += ", algorithm=" + AlgorithmToString(algorithm_);
 361   }
 362   std::string response = AssembleResponseDigest(method, path, credentials,
 363                                                 cnonce, nc);
 364   // No need to call HttpUtil::Quote() as the response digest cannot contain
 365   // any characters needing to be escaped.
 366   authorization += ", response=\"" + response + "\"";
 367
 368   if (!opaque_.empty()) {
 369     authorization += ", opaque=" + HttpUtil::Quote(opaque_);
 370   }
 371   if (qop_ != QOP_UNSPECIFIED) {
 372     // TODO(eroman): Supposedly IIS server requires quotes surrounding qop.
 373     authorization += ", qop=" + QopToString(qop_);
 374     authorization += ", nc=" + nc;
 375     authorization += ", cnonce=" + HttpUtil::Quote(cnonce);
 376   }
 377
 378   return authorization;
 379 }
 380
 381 }  // namespace net