mcs/class/System/System.Net/ServicePointManager.cs

   1 //
   2 // System.Net.ServicePointManager
   3 //
   4 // Authors:
   5 //   Lawrence Pit (loz@cable.a2000.nl)
   6 //   Gonzalo Paniagua Javier (gonzalo@novell.com)
   7 //
   8 // Copyright (c) 2003-2010 Novell, Inc (http://www.novell.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System;
  33 using System.Collections;
  34 using System.Collections.Specialized;
  35 using System.Configuration;
  36 using System.Net.Configuration;
  37 using System.Security.Cryptography.X509Certificates;
  38
  39 using System.Globalization;
  40 using System.Net.Security;
  41 #if SECURITY_DEP
  42 using System.Text.RegularExpressions;
  43 using Mono.Security;
  44 using Mono.Security.Cryptography;
  45 using Mono.Security.X509.Extensions;
  46 using Mono.Security.Protocol.Tls;
  47 using MSX = Mono.Security.X509;
  48 #endif
  49
  50 //
  51 // notes:
  52 // A service point manager manages service points (duh!).
  53 // A service point maintains a list of connections (per scheme + authority).
  54 // According to HttpWebRequest.ConnectionGroupName each connection group
  55 // creates additional connections. therefor, a service point has a hashtable
  56 // of connection groups where each value is a list of connections.
  57 //
  58 // when we need to make an HttpWebRequest, we need to do the following:
  59 // 1. find service point, given Uri and Proxy
  60 // 2. find connection group, given service point and group name
  61 // 3. find free connection in connection group, or create one (if ok due to limits)
  62 // 4. lease connection
  63 // 5. execute request
  64 // 6. when finished, return connection
  65 //
  66
  67
  68 namespace System.Net
  69 {
  70 #if MOONLIGHT
  71         internal class ServicePointManager {
  72 #else
  73         public class ServicePointManager {
  74 #endif
  75                 class SPKey {
  76                         Uri uri; // schema/host/port
  77                         bool use_connect;
  78
  79                         public SPKey (Uri uri, bool use_connect) {
  80                                 this.uri = uri;
  81                                 this.use_connect = use_connect;
  82                         }
  83
  84                         public Uri Uri {
  85                                 get { return uri; }
  86                         }
  87
  88                         public bool UseConnect {
  89                                 get { return use_connect; }
  90                         }
  91
  92                         public override int GetHashCode () {
  93                                 return uri.GetHashCode () + ((use_connect) ? 1 : 0);
  94                         }
  95
  96                         public override bool Equals (object obj) {
  97                                 SPKey other = obj as SPKey;
  98                                 if (obj == null) {
  99                                         return false;
 100                                 }
 101
 102                                 return (uri.Equals (other.uri) && other.use_connect == use_connect);
 103                         }
 104                 }
 105
 106                 private static HybridDictionary servicePoints = new HybridDictionary ();
 107
 108                 // Static properties
 109
 110                 private static ICertificatePolicy policy = new DefaultCertificatePolicy ();
 111                 private static int defaultConnectionLimit = DefaultPersistentConnectionLimit;
 112                 private static int maxServicePointIdleTime = 900000; // 15 minutes
 113                 private static int maxServicePoints = 0;
 114                 private static bool _checkCRL = false;
 115                 private static SecurityProtocolType _securityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls;
 116
 117 #if NET_1_1
 118 #if TARGET_JVM
 119                 static bool expectContinue = false;
 120 #else
 121                 static bool expectContinue = true;
 122 #endif
 123                 static bool useNagle;
 124 #endif
 125                 static RemoteCertificateValidationCallback server_cert_cb;
 126
 127                 // Fields
 128
 129                 public const int DefaultNonPersistentConnectionLimit = 4;
 130                 public const int DefaultPersistentConnectionLimit = 2;
 131
 132 #if !NET_2_1
 133                 const string configKey = "system.net/connectionManagement";
 134                 static ConnectionManagementData manager;
 135 #endif
 136
 137                 static ServicePointManager ()
 138                 {
 139 #if !NET_2_1
 140 #if NET_2_0 && CONFIGURATION_DEP
 141                         object cfg = ConfigurationManager.GetSection (configKey);
 142                         ConnectionManagementSection s = cfg as ConnectionManagementSection;
 143                         if (s != null) {
 144                                 manager = new ConnectionManagementData (null);
 145                                 foreach (ConnectionManagementElement e in s.ConnectionManagement)
 146                                         manager.Add (e.Address, e.MaxConnection);
 147
 148                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");
 149                                 return;
 150                         }
 151 #endif
 152                         manager = (ConnectionManagementData) ConfigurationSettings.GetConfig (configKey);
 153                         if (manager != null) {
 154                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");
 155                         }
 156 #endif
 157                 }
 158
 159                 // Constructors
 160                 private ServicePointManager ()
 161                 {
 162                 }
 163
 164                 // Properties
 165
 166 #if NET_2_0
 167                 [Obsolete ("Use ServerCertificateValidationCallback instead", false)]
 168 #endif
 169                 public static ICertificatePolicy CertificatePolicy {
 170                         get { return policy; }
 171                         set { policy = value; }
 172                 }
 173
 174 #if NET_1_0
 175                 // we need it for SslClientStream
 176                 internal
 177 #else
 178                 [MonoTODO("CRL checks not implemented")]
 179                 public
 180 #endif
 181                 static bool CheckCertificateRevocationList {
 182                         get { return _checkCRL; }
 183                         set { _checkCRL = false; }      // TODO - don't yet accept true
 184                 }
 185
 186                 public static int DefaultConnectionLimit {
 187                         get { return defaultConnectionLimit; }
 188                         set {
 189                                 if (value <= 0)
 190                                         throw new ArgumentOutOfRangeException ("value");
 191
 192                                 defaultConnectionLimit = value;
 193                         }
 194                 }
 195
 196 #if NET_2_0
 197                 static Exception GetMustImplement ()
 198                 {
 199                         return new NotImplementedException ();
 200                 }
 201
 202                 [MonoTODO]
 203                 public static int DnsRefreshTimeout
 204                 {
 205                         get {
 206                                 throw GetMustImplement ();
 207                         }
 208                         set {
 209                                 throw GetMustImplement ();
 210                         }
 211                 }
 212
 213                 [MonoTODO]
 214                 public static bool EnableDnsRoundRobin
 215                 {
 216                         get {
 217                                 throw GetMustImplement ();
 218                         }
 219                         set {
 220                                 throw GetMustImplement ();
 221                         }
 222                 }
 223 #endif
 224
 225                 public static int MaxServicePointIdleTime {
 226                         get {
 227                                 return maxServicePointIdleTime;
 228                         }
 229                         set {
 230                                 if (value < -2 || value > Int32.MaxValue)
 231                                         throw new ArgumentOutOfRangeException ("value");
 232                                 maxServicePointIdleTime = value;
 233                         }
 234                 }
 235
 236                 public static int MaxServicePoints {
 237                         get {
 238                                 return maxServicePoints;
 239                         }
 240                         set {
 241                                 if (value < 0)
 242                                         throw new ArgumentException ("value");
 243
 244                                 maxServicePoints = value;
 245                                 RecycleServicePoints ();
 246                         }
 247                 }
 248
 249 #if NET_1_0
 250                 // we need it for SslClientStream
 251                 internal
 252 #else
 253                 public
 254 #endif
 255                 static SecurityProtocolType SecurityProtocol {
 256                         get { return _securityProtocol; }
 257                         set { _securityProtocol = value; }
 258                 }
 259
 260                 public static RemoteCertificateValidationCallback ServerCertificateValidationCallback
 261                 {
 262                         get {
 263                                 return server_cert_cb;
 264                         }
 265                         set {
 266                                 server_cert_cb = value;
 267                         }
 268                 }
 269
 270 #if NET_1_1
 271                 public static bool Expect100Continue {
 272                         get { return expectContinue; }
 273                         set { expectContinue = value; }
 274                 }
 275
 276                 public static bool UseNagleAlgorithm {
 277                         get { return useNagle; }
 278                         set { useNagle = value; }
 279                 }
 280 #endif
 281                 // Methods
 282
 283                 public static ServicePoint FindServicePoint (Uri address)
 284                 {
 285                         return FindServicePoint (address, GlobalProxySelection.Select);
 286                 }
 287
 288                 public static ServicePoint FindServicePoint (string uriString, IWebProxy proxy)
 289                 {
 290                         return FindServicePoint (new Uri(uriString), proxy);
 291                 }
 292
 293                 public static ServicePoint FindServicePoint (Uri address, IWebProxy proxy)
 294                 {
 295                         if (address == null)
 296                                 throw new ArgumentNullException ("address");
 297
 298                         RecycleServicePoints ();
 299
 300                         bool usesProxy = false;
 301                         bool useConnect = false;
 302                         if (proxy != null && !proxy.IsBypassed(address)) {
 303                                 usesProxy = true;
 304                                 bool isSecure = address.Scheme == "https";
 305                                 address = proxy.GetProxy (address);
 306                                 if (address.Scheme != "http" && !isSecure)
 307                                         throw new NotSupportedException ("Proxy scheme not supported.");
 308
 309                                 if (isSecure && address.Scheme == "http")
 310                                         useConnect = true;
 311                         }
 312
 313                         address = new Uri (address.Scheme + "://" + address.Authority);
 314
 315                         ServicePoint sp = null;
 316                         lock (servicePoints) {
 317                                 SPKey key = new SPKey (address, useConnect);
 318                                 sp = servicePoints [key] as ServicePoint;
 319                                 if (sp != null)
 320                                         return sp;
 321
 322                                 if (maxServicePoints > 0 && servicePoints.Count >= maxServicePoints)
 323                                         throw new InvalidOperationException ("maximum number of service points reached");
 324
 325                                 string addr = address.ToString ();
 326 #if NET_2_1
 327                                 int limit = defaultConnectionLimit;
 328 #else
 329                                 int limit = (int) manager.GetMaxConnections (addr);
 330 #endif
 331                                 sp = new ServicePoint (address, limit, maxServicePointIdleTime);
 332 #if NET_1_1
 333                                 sp.Expect100Continue = expectContinue;
 334                                 sp.UseNagleAlgorithm = useNagle;
 335 #endif
 336                                 sp.UsesProxy = usesProxy;
 337                                 sp.UseConnect = useConnect;
 338                                 servicePoints.Add (key, sp);
 339                         }
 340
 341                         return sp;
 342                 }
 343
 344                 // Internal Methods
 345
 346                 internal static void RecycleServicePoints ()
 347                 {
 348                         ArrayList toRemove = new ArrayList ();
 349                         lock (servicePoints) {
 350                                 IDictionaryEnumerator e = servicePoints.GetEnumerator ();
 351                                 while (e.MoveNext ()) {
 352                                         ServicePoint sp = (ServicePoint) e.Value;
 353                                         if (sp.AvailableForRecycling) {
 354                                                 toRemove.Add (e.Key);
 355                                         }
 356                                 }
 357
 358                                 for (int i = 0; i < toRemove.Count; i++)
 359                                         servicePoints.Remove (toRemove [i]);
 360
 361                                 if (maxServicePoints == 0 || servicePoints.Count <= maxServicePoints)
 362                                         return;
 363
 364                                 // get rid of the ones with the longest idle time
 365                                 SortedList list = new SortedList (servicePoints.Count);
 366                                 e = servicePoints.GetEnumerator ();
 367                                 while (e.MoveNext ()) {
 368                                         ServicePoint sp = (ServicePoint) e.Value;
 369                                         if (sp.CurrentConnections == 0) {
 370                                                 while (list.ContainsKey (sp.IdleSince))
 371                                                         sp.IdleSince = sp.IdleSince.AddMilliseconds (1);
 372                                                 list.Add (sp.IdleSince, sp.Address);
 373                                         }
 374                                 }
 375
 376                                 for (int i = 0; i < list.Count && servicePoints.Count > maxServicePoints; i++)
 377                                         servicePoints.Remove (list.GetByIndex (i));
 378                         }
 379                 }
 380 #if NET_2_0 && SECURITY_DEP
 381                 internal class ChainValidationHelper {
 382                         object sender;
 383                         string host;
 384                         static bool is_macosx = System.IO.File.Exists (MSX.OSX509Certificates.SecurityLibrary);
 385
 386                         public ChainValidationHelper (object sender)
 387                         {
 388                                 this.sender = sender;
 389                         }
 390
 391                         public string Host {
 392                                 get {
 393                                         if (host == null && sender is HttpWebRequest)
 394                                                 host = ((HttpWebRequest) sender).Address.Host;
 395                                         return host;
 396                                 }
 397
 398                                 set { host = value; }
 399                         }
 400
 401                         // Used when the obsolete ICertificatePolicy is set to DefaultCertificatePolicy
 402                         // and the new ServerCertificateValidationCallback is not null
 403                         internal ValidationResult ValidateChain (Mono.Security.X509.X509CertificateCollection certs)
 404                         {
 405                                 // user_denied is true if the user callback is called and returns false
 406                                 bool user_denied = false;
 407                                 if (certs == null || certs.Count == 0)
 408                                         return null;
 409
 410                                 ICertificatePolicy policy = ServicePointManager.CertificatePolicy;
 411                                 RemoteCertificateValidationCallback cb = ServicePointManager.ServerCertificateValidationCallback;
 412
 413                                 X509Chain chain = new X509Chain ();
 414                                 chain.ChainPolicy = new X509ChainPolicy ();
 415                                 for (int i = 1; i < certs.Count; i++) {
 416                                         X509Certificate2 c2 = new X509Certificate2 (certs [i].RawData);
 417                                         chain.ChainPolicy.ExtraStore.Add (c2);
 418                                 }
 419
 420                                 X509Certificate2 leaf = new X509Certificate2 (certs [0].RawData);
 421                                 int status11 = 0; // Error code passed to the obsolete ICertificatePolicy callback
 422                                 SslPolicyErrors errors = 0;
 423                                 try {
 424                                         if (!chain.Build (leaf))
 425                                                 errors |= GetErrorsFromChain (chain);
 426                                 } catch (Exception e) {
 427                                         Console.Error.WriteLine ("ERROR building certificate chain: {0}", e);
 428                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 429                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 430                                 }
 431
 432                                 if (!CheckCertificateUsage (leaf)) {
 433                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 434                                         status11 = -2146762490; //CERT_E_PURPOSE 0x800B0106
 435                                 }
 436
 437                                 if (!CheckServerIdentity (certs [0], Host)) {
 438                                         errors |= SslPolicyErrors.RemoteCertificateNameMismatch;
 439                                         status11 = -2146762481; // CERT_E_CN_NO_MATCH 0x800B010F
 440                                 }
 441
 442                                 bool result = false;
 443                                 // No certificate root found means no mozroots or monotouch
 444 #if !MONOTOUCH
 445                                 if (is_macosx) {
 446 #endif
 447                                         // Attempt to use OSX certificates
 448                                         // Ideally we should return the SecTrustResult
 449                                         MSX.OSX509Certificates.SecTrustResult trustResult;
 450                                         try {
 451                                                 trustResult = MSX.OSX509Certificates.TrustEvaluateSsl (certs);
 452                                                 // We could use the other values of trustResult to pass this extra information
 453                                                 // to the .NET 2 callback for values like SecTrustResult.Confirm
 454                                                 result = (trustResult == MSX.OSX509Certificates.SecTrustResult.Proceed ||
 455                                                                   trustResult == MSX.OSX509Certificates.SecTrustResult.Unspecified);
 456
 457                                         } catch {
 458                                                 // Ignore
 459                                         }
 460                                         // Clear error status if the OS told us to trust the certificate
 461                                         if (result) {
 462                                                 status11 = 0;
 463                                                 errors = 0;
 464                                         }
 465 #if !MONOTOUCH
 466                                 }
 467 #endif
 468
 469                                 if (policy != null && (!(policy is DefaultCertificatePolicy) || cb == null)) {
 470                                         ServicePoint sp = null;
 471                                         HttpWebRequest req = sender as HttpWebRequest;
 472                                         if (req != null)
 473                                                 sp = req.ServicePoint;
 474                                         if (status11 == 0 && errors != 0)
 475                                                 status11 = GetStatusFromChain (chain);
 476
 477                                         // pre 2.0 callback
 478                                         result = policy.CheckValidationResult (sp, leaf, req, status11);
 479                                         user_denied = !result && !(policy is DefaultCertificatePolicy);
 480                                 }
 481                                 // If there's a 2.0 callback, it takes precedence
 482                                 if (cb != null) {
 483                                         result = cb (sender, leaf, chain, errors);
 484                                         user_denied = !result;
 485                                 }
 486                                 return new ValidationResult (result, user_denied, status11);
 487                         }
 488
 489                         static int GetStatusFromChain (X509Chain chain)
 490                         {
 491                                 long result = 0;
 492                                 foreach (var status in chain.ChainStatus) {
 493                                         X509ChainStatusFlags flags = status.Status;
 494                                         if (flags == X509ChainStatusFlags.NoError)
 495                                                 continue;
 496
 497                                         // CERT_E_EXPIRED
 498                                         if ((flags & X509ChainStatusFlags.NotTimeValid) != 0) result = 0x800B0101;
 499                                         // CERT_E_VALIDITYPERIODNESTING
 500                                         else if ((flags & X509ChainStatusFlags.NotTimeNested) != 0) result = 0x800B0102;
 501                                         // CERT_E_REVOKED
 502                                         else if ((flags & X509ChainStatusFlags.Revoked) != 0) result = 0x800B010C;
 503                                         // TRUST_E_CERT_SIGNATURE
 504                                         else if ((flags & X509ChainStatusFlags.NotSignatureValid) != 0) result = 0x80096004;
 505                                         // CERT_E_WRONG_USAGE
 506                                         else if ((flags & X509ChainStatusFlags.NotValidForUsage) != 0) result = 0x800B0110;
 507                                         // CERT_E_UNTRUSTEDROOT
 508                                         else if ((flags & X509ChainStatusFlags.UntrustedRoot) != 0) result = 0x800B0109;
 509                                         // CRYPT_E_NO_REVOCATION_CHECK
 510                                         else if ((flags & X509ChainStatusFlags.RevocationStatusUnknown) != 0) result = 0x80092012;
 511                                         // CERT_E_CHAINING
 512                                         else if ((flags & X509ChainStatusFlags.Cyclic) != 0) result = 0x800B010A;
 513                                         // TRUST_E_FAIL - generic
 514                                         else if ((flags & X509ChainStatusFlags.InvalidExtension) != 0) result = 0x800B010B;
 515                                         // CERT_E_UNTRUSTEDROOT
 516                                         else if ((flags & X509ChainStatusFlags.InvalidPolicyConstraints) != 0) result = 0x800B010D;
 517                                         // TRUST_E_BASIC_CONSTRAINTS
 518                                         else if ((flags & X509ChainStatusFlags.InvalidBasicConstraints) != 0) result = 0x80096019;
 519                                         // CERT_E_INVALID_NAME
 520                                         else if ((flags & X509ChainStatusFlags.InvalidNameConstraints) != 0) result = 0x800B0114;
 521                                         // CERT_E_INVALID_NAME
 522                                         else if ((flags & X509ChainStatusFlags.HasNotSupportedNameConstraint) != 0) result = 0x800B0114;
 523                                         // CERT_E_INVALID_NAME
 524                                         else if ((flags & X509ChainStatusFlags.HasNotDefinedNameConstraint) != 0) result = 0x800B0114;
 525                                         // CERT_E_INVALID_NAME
 526                                         else if ((flags & X509ChainStatusFlags.HasNotPermittedNameConstraint) != 0) result = 0x800B0114;
 527                                         // CERT_E_INVALID_NAME
 528                                         else if ((flags & X509ChainStatusFlags.HasExcludedNameConstraint) != 0) result = 0x800B0114;
 529                                         // CERT_E_CHAINING
 530                                         else if ((flags & X509ChainStatusFlags.PartialChain) != 0) result = 0x800B010A;
 531                                         // CERT_E_EXPIRED
 532                                         else if ((flags & X509ChainStatusFlags.CtlNotTimeValid) != 0) result = 0x800B0101;
 533                                         // TRUST_E_CERT_SIGNATURE
 534                                         else if ((flags & X509ChainStatusFlags.CtlNotSignatureValid) != 0) result = 0x80096004;
 535                                         // CERT_E_WRONG_USAGE
 536                                         else if ((flags & X509ChainStatusFlags.CtlNotValidForUsage) != 0) result = 0x800B0110;
 537                                         // CRYPT_E_NO_REVOCATION_CHECK
 538                                         else if ((flags & X509ChainStatusFlags.OfflineRevocation) != 0) result = 0x80092012;
 539                                         // CERT_E_ISSUERCHAINING
 540                                         else if ((flags & X509ChainStatusFlags.NoIssuanceChainPolicy) != 0) result = 0x800B0107;
 541                                         else result = 0x800B010B; // TRUST_E_FAIL - generic
 542
 543                                         break; // Exit the loop on the first error
 544                                 }
 545                                 return (int) result;
 546                         }
 547
 548                         static SslPolicyErrors GetErrorsFromChain (X509Chain chain)
 549                         {
 550                                 SslPolicyErrors errors = SslPolicyErrors.None;
 551                                 foreach (var status in chain.ChainStatus) {
 552                                         if (status.Status == X509ChainStatusFlags.NoError)
 553                                                 continue;
 554                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 555                                         break;
 556                                 }
 557                                 return errors;
 558                         }
 559
 560                         static X509KeyUsageFlags s_flags = X509KeyUsageFlags.DigitalSignature  |
 561                                                         X509KeyUsageFlags.KeyAgreement |
 562                                                         X509KeyUsageFlags.KeyEncipherment;
 563                         // Adapted to System 2.0+ from TlsServerCertificate.cs
 564                         //------------------------------
 565                         // Note: this method only works for RSA certificates
 566                         // DH certificates requires some changes - does anyone use one ?
 567                         static bool CheckCertificateUsage (X509Certificate2 cert)
 568                         {
 569                                 try {
 570                                         // certificate extensions are required for this
 571                                         // we "must" accept older certificates without proofs
 572                                         if (cert.Version < 3)
 573                                                 return true;
 574
 575                                         X509KeyUsageExtension kux = (X509KeyUsageExtension) cert.Extensions ["2.5.29.15"];
 576                                         X509EnhancedKeyUsageExtension eku = (X509EnhancedKeyUsageExtension) cert.Extensions ["2.5.29.37"];
 577                                         if (kux != null && eku != null) {
 578                                                 // RFC3280 states that when both KeyUsageExtension and
 579                                                 // ExtendedKeyUsageExtension are present then BOTH should
 580                                                 // be valid
 581                                                 if ((kux.KeyUsages & s_flags) == 0)
 582                                                         return false;
 583                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
 584                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
 585                                         } else if (kux != null) {
 586                                                 return ((kux.KeyUsages & s_flags) != 0);
 587                                         } else if (eku != null) {
 588                                                 // Server Authentication (1.3.6.1.5.5.7.3.1) or
 589                                                 // Netscape Server Gated Crypto (2.16.840.1.113730.4)
 590                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
 591                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
 592                                         }
 593
 594                                         // last chance - try with older (deprecated) Netscape extensions
 595                                         X509Extension ext = cert.Extensions ["2.16.840.1.113730.1.1"];
 596                                         if (ext != null) {
 597                                                 string text = ext.NetscapeCertType (false);
 598                                                 return text.IndexOf ("SSL Server Authentication") != -1;
 599                                         }
 600                                         return true;
 601                                 } catch (Exception e) {
 602                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
 603                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 604                                         return false;
 605                                 }
 606                         }
 607
 608                         // RFC2818 - HTTP Over TLS, Section 3.1
 609                         // http://www.ietf.org/rfc/rfc2818.txt
 610                         //
 611                         // 1.   if present MUST use subjectAltName dNSName as identity
 612                         // 1.1.         if multiples entries a match of any one is acceptable
 613                         // 1.2.         wildcard * is acceptable
 614                         // 2.   URI may be an IP address -> subjectAltName.iPAddress
 615                         // 2.1.         exact match is required
 616                         // 3.   Use of the most specific Common Name (CN=) in the Subject
 617                         // 3.1          Existing practice but DEPRECATED
 618                         static bool CheckServerIdentity (Mono.Security.X509.X509Certificate cert, string targetHost)
 619                         {
 620                                 try {
 621                                         Mono.Security.X509.X509Extension ext = cert.Extensions ["2.5.29.17"];
 622                                         // 1. subjectAltName
 623                                         if (ext != null) {
 624                                                 SubjectAltNameExtension subjectAltName = new SubjectAltNameExtension (ext);
 625                                                 // 1.1 - multiple dNSName
 626                                                 foreach (string dns in subjectAltName.DNSNames) {
 627                                                         // 1.2 TODO - wildcard support
 628                                                         if (Match (targetHost, dns))
 629                                                                 return true;
 630                                                 }
 631                                                 // 2. ipAddress
 632                                                 foreach (string ip in subjectAltName.IPAddresses) {
 633                                                         // 2.1. Exact match required
 634                                                         if (ip == targetHost)
 635                                                                 return true;
 636                                                 }
 637                                         }
 638                                         // 3. Common Name (CN=)
 639                                         return CheckDomainName (cert.SubjectName, targetHost);
 640                                 } catch (Exception e) {
 641                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
 642                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 643                                         return false;
 644                                 }
 645                         }
 646
 647                         static bool CheckDomainName (string subjectName, string targetHost)
 648                         {
 649                                 string  domainName = String.Empty;
 650                                 Regex search = new Regex(@"CN\s*=\s*([^,]*)");
 651                                 MatchCollection elements = search.Matches(subjectName);
 652                                 if (elements.Count == 1) {
 653                                         if (elements[0].Success)
 654                                                 domainName = elements[0].Groups[1].Value.ToString();
 655                                 }
 656
 657                                 return Match (targetHost, domainName);
 658                         }
 659
 660                         // ensure the pattern is valid wrt to RFC2595 and RFC2818
 661                         // http://www.ietf.org/rfc/rfc2595.txt
 662                         // http://www.ietf.org/rfc/rfc2818.txt
 663                         static bool Match (string hostname, string pattern)
 664                         {
 665                                 // check if this is a pattern
 666                                 int index = pattern.IndexOf ('*');
 667                                 if (index == -1) {
 668                                         // not a pattern, do a direct case-insensitive comparison
 669                                         return (String.Compare (hostname, pattern, true, CultureInfo.InvariantCulture) == 0);
 670                                 }
 671
 672                                 // check pattern validity
 673                                 // A "*" wildcard character MAY be used as the left-most name component in the certificate.
 674
 675                                 // unless this is the last char (valid)
 676                                 if (index != pattern.Length - 1) {
 677                                         // then the next char must be a dot .'.
 678                                         if (pattern [index + 1] != '.')
 679                                                 return false;
 680                                 }
 681
 682                                 // only one (A) wildcard is supported
 683                                 int i2 = pattern.IndexOf ('*', index + 1);
 684                                 if (i2 != -1)
 685                                         return false;
 686
 687                                 // match the end of the pattern
 688                                 string end = pattern.Substring (index + 1);
 689                                 int length = hostname.Length - end.Length;
 690                                 // no point to check a pattern that is longer than the hostname
 691                                 if (length <= 0)
 692                                         return false;
 693
 694                                 if (String.Compare (hostname, length, end, 0, end.Length, true, CultureInfo.InvariantCulture) != 0)
 695                                         return false;
 696
 697                                 // special case, we start with the wildcard
 698                                 if (index == 0) {
 699                                         // ensure we hostname non-matched part (start) doesn't contain a dot
 700                                         int i3 = hostname.IndexOf ('.');
 701                                         return ((i3 == -1) || (i3 >= (hostname.Length - end.Length)));
 702                                 }
 703
 704                                 // match the start of the pattern
 705                                 string start = pattern.Substring (0, index);
 706                                 return (String.Compare (hostname, 0, start, 0, start.Length, true, CultureInfo.InvariantCulture) == 0);
 707                         }
 708                 }
 709 #endif
 710         }
 711 }
 712