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 TARGET_JVM
 118                 static bool expectContinue = false;
 119 #else
 120                 static bool expectContinue = true;
 121 #endif
 122                 static bool useNagle;
 123                 static RemoteCertificateValidationCallback server_cert_cb;
 124                 static bool tcp_keepalive;
 125                 static int tcp_keepalive_time;
 126                 static int tcp_keepalive_interval;
 127
 128                 // Fields
 129
 130                 public const int DefaultNonPersistentConnectionLimit = 4;
 131 #if MONOTOUCH
 132                 public const int DefaultPersistentConnectionLimit = 10;
 133 #else
 134                 public const int DefaultPersistentConnectionLimit = 2;
 135 #endif
 136
 137 #if !NET_2_1
 138                 const string configKey = "system.net/connectionManagement";
 139                 static ConnectionManagementData manager;
 140 #endif
 141
 142                 static ServicePointManager ()
 143                 {
 144 #if !NET_2_1
 145 #if CONFIGURATION_DEP
 146                         object cfg = ConfigurationManager.GetSection (configKey);
 147                         ConnectionManagementSection s = cfg as ConnectionManagementSection;
 148                         if (s != null) {
 149                                 manager = new ConnectionManagementData (null);
 150                                 foreach (ConnectionManagementElement e in s.ConnectionManagement)
 151                                         manager.Add (e.Address, e.MaxConnection);
 152
 153                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");
 154                                 return;
 155                         }
 156 #endif
 157                         manager = (ConnectionManagementData) ConfigurationSettings.GetConfig (configKey);
 158                         if (manager != null) {
 159                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");
 160                         }
 161 #endif
 162                 }
 163
 164                 // Constructors
 165                 private ServicePointManager ()
 166                 {
 167                 }
 168
 169                 // Properties
 170
 171                 [Obsolete ("Use ServerCertificateValidationCallback instead", false)]
 172                 public static ICertificatePolicy CertificatePolicy {
 173                         get { return policy; }
 174                         set { policy = value; }
 175                 }
 176
 177                 [MonoTODO("CRL checks not implemented")]
 178                 public static bool CheckCertificateRevocationList {
 179                         get { return _checkCRL; }
 180                         set { _checkCRL = false; }      // TODO - don't yet accept true
 181                 }
 182
 183                 public static int DefaultConnectionLimit {
 184                         get { return defaultConnectionLimit; }
 185                         set {
 186                                 if (value <= 0)
 187                                         throw new ArgumentOutOfRangeException ("value");
 188
 189                                 defaultConnectionLimit = value;
 190                         }
 191                 }
 192
 193                 static Exception GetMustImplement ()
 194                 {
 195                         return new NotImplementedException ();
 196                 }
 197
 198                 [MonoTODO]
 199                 public static int DnsRefreshTimeout
 200                 {
 201                         get {
 202                                 throw GetMustImplement ();
 203                         }
 204                         set {
 205                                 throw GetMustImplement ();
 206                         }
 207                 }
 208
 209                 [MonoTODO]
 210                 public static bool EnableDnsRoundRobin
 211                 {
 212                         get {
 213                                 throw GetMustImplement ();
 214                         }
 215                         set {
 216                                 throw GetMustImplement ();
 217                         }
 218                 }
 219
 220                 public static int MaxServicePointIdleTime {
 221                         get {
 222                                 return maxServicePointIdleTime;
 223                         }
 224                         set {
 225                                 if (value < -2 || value > Int32.MaxValue)
 226                                         throw new ArgumentOutOfRangeException ("value");
 227                                 maxServicePointIdleTime = value;
 228                         }
 229                 }
 230
 231                 public static int MaxServicePoints {
 232                         get {
 233                                 return maxServicePoints;
 234                         }
 235                         set {
 236                                 if (value < 0)
 237                                         throw new ArgumentException ("value");
 238
 239                                 maxServicePoints = value;
 240                                 RecycleServicePoints ();
 241                         }
 242                 }
 243
 244 #if NET_1_0
 245                 // we need it for SslClientStream
 246                 internal
 247 #else
 248                 public
 249 #endif
 250                 static SecurityProtocolType SecurityProtocol {
 251                         get { return _securityProtocol; }
 252                         set { _securityProtocol = value; }
 253                 }
 254
 255                 public static RemoteCertificateValidationCallback ServerCertificateValidationCallback
 256                 {
 257                         get {
 258                                 return server_cert_cb;
 259                         }
 260                         set {
 261                                 server_cert_cb = value;
 262                         }
 263                 }
 264
 265                 public static bool Expect100Continue {
 266                         get { return expectContinue; }
 267                         set { expectContinue = value; }
 268                 }
 269
 270                 public static bool UseNagleAlgorithm {
 271                         get { return useNagle; }
 272                         set { useNagle = value; }
 273                 }
 274
 275                 // Methods
 276                 public static void SetTcpKeepAlive (bool enabled, int keepAliveTime, int keepAliveInterval)
 277                 {
 278                         if (enabled) {
 279                                 if (keepAliveTime <= 0)
 280                                         throw new ArgumentOutOfRangeException ("keepAliveTime", "Must be greater than 0");
 281                                 if (keepAliveInterval <= 0)
 282                                         throw new ArgumentOutOfRangeException ("keepAliveInterval", "Must be greater than 0");
 283                         }
 284
 285                         tcp_keepalive = enabled;
 286                         tcp_keepalive_time = keepAliveTime;
 287                         tcp_keepalive_interval = keepAliveInterval;
 288                 }
 289
 290                 public static ServicePoint FindServicePoint (Uri address)
 291                 {
 292                         return FindServicePoint (address, GlobalProxySelection.Select);
 293                 }
 294
 295                 public static ServicePoint FindServicePoint (string uriString, IWebProxy proxy)
 296                 {
 297                         return FindServicePoint (new Uri(uriString), proxy);
 298                 }
 299
 300                 public static ServicePoint FindServicePoint (Uri address, IWebProxy proxy)
 301                 {
 302                         if (address == null)
 303                                 throw new ArgumentNullException ("address");
 304
 305                         RecycleServicePoints ();
 306
 307                         var origAddress = new Uri (address.Scheme + "://" + address.Authority);
 308
 309                         bool usesProxy = false;
 310                         bool useConnect = false;
 311                         if (proxy != null && !proxy.IsBypassed(address)) {
 312                                 usesProxy = true;
 313                                 bool isSecure = address.Scheme == "https";
 314                                 address = proxy.GetProxy (address);
 315                                 if (address.Scheme != "http" && !isSecure)
 316                                         throw new NotSupportedException ("Proxy scheme not supported.");
 317
 318                                 if (isSecure && address.Scheme == "http")
 319                                         useConnect = true;
 320                         }
 321
 322                         address = new Uri (address.Scheme + "://" + address.Authority);
 323
 324                         ServicePoint sp = null;
 325                         lock (servicePoints) {
 326                                 SPKey key = new SPKey (origAddress, useConnect);
 327                                 sp = servicePoints [key] as ServicePoint;
 328                                 if (sp != null)
 329                                         return sp;
 330
 331                                 if (maxServicePoints > 0 && servicePoints.Count >= maxServicePoints)
 332                                         throw new InvalidOperationException ("maximum number of service points reached");
 333
 334                                 string addr = address.ToString ();
 335 #if NET_2_1
 336                                 int limit = defaultConnectionLimit;
 337 #else
 338                                 int limit = (int) manager.GetMaxConnections (addr);
 339 #endif
 340                                 sp = new ServicePoint (address, limit, maxServicePointIdleTime);
 341                                 sp.Expect100Continue = expectContinue;
 342                                 sp.UseNagleAlgorithm = useNagle;
 343                                 sp.UsesProxy = usesProxy;
 344                                 sp.UseConnect = useConnect;
 345                                 sp.SetTcpKeepAlive (tcp_keepalive, tcp_keepalive_time, tcp_keepalive_interval);
 346                                 servicePoints.Add (key, sp);
 347                         }
 348
 349                         return sp;
 350                 }
 351
 352                 // Internal Methods
 353
 354                 internal static void RecycleServicePoints ()
 355                 {
 356                         ArrayList toRemove = new ArrayList ();
 357                         lock (servicePoints) {
 358                                 IDictionaryEnumerator e = servicePoints.GetEnumerator ();
 359                                 while (e.MoveNext ()) {
 360                                         ServicePoint sp = (ServicePoint) e.Value;
 361                                         if (sp.AvailableForRecycling) {
 362                                                 toRemove.Add (e.Key);
 363                                         }
 364                                 }
 365
 366                                 for (int i = 0; i < toRemove.Count; i++)
 367                                         servicePoints.Remove (toRemove [i]);
 368
 369                                 if (maxServicePoints == 0 || servicePoints.Count <= maxServicePoints)
 370                                         return;
 371
 372                                 // get rid of the ones with the longest idle time
 373                                 SortedList list = new SortedList (servicePoints.Count);
 374                                 e = servicePoints.GetEnumerator ();
 375                                 while (e.MoveNext ()) {
 376                                         ServicePoint sp = (ServicePoint) e.Value;
 377                                         if (sp.CurrentConnections == 0) {
 378                                                 while (list.ContainsKey (sp.IdleSince))
 379                                                         sp.IdleSince = sp.IdleSince.AddMilliseconds (1);
 380                                                 list.Add (sp.IdleSince, sp.Address);
 381                                         }
 382                                 }
 383
 384                                 for (int i = 0; i < list.Count && servicePoints.Count > maxServicePoints; i++)
 385                                         servicePoints.Remove (list.GetByIndex (i));
 386                         }
 387                 }
 388 #if MOONLIGHT && SECURITY_DEP
 389                 internal class ChainValidationHelper {
 390                         object sender;
 391
 392                         public ChainValidationHelper (object sender)
 393                         {
 394                                 this.sender = sender;
 395                         }
 396
 397                         // no need to check certificates since we are either
 398                         // (a) loading from the site of origin (and we accepted its certificate to load from it)
 399                         // (b) loading from a cross-domain site and we downloaded the policy file using the browser stack
 400                         //     i.e. the certificate was accepted (or the policy would not be valid)
 401                         internal ValidationResult ValidateChain (Mono.Security.X509.X509CertificateCollection certs)
 402                         {
 403                                 return new ValidationResult (true, false, 0);
 404                         }
 405                 }
 406 #elif SECURITY_DEP
 407                 internal class ChainValidationHelper {
 408                         object sender;
 409                         string host;
 410                         static bool is_macosx = System.IO.File.Exists (MSX.OSX509Certificates.SecurityLibrary);
 411                         static X509RevocationMode revocation_mode;
 412
 413                         static ChainValidationHelper ()
 414                         {
 415 #if !MONOTOUCH
 416                                 revocation_mode = X509RevocationMode.NoCheck;
 417                                 try {
 418                                         string str = Environment.GetEnvironmentVariable ("MONO_X509_REVOCATION_MODE");
 419                                         if (String.IsNullOrEmpty (str))
 420                                                 return;
 421                                         revocation_mode = (X509RevocationMode) Enum.Parse (typeof (X509RevocationMode), str, true);
 422                                 } catch {
 423                                 }
 424 #endif
 425                         }
 426
 427                         public ChainValidationHelper (object sender)
 428                         {
 429                                 this.sender = sender;
 430                         }
 431
 432                         public string Host {
 433                                 get {
 434                                         if (host == null && sender is HttpWebRequest)
 435                                                 host = ((HttpWebRequest) sender).Address.Host;
 436                                         return host;
 437                                 }
 438
 439                                 set { host = value; }
 440                         }
 441
 442                         // Used when the obsolete ICertificatePolicy is set to DefaultCertificatePolicy
 443                         // and the new ServerCertificateValidationCallback is not null
 444                         internal ValidationResult ValidateChain (Mono.Security.X509.X509CertificateCollection certs)
 445                         {
 446                                 // user_denied is true if the user callback is called and returns false
 447                                 bool user_denied = false;
 448                                 if (certs == null || certs.Count == 0)
 449                                         return null;
 450
 451                                 ICertificatePolicy policy = ServicePointManager.CertificatePolicy;
 452                                 RemoteCertificateValidationCallback cb = ServicePointManager.ServerCertificateValidationCallback;
 453
 454                                 X509Certificate2 leaf = new X509Certificate2 (certs [0].RawData);
 455                                 int status11 = 0; // Error code passed to the obsolete ICertificatePolicy callback
 456                                 SslPolicyErrors errors = 0;
 457                                 X509Chain chain = null;
 458                                 bool result = false;
 459 #if MONOTOUCH
 460                                 // The X509Chain is not really usable with MonoTouch (since the decision is not based on this data)
 461                                 // However if someone wants to override the results (good or bad) from iOS then they will want all
 462                                 // the certificates that the server provided (which generally does not include the root) so, only
 463                                 // if there's a user callback, we'll create the X509Chain but won't build it
 464                                 // ref: https://bugzilla.xamarin.com/show_bug.cgi?id=7245
 465                                 if (cb != null) {
 466 #endif
 467                                 chain = new X509Chain ();
 468                                 chain.ChainPolicy = new X509ChainPolicy ();
 469                                 chain.ChainPolicy.RevocationMode = revocation_mode;
 470                                 for (int i = 1; i < certs.Count; i++) {
 471                                         X509Certificate2 c2 = new X509Certificate2 (certs [i].RawData);
 472                                         chain.ChainPolicy.ExtraStore.Add (c2);
 473                                 }
 474 #if MONOTOUCH
 475                                 }
 476 #else
 477                                 try {
 478                                         if (!chain.Build (leaf))
 479                                                 errors |= GetErrorsFromChain (chain);
 480                                 } catch (Exception e) {
 481                                         Console.Error.WriteLine ("ERROR building certificate chain: {0}", e);
 482                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 483                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 484                                 }
 485
 486                                 // for OSX and iOS we're using the native API to check for the SSL server policy and host names
 487                                 if (!is_macosx) {
 488                                         if (!CheckCertificateUsage (leaf)) {
 489                                                 errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 490                                                 status11 = -2146762490; //CERT_E_PURPOSE 0x800B0106
 491                                         }
 492
 493                                         if (!CheckServerIdentity (certs [0], Host)) {
 494                                                 errors |= SslPolicyErrors.RemoteCertificateNameMismatch;
 495                                                 status11 = -2146762481; // CERT_E_CN_NO_MATCH 0x800B010F
 496                                         }
 497                                 } else {
 498 #endif
 499                                         // Attempt to use OSX certificates
 500                                         // Ideally we should return the SecTrustResult
 501                                         MSX.OSX509Certificates.SecTrustResult trustResult = MSX.OSX509Certificates.SecTrustResult.Deny;
 502                                         try {
 503                                                 trustResult = MSX.OSX509Certificates.TrustEvaluateSsl (certs, Host);
 504                                                 // We could use the other values of trustResult to pass this extra information
 505                                                 // to the .NET 2 callback for values like SecTrustResult.Confirm
 506                                                 result = (trustResult == MSX.OSX509Certificates.SecTrustResult.Proceed ||
 507                                                                   trustResult == MSX.OSX509Certificates.SecTrustResult.Unspecified);
 508                                         } catch {
 509                                                 // Ignore
 510                                         }
 511
 512                                         if (result) {
 513                                                 // TrustEvaluateSsl was successful so there's no trust error
 514                                                 // IOW we discard our own chain (since we trust OSX one instead)
 515                                                 errors = 0;
 516                                         } else {
 517                                                 // callback and DefaultCertificatePolicy needs this since 'result' is not specified
 518                                                 status11 = (int) trustResult;
 519                                                 errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 520                                         }
 521 #if !MONOTOUCH
 522                                 }
 523 #endif
 524
 525 #if MONODROID
 526                                 result = AndroidPlatform.TrustEvaluateSsl (certs, sender, leaf, chain, errors);
 527                                 if (result) {
 528                                         // chain.Build() + GetErrorsFromChain() (above) will ALWAYS fail on
 529                                         // Android (there are no mozroots or preinstalled root certificates),
 530                                         // thus `errors` will ALWAYS have RemoteCertificateChainErrors.
 531                                         // Android just verified the chain; clear RemoteCertificateChainErrors.
 532                                         errors  &= ~SslPolicyErrors.RemoteCertificateChainErrors;
 533                                 }
 534 #endif
 535
 536                                 if (policy != null && (!(policy is DefaultCertificatePolicy) || cb == null)) {
 537                                         ServicePoint sp = null;
 538                                         HttpWebRequest req = sender as HttpWebRequest;
 539                                         if (req != null)
 540                                                 sp = req.ServicePointNoLock;
 541                                         if (status11 == 0 && errors != 0)
 542                                                 status11 = GetStatusFromChain (chain);
 543
 544                                         // pre 2.0 callback
 545                                         result = policy.CheckValidationResult (sp, leaf, req, status11);
 546                                         user_denied = !result && !(policy is DefaultCertificatePolicy);
 547                                 }
 548                                 // If there's a 2.0 callback, it takes precedence
 549                                 if (cb != null) {
 550                                         result = cb (sender, leaf, chain, errors);
 551                                         user_denied = !result;
 552                                 }
 553                                 return new ValidationResult (result, user_denied, status11);
 554                         }
 555
 556                         static int GetStatusFromChain (X509Chain chain)
 557                         {
 558                                 long result = 0;
 559                                 foreach (var status in chain.ChainStatus) {
 560                                         X509ChainStatusFlags flags = status.Status;
 561                                         if (flags == X509ChainStatusFlags.NoError)
 562                                                 continue;
 563
 564                                         // CERT_E_EXPIRED
 565                                         if ((flags & X509ChainStatusFlags.NotTimeValid) != 0) result = 0x800B0101;
 566                                         // CERT_E_VALIDITYPERIODNESTING
 567                                         else if ((flags & X509ChainStatusFlags.NotTimeNested) != 0) result = 0x800B0102;
 568                                         // CERT_E_REVOKED
 569                                         else if ((flags & X509ChainStatusFlags.Revoked) != 0) result = 0x800B010C;
 570                                         // TRUST_E_CERT_SIGNATURE
 571                                         else if ((flags & X509ChainStatusFlags.NotSignatureValid) != 0) result = 0x80096004;
 572                                         // CERT_E_WRONG_USAGE
 573                                         else if ((flags & X509ChainStatusFlags.NotValidForUsage) != 0) result = 0x800B0110;
 574                                         // CERT_E_UNTRUSTEDROOT
 575                                         else if ((flags & X509ChainStatusFlags.UntrustedRoot) != 0) result = 0x800B0109;
 576                                         // CRYPT_E_NO_REVOCATION_CHECK
 577                                         else if ((flags & X509ChainStatusFlags.RevocationStatusUnknown) != 0) result = 0x80092012;
 578                                         // CERT_E_CHAINING
 579                                         else if ((flags & X509ChainStatusFlags.Cyclic) != 0) result = 0x800B010A;
 580                                         // TRUST_E_FAIL - generic
 581                                         else if ((flags & X509ChainStatusFlags.InvalidExtension) != 0) result = 0x800B010B;
 582                                         // CERT_E_UNTRUSTEDROOT
 583                                         else if ((flags & X509ChainStatusFlags.InvalidPolicyConstraints) != 0) result = 0x800B010D;
 584                                         // TRUST_E_BASIC_CONSTRAINTS
 585                                         else if ((flags & X509ChainStatusFlags.InvalidBasicConstraints) != 0) result = 0x80096019;
 586                                         // CERT_E_INVALID_NAME
 587                                         else if ((flags & X509ChainStatusFlags.InvalidNameConstraints) != 0) result = 0x800B0114;
 588                                         // CERT_E_INVALID_NAME
 589                                         else if ((flags & X509ChainStatusFlags.HasNotSupportedNameConstraint) != 0) result = 0x800B0114;
 590                                         // CERT_E_INVALID_NAME
 591                                         else if ((flags & X509ChainStatusFlags.HasNotDefinedNameConstraint) != 0) result = 0x800B0114;
 592                                         // CERT_E_INVALID_NAME
 593                                         else if ((flags & X509ChainStatusFlags.HasNotPermittedNameConstraint) != 0) result = 0x800B0114;
 594                                         // CERT_E_INVALID_NAME
 595                                         else if ((flags & X509ChainStatusFlags.HasExcludedNameConstraint) != 0) result = 0x800B0114;
 596                                         // CERT_E_CHAINING
 597                                         else if ((flags & X509ChainStatusFlags.PartialChain) != 0) result = 0x800B010A;
 598                                         // CERT_E_EXPIRED
 599                                         else if ((flags & X509ChainStatusFlags.CtlNotTimeValid) != 0) result = 0x800B0101;
 600                                         // TRUST_E_CERT_SIGNATURE
 601                                         else if ((flags & X509ChainStatusFlags.CtlNotSignatureValid) != 0) result = 0x80096004;
 602                                         // CERT_E_WRONG_USAGE
 603                                         else if ((flags & X509ChainStatusFlags.CtlNotValidForUsage) != 0) result = 0x800B0110;
 604                                         // CRYPT_E_NO_REVOCATION_CHECK
 605                                         else if ((flags & X509ChainStatusFlags.OfflineRevocation) != 0) result = 0x80092012;
 606                                         // CERT_E_ISSUERCHAINING
 607                                         else if ((flags & X509ChainStatusFlags.NoIssuanceChainPolicy) != 0) result = 0x800B0107;
 608                                         else result = 0x800B010B; // TRUST_E_FAIL - generic
 609
 610                                         break; // Exit the loop on the first error
 611                                 }
 612                                 return (int) result;
 613                         }
 614 #if !MONOTOUCH
 615                         static SslPolicyErrors GetErrorsFromChain (X509Chain chain)
 616                         {
 617                                 SslPolicyErrors errors = SslPolicyErrors.None;
 618                                 foreach (var status in chain.ChainStatus) {
 619                                         if (status.Status == X509ChainStatusFlags.NoError)
 620                                                 continue;
 621                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
 622                                         break;
 623                                 }
 624                                 return errors;
 625                         }
 626
 627                         static X509KeyUsageFlags s_flags = X509KeyUsageFlags.DigitalSignature  |
 628                                                         X509KeyUsageFlags.KeyAgreement |
 629                                                         X509KeyUsageFlags.KeyEncipherment;
 630                         // Adapted to System 2.0+ from TlsServerCertificate.cs
 631                         //------------------------------
 632                         // Note: this method only works for RSA certificates
 633                         // DH certificates requires some changes - does anyone use one ?
 634                         static bool CheckCertificateUsage (X509Certificate2 cert)
 635                         {
 636                                 try {
 637                                         // certificate extensions are required for this
 638                                         // we "must" accept older certificates without proofs
 639                                         if (cert.Version < 3)
 640                                                 return true;
 641
 642                                         X509KeyUsageExtension kux = (cert.Extensions ["2.5.29.15"] as X509KeyUsageExtension);
 643                                         X509EnhancedKeyUsageExtension eku = (cert.Extensions ["2.5.29.37"] as X509EnhancedKeyUsageExtension);
 644                                         if (kux != null && eku != null) {
 645                                                 // RFC3280 states that when both KeyUsageExtension and
 646                                                 // ExtendedKeyUsageExtension are present then BOTH should
 647                                                 // be valid
 648                                                 if ((kux.KeyUsages & s_flags) == 0)
 649                                                         return false;
 650                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
 651                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
 652                                         } else if (kux != null) {
 653                                                 return ((kux.KeyUsages & s_flags) != 0);
 654                                         } else if (eku != null) {
 655                                                 // Server Authentication (1.3.6.1.5.5.7.3.1) or
 656                                                 // Netscape Server Gated Crypto (2.16.840.1.113730.4)
 657                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
 658                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
 659                                         }
 660
 661                                         // last chance - try with older (deprecated) Netscape extensions
 662                                         X509Extension ext = cert.Extensions ["2.16.840.1.113730.1.1"];
 663                                         if (ext != null) {
 664                                                 string text = ext.NetscapeCertType (false);
 665                                                 return text.IndexOf ("SSL Server Authentication", StringComparison.Ordinal) != -1;
 666                                         }
 667                                         return true;
 668                                 } catch (Exception e) {
 669                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
 670                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 671                                         return false;
 672                                 }
 673                         }
 674
 675                         // RFC2818 - HTTP Over TLS, Section 3.1
 676                         // http://www.ietf.org/rfc/rfc2818.txt
 677                         //
 678                         // 1.   if present MUST use subjectAltName dNSName as identity
 679                         // 1.1.         if multiples entries a match of any one is acceptable
 680                         // 1.2.         wildcard * is acceptable
 681                         // 2.   URI may be an IP address -> subjectAltName.iPAddress
 682                         // 2.1.         exact match is required
 683                         // 3.   Use of the most specific Common Name (CN=) in the Subject
 684                         // 3.1          Existing practice but DEPRECATED
 685                         static bool CheckServerIdentity (Mono.Security.X509.X509Certificate cert, string targetHost)
 686                         {
 687                                 try {
 688                                         Mono.Security.X509.X509Extension ext = cert.Extensions ["2.5.29.17"];
 689                                         // 1. subjectAltName
 690                                         if (ext != null) {
 691                                                 SubjectAltNameExtension subjectAltName = new SubjectAltNameExtension (ext);
 692                                                 // 1.1 - multiple dNSName
 693                                                 foreach (string dns in subjectAltName.DNSNames) {
 694                                                         // 1.2 TODO - wildcard support
 695                                                         if (Match (targetHost, dns))
 696                                                                 return true;
 697                                                 }
 698                                                 // 2. ipAddress
 699                                                 foreach (string ip in subjectAltName.IPAddresses) {
 700                                                         // 2.1. Exact match required
 701                                                         if (ip == targetHost)
 702                                                                 return true;
 703                                                 }
 704                                         }
 705                                         // 3. Common Name (CN=)
 706                                         return CheckDomainName (cert.SubjectName, targetHost);
 707                                 } catch (Exception e) {
 708                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
 709                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
 710                                         return false;
 711                                 }
 712                         }
 713
 714                         static bool CheckDomainName (string subjectName, string targetHost)
 715                         {
 716                                 string  domainName = String.Empty;
 717                                 Regex search = new Regex(@"CN\s*=\s*([^,]*)");
 718                                 MatchCollection elements = search.Matches(subjectName);
 719                                 if (elements.Count == 1) {
 720                                         if (elements[0].Success)
 721                                                 domainName = elements[0].Groups[1].Value.ToString();
 722                                 }
 723
 724                                 return Match (targetHost, domainName);
 725                         }
 726
 727                         // ensure the pattern is valid wrt to RFC2595 and RFC2818
 728                         // http://www.ietf.org/rfc/rfc2595.txt
 729                         // http://www.ietf.org/rfc/rfc2818.txt
 730                         static bool Match (string hostname, string pattern)
 731                         {
 732                                 // check if this is a pattern
 733                                 int index = pattern.IndexOf ('*');
 734                                 if (index == -1) {
 735                                         // not a pattern, do a direct case-insensitive comparison
 736                                         return (String.Compare (hostname, pattern, true, CultureInfo.InvariantCulture) == 0);
 737                                 }
 738
 739                                 // check pattern validity
 740                                 // A "*" wildcard character MAY be used as the left-most name component in the certificate.
 741
 742                                 // unless this is the last char (valid)
 743                                 if (index != pattern.Length - 1) {
 744                                         // then the next char must be a dot .'.
 745                                         if (pattern [index + 1] != '.')
 746                                                 return false;
 747                                 }
 748
 749                                 // only one (A) wildcard is supported
 750                                 int i2 = pattern.IndexOf ('*', index + 1);
 751                                 if (i2 != -1)
 752                                         return false;
 753
 754                                 // match the end of the pattern
 755                                 string end = pattern.Substring (index + 1);
 756                                 int length = hostname.Length - end.Length;
 757                                 // no point to check a pattern that is longer than the hostname
 758                                 if (length <= 0)
 759                                         return false;
 760
 761                                 if (String.Compare (hostname, length, end, 0, end.Length, true, CultureInfo.InvariantCulture) != 0)
 762                                         return false;
 763
 764                                 // special case, we start with the wildcard
 765                                 if (index == 0) {
 766                                         // ensure we hostname non-matched part (start) doesn't contain a dot
 767                                         int i3 = hostname.IndexOf ('.');
 768                                         return ((i3 == -1) || (i3 >= (hostname.Length - end.Length)));
 769                                 }
 770
 771                                 // match the start of the pattern
 772                                 string start = pattern.Substring (0, index);
 773                                 return (String.Compare (hostname, 0, start, 0, start.Length, true, CultureInfo.InvariantCulture) == 0);
 774                         }
 775 #endif
 776                 }
 777 #endif
 778         }
 779 }
 780