Merge pull request #129 from grumpydev/CryptoFixo
[mono.git] / 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                 static bool tcp_keepalive;
127                 static int tcp_keepalive_time;
128                 static int tcp_keepalive_interval;
129
130                 // Fields
131                 
132                 public const int DefaultNonPersistentConnectionLimit = 4;
133                 public const int DefaultPersistentConnectionLimit = 2;
134
135 #if !NET_2_1
136                 const string configKey = "system.net/connectionManagement";
137                 static ConnectionManagementData manager;
138 #endif
139                 
140                 static ServicePointManager ()
141                 {
142 #if !NET_2_1
143 #if NET_2_0 && CONFIGURATION_DEP
144                         object cfg = ConfigurationManager.GetSection (configKey);
145                         ConnectionManagementSection s = cfg as ConnectionManagementSection;
146                         if (s != null) {
147                                 manager = new ConnectionManagementData (null);
148                                 foreach (ConnectionManagementElement e in s.ConnectionManagement)
149                                         manager.Add (e.Address, e.MaxConnection);
150
151                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");                         
152                                 return;
153                         }
154 #endif
155                         manager = (ConnectionManagementData) ConfigurationSettings.GetConfig (configKey);
156                         if (manager != null) {
157                                 defaultConnectionLimit = (int) manager.GetMaxConnections ("*");                         
158                         }
159 #endif
160                 }
161
162                 // Constructors
163                 private ServicePointManager ()
164                 {
165                 }               
166                 
167                 // Properties
168                 
169 #if NET_2_0
170                 [Obsolete ("Use ServerCertificateValidationCallback instead", false)]
171 #endif
172                 public static ICertificatePolicy CertificatePolicy {
173                         get { return policy; }
174                         set { policy = value; }
175                 }
176
177 #if NET_1_0
178                 // we need it for SslClientStream
179                 internal
180 #else
181                 [MonoTODO("CRL checks not implemented")]
182                 public
183 #endif
184                 static bool CheckCertificateRevocationList {
185                         get { return _checkCRL; }
186                         set { _checkCRL = false; }      // TODO - don't yet accept true
187                 }
188                 
189                 public static int DefaultConnectionLimit {
190                         get { return defaultConnectionLimit; }
191                         set { 
192                                 if (value <= 0)
193                                         throw new ArgumentOutOfRangeException ("value");
194
195                                 defaultConnectionLimit = value; 
196                         }
197                 }
198
199 #if NET_2_0
200                 static Exception GetMustImplement ()
201                 {
202                         return new NotImplementedException ();
203                 }
204                 
205                 [MonoTODO]
206                 public static int DnsRefreshTimeout
207                 {
208                         get {
209                                 throw GetMustImplement ();
210                         }
211                         set {
212                                 throw GetMustImplement ();
213                         }
214                 }
215                 
216                 [MonoTODO]
217                 public static bool EnableDnsRoundRobin
218                 {
219                         get {
220                                 throw GetMustImplement ();
221                         }
222                         set {
223                                 throw GetMustImplement ();
224                         }
225                 }
226 #endif
227                 
228                 public static int MaxServicePointIdleTime {
229                         get { 
230                                 return maxServicePointIdleTime;
231                         }
232                         set { 
233                                 if (value < -2 || value > Int32.MaxValue)
234                                         throw new ArgumentOutOfRangeException ("value");
235                                 maxServicePointIdleTime = value;
236                         }
237                 }
238                 
239                 public static int MaxServicePoints {
240                         get { 
241                                 return maxServicePoints; 
242                         }
243                         set {  
244                                 if (value < 0)
245                                         throw new ArgumentException ("value");                          
246
247                                 maxServicePoints = value;
248                                 RecycleServicePoints ();
249                         }
250                 }
251
252 #if NET_1_0
253                 // we need it for SslClientStream
254                 internal
255 #else
256                 public
257 #endif
258                 static SecurityProtocolType SecurityProtocol {
259                         get { return _securityProtocol; }
260                         set { _securityProtocol = value; }
261                 }
262
263                 public static RemoteCertificateValidationCallback ServerCertificateValidationCallback
264                 {
265                         get {
266                                 return server_cert_cb;
267                         }
268                         set {
269                                 server_cert_cb = value;
270                         }
271                 }
272
273 #if NET_1_1
274                 public static bool Expect100Continue {
275                         get { return expectContinue; }
276                         set { expectContinue = value; }
277                 }
278
279                 public static bool UseNagleAlgorithm {
280                         get { return useNagle; }
281                         set { useNagle = value; }
282                 }
283 #endif
284                 // Methods
285                 public static void SetTcpKeepAlive (bool enabled, int keepAliveTime, int keepAliveInterval)
286                 {
287                         if (enabled) {
288                                 if (keepAliveTime <= 0)
289                                         throw new ArgumentOutOfRangeException ("keepAliveTime", "Must be greater than 0");
290                                 if (keepAliveInterval <= 0)
291                                         throw new ArgumentOutOfRangeException ("keepAliveInterval", "Must be greater than 0");
292                         }
293
294                         tcp_keepalive = enabled;
295                         tcp_keepalive_time = keepAliveTime;
296                         tcp_keepalive_interval = keepAliveInterval;
297                 }
298
299                 public static ServicePoint FindServicePoint (Uri address) 
300                 {
301                         return FindServicePoint (address, GlobalProxySelection.Select);
302                 }
303                 
304                 public static ServicePoint FindServicePoint (string uriString, IWebProxy proxy)
305                 {
306                         return FindServicePoint (new Uri(uriString), proxy);
307                 }
308
309                 public static ServicePoint FindServicePoint (Uri address, IWebProxy proxy)
310                 {
311                         if (address == null)
312                                 throw new ArgumentNullException ("address");
313
314                         RecycleServicePoints ();
315                         
316                         bool usesProxy = false;
317                         bool useConnect = false;
318                         if (proxy != null && !proxy.IsBypassed(address)) {
319                                 usesProxy = true;
320                                 bool isSecure = address.Scheme == "https";
321                                 address = proxy.GetProxy (address);
322                                 if (address.Scheme != "http" && !isSecure)
323                                         throw new NotSupportedException ("Proxy scheme not supported.");
324
325                                 if (isSecure && address.Scheme == "http")
326                                         useConnect = true;
327                         } 
328
329                         address = new Uri (address.Scheme + "://" + address.Authority);
330                         
331                         ServicePoint sp = null;
332                         lock (servicePoints) {
333                                 SPKey key = new SPKey (address, useConnect);
334                                 sp = servicePoints [key] as ServicePoint;
335                                 if (sp != null)
336                                         return sp;
337
338                                 if (maxServicePoints > 0 && servicePoints.Count >= maxServicePoints)
339                                         throw new InvalidOperationException ("maximum number of service points reached");
340
341                                 string addr = address.ToString ();
342 #if NET_2_1
343                                 int limit = defaultConnectionLimit;
344 #else
345                                 int limit = (int) manager.GetMaxConnections (addr);
346 #endif
347                                 sp = new ServicePoint (address, limit, maxServicePointIdleTime);
348                                 sp.Expect100Continue = expectContinue;
349                                 sp.UseNagleAlgorithm = useNagle;
350                                 sp.UsesProxy = usesProxy;
351                                 sp.UseConnect = useConnect;
352                                 sp.SetTcpKeepAlive (tcp_keepalive, tcp_keepalive_time, tcp_keepalive_interval);
353                                 servicePoints.Add (key, sp);
354                         }
355                         
356                         return sp;
357                 }
358                 
359                 // Internal Methods
360
361                 internal static void RecycleServicePoints ()
362                 {
363                         ArrayList toRemove = new ArrayList ();
364                         lock (servicePoints) {
365                                 IDictionaryEnumerator e = servicePoints.GetEnumerator ();
366                                 while (e.MoveNext ()) {
367                                         ServicePoint sp = (ServicePoint) e.Value;
368                                         if (sp.AvailableForRecycling) {
369                                                 toRemove.Add (e.Key);
370                                         }
371                                 }
372                                 
373                                 for (int i = 0; i < toRemove.Count; i++) 
374                                         servicePoints.Remove (toRemove [i]);
375
376                                 if (maxServicePoints == 0 || servicePoints.Count <= maxServicePoints)
377                                         return;
378
379                                 // get rid of the ones with the longest idle time
380                                 SortedList list = new SortedList (servicePoints.Count);
381                                 e = servicePoints.GetEnumerator ();
382                                 while (e.MoveNext ()) {
383                                         ServicePoint sp = (ServicePoint) e.Value;
384                                         if (sp.CurrentConnections == 0) {
385                                                 while (list.ContainsKey (sp.IdleSince))
386                                                         sp.IdleSince = sp.IdleSince.AddMilliseconds (1);
387                                                 list.Add (sp.IdleSince, sp.Address);
388                                         }
389                                 }
390                                 
391                                 for (int i = 0; i < list.Count && servicePoints.Count > maxServicePoints; i++)
392                                         servicePoints.Remove (list.GetByIndex (i));
393                         }
394                 }
395 #if MOONLIGHT && SECURITY_DEP
396                 internal class ChainValidationHelper {
397                         object sender;
398
399                         public ChainValidationHelper (object sender)
400                         {
401                                 this.sender = sender;
402                         }
403
404                         // no need to check certificates since we are either
405                         // (a) loading from the site of origin (and we accepted its certificate to load from it)
406                         // (b) loading from a cross-domain site and we downloaded the policy file using the browser stack
407                         //     i.e. the certificate was accepted (or the policy would not be valid)
408                         internal ValidationResult ValidateChain (Mono.Security.X509.X509CertificateCollection certs)
409                         {
410                                 return new ValidationResult (true, false, 0);
411                         }
412                 }
413 #elif NET_2_0 && SECURITY_DEP
414                 internal class ChainValidationHelper {
415                         object sender;
416                         string host;
417                         static bool is_macosx = System.IO.File.Exists (MSX.OSX509Certificates.SecurityLibrary);
418                         static X509RevocationMode revocation_mode;
419
420 #if MONODROID
421                         static readonly Converter<Mono.Security.X509.X509CertificateCollection, bool> monodroidCallback;
422 #endif
423
424                         static ChainValidationHelper ()
425                         {
426 #if MONODROID
427                                 monodroidCallback = (Converter<Mono.Security.X509.X509CertificateCollection, bool>)
428                                         Delegate.CreateDelegate (typeof(Converter<Mono.Security.X509.X509CertificateCollection, bool>), 
429                                                         Type.GetType ("Android.Runtime.AndroidEnvironment, Mono.Android", true)
430                                                         .GetMethod ("TrustEvaluateSsl", 
431                                                                 System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic));
432 #endif
433                                 revocation_mode = X509RevocationMode.NoCheck;
434                                 try {
435                                         string str = Environment.GetEnvironmentVariable ("MONO_X509_REVOCATION_MODE");
436                                         if (String.IsNullOrEmpty (str))
437                                                 return;
438                                         revocation_mode = (X509RevocationMode) Enum.Parse (typeof (X509RevocationMode), str, true);
439                                 } catch {
440                                 }
441                         }
442
443                         public ChainValidationHelper (object sender)
444                         {
445                                 this.sender = sender;
446                         }
447
448                         public string Host {
449                                 get {
450                                         if (host == null && sender is HttpWebRequest)
451                                                 host = ((HttpWebRequest) sender).Address.Host;
452                                         return host;
453                                 }
454
455                                 set { host = value; }
456                         }
457
458                         // Used when the obsolete ICertificatePolicy is set to DefaultCertificatePolicy
459                         // and the new ServerCertificateValidationCallback is not null
460                         internal ValidationResult ValidateChain (Mono.Security.X509.X509CertificateCollection certs)
461                         {
462                                 // user_denied is true if the user callback is called and returns false
463                                 bool user_denied = false;
464                                 if (certs == null || certs.Count == 0)
465                                         return null;
466
467                                 ICertificatePolicy policy = ServicePointManager.CertificatePolicy;
468                                 RemoteCertificateValidationCallback cb = ServicePointManager.ServerCertificateValidationCallback;
469
470                                 X509Chain chain = new X509Chain ();
471                                 chain.ChainPolicy = new X509ChainPolicy ();
472                                 chain.ChainPolicy.RevocationMode = revocation_mode;
473                                 for (int i = 1; i < certs.Count; i++) {
474                                         X509Certificate2 c2 = new X509Certificate2 (certs [i].RawData);
475                                         chain.ChainPolicy.ExtraStore.Add (c2);
476                                 }
477
478                                 X509Certificate2 leaf = new X509Certificate2 (certs [0].RawData);
479                                 int status11 = 0; // Error code passed to the obsolete ICertificatePolicy callback
480                                 SslPolicyErrors errors = 0;
481                                 try {
482                                         if (!chain.Build (leaf))
483                                                 errors |= GetErrorsFromChain (chain);
484                                 } catch (Exception e) {
485                                         Console.Error.WriteLine ("ERROR building certificate chain: {0}", e);
486                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
487                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
488                                 }
489
490                                 if (!CheckCertificateUsage (leaf)) {
491                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
492                                         status11 = -2146762490; //CERT_E_PURPOSE 0x800B0106
493                                 }
494
495                                 if (!CheckServerIdentity (certs [0], Host)) {
496                                         errors |= SslPolicyErrors.RemoteCertificateNameMismatch;
497                                         status11 = -2146762481; // CERT_E_CN_NO_MATCH 0x800B010F
498                                 }
499
500                                 bool result = false;
501                                 // No certificate root found means no mozroots or monotouch
502 #if !MONOTOUCH
503                                 if (is_macosx) {
504 #endif
505                                         // Attempt to use OSX certificates
506                                         // Ideally we should return the SecTrustResult
507                                         MSX.OSX509Certificates.SecTrustResult trustResult;
508                                         try {
509                                                 trustResult = MSX.OSX509Certificates.TrustEvaluateSsl (certs);
510                                                 // We could use the other values of trustResult to pass this extra information
511                                                 // to the .NET 2 callback for values like SecTrustResult.Confirm
512                                                 result = (trustResult == MSX.OSX509Certificates.SecTrustResult.Proceed ||
513                                                                   trustResult == MSX.OSX509Certificates.SecTrustResult.Unspecified);
514
515                                         } catch {
516                                                 // Ignore
517                                         }
518                                         // Clear error status if the OS told us to trust the certificate
519                                         if (result) {
520                                                 status11 = 0;
521                                                 errors = 0;
522                                         }
523 #if !MONOTOUCH
524                                 }
525 #endif
526
527 #if MONODROID
528                                 result = monodroidCallback (certs);
529                                 if (result) {
530                                         status11 = 0;
531                                         errors = 0;
532                                 }
533 #endif
534
535                                 if (policy != null && (!(policy is DefaultCertificatePolicy) || cb == null)) {
536                                         ServicePoint sp = null;
537                                         HttpWebRequest req = sender as HttpWebRequest;
538                                         if (req != null)
539                                                 sp = req.ServicePoint;
540                                         if (status11 == 0 && errors != 0)
541                                                 status11 = GetStatusFromChain (chain);
542
543                                         // pre 2.0 callback
544                                         result = policy.CheckValidationResult (sp, leaf, req, status11);
545                                         user_denied = !result && !(policy is DefaultCertificatePolicy);
546                                 }
547                                 // If there's a 2.0 callback, it takes precedence
548                                 if (cb != null) {
549                                         result = cb (sender, leaf, chain, errors);
550                                         user_denied = !result;
551                                 }
552                                 return new ValidationResult (result, user_denied, status11);
553                         }
554
555                         static int GetStatusFromChain (X509Chain chain)
556                         {
557                                 long result = 0;
558                                 foreach (var status in chain.ChainStatus) {
559                                         X509ChainStatusFlags flags = status.Status;
560                                         if (flags == X509ChainStatusFlags.NoError)
561                                                 continue;
562
563                                         // CERT_E_EXPIRED
564                                         if ((flags & X509ChainStatusFlags.NotTimeValid) != 0) result = 0x800B0101;
565                                         // CERT_E_VALIDITYPERIODNESTING
566                                         else if ((flags & X509ChainStatusFlags.NotTimeNested) != 0) result = 0x800B0102;
567                                         // CERT_E_REVOKED
568                                         else if ((flags & X509ChainStatusFlags.Revoked) != 0) result = 0x800B010C;
569                                         // TRUST_E_CERT_SIGNATURE
570                                         else if ((flags & X509ChainStatusFlags.NotSignatureValid) != 0) result = 0x80096004;
571                                         // CERT_E_WRONG_USAGE
572                                         else if ((flags & X509ChainStatusFlags.NotValidForUsage) != 0) result = 0x800B0110;
573                                         // CERT_E_UNTRUSTEDROOT
574                                         else if ((flags & X509ChainStatusFlags.UntrustedRoot) != 0) result = 0x800B0109;
575                                         // CRYPT_E_NO_REVOCATION_CHECK
576                                         else if ((flags & X509ChainStatusFlags.RevocationStatusUnknown) != 0) result = 0x80092012;
577                                         // CERT_E_CHAINING
578                                         else if ((flags & X509ChainStatusFlags.Cyclic) != 0) result = 0x800B010A;
579                                         // TRUST_E_FAIL - generic
580                                         else if ((flags & X509ChainStatusFlags.InvalidExtension) != 0) result = 0x800B010B;
581                                         // CERT_E_UNTRUSTEDROOT
582                                         else if ((flags & X509ChainStatusFlags.InvalidPolicyConstraints) != 0) result = 0x800B010D;
583                                         // TRUST_E_BASIC_CONSTRAINTS
584                                         else if ((flags & X509ChainStatusFlags.InvalidBasicConstraints) != 0) result = 0x80096019;
585                                         // CERT_E_INVALID_NAME
586                                         else if ((flags & X509ChainStatusFlags.InvalidNameConstraints) != 0) result = 0x800B0114;
587                                         // CERT_E_INVALID_NAME
588                                         else if ((flags & X509ChainStatusFlags.HasNotSupportedNameConstraint) != 0) result = 0x800B0114;
589                                         // CERT_E_INVALID_NAME
590                                         else if ((flags & X509ChainStatusFlags.HasNotDefinedNameConstraint) != 0) result = 0x800B0114;
591                                         // CERT_E_INVALID_NAME
592                                         else if ((flags & X509ChainStatusFlags.HasNotPermittedNameConstraint) != 0) result = 0x800B0114;
593                                         // CERT_E_INVALID_NAME
594                                         else if ((flags & X509ChainStatusFlags.HasExcludedNameConstraint) != 0) result = 0x800B0114;
595                                         // CERT_E_CHAINING
596                                         else if ((flags & X509ChainStatusFlags.PartialChain) != 0) result = 0x800B010A;
597                                         // CERT_E_EXPIRED
598                                         else if ((flags & X509ChainStatusFlags.CtlNotTimeValid) != 0) result = 0x800B0101;
599                                         // TRUST_E_CERT_SIGNATURE
600                                         else if ((flags & X509ChainStatusFlags.CtlNotSignatureValid) != 0) result = 0x80096004;
601                                         // CERT_E_WRONG_USAGE
602                                         else if ((flags & X509ChainStatusFlags.CtlNotValidForUsage) != 0) result = 0x800B0110;
603                                         // CRYPT_E_NO_REVOCATION_CHECK
604                                         else if ((flags & X509ChainStatusFlags.OfflineRevocation) != 0) result = 0x80092012;
605                                         // CERT_E_ISSUERCHAINING
606                                         else if ((flags & X509ChainStatusFlags.NoIssuanceChainPolicy) != 0) result = 0x800B0107;
607                                         else result = 0x800B010B; // TRUST_E_FAIL - generic
608
609                                         break; // Exit the loop on the first error
610                                 }
611                                 return (int) result;
612                         }
613
614                         static SslPolicyErrors GetErrorsFromChain (X509Chain chain)
615                         {
616                                 SslPolicyErrors errors = SslPolicyErrors.None;
617                                 foreach (var status in chain.ChainStatus) {
618                                         if (status.Status == X509ChainStatusFlags.NoError)
619                                                 continue;
620                                         errors |= SslPolicyErrors.RemoteCertificateChainErrors;
621                                         break;
622                                 }
623                                 return errors;
624                         }
625
626                         static X509KeyUsageFlags s_flags = X509KeyUsageFlags.DigitalSignature  | 
627                                                         X509KeyUsageFlags.KeyAgreement |
628                                                         X509KeyUsageFlags.KeyEncipherment;
629                         // Adapted to System 2.0+ from TlsServerCertificate.cs
630                         //------------------------------
631                         // Note: this method only works for RSA certificates
632                         // DH certificates requires some changes - does anyone use one ?
633                         static bool CheckCertificateUsage (X509Certificate2 cert) 
634                         {
635                                 try {
636                                         // certificate extensions are required for this
637                                         // we "must" accept older certificates without proofs
638                                         if (cert.Version < 3)
639                                                 return true;
640
641                                         X509KeyUsageExtension kux = (cert.Extensions ["2.5.29.15"] as X509KeyUsageExtension);
642                                         X509EnhancedKeyUsageExtension eku = (cert.Extensions ["2.5.29.37"] as X509EnhancedKeyUsageExtension);
643                                         if (kux != null && eku != null) {
644                                                 // RFC3280 states that when both KeyUsageExtension and 
645                                                 // ExtendedKeyUsageExtension are present then BOTH should
646                                                 // be valid
647                                                 if ((kux.KeyUsages & s_flags) == 0)
648                                                         return false;
649                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
650                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
651                                         } else if (kux != null) {
652                                                 return ((kux.KeyUsages & s_flags) != 0);
653                                         } else if (eku != null) {
654                                                 // Server Authentication (1.3.6.1.5.5.7.3.1) or
655                                                 // Netscape Server Gated Crypto (2.16.840.1.113730.4)
656                                                 return eku.EnhancedKeyUsages ["1.3.6.1.5.5.7.3.1"] != null ||
657                                                         eku.EnhancedKeyUsages ["2.16.840.1.113730.4.1"] != null;
658                                         }
659
660                                         // last chance - try with older (deprecated) Netscape extensions
661                                         X509Extension ext = cert.Extensions ["2.16.840.1.113730.1.1"];
662                                         if (ext != null) {
663                                                 string text = ext.NetscapeCertType (false);
664                                                 return text.IndexOf ("SSL Server Authentication", StringComparison.Ordinal) != -1;
665                                         }
666                                         return true;
667                                 } catch (Exception e) {
668                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
669                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
670                                         return false;
671                                 }
672                         }
673
674                         // RFC2818 - HTTP Over TLS, Section 3.1
675                         // http://www.ietf.org/rfc/rfc2818.txt
676                         // 
677                         // 1.   if present MUST use subjectAltName dNSName as identity
678                         // 1.1.         if multiples entries a match of any one is acceptable
679                         // 1.2.         wildcard * is acceptable
680                         // 2.   URI may be an IP address -> subjectAltName.iPAddress
681                         // 2.1.         exact match is required
682                         // 3.   Use of the most specific Common Name (CN=) in the Subject
683                         // 3.1          Existing practice but DEPRECATED
684                         static bool CheckServerIdentity (Mono.Security.X509.X509Certificate cert, string targetHost) 
685                         {
686                                 try {
687                                         Mono.Security.X509.X509Extension ext = cert.Extensions ["2.5.29.17"];
688                                         // 1. subjectAltName
689                                         if (ext != null) {
690                                                 SubjectAltNameExtension subjectAltName = new SubjectAltNameExtension (ext);
691                                                 // 1.1 - multiple dNSName
692                                                 foreach (string dns in subjectAltName.DNSNames) {
693                                                         // 1.2 TODO - wildcard support
694                                                         if (Match (targetHost, dns))
695                                                                 return true;
696                                                 }
697                                                 // 2. ipAddress
698                                                 foreach (string ip in subjectAltName.IPAddresses) {
699                                                         // 2.1. Exact match required
700                                                         if (ip == targetHost)
701                                                                 return true;
702                                                 }
703                                         }
704                                         // 3. Common Name (CN=)
705                                         return CheckDomainName (cert.SubjectName, targetHost);
706                                 } catch (Exception e) {
707                                         Console.Error.WriteLine ("ERROR processing certificate: {0}", e);
708                                         Console.Error.WriteLine ("Please, report this problem to the Mono team");
709                                         return false;
710                                 }
711                         }
712
713                         static bool CheckDomainName (string subjectName, string targetHost)
714                         {
715                                 string  domainName = String.Empty;
716                                 Regex search = new Regex(@"CN\s*=\s*([^,]*)");
717                                 MatchCollection elements = search.Matches(subjectName);
718                                 if (elements.Count == 1) {
719                                         if (elements[0].Success)
720                                                 domainName = elements[0].Groups[1].Value.ToString();
721                                 }
722
723                                 return Match (targetHost, domainName);
724                         }
725
726                         // ensure the pattern is valid wrt to RFC2595 and RFC2818
727                         // http://www.ietf.org/rfc/rfc2595.txt
728                         // http://www.ietf.org/rfc/rfc2818.txt
729                         static bool Match (string hostname, string pattern)
730                         {
731                                 // check if this is a pattern
732                                 int index = pattern.IndexOf ('*');
733                                 if (index == -1) {
734                                         // not a pattern, do a direct case-insensitive comparison
735                                         return (String.Compare (hostname, pattern, true, CultureInfo.InvariantCulture) == 0);
736                                 }
737
738                                 // check pattern validity
739                                 // A "*" wildcard character MAY be used as the left-most name component in the certificate.
740
741                                 // unless this is the last char (valid)
742                                 if (index != pattern.Length - 1) {
743                                         // then the next char must be a dot .'.
744                                         if (pattern [index + 1] != '.')
745                                                 return false;
746                                 }
747
748                                 // only one (A) wildcard is supported
749                                 int i2 = pattern.IndexOf ('*', index + 1);
750                                 if (i2 != -1)
751                                         return false;
752
753                                 // match the end of the pattern
754                                 string end = pattern.Substring (index + 1);
755                                 int length = hostname.Length - end.Length;
756                                 // no point to check a pattern that is longer than the hostname
757                                 if (length <= 0)
758                                         return false;
759
760                                 if (String.Compare (hostname, length, end, 0, end.Length, true, CultureInfo.InvariantCulture) != 0)
761                                         return false;
762
763                                 // special case, we start with the wildcard
764                                 if (index == 0) {
765                                         // ensure we hostname non-matched part (start) doesn't contain a dot
766                                         int i3 = hostname.IndexOf ('.');
767                                         return ((i3 == -1) || (i3 >= (hostname.Length - end.Length)));
768                                 }
769
770                                 // match the start of the pattern
771                                 string start = pattern.Substring (0, index);
772                                 return (String.Compare (hostname, 0, start, 0, start.Length, true, CultureInfo.InvariantCulture) == 0);
773                         }
774                 }
775 #endif
776         }
777 }
778