mcs/class/Mono.Security/Mono.Security.Protocol.Tls.Handshake.Server/TlsClientCertificate.cs

   1 // Transport Security Layer (TLS)
   2 // Copyright (c) 2003-2004 Carlos Guzman Alvarez
   3 // Copyright (C) 2006 Novell, Inc (http://www.novell.com)
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining
   6 // a copy of this software and associated documentation files (the
   7 // "Software"), to deal in the Software without restriction, including
   8 // without limitation the rights to use, copy, modify, merge, publish,
   9 // distribute, sublicense, and/or sell copies of the Software, and to
  10 // permit persons to whom the Software is furnished to do so, subject to
  11 // the following conditions:
  12 //
  13 // The above copyright notice and this permission notice shall be
  14 // included in all copies or substantial portions of the Software.
  15 //
  16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  18 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  19 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  20 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  21 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  22 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23 //
  24
  25 using System;
  26 using System.Collections;
  27 using SSCX = System.Security.Cryptography.X509Certificates;
  28 using Mono.Security.X509;
  29 using Mono.Security.X509.Extensions;
  30
  31 namespace Mono.Security.Protocol.Tls.Handshake.Server
  32 {
  33         internal class TlsClientCertificate : HandshakeMessage
  34         {
  35                 #region Fields
  36
  37                 private X509CertificateCollection clientCertificates;
  38
  39                 #endregion
  40
  41                 #region Constructors
  42
  43                 public TlsClientCertificate(Context context, byte[] buffer)
  44                         : base(context, HandshakeType.Certificate, buffer)
  45                 {
  46                 }
  47
  48                 #endregion
  49
  50                 #region Methods
  51
  52                 public override void Update()
  53                 {
  54                         foreach (X509Certificate certificate in clientCertificates) {
  55                                 this.Context.ClientSettings.Certificates.Add (new SSCX.X509Certificate (certificate.RawData));
  56                         }
  57                 }
  58
  59                 public bool HasCertificate {
  60                         get { return clientCertificates.Count > 0; }
  61                 }
  62
  63                 #endregion
  64
  65                 #region Protected Methods
  66
  67                 protected override void ProcessAsSsl3()
  68                 {
  69                         this.ProcessAsTls1();
  70                 }
  71
  72                 protected override void ProcessAsTls1()
  73                 {
  74                         int bytesRead = 0;
  75                         int length = this.ReadInt24 ();
  76                         this.clientCertificates = new X509CertificateCollection ();
  77                         while (length > bytesRead) {
  78                                 int certLength = this.ReadInt24 ();
  79                                 bytesRead += certLength + 3;
  80                                 byte[] cert = this.ReadBytes (certLength);
  81                                 this.clientCertificates.Add (new X509Certificate (cert));
  82                         }
  83
  84                         if (this.clientCertificates.Count > 0)
  85                         {
  86                                 this.validateCertificates (this.clientCertificates);
  87                         }
  88                         else if ((this.Context as ServerContext).ClientCertificateRequired)
  89                         {
  90                                 throw new TlsException (AlertDescription.NoCertificate);
  91                         }
  92                 }
  93
  94                 #endregion
  95
  96                 #region Private Methods
  97
  98                 private bool checkCertificateUsage (X509Certificate cert)
  99                 {
 100                         ServerContext context = (ServerContext)this.Context;
 101
 102                         // certificate extensions are required for this
 103                         // we "must" accept older certificates without proofs
 104                         if (cert.Version < 3)
 105                                 return true;
 106
 107                         KeyUsages ku = KeyUsages.none;
 108                         switch (context.Negotiating.Cipher.ExchangeAlgorithmType)
 109                         {
 110                                 case ExchangeAlgorithmType.RsaSign:
 111                                 case ExchangeAlgorithmType.RsaKeyX:
 112                                         ku = KeyUsages.digitalSignature;
 113                                         break;
 114                                 case ExchangeAlgorithmType.DiffieHellman:
 115                                         ku = KeyUsages.keyAgreement;
 116                                         break;
 117                                 case ExchangeAlgorithmType.Fortezza:
 118                                         return false; // unsupported certificate type
 119                         }
 120
 121                         KeyUsageExtension kux = null;
 122                         ExtendedKeyUsageExtension eku = null;
 123
 124                         X509Extension xtn = cert.Extensions["2.5.29.15"];
 125                         if (xtn != null)
 126                                 kux = new KeyUsageExtension (xtn);
 127
 128                         xtn = cert.Extensions["2.5.29.37"];
 129                         if (xtn != null)
 130                                 eku = new ExtendedKeyUsageExtension (xtn);
 131
 132                         if ((kux != null) && (eku != null))
 133                         {
 134                                 // RFC3280 states that when both KeyUsageExtension and
 135                                 // ExtendedKeyUsageExtension are present then BOTH should
 136                                 // be valid
 137                                 return (kux.Support (ku) &&
 138                                         eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2"));
 139                         }
 140                         else if (kux != null)
 141                         {
 142                                 return kux.Support (ku);
 143                         }
 144                         else if (eku != null)
 145                         {
 146                                 // Client Authentication (1.3.6.1.5.5.7.3.2)
 147                                 return eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2");
 148                         }
 149
 150                         // last chance - try with older (deprecated) Netscape extensions
 151                         xtn = cert.Extensions["2.16.840.1.113730.1.1"];
 152                         if (xtn != null)
 153                         {
 154                                 NetscapeCertTypeExtension ct = new NetscapeCertTypeExtension (xtn);
 155                                 return ct.Support (NetscapeCertTypeExtension.CertTypes.SslClient);
 156                         }
 157
 158                         // certificate isn't valid for SSL server usage
 159                         return false;
 160                 }
 161
 162                 private void validateCertificates (X509CertificateCollection certificates)
 163                 {
 164                         ServerContext context = (ServerContext)this.Context;
 165                         AlertDescription description = AlertDescription.BadCertificate;
 166                         SSCX.X509Certificate client = null;
 167                         int[] certificateErrors = null;
 168
 169                         // note: certificate may be null is no certificate is sent
 170                         // (e.g. optional mutual authentication)
 171                         if (certificates.Count > 0) {
 172                                 X509Certificate leaf = certificates[0];
 173
 174                                 ArrayList errors = new ArrayList ();
 175
 176                                 // SSL specific check - not all certificates can be
 177                                 // used to server-side SSL some rules applies after
 178                                 // all ;-)
 179                                 if (!checkCertificateUsage (leaf))
 180                                 {
 181                                         // WinError.h CERT_E_PURPOSE 0x800B0106
 182                                         errors.Add ((int)-2146762490);
 183                                 }
 184
 185                                 X509Chain verify;
 186                                 // was a chain supplied ? if so use it, if not
 187                                 if (certificates.Count > 1) {
 188                                         // if so use it (and don't build our own)
 189                                         X509CertificateCollection chain = new X509CertificateCollection (certificates);
 190                                         chain.Remove (leaf);
 191                                         verify = new X509Chain (chain);
 192                                 } else {
 193                                         // if not, then let's build our own (based on what's available in the stores)
 194                                         verify = new X509Chain ();
 195                                 }
 196
 197                                 bool result = false;
 198
 199                                 try
 200                                 {
 201                                         result = verify.Build (leaf);
 202                                 }
 203                                 catch (Exception)
 204                                 {
 205                                         result = false;
 206                                 }
 207
 208                                 if (!result)
 209                                 {
 210                                         switch (verify.Status)
 211                                         {
 212                                                 case X509ChainStatusFlags.InvalidBasicConstraints:
 213                                                         // WinError.h TRUST_E_BASIC_CONSTRAINTS 0x80096019
 214                                                         errors.Add ((int)-2146869223);
 215                                                         break;
 216
 217                                                 case X509ChainStatusFlags.NotSignatureValid:
 218                                                         // WinError.h TRUST_E_BAD_DIGEST 0x80096010
 219                                                         errors.Add ((int)-2146869232);
 220                                                         break;
 221
 222                                                 case X509ChainStatusFlags.NotTimeNested:
 223                                                         // WinError.h CERT_E_VALIDITYPERIODNESTING 0x800B0102
 224                                                         errors.Add ((int)-2146762494);
 225                                                         break;
 226
 227                                                 case X509ChainStatusFlags.NotTimeValid:
 228                                                         // WinError.h CERT_E_EXPIRED 0x800B0101
 229                                                         description = AlertDescription.CertificateExpired;
 230                                                         errors.Add ((int)-2146762495);
 231                                                         break;
 232
 233                                                 case X509ChainStatusFlags.PartialChain:
 234                                                         // WinError.h CERT_E_CHAINING 0x800B010A
 235                                                         description = AlertDescription.UnknownCA;
 236                                                         errors.Add ((int)-2146762486);
 237                                                         break;
 238
 239                                                 case X509ChainStatusFlags.UntrustedRoot:
 240                                                         // WinError.h CERT_E_UNTRUSTEDROOT 0x800B0109
 241                                                         description = AlertDescription.UnknownCA;
 242                                                         errors.Add ((int)-2146762487);
 243                                                         break;
 244
 245                                                 default:
 246                                                         // unknown error
 247                                                         description = AlertDescription.CertificateUnknown;
 248                                                         errors.Add ((int)verify.Status);
 249                                                         break;
 250                                         }
 251                                 }
 252                                 client = new SSCX.X509Certificate (leaf.RawData);
 253                                 certificateErrors = (int[])errors.ToArray (typeof (int));
 254                         }
 255                         else
 256                         {
 257                                 certificateErrors = new int[0];
 258                         }
 259
 260                         SSCX.X509CertificateCollection certCollection = new SSCX.X509CertificateCollection ();
 261                         foreach (X509Certificate certificate in certificates) {
 262                                 certCollection.Add (new SSCX.X509Certificate (certificate.RawData));
 263                         }
 264                         if (!context.SslStream.RaiseClientCertificateValidation(client, certificateErrors))
 265                         {
 266                                 throw new TlsException (
 267                                         description,
 268                                         "Invalid certificate received from client.");
 269                         }
 270
 271                         this.Context.ClientSettings.ClientCertificate = client;
 272                 }
 273
 274                 #endregion
 275         }
 276 }