mcs/class/Mono.Security/Mono.Security.X509/X509Certificate.cs

   1 //
   2 // X509Certificates.cs: Handles X.509 certificates.
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   8 // Copyright (C) 2004-2006 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Runtime.Serialization;
  32 using System.Security.Cryptography;
  33 using SSCX = System.Security.Cryptography.X509Certificates;
  34 using System.Security.Permissions;
  35 using System.Text;
  36
  37 namespace Mono.Security.X509 {
  38
  39         // References:
  40         // a.   Internet X.509 Public Key Infrastructure Certificate and CRL Profile
  41         //      http://www.ietf.org/rfc/rfc3280.txt
  42         // b.   ITU ASN.1 standards (free download)
  43         //      http://www.itu.int/ITU-T/studygroups/com17/languages/
  44
  45 #if INSIDE_CORLIB
  46         internal class X509Certificate : ISerializable {
  47 #else
  48         public class X509Certificate : ISerializable {
  49 #endif
  50
  51                 private ASN1 decoder;
  52
  53                 private byte[] m_encodedcert;
  54                 private DateTime m_from;
  55                 private DateTime m_until;
  56                 private ASN1 issuer;
  57                 private string m_issuername;
  58                 private string m_keyalgo;
  59                 private byte[] m_keyalgoparams;
  60                 private ASN1 subject;
  61                 private string m_subject;
  62                 private byte[] m_publickey;
  63                 private byte[] signature;
  64                 private string m_signaturealgo;
  65                 private byte[] m_signaturealgoparams;
  66                 private byte[] certhash;
  67                 private RSA _rsa;
  68                 private DSA _dsa;
  69
  70                 // from http://www.ietf.org/rfc/rfc2459.txt
  71                 //
  72                 //Certificate  ::=  SEQUENCE  {
  73                 //     tbsCertificate       TBSCertificate,
  74                 //     signatureAlgorithm   AlgorithmIdentifier,
  75                 //     signature            BIT STRING  }
  76                 //
  77                 //TBSCertificate  ::=  SEQUENCE  {
  78                 //     version         [0]  Version DEFAULT v1,
  79                 //     serialNumber         CertificateSerialNumber,
  80                 //     signature            AlgorithmIdentifier,
  81                 //     issuer               Name,
  82                 //     validity             Validity,
  83                 //     subject              Name,
  84                 //     subjectPublicKeyInfo SubjectPublicKeyInfo,
  85                 //     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
  86                 //                          -- If present, version shall be v2 or v3
  87                 //     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
  88                 //                          -- If present, version shall be v2 or v3
  89                 //     extensions      [3]  Extensions OPTIONAL
  90                 //                          -- If present, version shall be v3 --  }
  91                 private int version;
  92                 private byte[] serialnumber;
  93
  94                 private byte[] issuerUniqueID;
  95                 private byte[] subjectUniqueID;
  96                 private X509ExtensionCollection extensions;
  97
  98                 private static string encoding_error = Locale.GetText ("Input data cannot be coded as a valid certificate.");
  99
 100
 101                 // that's were the real job is!
 102                 private void Parse (byte[] data)
 103                 {
 104                         try {
 105                                 decoder = new ASN1 (data);
 106                                 // Certificate
 107                                 if (decoder.Tag != 0x30)
 108                                         throw new CryptographicException (encoding_error);
 109                                 // Certificate / TBSCertificate
 110                                 if (decoder [0].Tag != 0x30)
 111                                         throw new CryptographicException (encoding_error);
 112
 113                                 ASN1 tbsCertificate = decoder [0];
 114
 115                                 int tbs = 0;
 116                                 // Certificate / TBSCertificate / Version
 117                                 ASN1 v = decoder [0][tbs];
 118                                 version = 1;                    // DEFAULT v1
 119                                 if ((v.Tag == 0xA0) && (v.Count > 0)) {
 120                                         // version (optional) is present only in v2+ certs
 121                                         version += v [0].Value [0];     // zero based
 122                                         tbs++;
 123                                 }
 124
 125                                 // Certificate / TBSCertificate / CertificateSerialNumber
 126                                 ASN1 sn = decoder [0][tbs++];
 127                                 if (sn.Tag != 0x02)
 128                                         throw new CryptographicException (encoding_error);
 129                                 serialnumber = sn.Value;
 130                                 Array.Reverse (serialnumber, 0, serialnumber.Length);
 131
 132                                 // Certificate / TBSCertificate / AlgorithmIdentifier
 133                                 tbs++;
 134                                 // ASN1 signatureAlgo = tbsCertificate.Element (tbs++, 0x30);
 135
 136                                 issuer = tbsCertificate.Element (tbs++, 0x30);
 137                                 m_issuername = X501.ToString (issuer);
 138
 139                                 ASN1 validity = tbsCertificate.Element (tbs++, 0x30);
 140                                 ASN1 notBefore = validity [0];
 141                                 m_from = ASN1Convert.ToDateTime (notBefore);
 142                                 ASN1 notAfter = validity [1];
 143                                 m_until = ASN1Convert.ToDateTime (notAfter);
 144
 145                                 subject = tbsCertificate.Element (tbs++, 0x30);
 146                                 m_subject = X501.ToString (subject);
 147
 148                                 ASN1 subjectPublicKeyInfo = tbsCertificate.Element (tbs++, 0x30);
 149
 150                                 ASN1 algorithm = subjectPublicKeyInfo.Element (0, 0x30);
 151                                 ASN1 algo = algorithm.Element (0, 0x06);
 152                                 m_keyalgo = ASN1Convert.ToOid (algo);
 153                                 // parameters ANY DEFINED BY algorithm OPTIONAL
 154                                 // so we dont ask for a specific (Element) type and return DER
 155                                 ASN1 parameters = algorithm [1];
 156                                 m_keyalgoparams = ((algorithm.Count > 1) ? parameters.GetBytes () : null);
 157
 158                                 ASN1 subjectPublicKey = subjectPublicKeyInfo.Element (1, 0x03);
 159                                 // we must drop th first byte (which is the number of unused bits
 160                                 // in the BITSTRING)
 161                                 int n = subjectPublicKey.Length - 1;
 162                                 m_publickey = new byte [n];
 163                                 Buffer.BlockCopy (subjectPublicKey.Value, 1, m_publickey, 0, n);
 164
 165                                 // signature processing
 166                                 byte[] bitstring = decoder [2].Value;
 167                                 // first byte contains unused bits in first byte
 168                                 signature = new byte [bitstring.Length - 1];
 169                                 Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
 170
 171                                 algorithm = decoder [1];
 172                                 algo = algorithm.Element (0, 0x06);
 173                                 m_signaturealgo = ASN1Convert.ToOid (algo);
 174                                 parameters = algorithm [1];
 175                                 if (parameters != null)
 176                                         m_signaturealgoparams = parameters.GetBytes ();
 177                                 else
 178                                         m_signaturealgoparams = null;
 179
 180                                 // Certificate / TBSCertificate / issuerUniqueID
 181                                 ASN1 issuerUID = tbsCertificate.Element (tbs, 0x81);
 182                                 if (issuerUID != null) {
 183                                         tbs++;
 184                                         issuerUniqueID = issuerUID.Value;
 185                                 }
 186
 187                                 // Certificate / TBSCertificate / subjectUniqueID
 188                                 ASN1 subjectUID = tbsCertificate.Element (tbs, 0x82);
 189                                 if (subjectUID != null) {
 190                                         tbs++;
 191                                         subjectUniqueID = subjectUID.Value;
 192                                 }
 193
 194                                 // Certificate / TBSCertificate / Extensions
 195                                 ASN1 extns = tbsCertificate.Element (tbs, 0xA3);
 196                                 if ((extns != null) && (extns.Count == 1))
 197                                         extensions = new X509ExtensionCollection (extns [0]);
 198                                 else
 199                                         extensions = new X509ExtensionCollection (null);
 200
 201                                 // keep a copy of the original data
 202                                 m_encodedcert = (byte[]) data.Clone ();
 203                         }
 204                         catch (Exception ex) {
 205                                 throw new CryptographicException (encoding_error, ex);
 206                         }
 207                 }
 208
 209                 // constructors
 210
 211                 public X509Certificate (byte[] data)
 212                 {
 213                         if (data != null) {
 214                                 // does it looks like PEM ?
 215                                 if ((data.Length > 0) && (data [0] != 0x30)) {
 216                                         try {
 217                                                 data = PEM ("CERTIFICATE", data);
 218                                         }
 219                                         catch (Exception ex) {
 220                                                 throw new CryptographicException (encoding_error, ex);
 221                                         }
 222                                 }
 223                                 Parse (data);
 224                         }
 225                 }
 226
 227                 private byte[] GetUnsignedBigInteger (byte[] integer)
 228                 {
 229                         if (integer [0] == 0x00) {
 230                                 // this first byte is added so we're sure it's an unsigned integer
 231                                 // however we can't feed it into RSAParameters or DSAParameters
 232                                 int length = integer.Length - 1;
 233                                 byte[] uinteger = new byte [length];
 234                                 Buffer.BlockCopy (integer, 1, uinteger, 0, length);
 235                                 return uinteger;
 236                         }
 237                         else
 238                                 return integer;
 239                 }
 240
 241                 // public methods
 242
 243                 public DSA DSA {
 244                         get {
 245                                 if (m_keyalgoparams == null)
 246                                         throw new CryptographicException ("Missing key algorithm parameters.");
 247
 248                                 if (_dsa == null) {
 249                                         DSAParameters dsaParams = new DSAParameters ();
 250                                         // for DSA m_publickey contains 1 ASN.1 integer - Y
 251                                         ASN1 pubkey = new ASN1 (m_publickey);
 252                                         if ((pubkey == null) || (pubkey.Tag != 0x02))
 253                                                 return null;
 254                                         dsaParams.Y = GetUnsignedBigInteger (pubkey.Value);
 255
 256                                         ASN1 param = new ASN1 (m_keyalgoparams);
 257                                         if ((param == null) || (param.Tag != 0x30) || (param.Count < 3))
 258                                                 return null;
 259                                         if ((param [0].Tag != 0x02) || (param [1].Tag != 0x02) || (param [2].Tag != 0x02))
 260                                                 return null;
 261                                         dsaParams.P = GetUnsignedBigInteger (param [0].Value);
 262                                         dsaParams.Q = GetUnsignedBigInteger (param [1].Value);
 263                                         dsaParams.G = GetUnsignedBigInteger (param [2].Value);
 264
 265                                         // BUG: MS BCL 1.0 can't import a key which
 266                                         // isn't the same size as the one present in
 267                                         // the container.
 268                                         _dsa = (DSA) new DSACryptoServiceProvider (dsaParams.Y.Length << 3);
 269                                         _dsa.ImportParameters (dsaParams);
 270                                 }
 271                                 return _dsa;
 272                         }
 273
 274                         set {
 275                                 _dsa = value;
 276                                 if (value != null)
 277                                         _rsa = null;
 278                         }
 279                 }
 280
 281                 public X509ExtensionCollection Extensions {
 282                         get { return extensions; }
 283                 }
 284
 285                 public byte[] Hash {
 286                         get {
 287                                 if (certhash == null) {
 288                                         HashAlgorithm hash = null;
 289                                         switch (m_signaturealgo) {
 290                                                 case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 291                                                         // maybe someone installed MD2 ?
 292 #if INSIDE_CORLIB
 293                                                         hash = HashAlgorithm.Create ("MD2");
 294 #else
 295                                                         hash = Mono.Security.Cryptography.MD2.Create ();
 296 #endif
 297                                                         break;
 298                                                 case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 299                                                         hash = MD5.Create ();
 300                                                         break;
 301                                                 case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 302                                                 case "1.3.14.3.2.29":           // SHA1 with RSA signature
 303                                                 case "1.2.840.10040.4.3":       // SHA1-1 with DSA
 304                                                         hash = SHA1.Create ();
 305                                                         break;
 306                                                 case "1.2.840.113549.1.1.11":   // SHA-256 with RSA Encryption
 307                                                         hash = SHA256.Create ();
 308                                                         break;
 309                                                 default:
 310                                                         return null;
 311                                         }
 312                                         if ((decoder == null) || (decoder.Count < 1))
 313                                                 return null;
 314                                         byte[] toBeSigned = decoder [0].GetBytes ();
 315                                         certhash = hash.ComputeHash (toBeSigned, 0, toBeSigned.Length);
 316                                 }
 317                                 return (byte[]) certhash.Clone ();
 318                         }
 319                 }
 320
 321                 public virtual string IssuerName {
 322                         get { return m_issuername; }
 323                 }
 324
 325                 public virtual string KeyAlgorithm {
 326                         get { return m_keyalgo; }
 327                 }
 328
 329                 public virtual byte[] KeyAlgorithmParameters {
 330                         get {
 331                                 if (m_keyalgoparams == null)
 332                                         return null;
 333                                 return (byte[]) m_keyalgoparams.Clone ();
 334                         }
 335                         set { m_keyalgoparams = value; }
 336                 }
 337
 338                 public virtual byte[] PublicKey {
 339                         get {
 340                                 if (m_publickey == null)
 341                                         return null;
 342                                 return (byte[]) m_publickey.Clone ();
 343                         }
 344                 }
 345
 346                 public virtual RSA RSA {
 347                         get {
 348                                 if (_rsa == null) {
 349                                         RSAParameters rsaParams = new RSAParameters ();
 350                                         // for RSA m_publickey contains 2 ASN.1 integers
 351                                         // the modulus and the public exponent
 352                                         ASN1 pubkey = new ASN1 (m_publickey);
 353                                         ASN1 modulus = pubkey [0];
 354                                         if ((modulus == null) || (modulus.Tag != 0x02))
 355                                                 return null;
 356                                         ASN1 exponent = pubkey [1];
 357                                         if (exponent.Tag != 0x02)
 358                                                 return null;
 359
 360                                         rsaParams.Modulus = GetUnsignedBigInteger (modulus.Value);
 361                                         rsaParams.Exponent = exponent.Value;
 362
 363                                         // BUG: MS BCL 1.0 can't import a key which
 364                                         // isn't the same size as the one present in
 365                                         // the container.
 366                                         int keySize = (rsaParams.Modulus.Length << 3);
 367                                         _rsa = (RSA) new RSACryptoServiceProvider (keySize);
 368                                         _rsa.ImportParameters (rsaParams);
 369                                 }
 370                                 return _rsa;
 371                         }
 372
 373                         set {
 374                                 if (value != null)
 375                                         _dsa = null;
 376                                 _rsa = value;
 377                         }
 378                 }
 379
 380                 public virtual byte[] RawData {
 381                         get {
 382                                 if (m_encodedcert == null)
 383                                         return null;
 384                                 return (byte[]) m_encodedcert.Clone ();
 385                         }
 386                 }
 387
 388                 public virtual byte[] SerialNumber {
 389                         get {
 390                                 if (serialnumber == null)
 391                                         return null;
 392                                 return (byte[]) serialnumber.Clone ();
 393                         }
 394                 }
 395
 396                 public virtual byte[] Signature {
 397                         get {
 398                                 if (signature == null)
 399                                         return null;
 400
 401                                 switch (m_signaturealgo) {
 402                                         case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 403                                         case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 404                                         case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 405                                         case "1.3.14.3.2.29":           // SHA1 with RSA signature
 406                                         case "1.2.840.113549.1.1.11":   // SHA-256 with RSA Encryption
 407                                                 return (byte[]) signature.Clone ();
 408
 409                                         case "1.2.840.10040.4.3":       // SHA-1 with DSA
 410                                                 ASN1 sign = new ASN1 (signature);
 411                                                 if ((sign == null) || (sign.Count != 2))
 412                                                         return null;
 413                                                 byte[] part1 = sign [0].Value;
 414                                                 byte[] part2 = sign [1].Value;
 415                                                 byte[] sig = new byte [40];
 416                                                 // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 417                                                 // parts may be more than 20 bytes (i.e. first byte > 0x80, negative)
 418                                                 int s1 = System.Math.Max (0, part1.Length - 20);
 419                                                 int e1 = System.Math.Max (0, 20 - part1.Length);
 420                                                 Buffer.BlockCopy (part1, s1, sig, e1, part1.Length - s1);
 421                                                 int s2 = System.Math.Max (0, part2.Length - 20);
 422                                                 int e2 = System.Math.Max (20, 40 - part2.Length);
 423                                                 Buffer.BlockCopy (part2, s2, sig, e2, part2.Length - s2);
 424                                                 return sig;
 425
 426                                         default:
 427                                                 throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 428                                 }
 429                         }
 430                 }
 431
 432                 public virtual string SignatureAlgorithm {
 433                         get { return m_signaturealgo; }
 434                 }
 435
 436                 public virtual byte[] SignatureAlgorithmParameters {
 437                         get {
 438                                 if (m_signaturealgoparams == null)
 439                                         return m_signaturealgoparams;
 440                                 return (byte[]) m_signaturealgoparams.Clone ();
 441                         }
 442                 }
 443
 444                 public virtual string SubjectName {
 445                         get { return m_subject; }
 446                 }
 447
 448                 public virtual DateTime ValidFrom {
 449                         get { return m_from; }
 450                 }
 451
 452                 public virtual DateTime ValidUntil {
 453                         get { return m_until; }
 454                 }
 455
 456                 public int Version {
 457                         get { return version; }
 458                 }
 459
 460                 public bool IsCurrent {
 461                         get { return WasCurrent (DateTime.UtcNow); }
 462                 }
 463
 464                 public bool WasCurrent (DateTime instant)
 465                 {
 466                         return ((instant > ValidFrom) && (instant <= ValidUntil));
 467                 }
 468
 469                 // uncommon v2 "extension"
 470                 public byte[] IssuerUniqueIdentifier {
 471                         get {
 472                                 if (issuerUniqueID == null)
 473                                         return null;
 474                                 return (byte[]) issuerUniqueID.Clone ();
 475                         }
 476                 }
 477
 478                 // uncommon v2 "extension"
 479                 public byte[] SubjectUniqueIdentifier {
 480                         get {
 481                                 if (subjectUniqueID == null)
 482                                         return null;
 483                                 return (byte[]) subjectUniqueID.Clone ();
 484                         }
 485                 }
 486
 487                 internal bool VerifySignature (DSA dsa)
 488                 {
 489                         // signatureOID is check by both this.Hash and this.Signature
 490                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 491                         // only SHA-1 is supported
 492                         v.SetHashAlgorithm ("SHA1");
 493                         return v.VerifySignature (this.Hash, this.Signature);
 494                 }
 495
 496                 internal bool VerifySignature (RSA rsa)
 497                 {
 498                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 499                         switch (m_signaturealgo) {
 500                                 // MD2 with RSA encryption
 501                                 case "1.2.840.113549.1.1.2":
 502                                         // maybe someone installed MD2 ?
 503                                         v.SetHashAlgorithm ("MD2");
 504                                         break;
 505                                 // MD5 with RSA encryption
 506                                 case "1.2.840.113549.1.1.4":
 507                                         v.SetHashAlgorithm ("MD5");
 508                                         break;
 509                                 // SHA-1 with RSA Encryption
 510                                 case "1.2.840.113549.1.1.5":
 511                                 case "1.3.14.3.2.29":
 512                                         v.SetHashAlgorithm ("SHA1");
 513                                         break;
 514                                 // SHA-256 with RSA Encryption
 515                                 case "1.2.840.113549.1.1.11":
 516                                         v.SetHashAlgorithm ("SHA256");
 517                                         break;
 518                                 default:
 519                                         throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 520                         }
 521                         return v.VerifySignature (this.Hash, this.Signature);
 522                 }
 523
 524                 public bool VerifySignature (AsymmetricAlgorithm aa)
 525                 {
 526                         if (aa == null)
 527                                 throw new ArgumentNullException ("aa");
 528
 529                         if (aa is RSA)
 530                                 return VerifySignature (aa as RSA);
 531                         else if (aa is DSA)
 532                                 return VerifySignature (aa as DSA);
 533                         else
 534                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 535                 }
 536
 537                 public bool CheckSignature (byte[] hash, string hashAlgorithm, byte[] signature)
 538                 {
 539                         RSACryptoServiceProvider r = (RSACryptoServiceProvider) RSA;
 540                         return r.VerifyHash (hash, hashAlgorithm, signature);
 541                 }
 542
 543                 public bool IsSelfSigned {
 544                         get {
 545                                 if (m_issuername != m_subject)
 546                                         return false;
 547
 548                                 try {
 549                                         if (RSA != null)
 550                                                 return VerifySignature (RSA);
 551                                         else if (DSA != null)
 552                                                 return VerifySignature (DSA);
 553                                         else
 554                                                 return false; // e.g. a certificate with only DSA parameters
 555                                 }
 556                                 catch (CryptographicException) {
 557                                         return false;
 558                                 }
 559                         }
 560                 }
 561
 562                 public ASN1 GetIssuerName ()
 563                 {
 564                         return issuer;
 565                 }
 566
 567                 public ASN1 GetSubjectName ()
 568                 {
 569                         return subject;
 570                 }
 571
 572                 protected X509Certificate (SerializationInfo info, StreamingContext context)
 573                 {
 574                         Parse ((byte[]) info.GetValue ("raw", typeof (byte[])));
 575                 }
 576
 577                 [SecurityPermission (SecurityAction.Demand, SerializationFormatter = true)]
 578                 public virtual void GetObjectData (SerializationInfo info, StreamingContext context)
 579                 {
 580                         info.AddValue ("raw", m_encodedcert);
 581                         // note: we NEVER serialize the private key
 582                 }
 583
 584                 static byte[] PEM (string type, byte[] data)
 585                 {
 586                         string pem = Encoding.ASCII.GetString (data);
 587                         string header = String.Format ("-----BEGIN {0}-----", type);
 588                         string footer = String.Format ("-----END {0}-----", type);
 589                         int start = pem.IndexOf (header) + header.Length;
 590                         int end = pem.IndexOf (footer, start);
 591                         string base64 = pem.Substring (start, (end - start));
 592                         return Convert.FromBase64String (base64);
 593                 }
 594         }
 595 }