mcs/class/corlib/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 using Mono.Security.Cryptography;
  38
  39 namespace Mono.Security.X509 {
  40
  41         // References:
  42         // a.   Internet X.509 Public Key Infrastructure Certificate and CRL Profile
  43         //      http://www.ietf.org/rfc/rfc3280.txt
  44         // b.   ITU ASN.1 standards (free download)
  45         //      http://www.itu.int/ITU-T/studygroups/com17/languages/
  46
  47 #if INSIDE_CORLIB && !MOONLIGHT
  48         internal class X509Certificate : ISerializable {
  49 #else
  50         public class X509Certificate : ISerializable {
  51 #endif
  52                 const string encoding_error = "Input data cannot be coded as a valid certificate.";
  53
  54                 private ASN1 decoder;
  55
  56                 private byte[] m_encodedcert;
  57                 private DateTime m_from;
  58                 private DateTime m_until;
  59                 private ASN1 issuer;
  60                 private string m_issuername;
  61                 private string m_keyalgo;
  62                 private byte[] m_keyalgoparams;
  63                 private ASN1 subject;
  64                 private string m_subject;
  65                 private byte[] m_publickey;
  66                 private byte[] signature;
  67                 private string m_signaturealgo;
  68                 private byte[] m_signaturealgoparams;
  69                 private byte[] certhash;
  70                 private RSA _rsa;
  71                 private DSA _dsa;
  72
  73                 // from http://www.ietf.org/rfc/rfc2459.txt
  74                 //
  75                 //Certificate  ::=  SEQUENCE  {
  76                 //     tbsCertificate       TBSCertificate,
  77                 //     signatureAlgorithm   AlgorithmIdentifier,
  78                 //     signature            BIT STRING  }
  79                 //
  80                 //TBSCertificate  ::=  SEQUENCE  {
  81                 //     version         [0]  Version DEFAULT v1,
  82                 //     serialNumber         CertificateSerialNumber,
  83                 //     signature            AlgorithmIdentifier,
  84                 //     issuer               Name,
  85                 //     validity             Validity,
  86                 //     subject              Name,
  87                 //     subjectPublicKeyInfo SubjectPublicKeyInfo,
  88                 //     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
  89                 //                          -- If present, version shall be v2 or v3
  90                 //     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
  91                 //                          -- If present, version shall be v2 or v3
  92                 //     extensions      [3]  Extensions OPTIONAL
  93                 //                          -- If present, version shall be v3 --  }
  94                 private int version;
  95                 private byte[] serialnumber;
  96
  97                 private byte[] issuerUniqueID;
  98                 private byte[] subjectUniqueID;
  99                 private X509ExtensionCollection extensions;
 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 #if MOONLIGHT
 269                                         _dsa = new DSAManaged (dsaParams.Y.Length << 3);
 270 #else
 271                                         _dsa = (DSA) new DSACryptoServiceProvider (dsaParams.Y.Length << 3);
 272                                         _dsa.ImportParameters (dsaParams);
 273 #endif
 274                                 }
 275                                 return _dsa;
 276                         }
 277
 278                         set {
 279                                 _dsa = value;
 280                                 if (value != null)
 281                                         _rsa = null;
 282                         }
 283                 }
 284
 285                 public X509ExtensionCollection Extensions {
 286                         get { return extensions; }
 287                 }
 288
 289                 public byte[] Hash {
 290                         get {
 291                                 if (certhash == null) {
 292                                         HashAlgorithm hash = null;
 293                                         switch (m_signaturealgo) {
 294                                                 case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 295                                                         // maybe someone installed MD2 ?
 296 #if INSIDE_CORLIB
 297                                                         hash = HashAlgorithm.Create ("MD2");
 298 #else
 299                                                         hash = Mono.Security.Cryptography.MD2.Create ();
 300 #endif
 301                                                         break;
 302                                                 case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 303                                                         hash = MD5.Create ();
 304                                                         break;
 305                                                 case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 306                                                 case "1.3.14.3.2.29":           // SHA1 with RSA signature
 307                                                 case "1.2.840.10040.4.3":       // SHA1-1 with DSA
 308                                                         hash = SHA1.Create ();
 309                                                         break;
 310                                                 default:
 311                                                         return null;
 312                                         }
 313                                         if ((decoder == null) || (decoder.Count < 1))
 314                                                 return null;
 315                                         byte[] toBeSigned = decoder [0].GetBytes ();
 316                                         certhash = hash.ComputeHash (toBeSigned, 0, toBeSigned.Length);
 317                                 }
 318                                 return (byte[]) certhash.Clone ();
 319                         }
 320                 }
 321
 322                 public virtual string IssuerName {
 323                         get { return m_issuername; }
 324                 }
 325
 326                 public virtual string KeyAlgorithm {
 327                         get { return m_keyalgo; }
 328                 }
 329
 330                 public virtual byte[] KeyAlgorithmParameters {
 331                         get {
 332                                 if (m_keyalgoparams == null)
 333                                         return null;
 334                                 return (byte[]) m_keyalgoparams.Clone ();
 335                         }
 336                         set { m_keyalgoparams = value; }
 337                 }
 338
 339                 public virtual byte[] PublicKey {
 340                         get {
 341                                 if (m_publickey == null)
 342                                         return null;
 343                                 return (byte[]) m_publickey.Clone ();
 344                         }
 345                 }
 346
 347                 public virtual RSA RSA {
 348                         get {
 349                                 if (_rsa == null) {
 350                                         RSAParameters rsaParams = new RSAParameters ();
 351                                         // for RSA m_publickey contains 2 ASN.1 integers
 352                                         // the modulus and the public exponent
 353                                         ASN1 pubkey = new ASN1 (m_publickey);
 354                                         ASN1 modulus = pubkey [0];
 355                                         if ((modulus == null) || (modulus.Tag != 0x02))
 356                                                 return null;
 357                                         ASN1 exponent = pubkey [1];
 358                                         if (exponent.Tag != 0x02)
 359                                                 return null;
 360
 361                                         rsaParams.Modulus = GetUnsignedBigInteger (modulus.Value);
 362                                         rsaParams.Exponent = exponent.Value;
 363
 364                                         // BUG: MS BCL 1.0 can't import a key which
 365                                         // isn't the same size as the one present in
 366                                         // the container.
 367                                         int keySize = (rsaParams.Modulus.Length << 3);
 368 #if MOONLIGHT
 369                                         _rsa = new RSAManaged (keySize);
 370 #else
 371                                         _rsa = (RSA) new RSACryptoServiceProvider (keySize);
 372                                         _rsa.ImportParameters (rsaParams);
 373 #endif
 374                                 }
 375                                 return _rsa;
 376                         }
 377
 378                         set {
 379                                 if (value != null)
 380                                         _dsa = null;
 381                                 _rsa = value;
 382                         }
 383                 }
 384
 385                 public virtual byte[] RawData {
 386                         get {
 387                                 if (m_encodedcert == null)
 388                                         return null;
 389                                 return (byte[]) m_encodedcert.Clone ();
 390                         }
 391                 }
 392
 393                 public virtual byte[] SerialNumber {
 394                         get {
 395                                 if (serialnumber == null)
 396                                         return null;
 397                                 return (byte[]) serialnumber.Clone ();
 398                         }
 399                 }
 400
 401                 public virtual byte[] Signature {
 402                         get {
 403                                 if (signature == null)
 404                                         return null;
 405
 406                                 switch (m_signaturealgo) {
 407                                         case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 408                                         case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 409                                         case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 410                                         case "1.3.14.3.2.29":           // SHA1 with RSA signature
 411                                                 return (byte[]) signature.Clone ();
 412
 413                                         case "1.2.840.10040.4.3":       // SHA-1 with DSA
 414                                                 ASN1 sign = new ASN1 (signature);
 415                                                 if ((sign == null) || (sign.Count != 2))
 416                                                         return null;
 417                                                 byte[] part1 = sign [0].Value;
 418                                                 byte[] part2 = sign [1].Value;
 419                                                 byte[] sig = new byte [40];
 420                                                 // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 421                                                 // parts may be more than 20 bytes (i.e. first byte > 0x80, negative)
 422                                                 int s1 = System.Math.Max (0, part1.Length - 20);
 423                                                 int e1 = System.Math.Max (0, 20 - part1.Length);
 424                                                 Buffer.BlockCopy (part1, s1, sig, e1, part1.Length - s1);
 425                                                 int s2 = System.Math.Max (0, part2.Length - 20);
 426                                                 int e2 = System.Math.Max (20, 40 - part2.Length);
 427                                                 Buffer.BlockCopy (part2, s2, sig, e2, part2.Length - s2);
 428                                                 return sig;
 429
 430                                         default:
 431                                                 throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 432                                 }
 433                         }
 434                 }
 435
 436                 public virtual string SignatureAlgorithm {
 437                         get { return m_signaturealgo; }
 438                 }
 439
 440                 public virtual byte[] SignatureAlgorithmParameters {
 441                         get {
 442                                 if (m_signaturealgoparams == null)
 443                                         return m_signaturealgoparams;
 444                                 return (byte[]) m_signaturealgoparams.Clone ();
 445                         }
 446                 }
 447
 448                 public virtual string SubjectName {
 449                         get { return m_subject; }
 450                 }
 451
 452                 public virtual DateTime ValidFrom {
 453                         get { return m_from; }
 454                 }
 455
 456                 public virtual DateTime ValidUntil {
 457                         get { return m_until; }
 458                 }
 459
 460                 public int Version {
 461                         get { return version; }
 462                 }
 463
 464                 public bool IsCurrent {
 465                         get { return WasCurrent (DateTime.UtcNow); }
 466                 }
 467
 468                 public bool WasCurrent (DateTime instant)
 469                 {
 470                         return ((instant > ValidFrom) && (instant <= ValidUntil));
 471                 }
 472
 473                 // uncommon v2 "extension"
 474                 public byte[] IssuerUniqueIdentifier {
 475                         get {
 476                                 if (issuerUniqueID == null)
 477                                         return null;
 478                                 return (byte[]) issuerUniqueID.Clone ();
 479                         }
 480                 }
 481
 482                 // uncommon v2 "extension"
 483                 public byte[] SubjectUniqueIdentifier {
 484                         get {
 485                                 if (subjectUniqueID == null)
 486                                         return null;
 487                                 return (byte[]) subjectUniqueID.Clone ();
 488                         }
 489                 }
 490
 491                 internal bool VerifySignature (DSA dsa)
 492                 {
 493                         // signatureOID is check by both this.Hash and this.Signature
 494                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 495                         // only SHA-1 is supported
 496                         v.SetHashAlgorithm ("SHA1");
 497                         return v.VerifySignature (this.Hash, this.Signature);
 498                 }
 499
 500                 internal string GetHashNameFromOID (string oid)
 501                 {
 502                         switch (oid) {
 503                         // MD2 with RSA encryption
 504                         case "1.2.840.113549.1.1.2":
 505                                 // maybe someone installed MD2 ?
 506                                 return "MD2";
 507                         // MD5 with RSA encryption
 508                         case "1.2.840.113549.1.1.4":
 509                                 return "MD5";
 510                         // SHA-1 with RSA Encryption
 511                         case "1.2.840.113549.1.1.5":
 512                         case "1.3.14.3.2.29":
 513                                 return "SHA1";
 514                         default:
 515                                 return null;
 516                         }
 517                 }
 518
 519                 internal bool VerifySignature (RSA rsa)
 520                 {
 521                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 522                         string hashName = GetHashNameFromOID (m_signaturealgo);
 523                         if (hashName == null)
 524                                 throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 525
 526                         v.SetHashAlgorithm (hashName);
 527                         return v.VerifySignature (this.Hash, this.Signature);
 528                 }
 529
 530                 public bool VerifySignature (AsymmetricAlgorithm aa)
 531                 {
 532                         if (aa == null)
 533                                 throw new ArgumentNullException ("aa");
 534
 535                         if (aa is RSA)
 536                                 return VerifySignature (aa as RSA);
 537                         else if (aa is DSA)
 538                                 return VerifySignature (aa as DSA);
 539                         else
 540                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 541                 }
 542
 543                 public bool CheckSignature (byte[] hash, string hashAlgorithm, byte[] signature)
 544                 {
 545 #if MOONLIGHT
 546                         string hashName = GetHashNameFromOID (hashAlgorithm);
 547                         HashAlgorithm algo = HashAlgorithm.Create (hashName);
 548                         return PKCS1.Verify_v15 (RSA, algo, hash, signature);
 549 #else
 550                         RSACryptoServiceProvider r = (RSACryptoServiceProvider) RSA;
 551                         return r.VerifyHash (hash, hashAlgorithm, signature);
 552 #endif
 553                 }
 554
 555                 public bool IsSelfSigned {
 556                         get {
 557                                 if (m_issuername == m_subject)
 558                                         return VerifySignature (RSA);
 559                                 else
 560                                         return false;
 561                         }
 562                 }
 563
 564                 public ASN1 GetIssuerName ()
 565                 {
 566                         return issuer;
 567                 }
 568
 569                 public ASN1 GetSubjectName ()
 570                 {
 571                         return subject;
 572                 }
 573
 574                 protected X509Certificate (SerializationInfo info, StreamingContext context)
 575                 {
 576                         Parse ((byte[]) info.GetValue ("raw", typeof (byte[])));
 577                 }
 578
 579                 [SecurityPermission (SecurityAction.Demand, SerializationFormatter = true)]
 580                 public virtual void GetObjectData (SerializationInfo info, StreamingContext context)
 581                 {
 582                         info.AddValue ("raw", m_encodedcert);
 583                         // note: we NEVER serialize the private key
 584                 }
 585
 586                 static byte[] PEM (string type, byte[] data)
 587                 {
 588                         string pem = Encoding.ASCII.GetString (data);
 589                         string header = String.Format ("-----BEGIN {0}-----", type);
 590                         string footer = String.Format ("-----END {0}-----", type);
 591                         int start = pem.IndexOf (header) + header.Length;
 592                         int end = pem.IndexOf (footer, start);
 593                         string base64 = pem.Substring (start, (end - start));
 594                         return Convert.FromBase64String (base64);
 595                 }
 596         }
 597 }