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 // (C) 2004 Novell (http://www.novell.com)
   9 //
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System;
  35 using System.Security.Cryptography;
  36 using SSCX = System.Security.Cryptography.X509Certificates;
  37 using System.Text;
  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
  48         internal
  49 #else
  50         public
  51 #endif
  52         class X509Certificate {
  53
  54                 private ASN1 decoder;
  55
  56                 private byte[] m_encodedcert;
  57                 private DateTime m_from;
  58                 private DateTime m_until;
  59                 private string m_issuername;
  60                 private string m_keyalgo;
  61                 private byte[] m_keyalgoparams;
  62                 private string m_subject;
  63                 private byte[] m_publickey;
  64                 private byte[] signature;
  65                 private string m_signaturealgo;
  66                 private byte[] m_signaturealgoparams;
  67                 private byte[] certhash;
  68
  69                 // from http://www.ietf.org/rfc/rfc2459.txt
  70                 //
  71                 //Certificate  ::=  SEQUENCE  {
  72                 //     tbsCertificate       TBSCertificate,
  73                 //     signatureAlgorithm   AlgorithmIdentifier,
  74                 //     signature            BIT STRING  }
  75                 //
  76                 //TBSCertificate  ::=  SEQUENCE  {
  77                 //     version         [0]  Version DEFAULT v1,
  78                 //     serialNumber         CertificateSerialNumber,
  79                 //     signature            AlgorithmIdentifier,
  80                 //     issuer               Name,
  81                 //     validity             Validity,
  82                 //     subject              Name,
  83                 //     subjectPublicKeyInfo SubjectPublicKeyInfo,
  84                 //     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
  85                 //                          -- If present, version shall be v2 or v3
  86                 //     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
  87                 //                          -- If present, version shall be v2 or v3
  88                 //     extensions      [3]  Extensions OPTIONAL
  89                 //                          -- If present, version shall be v3 --  }
  90                 private int version;
  91                 private byte[] serialnumber;
  92
  93                 private byte[] issuerUniqueID;
  94                 private byte[] subjectUniqueID;
  95                 private X509ExtensionCollection extensions;
  96
  97                 // that's were the real job is!
  98                 private void Parse (byte[] data)
  99                 {
 100                         string e = "Input data cannot be coded as a valid certificate.";
 101                         try {
 102                                 decoder = new ASN1 (data);
 103                                 // Certificate
 104                                 if (decoder.Tag != 0x30)
 105                                         throw new CryptographicException (e);
 106                                 // Certificate / TBSCertificate
 107                                 if (decoder [0].Tag != 0x30)
 108                                         throw new CryptographicException (e);
 109
 110                                 ASN1 tbsCertificate = decoder [0];
 111
 112                                 int tbs = 0;
 113                                 // Certificate / TBSCertificate / Version
 114                                 ASN1 v = decoder [0][tbs];
 115                                 version = 1;                    // DEFAULT v1
 116                                 if (v.Tag == 0xA0) {
 117                                         // version (optional) is present only in v2+ certs
 118                                         version += v.Value [0]; // zero based
 119                                         tbs++;
 120                                 }
 121
 122                                 // Certificate / TBSCertificate / CertificateSerialNumber
 123                                 ASN1 sn = decoder [0][tbs++];
 124                                 if (sn.Tag != 0x02)
 125                                         throw new CryptographicException (e);
 126                                 serialnumber = sn.Value;
 127                                 Array.Reverse (serialnumber, 0, serialnumber.Length);
 128
 129                                 // Certificate / TBSCertificate / AlgorithmIdentifier
 130                                 ASN1 signatureAlgo = tbsCertificate.Element (tbs++, 0x30);
 131
 132                                 ASN1 issuer = tbsCertificate.Element (tbs++, 0x30);
 133                                 m_issuername = X501.ToString (issuer);
 134
 135                                 ASN1 validity = tbsCertificate.Element (tbs++, 0x30);
 136                                 ASN1 notBefore = validity [0];
 137                                 m_from = ASN1Convert.ToDateTime (notBefore);
 138                                 ASN1 notAfter = validity [1];
 139                                 m_until = ASN1Convert.ToDateTime (notAfter);
 140
 141                                 ASN1 subject = tbsCertificate.Element (tbs++, 0x30);
 142                                 m_subject = X501.ToString (subject);
 143
 144                                 ASN1 subjectPublicKeyInfo = tbsCertificate.Element (tbs++, 0x30);
 145
 146                                 ASN1 algorithm = subjectPublicKeyInfo.Element (0, 0x30);
 147                                 ASN1 algo = algorithm.Element (0, 0x06);
 148                                 m_keyalgo = ASN1Convert.ToOid (algo);
 149                                 // parameters ANY DEFINED BY algorithm OPTIONAL
 150                                 // so we dont ask for a specific (Element) type and return DER
 151                                 ASN1 parameters = algorithm [1];
 152                                 m_keyalgoparams = ((algorithm.Count > 1) ? parameters.GetBytes () : null);
 153
 154                                 ASN1 subjectPublicKey = subjectPublicKeyInfo.Element (1, 0x03);
 155                                 // we must drop th first byte (which is the number of unused bits
 156                                 // in the BITSTRING)
 157                                 int n = subjectPublicKey.Length - 1;
 158                                 m_publickey = new byte [n];
 159                                 Buffer.BlockCopy (subjectPublicKey.Value, 1, m_publickey, 0, n);
 160
 161                                 // signature processing
 162                                 byte[] bitstring = decoder [2].Value;
 163                                 // first byte contains unused bits in first byte
 164                                 signature = new byte [bitstring.Length - 1];
 165                                 Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
 166
 167                                 algorithm = decoder [1];
 168                                 algo = algorithm.Element (0, 0x06);
 169                                 m_signaturealgo = ASN1Convert.ToOid (algo);
 170                                 parameters = algorithm [1];
 171                                 if (parameters != null)
 172                                         m_signaturealgoparams = parameters.GetBytes ();
 173                                 else
 174                                         m_signaturealgoparams = null;
 175
 176                                 // Certificate / TBSCertificate / issuerUniqueID
 177                                 ASN1 issuerUID = tbsCertificate.Element (tbs, 0xA1);
 178                                 if (issuerUID != null) {
 179                                         tbs++;
 180                                         issuerUniqueID = issuerUID.Value;
 181                                 }
 182
 183                                 // Certificate / TBSCertificate / subjectUniqueID
 184                                 ASN1 subjectUID = tbsCertificate.Element (tbs, 0xA2);
 185                                 if (subjectUID != null) {
 186                                         tbs++;
 187                                         subjectUniqueID = subjectUID.Value;
 188                                 }
 189
 190                                 // Certificate / TBSCertificate / Extensions
 191                                 ASN1 extns = tbsCertificate.Element (tbs, 0xA3);
 192                                 if ((extns != null) && (extns.Count == 1))
 193                                         extensions = new X509ExtensionCollection (extns [0]);
 194                                 else
 195                                         extensions = new X509ExtensionCollection (null);
 196
 197                                 // keep a copy of the original data
 198                                 m_encodedcert = (byte[]) data.Clone ();
 199                         }
 200                         catch (Exception ex) {
 201                                 throw new CryptographicException (e, ex);
 202                         }
 203                 }
 204
 205                 // constructors
 206
 207                 public X509Certificate (byte[] data)
 208                 {
 209                         if (data != null)
 210                                 Parse (data);
 211                 }
 212
 213                 private byte[] GetUnsignedBigInteger (byte[] integer)
 214                 {
 215                         if (integer [0] == 0x00) {
 216                                 // this first byte is added so we're sure it's an unsigned integer
 217                                 // however we can't feed it into RSAParameters or DSAParameters
 218                                 int length = integer.Length - 1;
 219                                 byte[] uinteger = new byte [length];
 220                                 Buffer.BlockCopy (integer, 1, uinteger, 0, length);
 221                                 return uinteger;
 222                         }
 223                         else
 224                                 return integer;
 225                 }
 226
 227                 // public methods
 228
 229                 public DSA DSA {
 230                         get {
 231                                 DSAParameters dsaParams = new DSAParameters ();
 232                                 // for DSA m_publickey contains 1 ASN.1 integer - Y
 233                                 ASN1 pubkey = new ASN1 (m_publickey);
 234                                 if ((pubkey == null) || (pubkey.Tag != 0x02))
 235                                         return null;
 236                                 dsaParams.Y = GetUnsignedBigInteger (pubkey.Value);
 237
 238                                 ASN1 param = new ASN1 (m_keyalgoparams);
 239                                 if ((param == null) || (param.Tag != 0x30) || (param.Count < 3))
 240                                         return null;
 241                                 if ((param [0].Tag != 0x02) || (param [1].Tag != 0x02) || (param [2].Tag != 0x02))
 242                                         return null;
 243                                 dsaParams.P = GetUnsignedBigInteger (param [0].Value);
 244                                 dsaParams.Q = GetUnsignedBigInteger (param [1].Value);
 245                                 dsaParams.G = GetUnsignedBigInteger (param [2].Value);
 246
 247                                 // BUG: MS BCL 1.0 can't import a key which
 248                                 // isn't the same size as the one present in
 249                                 // the container.
 250                                 DSACryptoServiceProvider dsa = new DSACryptoServiceProvider (dsaParams.Y.Length << 3);
 251                                 dsa.ImportParameters (dsaParams);
 252                                 return (DSA) dsa;
 253                         }
 254                 }
 255
 256                 public X509ExtensionCollection Extensions {
 257                         get { return extensions; }
 258                 }
 259
 260                 public byte[] Hash {
 261                         get {
 262                                 if (certhash == null) {
 263                                         HashAlgorithm hash = null;
 264                                         switch (m_signaturealgo) {
 265                                                 case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 266                                                         // maybe someone installed MD2 ?
 267                                                         hash = HashAlgorithm.Create ("MD2");
 268                                                         break;
 269                                                 case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 270                                                         hash = MD5.Create ();
 271                                                         break;
 272                                                 case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 273                                                 case "1.3.14.3.2.29":           // SHA1 with RSA signature
 274                                                 case "1.2.840.10040.4.3":       // SHA1-1 with DSA
 275                                                         hash = SHA1.Create ();
 276                                                         break;
 277                                                 default:
 278                                                         return null;
 279                                         }
 280                                         if ((decoder == null) || (decoder.Count < 1))
 281                                                 return null;
 282                                         byte[] toBeSigned = decoder [0].GetBytes ();
 283                                         certhash = hash.ComputeHash (toBeSigned, 0, toBeSigned.Length);
 284                                 }
 285                                 return (byte[]) certhash.Clone ();
 286                         }
 287                 }
 288
 289                 public virtual string IssuerName {
 290                         get { return m_issuername; }
 291                 }
 292
 293                 public virtual string KeyAlgorithm {
 294                         get { return m_keyalgo; }
 295                 }
 296
 297                 public virtual byte[] KeyAlgorithmParameters {
 298                         get {
 299                                 if (m_keyalgoparams == null)
 300                                         return null;
 301                                 return (byte[]) m_keyalgoparams.Clone ();
 302                         }
 303                 }
 304
 305                 public virtual byte[] PublicKey {
 306                         get {
 307                                 if (m_publickey == null)
 308                                         return null;
 309                                 return (byte[]) m_publickey.Clone ();
 310                         }
 311                 }
 312
 313                 public virtual RSA RSA {
 314                         get {
 315                                 RSAParameters rsaParams = new RSAParameters ();
 316                                 // for RSA m_publickey contains 2 ASN.1 integers
 317                                 // the modulus and the public exponent
 318                                 ASN1 pubkey = new ASN1 (m_publickey);
 319                                 ASN1 modulus = pubkey [0];
 320                                 if ((modulus == null) || (modulus.Tag != 0x02))
 321                                         return null;
 322                                 ASN1 exponent = pubkey [1];
 323                                 if (exponent.Tag != 0x02)
 324                                         return null;
 325
 326                                 rsaParams.Modulus = GetUnsignedBigInteger (modulus.Value);
 327                                 rsaParams.Exponent = exponent.Value;
 328
 329                                 // BUG: MS BCL 1.0 can't import a key which
 330                                 // isn't the same size as the one present in
 331                                 // the container.
 332                                 int keySize = (rsaParams.Modulus.Length << 3);
 333                                 RSACryptoServiceProvider rsa = new RSACryptoServiceProvider (keySize);
 334                                 rsa.ImportParameters (rsaParams);
 335                                 return (RSA)rsa;
 336                         }
 337                 }
 338
 339                 public virtual byte[] RawData {
 340                         get { return (byte[]) m_encodedcert.Clone (); }
 341                 }
 342
 343                 public virtual byte[] SerialNumber {
 344                         get {
 345                                 if (serialnumber == null)
 346                                         return null;
 347                                 return (byte[]) serialnumber.Clone ();
 348                         }
 349                 }
 350
 351                 public virtual byte[] Signature {
 352                         get {
 353                                 if (signature == null)
 354                                         return null;
 355
 356                                 switch (m_signaturealgo) {
 357                                         case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 358                                         case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 359                                         case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 360                                         case "1.3.14.3.2.29":           // SHA1 with RSA signature
 361                                                 return (byte[]) signature.Clone ();
 362
 363                                         case "1.2.840.10040.4.3":       // SHA-1 with DSA
 364                                                 ASN1 sign = new ASN1 (signature);
 365                                                 if ((sign == null) || (sign.Count != 2))
 366                                                         return null;
 367                                                 // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 368                                                 byte[] part1 = sign [0].Value;
 369                                                 byte[] part2 = sign [1].Value;
 370                                                 byte[] sig = new byte [40];
 371                                                 Buffer.BlockCopy (part1, 0, sig, (20 - part1.Length), part1.Length);
 372                                                 Buffer.BlockCopy (part2, 0, sig, (40 - part2.Length), part2.Length);
 373                                                 return sig;
 374
 375                                         default:
 376                                                 throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 377                                 }
 378                         }
 379                 }
 380
 381                 public virtual string SignatureAlgorithm {
 382                         get { return m_signaturealgo; }
 383                 }
 384
 385                 public virtual byte[] SignatureAlgorithmParameters {
 386                         get {
 387                                 if (m_signaturealgoparams == null)
 388                                         return m_signaturealgoparams;
 389                                 return (byte[]) m_signaturealgoparams.Clone ();
 390                         }
 391                 }
 392
 393                 public virtual string SubjectName {
 394                         get { return m_subject; }
 395                 }
 396
 397                 public virtual DateTime ValidFrom {
 398                         get { return m_from; }
 399                 }
 400
 401                 public virtual DateTime ValidUntil {
 402                         get { return m_until; }
 403                 }
 404
 405                 public int Version {
 406                         get { return version; }
 407                 }
 408
 409                 public bool IsCurrent {
 410                         get { return WasCurrent (DateTime.UtcNow); }
 411                 }
 412
 413                 public bool WasCurrent (DateTime instant)
 414                 {
 415                         return ((instant > ValidFrom) && (instant <= ValidUntil));
 416                 }
 417
 418                 internal bool VerifySignature (DSA dsa)
 419                 {
 420                         // signatureOID is check by both this.Hash and this.Signature
 421                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 422                         // only SHA-1 is supported
 423                         v.SetHashAlgorithm ("SHA1");
 424                         return v.VerifySignature (this.Hash, this.Signature);
 425                 }
 426
 427                 internal bool VerifySignature (RSA rsa)
 428                 {
 429                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 430                         switch (m_signaturealgo) {
 431                                 // MD2 with RSA encryption
 432                                 case "1.2.840.113549.1.1.2":
 433                                         // maybe someone installed MD2 ?
 434                                         v.SetHashAlgorithm ("MD2");
 435                                         break;
 436                                 // MD5 with RSA encryption
 437                                 case "1.2.840.113549.1.1.4":
 438                                         v.SetHashAlgorithm ("MD5");
 439                                         break;
 440                                 // SHA-1 with RSA Encryption
 441                                 case "1.2.840.113549.1.1.5":
 442                                 case "1.3.14.3.2.29":
 443                                         v.SetHashAlgorithm ("SHA1");
 444                                         break;
 445                                 default:
 446                                         throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 447                         }
 448                         return v.VerifySignature (this.Hash, this.Signature);
 449                 }
 450
 451                 public bool VerifySignature (AsymmetricAlgorithm aa)
 452                 {
 453                         if (aa == null)
 454                                 throw new ArgumentNullException ("aa");
 455
 456                         if (aa is RSA)
 457                                 return VerifySignature (aa as RSA);
 458                         else if (aa is DSA)
 459                                 return VerifySignature (aa as DSA);
 460                         else
 461                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 462                 }
 463
 464                 public bool CheckSignature (byte[] hash, string hashAlgorithm, byte[] signature)
 465                 {
 466                         RSACryptoServiceProvider r = (RSACryptoServiceProvider) RSA;
 467                         return r.VerifyHash (hash, hashAlgorithm, signature);
 468                 }
 469
 470                 public bool IsSelfSigned {
 471                         get {
 472                                 if (m_issuername == m_subject)
 473                                         return VerifySignature (RSA);
 474                                 else
 475                                         return false;
 476                         }
 477                 }
 478         }
 479 }