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

   1 //
   2 // X509Certificates.cs: Handles X.509 certificates.
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@xamarin.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 // Copyright 2013 Xamarin Inc. (http://www.xamarin.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Runtime.Serialization;
  33 using System.Security.Cryptography;
  34 using SSCX = System.Security.Cryptography.X509Certificates;
  35 using System.Security.Permissions;
  36 using System.Text;
  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
  48         internal class X509Certificate : ISerializable {
  49 #else
  50         public class X509Certificate : ISerializable {
  51 #endif
  52
  53                 private ASN1 decoder;
  54
  55                 private byte[] m_encodedcert;
  56                 private DateTime m_from;
  57                 private DateTime m_until;
  58                 private ASN1 issuer;
  59                 private string m_issuername;
  60                 private string m_keyalgo;
  61                 private byte[] m_keyalgoparams;
  62                 private ASN1 subject;
  63                 private string m_subject;
  64                 private byte[] m_publickey;
  65                 private byte[] signature;
  66                 private string m_signaturealgo;
  67                 private byte[] m_signaturealgoparams;
  68                 private byte[] certhash;
  69                 private RSA _rsa;
  70                 private DSA _dsa;
  71
  72                 // from http://www.ietf.org/rfc/rfc2459.txt
  73                 //
  74                 //Certificate  ::=  SEQUENCE  {
  75                 //     tbsCertificate       TBSCertificate,
  76                 //     signatureAlgorithm   AlgorithmIdentifier,
  77                 //     signature            BIT STRING  }
  78                 //
  79                 //TBSCertificate  ::=  SEQUENCE  {
  80                 //     version         [0]  Version DEFAULT v1,
  81                 //     serialNumber         CertificateSerialNumber,
  82                 //     signature            AlgorithmIdentifier,
  83                 //     issuer               Name,
  84                 //     validity             Validity,
  85                 //     subject              Name,
  86                 //     subjectPublicKeyInfo SubjectPublicKeyInfo,
  87                 //     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
  88                 //                          -- If present, version shall be v2 or v3
  89                 //     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
  90                 //                          -- If present, version shall be v2 or v3
  91                 //     extensions      [3]  Extensions OPTIONAL
  92                 //                          -- If present, version shall be v3 --  }
  93                 private int version;
  94                 private byte[] serialnumber;
  95
  96                 private byte[] issuerUniqueID;
  97                 private byte[] subjectUniqueID;
  98                 private X509ExtensionCollection extensions;
  99
 100                 private static string encoding_error = Locale.GetText ("Input data cannot be coded as a valid certificate.");
 101
 102
 103                 // that's were the real job is!
 104                 private void Parse (byte[] data)
 105                 {
 106                         try {
 107                                 decoder = new ASN1 (data);
 108                                 // Certificate
 109                                 if (decoder.Tag != 0x30)
 110                                         throw new CryptographicException (encoding_error);
 111                                 // Certificate / TBSCertificate
 112                                 if (decoder [0].Tag != 0x30)
 113                                         throw new CryptographicException (encoding_error);
 114
 115                                 ASN1 tbsCertificate = decoder [0];
 116
 117                                 int tbs = 0;
 118                                 // Certificate / TBSCertificate / Version
 119                                 ASN1 v = decoder [0][tbs];
 120                                 version = 1;                    // DEFAULT v1
 121                                 if ((v.Tag == 0xA0) && (v.Count > 0)) {
 122                                         // version (optional) is present only in v2+ certs
 123                                         version += v [0].Value [0];     // zero based
 124                                         tbs++;
 125                                 }
 126
 127                                 // Certificate / TBSCertificate / CertificateSerialNumber
 128                                 ASN1 sn = decoder [0][tbs++];
 129                                 if (sn.Tag != 0x02)
 130                                         throw new CryptographicException (encoding_error);
 131                                 serialnumber = sn.Value;
 132                                 Array.Reverse (serialnumber, 0, serialnumber.Length);
 133
 134                                 // Certificate / TBSCertificate / AlgorithmIdentifier
 135                                 tbs++;
 136                                 // ASN1 signatureAlgo = tbsCertificate.Element (tbs++, 0x30);
 137
 138                                 issuer = tbsCertificate.Element (tbs++, 0x30);
 139                                 m_issuername = X501.ToString (issuer);
 140
 141                                 ASN1 validity = tbsCertificate.Element (tbs++, 0x30);
 142                                 ASN1 notBefore = validity [0];
 143                                 m_from = ASN1Convert.ToDateTime (notBefore);
 144                                 ASN1 notAfter = validity [1];
 145                                 m_until = ASN1Convert.ToDateTime (notAfter);
 146
 147                                 subject = tbsCertificate.Element (tbs++, 0x30);
 148                                 m_subject = X501.ToString (subject);
 149
 150                                 ASN1 subjectPublicKeyInfo = tbsCertificate.Element (tbs++, 0x30);
 151
 152                                 ASN1 algorithm = subjectPublicKeyInfo.Element (0, 0x30);
 153                                 ASN1 algo = algorithm.Element (0, 0x06);
 154                                 m_keyalgo = ASN1Convert.ToOid (algo);
 155                                 // parameters ANY DEFINED BY algorithm OPTIONAL
 156                                 // so we dont ask for a specific (Element) type and return DER
 157                                 ASN1 parameters = algorithm [1];
 158                                 m_keyalgoparams = ((algorithm.Count > 1) ? parameters.GetBytes () : null);
 159
 160                                 ASN1 subjectPublicKey = subjectPublicKeyInfo.Element (1, 0x03);
 161                                 // we must drop th first byte (which is the number of unused bits
 162                                 // in the BITSTRING)
 163                                 int n = subjectPublicKey.Length - 1;
 164                                 m_publickey = new byte [n];
 165                                 Buffer.BlockCopy (subjectPublicKey.Value, 1, m_publickey, 0, n);
 166
 167                                 // signature processing
 168                                 byte[] bitstring = decoder [2].Value;
 169                                 // first byte contains unused bits in first byte
 170                                 signature = new byte [bitstring.Length - 1];
 171                                 Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
 172
 173                                 algorithm = decoder [1];
 174                                 algo = algorithm.Element (0, 0x06);
 175                                 m_signaturealgo = ASN1Convert.ToOid (algo);
 176                                 parameters = algorithm [1];
 177                                 if (parameters != null)
 178                                         m_signaturealgoparams = parameters.GetBytes ();
 179                                 else
 180                                         m_signaturealgoparams = null;
 181
 182                                 // Certificate / TBSCertificate / issuerUniqueID
 183                                 ASN1 issuerUID = tbsCertificate.Element (tbs, 0x81);
 184                                 if (issuerUID != null) {
 185                                         tbs++;
 186                                         issuerUniqueID = issuerUID.Value;
 187                                 }
 188
 189                                 // Certificate / TBSCertificate / subjectUniqueID
 190                                 ASN1 subjectUID = tbsCertificate.Element (tbs, 0x82);
 191                                 if (subjectUID != null) {
 192                                         tbs++;
 193                                         subjectUniqueID = subjectUID.Value;
 194                                 }
 195
 196                                 // Certificate / TBSCertificate / Extensions
 197                                 ASN1 extns = tbsCertificate.Element (tbs, 0xA3);
 198                                 if ((extns != null) && (extns.Count == 1))
 199                                         extensions = new X509ExtensionCollection (extns [0]);
 200                                 else
 201                                         extensions = new X509ExtensionCollection (null);
 202
 203                                 // keep a copy of the original data
 204                                 m_encodedcert = (byte[]) data.Clone ();
 205                         }
 206                         catch (Exception ex) {
 207                                 throw new CryptographicException (encoding_error, ex);
 208                         }
 209                 }
 210
 211                 // constructors
 212
 213                 public X509Certificate (byte[] data)
 214                 {
 215                         if (data != null) {
 216                                 // does it looks like PEM ?
 217                                 if ((data.Length > 0) && (data [0] != 0x30)) {
 218                                         try {
 219                                                 data = PEM ("CERTIFICATE", data);
 220                                         }
 221                                         catch (Exception ex) {
 222                                                 throw new CryptographicException (encoding_error, ex);
 223                                         }
 224                                 }
 225                                 Parse (data);
 226                         }
 227                 }
 228
 229                 private byte[] GetUnsignedBigInteger (byte[] integer)
 230                 {
 231                         if (integer [0] == 0x00) {
 232                                 // this first byte is added so we're sure it's an unsigned integer
 233                                 // however we can't feed it into RSAParameters or DSAParameters
 234                                 int length = integer.Length - 1;
 235                                 byte[] uinteger = new byte [length];
 236                                 Buffer.BlockCopy (integer, 1, uinteger, 0, length);
 237                                 return uinteger;
 238                         }
 239                         else
 240                                 return integer;
 241                 }
 242
 243                 // public methods
 244
 245                 public DSA DSA {
 246                         get {
 247                                 if (m_keyalgoparams == null)
 248                                         throw new CryptographicException ("Missing key algorithm parameters.");
 249
 250                                 if (_dsa == null) {
 251                                         DSAParameters dsaParams = new DSAParameters ();
 252                                         // for DSA m_publickey contains 1 ASN.1 integer - Y
 253                                         ASN1 pubkey = new ASN1 (m_publickey);
 254                                         if ((pubkey == null) || (pubkey.Tag != 0x02))
 255                                                 return null;
 256                                         dsaParams.Y = GetUnsignedBigInteger (pubkey.Value);
 257
 258                                         ASN1 param = new ASN1 (m_keyalgoparams);
 259                                         if ((param == null) || (param.Tag != 0x30) || (param.Count < 3))
 260                                                 return null;
 261                                         if ((param [0].Tag != 0x02) || (param [1].Tag != 0x02) || (param [2].Tag != 0x02))
 262                                                 return null;
 263                                         dsaParams.P = GetUnsignedBigInteger (param [0].Value);
 264                                         dsaParams.Q = GetUnsignedBigInteger (param [1].Value);
 265                                         dsaParams.G = GetUnsignedBigInteger (param [2].Value);
 266
 267                                         // BUG: MS BCL 1.0 can't import a key which
 268                                         // isn't the same size as the one present in
 269                                         // the container.
 270                                         _dsa = (DSA) new DSACryptoServiceProvider (dsaParams.Y.Length << 3);
 271                                         _dsa.ImportParameters (dsaParams);
 272                                 }
 273                                 return _dsa;
 274                         }
 275
 276                         set {
 277                                 _dsa = value;
 278                                 if (value != null)
 279                                         _rsa = null;
 280                         }
 281                 }
 282
 283                 public X509ExtensionCollection Extensions {
 284                         get { return extensions; }
 285                 }
 286
 287                 public byte[] Hash {
 288                         get {
 289                                 if (certhash == null) {
 290                                         if ((decoder == null) || (decoder.Count < 1))
 291                                                 return null;
 292                                         string algo = PKCS1.HashNameFromOid (m_signaturealgo, false);
 293                                         if (algo == null)
 294                                                 return null;
 295                                         byte[] toBeSigned = decoder [0].GetBytes ();
 296                                         using (var hash = PKCS1.CreateFromName (algo))
 297                                                 certhash = hash.ComputeHash (toBeSigned, 0, toBeSigned.Length);
 298                                 }
 299                                 return (byte[]) certhash.Clone ();
 300                         }
 301                 }
 302
 303                 public virtual string IssuerName {
 304                         get { return m_issuername; }
 305                 }
 306
 307                 public virtual string KeyAlgorithm {
 308                         get { return m_keyalgo; }
 309                 }
 310
 311                 public virtual byte[] KeyAlgorithmParameters {
 312                         get {
 313                                 if (m_keyalgoparams == null)
 314                                         return null;
 315                                 return (byte[]) m_keyalgoparams.Clone ();
 316                         }
 317                         set { m_keyalgoparams = value; }
 318                 }
 319
 320                 public virtual byte[] PublicKey {
 321                         get {
 322                                 if (m_publickey == null)
 323                                         return null;
 324                                 return (byte[]) m_publickey.Clone ();
 325                         }
 326                 }
 327
 328                 public virtual RSA RSA {
 329                         get {
 330                                 if (_rsa == null) {
 331                                         RSAParameters rsaParams = new RSAParameters ();
 332                                         // for RSA m_publickey contains 2 ASN.1 integers
 333                                         // the modulus and the public exponent
 334                                         ASN1 pubkey = new ASN1 (m_publickey);
 335                                         ASN1 modulus = pubkey [0];
 336                                         if ((modulus == null) || (modulus.Tag != 0x02))
 337                                                 return null;
 338                                         ASN1 exponent = pubkey [1];
 339                                         if (exponent.Tag != 0x02)
 340                                                 return null;
 341
 342                                         rsaParams.Modulus = GetUnsignedBigInteger (modulus.Value);
 343                                         rsaParams.Exponent = exponent.Value;
 344
 345                                         // BUG: MS BCL 1.0 can't import a key which
 346                                         // isn't the same size as the one present in
 347                                         // the container.
 348                                         int keySize = (rsaParams.Modulus.Length << 3);
 349                                         _rsa = (RSA) new RSACryptoServiceProvider (keySize);
 350                                         _rsa.ImportParameters (rsaParams);
 351                                 }
 352                                 return _rsa;
 353                         }
 354
 355                         set {
 356                                 if (value != null)
 357                                         _dsa = null;
 358                                 _rsa = value;
 359                         }
 360                 }
 361
 362                 public virtual byte[] RawData {
 363                         get {
 364                                 if (m_encodedcert == null)
 365                                         return null;
 366                                 return (byte[]) m_encodedcert.Clone ();
 367                         }
 368                 }
 369
 370                 public virtual byte[] SerialNumber {
 371                         get {
 372                                 if (serialnumber == null)
 373                                         return null;
 374                                 return (byte[]) serialnumber.Clone ();
 375                         }
 376                 }
 377
 378                 public virtual byte[] Signature {
 379                         get {
 380                                 if (signature == null)
 381                                         return null;
 382
 383                                 switch (m_signaturealgo) {
 384                                         case "1.2.840.113549.1.1.2":    // MD2 with RSA encryption
 385                                         case "1.2.840.113549.1.1.3":    // MD4 with RSA encryption
 386                                         case "1.2.840.113549.1.1.4":    // MD5 with RSA encryption
 387                                         case "1.2.840.113549.1.1.5":    // SHA-1 with RSA Encryption
 388                                         case "1.3.14.3.2.29":           // SHA1 with RSA signature
 389                                         case "1.2.840.113549.1.1.11":   // SHA-256 with RSA Encryption
 390                                         case "1.2.840.113549.1.1.12":   // SHA-384 with RSA Encryption
 391                                         case "1.2.840.113549.1.1.13":   // SHA-512 with RSA Encryption
 392                                         case "1.3.36.3.3.1.2":                  // RIPEMD160 with RSA Encryption
 393                                                 return (byte[]) signature.Clone ();
 394
 395                                         case "1.2.840.10040.4.3":       // SHA-1 with DSA
 396                                                 ASN1 sign = new ASN1 (signature);
 397                                                 if ((sign == null) || (sign.Count != 2))
 398                                                         return null;
 399                                                 byte[] part1 = sign [0].Value;
 400                                                 byte[] part2 = sign [1].Value;
 401                                                 byte[] sig = new byte [40];
 402                                                 // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 403                                                 // parts may be more than 20 bytes (i.e. first byte > 0x80, negative)
 404                                                 int s1 = System.Math.Max (0, part1.Length - 20);
 405                                                 int e1 = System.Math.Max (0, 20 - part1.Length);
 406                                                 Buffer.BlockCopy (part1, s1, sig, e1, part1.Length - s1);
 407                                                 int s2 = System.Math.Max (0, part2.Length - 20);
 408                                                 int e2 = System.Math.Max (20, 40 - part2.Length);
 409                                                 Buffer.BlockCopy (part2, s2, sig, e2, part2.Length - s2);
 410                                                 return sig;
 411
 412                                         default:
 413                                                 throw new CryptographicException ("Unsupported hash algorithm: " + m_signaturealgo);
 414                                 }
 415                         }
 416                 }
 417
 418                 public virtual string SignatureAlgorithm {
 419                         get { return m_signaturealgo; }
 420                 }
 421
 422                 public virtual byte[] SignatureAlgorithmParameters {
 423                         get {
 424                                 if (m_signaturealgoparams == null)
 425                                         return m_signaturealgoparams;
 426                                 return (byte[]) m_signaturealgoparams.Clone ();
 427                         }
 428                 }
 429
 430                 public virtual string SubjectName {
 431                         get { return m_subject; }
 432                 }
 433
 434                 public virtual DateTime ValidFrom {
 435                         get { return m_from; }
 436                 }
 437
 438                 public virtual DateTime ValidUntil {
 439                         get { return m_until; }
 440                 }
 441
 442                 public int Version {
 443                         get { return version; }
 444                 }
 445
 446                 public bool IsCurrent {
 447                         get { return WasCurrent (DateTime.UtcNow); }
 448                 }
 449
 450                 public bool WasCurrent (DateTime instant)
 451                 {
 452                         return ((instant > ValidFrom) && (instant <= ValidUntil));
 453                 }
 454
 455                 // uncommon v2 "extension"
 456                 public byte[] IssuerUniqueIdentifier {
 457                         get {
 458                                 if (issuerUniqueID == null)
 459                                         return null;
 460                                 return (byte[]) issuerUniqueID.Clone ();
 461                         }
 462                 }
 463
 464                 // uncommon v2 "extension"
 465                 public byte[] SubjectUniqueIdentifier {
 466                         get {
 467                                 if (subjectUniqueID == null)
 468                                         return null;
 469                                 return (byte[]) subjectUniqueID.Clone ();
 470                         }
 471                 }
 472
 473                 internal bool VerifySignature (DSA dsa)
 474                 {
 475                         // signatureOID is check by both this.Hash and this.Signature
 476                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 477                         // only SHA-1 is supported
 478                         v.SetHashAlgorithm ("SHA1");
 479                         return v.VerifySignature (this.Hash, this.Signature);
 480                 }
 481
 482                 internal bool VerifySignature (RSA rsa)
 483                 {
 484                         // SHA1-1 with DSA
 485                         if (m_signaturealgo == "1.2.840.10040.4.3")
 486                                 return false;
 487                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 488                         v.SetHashAlgorithm (PKCS1.HashNameFromOid (m_signaturealgo));
 489                         return v.VerifySignature (this.Hash, this.Signature);
 490                 }
 491
 492                 public bool VerifySignature (AsymmetricAlgorithm aa)
 493                 {
 494                         if (aa == null)
 495                                 throw new ArgumentNullException ("aa");
 496
 497                         if (aa is RSA)
 498                                 return VerifySignature (aa as RSA);
 499                         else if (aa is DSA)
 500                                 return VerifySignature (aa as DSA);
 501                         else
 502                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 503                 }
 504
 505                 public bool CheckSignature (byte[] hash, string hashAlgorithm, byte[] signature)
 506                 {
 507                         RSACryptoServiceProvider r = (RSACryptoServiceProvider) RSA;
 508                         return r.VerifyHash (hash, hashAlgorithm, signature);
 509                 }
 510
 511                 public bool IsSelfSigned {
 512                         get {
 513                                 if (m_issuername != m_subject)
 514                                         return false;
 515
 516                                 try {
 517                                         if (RSA != null)
 518                                                 return VerifySignature (RSA);
 519                                         else if (DSA != null)
 520                                                 return VerifySignature (DSA);
 521                                         else
 522                                                 return false; // e.g. a certificate with only DSA parameters
 523                                 }
 524                                 catch (CryptographicException) {
 525                                         return false;
 526                                 }
 527                         }
 528                 }
 529
 530                 public ASN1 GetIssuerName ()
 531                 {
 532                         return issuer;
 533                 }
 534
 535                 public ASN1 GetSubjectName ()
 536                 {
 537                         return subject;
 538                 }
 539
 540                 protected X509Certificate (SerializationInfo info, StreamingContext context)
 541                 {
 542                         Parse ((byte[]) info.GetValue ("raw", typeof (byte[])));
 543                 }
 544
 545                 [SecurityPermission (SecurityAction.Demand, SerializationFormatter = true)]
 546                 public virtual void GetObjectData (SerializationInfo info, StreamingContext context)
 547                 {
 548                         info.AddValue ("raw", m_encodedcert);
 549                         // note: we NEVER serialize the private key
 550                 }
 551
 552                 static byte[] PEM (string type, byte[] data)
 553                 {
 554                         string pem = Encoding.ASCII.GetString (data);
 555                         string header = String.Format ("-----BEGIN {0}-----", type);
 556                         string footer = String.Format ("-----END {0}-----", type);
 557                         int start = pem.IndexOf (header) + header.Length;
 558                         int end = pem.IndexOf (footer, start);
 559                         string base64 = pem.Substring (start, (end - start));
 560                         return Convert.FromBase64String (base64);
 561                 }
 562         }
 563 }