mcs/class/Mono.Security/Mono.Security.X509/X509CRL.cs

   1 //
   2 // X509CRL.cs: Handles X.509 certificates revocation lists.
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2004,2006 Novell Inc. (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections;
  31 using System.Globalization;
  32 using System.IO;
  33 using System.Security.Cryptography;
  34
  35 using Mono.Security.X509.Extensions;
  36
  37 namespace Mono.Security.X509 {
  38         /*
  39          * CertificateList  ::=  SEQUENCE  {
  40          *      tbsCertList          TBSCertList,
  41          *      signatureAlgorithm   AlgorithmIdentifier,
  42          *      signature            BIT STRING
  43          * }
  44          *
  45          * TBSCertList  ::=  SEQUENCE  {
  46          *      version                 Version OPTIONAL,
  47          *              -- if present, MUST be v2
  48          *      signature               AlgorithmIdentifier,
  49          *      issuer                  Name,
  50          *      thisUpdate              Time,
  51          *      nextUpdate              Time OPTIONAL,
  52          *      revokedCertificates     SEQUENCE OF SEQUENCE  {
  53          *              userCertificate         CertificateSerialNumber,
  54          *              revocationDate          Time,
  55          *              crlEntryExtensions      Extensions OPTIONAL
  56          *                      -- if present, MUST be v2
  57          *      }  OPTIONAL,
  58          *      crlExtensions           [0] Extensions OPTIONAL }
  59          *              -- if present, MUST be v2
  60          */
  61 #if INSIDE_CORLIB
  62         internal
  63 #else
  64         public
  65 #endif
  66         class X509Crl {
  67
  68                 public class X509CrlEntry {
  69
  70                         private byte[] sn;
  71                         private DateTime revocationDate;
  72                         private X509ExtensionCollection extensions;
  73
  74                         internal X509CrlEntry (byte[] serialNumber, DateTime revocationDate, X509ExtensionCollection extensions)
  75                         {
  76                                 sn = serialNumber;
  77                                 this.revocationDate = revocationDate;
  78                                 if (extensions == null)
  79                                         this.extensions = new X509ExtensionCollection ();
  80                                 else
  81                                         this.extensions = extensions;
  82                         }
  83
  84                         internal X509CrlEntry (ASN1 entry)
  85                         {
  86                                 sn = entry [0].Value;
  87                                 Array.Reverse (sn);
  88                                 revocationDate = ASN1Convert.ToDateTime (entry [1]);
  89                                 extensions = new X509ExtensionCollection (entry [2]);
  90                         }
  91
  92                         public byte[] SerialNumber {
  93                                 get { return (byte[]) sn.Clone (); }
  94                         }
  95
  96                         public DateTime RevocationDate {
  97                                 get { return revocationDate; }
  98                         }
  99
 100                         public X509ExtensionCollection Extensions {
 101                                 get { return extensions; }
 102                         }
 103
 104                         public byte[] GetBytes ()
 105                         {
 106                                 ASN1 sequence = new ASN1 (0x30);
 107                                 sequence.Add (new ASN1 (0x02, sn));
 108                                 sequence.Add (ASN1Convert.FromDateTime (revocationDate));
 109                                 if (extensions.Count > 0)
 110                                         sequence.Add (new ASN1 (extensions.GetBytes ()));
 111                                 return sequence.GetBytes ();
 112                         }
 113                 }
 114
 115                 private string issuer;
 116                 private byte version;
 117                 private DateTime thisUpdate;
 118                 private DateTime nextUpdate;
 119                 private ArrayList entries;
 120                 private string signatureOID;
 121                 private byte[] signature;
 122                 private X509ExtensionCollection extensions;
 123                 private byte[] encoded;
 124                 private byte[] hash_value;
 125
 126                 public X509Crl (byte[] crl)
 127                 {
 128                         if (crl == null)
 129                                 throw new ArgumentNullException ("crl");
 130                         encoded = (byte[]) crl.Clone ();
 131                         Parse (encoded);
 132                 }
 133
 134                 private void Parse (byte[] crl)
 135                 {
 136                         string e = "Input data cannot be coded as a valid CRL.";
 137                         try {
 138                                 // CertificateList  ::=  SEQUENCE  {
 139                                 ASN1 encodedCRL = new ASN1 (encoded);
 140                                 if ((encodedCRL.Tag != 0x30) || (encodedCRL.Count != 3))
 141                                         throw new CryptographicException (e);
 142
 143                                 // CertificateList / TBSCertList,
 144                                 ASN1 toBeSigned = encodedCRL [0];
 145                                 if ((toBeSigned.Tag != 0x30) || (toBeSigned.Count < 3))
 146                                         throw new CryptographicException (e);
 147
 148                                 int n = 0;
 149                                 // CertificateList / TBSCertList / Version OPTIONAL, -- if present, MUST be v2
 150                                 if (toBeSigned [n].Tag == 0x02) {
 151                                         version = (byte) (toBeSigned [n++].Value [0] + 1);
 152                                 }
 153                                 else
 154                                         version = 1; // DEFAULT
 155                                 // CertificateList / TBSCertList / AlgorithmIdentifier,
 156                                 signatureOID = ASN1Convert.ToOid (toBeSigned [n++][0]);
 157                                 // CertificateList / TBSCertList / Name,
 158                                 issuer = X501.ToString (toBeSigned [n++]);
 159                                 // CertificateList / TBSCertList / Time,
 160                                 thisUpdate = ASN1Convert.ToDateTime (toBeSigned [n++]);
 161                                 // CertificateList / TBSCertList / Time OPTIONAL,
 162                                 ASN1 next = toBeSigned [n++];
 163                                 if ((next.Tag == 0x17) || (next.Tag == 0x18)) {
 164                                         nextUpdate = ASN1Convert.ToDateTime (next);
 165                                         next = toBeSigned [n++];
 166                                 }
 167                                 // CertificateList / TBSCertList / revokedCertificates  SEQUENCE OF SEQUENCE  {
 168                                 entries = new ArrayList ();
 169                                 // this is OPTIONAL so it may not be present if no entries exists
 170                                 if ((next != null) && (next.Tag == 0x30)) {
 171                                         ASN1 revokedCertificates = next;
 172                                         for (int i=0; i < revokedCertificates.Count; i++) {
 173                                                 entries.Add (new X509CrlEntry (revokedCertificates [i]));
 174                                         }
 175                                 } else {
 176                                         n--;
 177                                 }
 178                                 // CertificateList / TBSCertList / crlExtensions [0] Extensions OPTIONAL }
 179                                 ASN1 extns = toBeSigned [n];
 180                                 if ((extns != null) && (extns.Tag == 0xA0) && (extns.Count == 1))
 181                                         extensions = new X509ExtensionCollection (extns [0]);
 182                                 else
 183                                         extensions = new X509ExtensionCollection (null); // result in a read only object
 184                                 // CertificateList / AlgorithmIdentifier
 185                                 string signatureAlgorithm = ASN1Convert.ToOid (encodedCRL [1][0]);
 186                                 if (signatureOID != signatureAlgorithm)
 187                                         throw new CryptographicException (e + " [Non-matching signature algorithms in CRL]");
 188
 189                                 // CertificateList / BIT STRING
 190                                 byte[] bitstring = encodedCRL [2].Value;
 191                                 // first byte contains unused bits in first byte
 192                                 signature = new byte [bitstring.Length - 1];
 193                                 Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
 194                         }
 195                         catch {
 196                                 throw new CryptographicException (e);
 197                         }
 198                 }
 199
 200                 public ArrayList Entries {
 201                         get { return ArrayList.ReadOnly (entries); }
 202                 }
 203
 204                 public X509CrlEntry this [int index] {
 205                         get { return (X509CrlEntry) entries [index]; }
 206                 }
 207
 208                 public X509CrlEntry this [byte[] serialNumber] {
 209                         get { return GetCrlEntry (serialNumber); }
 210                 }
 211
 212                 public X509ExtensionCollection Extensions {
 213                         get { return extensions; }
 214                 }
 215
 216                 public byte[] Hash {
 217                         get {
 218                                 if (hash_value == null) {
 219                                         ASN1 encodedCRL = new ASN1 (encoded);
 220                                         byte[] toBeSigned = encodedCRL [0].GetBytes ();
 221                                         HashAlgorithm ha = HashAlgorithm.Create (GetHashName ());
 222                                         hash_value = ha.ComputeHash (toBeSigned);
 223                                 }
 224                                 return hash_value;
 225                         }
 226                 }
 227
 228                 public string IssuerName {
 229                         get { return issuer; }
 230                 }
 231
 232                 public DateTime NextUpdate {
 233                         get { return nextUpdate; }
 234                 }
 235
 236                 public DateTime ThisUpdate {
 237                         get { return thisUpdate; }
 238                 }
 239
 240                 public string SignatureAlgorithm {
 241                         get { return signatureOID; }
 242                 }
 243
 244                 public byte[] Signature {
 245                         get {
 246                                 if (signature == null)
 247                                         return null;
 248                                 return (byte[]) signature.Clone ();
 249                         }
 250                 }
 251
 252                 public byte[] RawData {
 253                         get { return (byte[]) encoded.Clone (); }
 254                 }
 255
 256                 public byte Version {
 257                         get { return version; }
 258                 }
 259
 260                 public bool IsCurrent {
 261                         get { return WasCurrent (DateTime.Now); }
 262                 }
 263
 264                 public bool WasCurrent (DateTime instant)
 265                 {
 266                         if (nextUpdate == DateTime.MinValue)
 267                                 return (instant >= thisUpdate);
 268                         else
 269                                 return ((instant >= thisUpdate) && (instant <= nextUpdate));
 270                 }
 271
 272                 public byte[] GetBytes ()
 273                 {
 274                         return (byte[]) encoded.Clone ();
 275                 }
 276
 277                 private bool Compare (byte[] array1, byte[] array2)
 278                 {
 279                         if ((array1 == null) && (array2 == null))
 280                                 return true;
 281                         if ((array1 == null) || (array2 == null))
 282                                 return false;
 283                         if (array1.Length != array2.Length)
 284                                 return false;
 285                         for (int i=0; i < array1.Length; i++) {
 286                                 if (array1 [i] != array2 [i])
 287                                         return false;
 288                         }
 289                         return true;
 290                 }
 291
 292                 public X509CrlEntry GetCrlEntry (X509Certificate x509)
 293                 {
 294                         if (x509 == null)
 295                                 throw new ArgumentNullException ("x509");
 296
 297                         return GetCrlEntry (x509.SerialNumber);
 298                 }
 299
 300                 public X509CrlEntry GetCrlEntry (byte[] serialNumber)
 301                 {
 302                         if (serialNumber == null)
 303                                 throw new ArgumentNullException ("serialNumber");
 304
 305                         for (int i=0; i < entries.Count; i++) {
 306                                 X509CrlEntry entry = (X509CrlEntry) entries [i];
 307                                 if (Compare (serialNumber, entry.SerialNumber))
 308                                         return entry;
 309                         }
 310                         return null;
 311                 }
 312
 313                 public bool VerifySignature (X509Certificate x509)
 314                 {
 315                         if (x509 == null)
 316                                 throw new ArgumentNullException ("x509");
 317
 318                         // 1. x509 certificate must be a CA certificate (unknown for v1 or v2 certs)
 319                         if (x509.Version >= 3) {
 320                                 BasicConstraintsExtension basicConstraints = null;
 321                                 // 1.2. Check for ca = true in BasicConstraint
 322                                 X509Extension ext = x509.Extensions ["2.5.29.19"];
 323                                 if (ext != null) {
 324                                         basicConstraints = new BasicConstraintsExtension (ext);
 325                                         if (!basicConstraints.CertificateAuthority)
 326                                                 return false;
 327                                 }
 328                                 // 1.1. Check for "cRLSign" bit in KeyUsage extension
 329                                 ext = x509.Extensions ["2.5.29.15"];
 330                                 if (ext != null) {
 331                                         KeyUsageExtension keyUsage = new KeyUsageExtension (ext);
 332                                         if (!keyUsage.Support (KeyUsages.cRLSign)) {
 333                                                 // 2nd chance if basicConstraints is CertificateAuthority
 334                                                 // and KeyUsage support digitalSignature
 335                                                 if ((basicConstraints == null) || !keyUsage.Support (KeyUsages.digitalSignature))
 336                                                         return false;
 337                                         }
 338                                 }
 339                         }
 340                         // 2. CRL issuer must match CA subject name
 341                         if (issuer != x509.SubjectName)
 342                                 return false;
 343                         // 3. Check the CRL signature with the CA certificate public key
 344                         switch (signatureOID) {
 345                                 case "1.2.840.10040.4.3":
 346                                         return VerifySignature (x509.DSA);
 347                                 default:
 348                                         return VerifySignature (x509.RSA);
 349                         }
 350                 }
 351
 352                 private string GetHashName ()
 353                 {
 354                         switch (signatureOID) {
 355                         // MD2 with RSA encryption
 356                         case "1.2.840.113549.1.1.2":
 357                                 // maybe someone installed MD2 ?
 358                                 return "MD2";
 359                         // MD5 with RSA encryption
 360                         case "1.2.840.113549.1.1.4":
 361                                 return "MD5";
 362                         // SHA-1 with DSA
 363                         case "1.2.840.10040.4.3":
 364                         // SHA-1 with RSA Encryption
 365                         case "1.2.840.113549.1.1.5":
 366                                 return "SHA1";
 367                         default:
 368                                 throw new CryptographicException ("Unsupported hash algorithm: " + signatureOID);
 369                         }
 370                 }
 371
 372                 internal bool VerifySignature (DSA dsa)
 373                 {
 374                         if (signatureOID != "1.2.840.10040.4.3")
 375                                 throw new CryptographicException ("Unsupported hash algorithm: " + signatureOID);
 376                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 377                         // only SHA-1 is supported
 378                         v.SetHashAlgorithm ("SHA1");
 379                         ASN1 sign = new ASN1 (signature);
 380                         if ((sign == null) || (sign.Count != 2))
 381                                 return false;
 382                         // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 383                         byte[] part1 = sign [0].Value;
 384                         byte[] part2 = sign [1].Value;
 385                         byte[] sig = new byte [40];
 386                         // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 387                         // parts may be more than 20 bytes (i.e. first byte > 0x80, negative)
 388                         int s1 = System.Math.Max (0, part1.Length - 20);
 389                         int e1 = System.Math.Max (0, 20 - part1.Length);
 390                         Buffer.BlockCopy (part1, s1, sig, e1, part1.Length - s1);
 391                         int s2 = System.Math.Max (0, part2.Length - 20);
 392                         int e2 = System.Math.Max (20, 40 - part2.Length);
 393                         Buffer.BlockCopy (part2, s2, sig, e2, part2.Length - s2);
 394                         return v.VerifySignature (Hash, sig);
 395                 }
 396
 397                 internal bool VerifySignature (RSA rsa)
 398                 {
 399                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 400                         v.SetHashAlgorithm (GetHashName ());
 401                         return v.VerifySignature (Hash, signature);
 402                 }
 403
 404                 public bool VerifySignature (AsymmetricAlgorithm aa)
 405                 {
 406                         if (aa == null)
 407                                 throw new ArgumentNullException ("aa");
 408
 409                         // only validate the signature (in case we don't have the CA certificate)
 410                         if (aa is RSA)
 411                                 return VerifySignature (aa as RSA);
 412                         else if (aa is DSA)
 413                                 return VerifySignature (aa as DSA);
 414                         else
 415                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 416                 }
 417
 418                 static public X509Crl CreateFromFile (string filename)
 419                 {
 420                         byte[] crl = null;
 421                         using (FileStream fs = File.Open (filename, FileMode.Open, FileAccess.Read, FileShare.Read)) {
 422                                 crl = new byte [fs.Length];
 423                                 fs.Read (crl, 0, crl.Length);
 424                                 fs.Close ();
 425                         }
 426                         return new X509Crl (crl);
 427                 }
 428         }
 429 }