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 // (C) 2004 Novell (http://www.novell.com)
   8 //
   9
  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.Collections;
  33 using System.Globalization;
  34 using System.IO;
  35 using System.Security.Cryptography;
  36
  37 using Mono.Security.X509.Extensions;
  38
  39 namespace Mono.Security.X509 {
  40         /*
  41          * CertificateList  ::=  SEQUENCE  {
  42          *      tbsCertList          TBSCertList,
  43          *      signatureAlgorithm   AlgorithmIdentifier,
  44          *      signature            BIT STRING
  45          * }
  46          *
  47          * TBSCertList  ::=  SEQUENCE  {
  48          *      version                 Version OPTIONAL,
  49          *              -- if present, MUST be v2
  50          *      signature               AlgorithmIdentifier,
  51          *      issuer                  Name,
  52          *      thisUpdate              Time,
  53          *      nextUpdate              Time OPTIONAL,
  54          *      revokedCertificates     SEQUENCE OF SEQUENCE  {
  55          *              userCertificate         CertificateSerialNumber,
  56          *              revocationDate          Time,
  57          *              crlEntryExtensions      Extensions OPTIONAL
  58          *                      -- if present, MUST be v2
  59          *      }  OPTIONAL,
  60          *      crlExtensions           [0] Extensions OPTIONAL }
  61          *              -- if present, MUST be v2
  62          */
  63 #if INSIDE_CORLIB
  64         internal
  65 #else
  66         public
  67 #endif
  68         class X509Crl {
  69
  70                 public class X509CrlEntry {
  71
  72                         private byte[] sn;
  73                         private DateTime revocationDate;
  74                         private X509ExtensionCollection extensions;
  75
  76                         internal X509CrlEntry (byte[] serialNumber, DateTime revocationDate, X509ExtensionCollection extensions)
  77                         {
  78                                 sn = serialNumber;
  79                                 this.revocationDate = revocationDate;
  80                                 if (extensions == null)
  81                                         this.extensions = new X509ExtensionCollection ();
  82                                 else
  83                                         this.extensions = extensions;
  84                         }
  85
  86                         internal X509CrlEntry (ASN1 entry)
  87                         {
  88                                 sn = entry [0].Value;
  89                                 Array.Reverse (sn);
  90                                 revocationDate = ASN1Convert.ToDateTime (entry [1]);
  91                                 extensions = new X509ExtensionCollection (entry [2]);
  92                         }
  93
  94                         public byte[] SerialNumber {
  95                                 get { return (byte[]) sn.Clone (); }
  96                         }
  97
  98                         public DateTime RevocationDate {
  99                                 get { return revocationDate; }
 100                         }
 101
 102                         public X509ExtensionCollection Extensions {
 103                                 get { return extensions; }
 104                         }
 105
 106                         public byte[] GetBytes ()
 107                         {
 108                                 ASN1 sequence = new ASN1 (0x30);
 109                                 sequence.Add (new ASN1 (0x02, sn));
 110                                 sequence.Add (ASN1Convert.FromDateTime (revocationDate));
 111                                 if (extensions.Count > 0)
 112                                         sequence.Add (new ASN1 (extensions.GetBytes ()));
 113                                 return sequence.GetBytes ();
 114                         }
 115                 }
 116
 117                 private string issuer;
 118                 private byte version;
 119                 private DateTime thisUpdate;
 120                 private DateTime nextUpdate;
 121                 private ArrayList entries;
 122                 private string signatureOID;
 123                 private byte[] signature;
 124                 private X509ExtensionCollection extensions;
 125                 private byte[] encoded;
 126
 127                 public X509Crl (byte[] crl)
 128                 {
 129                         if (crl == null)
 130                                 throw new ArgumentNullException ("crl");
 131                         encoded = (byte[]) crl.Clone ();
 132                         Parse (encoded);
 133                 }
 134
 135                 private void Parse (byte[] crl)
 136                 {
 137                         string e = "Input data cannot be coded as a valid CRL.";
 138                         try {
 139                                 // CertificateList  ::=  SEQUENCE  {
 140                                 ASN1 encodedCRL = new ASN1 (encoded);
 141                                 if ((encodedCRL.Tag != 0x30) || (encodedCRL.Count != 3))
 142                                         throw new CryptographicException (e);
 143
 144                                 // CertificateList / TBSCertList,
 145                                 ASN1 toBeSigned = encodedCRL [0];
 146                                 if ((toBeSigned.Tag != 0x30) || (toBeSigned.Count < 3))
 147                                         throw new CryptographicException (e);
 148
 149                                 int n = 0;
 150                                 // CertificateList / TBSCertList / Version OPTIONAL, -- if present, MUST be v2
 151                                 if (toBeSigned [n].Tag == 0x02) {
 152                                         version = (byte) (toBeSigned [n++].Value [0] + 1);
 153                                 }
 154                                 else
 155                                         version = 1; // DEFAULT
 156                                 // CertificateList / TBSCertList / AlgorithmIdentifier,
 157                                 signatureOID = ASN1Convert.ToOid (toBeSigned [n++][0]);
 158                                 // CertificateList / TBSCertList / Name,
 159                                 issuer = X501.ToString (toBeSigned [n++]);
 160                                 // CertificateList / TBSCertList / Time,
 161                                 thisUpdate = ASN1Convert.ToDateTime (toBeSigned [n++]);
 162                                 // CertificateList / TBSCertList / Time OPTIONAL,
 163                                 ASN1 next = toBeSigned [n++];
 164                                 if ((next.Tag == 0x17) || (next.Tag == 0x18)) {
 165                                         nextUpdate = ASN1Convert.ToDateTime (next);
 166                                         next = toBeSigned [n++];
 167                                 }
 168                                 // CertificateList / TBSCertList / revokedCertificates  SEQUENCE OF SEQUENCE  {
 169                                 entries = new ArrayList ();
 170                                 ASN1 revokedCertificates = next;
 171                                 for (int i=0; i < revokedCertificates.Count; i++) {
 172                                         entries.Add (new X509CrlEntry (revokedCertificates [i]));
 173                                 }
 174                                 // CertificateList / TBSCertList / crlExtensions [0] Extensions OPTIONAL }
 175                                 ASN1 extns = toBeSigned [n];
 176                                 if ((extns != null) && (extns.Tag == 0xA0) && (extns.Count == 1))
 177                                         extensions = new X509ExtensionCollection (extns [0]);
 178                                 else
 179                                         extensions = new X509ExtensionCollection (null); // result in a read only object
 180                                 // CertificateList / AlgorithmIdentifier
 181                                 string signatureAlgorithm = ASN1Convert.ToOid (encodedCRL [1][0]);
 182                                 if (signatureOID != signatureAlgorithm)
 183                                         throw new CryptographicException (e + " [Non-matching signature algorithms in CRL]");
 184
 185                                 // CertificateList / BIT STRING
 186                                 byte[] bitstring = encodedCRL [2].Value;
 187                                 // first byte contains unused bits in first byte
 188                                 signature = new byte [bitstring.Length - 1];
 189                                 Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
 190                         }
 191                         catch {
 192                                 throw new CryptographicException (e);
 193                         }
 194                 }
 195
 196                 public ArrayList Entries {
 197                         get { return ArrayList.ReadOnly (entries); }
 198                 }
 199
 200                 public X509CrlEntry this [int index] {
 201                         get { return (X509CrlEntry) entries [index]; }
 202                 }
 203
 204                 public X509CrlEntry this [byte[] serialNumber] {
 205                         get { return GetCrlEntry (serialNumber); }
 206                 }
 207
 208                 public X509ExtensionCollection Extensions {
 209                         get { return extensions; }
 210                 }
 211
 212                 public string IssuerName {
 213                         get { return issuer; }
 214                 }
 215
 216                 public DateTime NextUpdate {
 217                         get { return nextUpdate; }
 218                 }
 219
 220                 public DateTime ThisUpdate {
 221                         get { return thisUpdate; }
 222                 }
 223
 224                 public string SignatureAlgorithm {
 225                         get { return signatureOID; }
 226                 }
 227
 228                 public byte[] Signature {
 229                         get {
 230                                 if (signature == null)
 231                                         return null;
 232                                 return (byte[]) signature.Clone ();
 233                         }
 234                 }
 235
 236                 public byte Version {
 237                         get { return version; }
 238                 }
 239
 240                 public bool IsCurrent {
 241                         get { return WasCurrent (DateTime.UtcNow); }
 242                 }
 243
 244                 public bool WasCurrent (DateTime instant)
 245                 {
 246                         if (nextUpdate == DateTime.MinValue)
 247                                 return (instant >= thisUpdate);
 248                         else
 249                                 return ((instant >= thisUpdate) && (instant <= nextUpdate));
 250                 }
 251
 252                 public byte[] GetBytes ()
 253                 {
 254                         return (byte[]) encoded.Clone ();
 255                 }
 256
 257                 private bool Compare (byte[] array1, byte[] array2)
 258                 {
 259                         if ((array1 == null) && (array2 == null))
 260                                 return true;
 261                         if ((array1 == null) || (array2 == null))
 262                                 return false;
 263                         if (array1.Length != array2.Length)
 264                                 return false;
 265                         for (int i=0; i < array1.Length; i++) {
 266                                 if (array1 [i] != array2 [i])
 267                                         return false;
 268                         }
 269                         return true;
 270                 }
 271
 272                 public X509CrlEntry GetCrlEntry (X509Certificate x509)
 273                 {
 274                         if (x509 == null)
 275                                 throw new ArgumentNullException ("x509");
 276
 277                         return GetCrlEntry (x509.SerialNumber);
 278                 }
 279
 280                 public X509CrlEntry GetCrlEntry (byte[] serialNumber)
 281                 {
 282                         if (serialNumber == null)
 283                                 throw new ArgumentNullException ("serialNumber");
 284
 285                         for (int i=0; i < entries.Count; i++) {
 286                                 X509CrlEntry entry = (X509CrlEntry) entries [i];
 287                                 if (Compare (serialNumber, entry.SerialNumber))
 288                                         return entry;
 289                         }
 290                         return null;
 291                 }
 292
 293                 public bool VerifySignature (X509Certificate x509)
 294                 {
 295                         if (x509 == null)
 296                                 throw new ArgumentNullException ("x509");
 297
 298                         // 1. x509 certificate must be a CA certificate (unknown for v1 or v2 certs)
 299                         if (x509.Version >= 3) {
 300                                 // 1.1. Check for "cRLSign" bit in KeyUsage extension
 301                                 X509Extension ext = x509.Extensions ["2.5.29.15"];
 302                                 if (ext != null) {
 303                                         KeyUsageExtension keyUsage = new KeyUsageExtension (ext);
 304                                         if (!keyUsage.Support (KeyUsages.cRLSign))
 305                                                 return false;
 306                                 }
 307                                 // 1.2. Check for ca = true in BasicConstraint
 308                                 ext = x509.Extensions ["2.5.29.19"];
 309                                 if (ext != null) {
 310                                         BasicConstraintsExtension basicConstraints = new BasicConstraintsExtension (ext);
 311                                         if (!basicConstraints.CertificateAuthority)
 312                                                 return false;
 313                                 }
 314                         }
 315                         // 2. CRL issuer must match CA subject name
 316                         if (issuer != x509.SubjectName)
 317                                 return false;
 318                         // 3. Check the CRL signature with the CA certificate public key
 319                         switch (signatureOID) {
 320                                 case "1.2.840.10040.4.3":
 321                                         return VerifySignature (x509.DSA);
 322                                 default:
 323                                         return VerifySignature (x509.RSA);
 324                         }
 325                 }
 326
 327                 private byte[] GetHash (string hashName)
 328                 {
 329                         ASN1 encodedCRL = new ASN1 (encoded);
 330                         byte[] toBeSigned = encodedCRL [0].GetBytes ();
 331                         HashAlgorithm ha = HashAlgorithm.Create (hashName);
 332                         return ha.ComputeHash (toBeSigned);
 333                 }
 334
 335                 internal bool VerifySignature (DSA dsa)
 336                 {
 337                         if (signatureOID != "1.2.840.10040.4.3")
 338                                 throw new CryptographicException ("Unsupported hash algorithm: " + signatureOID);
 339                         DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
 340                         // only SHA-1 is supported
 341                         string hashName = "SHA1";
 342                         v.SetHashAlgorithm (hashName);
 343                         ASN1 sign = new ASN1 (signature);
 344                         if ((sign == null) || (sign.Count != 2))
 345                                 return false;
 346                         // parts may be less than 20 bytes (i.e. first bytes were 0x00)
 347                         byte[] part1 = sign [0].Value;
 348                         byte[] part2 = sign [1].Value;
 349                         byte[] sig = new byte [40];
 350                         Buffer.BlockCopy (part1, 0, sig, (20 - part1.Length), part1.Length);
 351                         Buffer.BlockCopy (part2, 0, sig, (40 - part2.Length), part2.Length);
 352                         return v.VerifySignature (GetHash (hashName), sig);
 353                 }
 354
 355                 internal bool VerifySignature (RSA rsa)
 356                 {
 357                         RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
 358                         string hashName = null;
 359                         switch (signatureOID) {
 360                                 // MD2 with RSA encryption
 361                                 case "1.2.840.113549.1.1.2":
 362                                         // maybe someone installed MD2 ?
 363                                         hashName = "MD2";
 364                                         break;
 365                                 // MD5 with RSA encryption
 366                                 case "1.2.840.113549.1.1.4":
 367                                         hashName = "MD5";
 368                                         break;
 369                                 // SHA-1 with RSA Encryption
 370                                 case "1.2.840.113549.1.1.5":
 371                                         hashName = "SHA1";
 372                                         break;
 373                                 default:
 374                                         throw new CryptographicException ("Unsupported hash algorithm: " + signatureOID);
 375                         }
 376                         v.SetHashAlgorithm (hashName);
 377                         return v.VerifySignature (GetHash (hashName), signature);
 378                 }
 379
 380                 public bool VerifySignature (AsymmetricAlgorithm aa)
 381                 {
 382                         if (aa == null)
 383                                 throw new ArgumentNullException ("aa");
 384
 385                         // only validate the signature (in case we don't have the CA certificate)
 386                         if (aa is RSA)
 387                                 return VerifySignature (aa as RSA);
 388                         else if (aa is DSA)
 389                                 return VerifySignature (aa as DSA);
 390                         else
 391                                 throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
 392                 }
 393
 394                 static public X509Crl CreateFromFile (string filename)
 395                 {
 396                         byte[] crl = null;
 397                         using (FileStream fs = File.Open (filename, FileMode.Open, FileAccess.Read, FileShare.Read)) {
 398                                 crl = new byte [fs.Length];
 399                                 fs.Read (crl, 0, crl.Length);
 400                                 fs.Close ();
 401                         }
 402                         return new X509Crl (crl);
 403                 }
 404         }
 405 }