mcs/class/Mono.Security/Mono.Security.Authenticode/AuthenticodeFormatter.cs

   1 //
   2 // AuthenticodeFormatter.cs: Authenticode signature generator
   3 //
   4 // Author:
   5 //      Sebastien Pouliot <sebastien@ximian.com>
   6 //
   7 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   8 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Collections;
  32 using System.Globalization;
  33 using System.IO;
  34 using System.Security.Cryptography;
  35 using System.Text;
  36 using System.Net;
  37
  38 using Mono.Security;
  39 using Mono.Security.X509;
  40
  41 namespace Mono.Security.Authenticode {
  42
  43         public class AuthenticodeFormatter : AuthenticodeBase {
  44
  45                 private Authority authority;
  46                 private X509CertificateCollection certs;
  47                 private ArrayList crls;
  48                 private string hash;
  49                 private RSA rsa;
  50                 private Uri timestamp;
  51                 private ASN1 authenticode;
  52                 private PKCS7.SignedData pkcs7;
  53                 private string description;
  54                 private Uri url;
  55                 private byte [] entry;
  56
  57                 public AuthenticodeFormatter () : base ()
  58                 {
  59                         certs = new X509CertificateCollection ();
  60                         crls = new ArrayList ();
  61                         authority = Authority.Maximum;
  62                         pkcs7 = new PKCS7.SignedData ();
  63                 }
  64
  65                 public Authority Authority {
  66                         get { return authority; }
  67                         set { authority = value; }
  68                 }
  69
  70                 public X509CertificateCollection Certificates {
  71                         get { return certs; }
  72                 }
  73
  74                 public ArrayList Crl {
  75                         get { return crls; }
  76                 }
  77
  78                 public string Hash {
  79                         get {
  80                                 if (hash == null)
  81                                         hash = "MD5";
  82                                 return hash;
  83                         }
  84                         set {
  85                                 if (value == null)
  86                                         throw new ArgumentNullException ("Hash");
  87
  88                                 string h = value.ToUpper (CultureInfo.InvariantCulture);
  89                                 switch (h) {
  90                                         case "MD5":
  91                                         case "SHA1":
  92                                                 hash = h;
  93                                                 break;
  94                                         default:
  95                                                 throw new ArgumentException ("Invalid Authenticode hash algorithm");
  96                                 }
  97                         }
  98                 }
  99
 100                 public RSA RSA {
 101                         get { return rsa; }
 102                         set { rsa = value; }
 103                 }
 104
 105                 public Uri TimestampUrl {
 106                         get { return timestamp; }
 107                         set { timestamp = value; }
 108                 }
 109
 110                 public string Description {
 111                         get { return description; }
 112                         set { description = value; }
 113                 }
 114
 115                 public Uri Url {
 116                         get { return url; }
 117                         set { url = value; }
 118                 }
 119
 120                 private ASN1 AlgorithmIdentifier (string oid)
 121                 {
 122                         ASN1 ai = new ASN1 (0x30);
 123                         ai.Add (ASN1Convert.FromOid (oid));
 124                         ai.Add (new ASN1 (0x05));       // NULL
 125                         return ai;
 126                 }
 127
 128                 private ASN1 Attribute (string oid, ASN1 value)
 129                 {
 130                         ASN1 attr = new ASN1 (0x30);
 131                         attr.Add (ASN1Convert.FromOid (oid));
 132                         ASN1 aset = attr.Add (new ASN1 (0x31));
 133                         aset.Add (value);
 134                         return attr;
 135                 }
 136
 137                 private ASN1 Opus (string description, string url)
 138                 {
 139                         ASN1 opus = new ASN1 (0x30);
 140                         if (description != null) {
 141                                 ASN1 part1 = opus.Add (new ASN1 (0xA0));
 142                                 part1.Add (new ASN1 (0x80, Encoding.BigEndianUnicode.GetBytes (description)));
 143                         }
 144                         if (url != null) {
 145                                 ASN1 part2 = opus.Add (new ASN1 (0xA1));
 146                                 part2.Add (new ASN1 (0x80, Encoding.ASCII.GetBytes (url)));
 147                         }
 148                         return opus;
 149                 }
 150
 151                 // pkcs 1
 152                 private const string rsaEncryption = "1.2.840.113549.1.1.1";
 153                 // pkcs 7
 154                 private const string data = "1.2.840.113549.1.7.1";
 155                 private const string signedData = "1.2.840.113549.1.7.2";
 156                 // pkcs 9
 157                 private const string contentType = "1.2.840.113549.1.9.3";
 158                 private const string messageDigest  = "1.2.840.113549.1.9.4";
 159                 private const string countersignature = "1.2.840.113549.1.9.6";
 160                 // microsoft spc (software publisher certificate)
 161                 private const string spcStatementType = "1.3.6.1.4.1.311.2.1.11";
 162                 private const string spcSpOpusInfo = "1.3.6.1.4.1.311.2.1.12";
 163                 private const string spcPelmageData = "1.3.6.1.4.1.311.2.1.15";
 164                 private const string individualCodeSigning = "1.3.6.1.4.1.311.2.1.21";
 165                 private const string commercialCodeSigning = "1.3.6.1.4.1.311.2.1.22";
 166                 private const string timestampCountersignature = "1.3.6.1.4.1.311.3.2.1";
 167
 168                 //private static byte[] version = { 0x01 };
 169                 private static byte[] obsolete = { 0x03, 0x01, 0x00, 0xA0, 0x20, 0xA2, 0x1E, 0x80, 0x1C, 0x00, 0x3C, 0x00, 0x3C, 0x00, 0x3C, 0x00, 0x4F, 0x00, 0x62, 0x00, 0x73, 0x00, 0x6F, 0x00, 0x6C, 0x00, 0x65, 0x00, 0x74, 0x00, 0x65, 0x00, 0x3E, 0x00, 0x3E, 0x00, 0x3E };
 170
 171                 private byte[] Header (byte[] fileHash, string hashAlgorithm)
 172                 {
 173                         string hashOid = CryptoConfig.MapNameToOID (hashAlgorithm);
 174                         ASN1 content = new ASN1 (0x30);
 175                         ASN1 c1 = content.Add (new ASN1 (0x30));
 176                         c1.Add (ASN1Convert.FromOid (spcPelmageData));
 177                         c1.Add (new ASN1 (0x30, obsolete));
 178                         ASN1 c2 = content.Add (new ASN1 (0x30));
 179                         c2.Add (AlgorithmIdentifier (hashOid));
 180                         c2.Add (new ASN1 (0x04, fileHash));
 181
 182                         pkcs7.HashName = hashAlgorithm;
 183                         pkcs7.Certificates.AddRange (certs);
 184                         pkcs7.ContentInfo.ContentType = spcIndirectDataContext;
 185                         pkcs7.ContentInfo.Content.Add (content);
 186
 187                         pkcs7.SignerInfo.Certificate = certs [0];
 188                         pkcs7.SignerInfo.Key = rsa;
 189
 190                         ASN1 opus = null;
 191                         if (url == null)
 192                                 opus = Attribute (spcSpOpusInfo, Opus (description, null));
 193                         else
 194                                 opus = Attribute (spcSpOpusInfo, Opus (description, url.ToString ()));
 195                         pkcs7.SignerInfo.AuthenticatedAttributes.Add (opus);
 196                         pkcs7.SignerInfo.AuthenticatedAttributes.Add (Attribute (spcStatementType, new ASN1 (0x30, ASN1Convert.FromOid (commercialCodeSigning).GetBytes ())));
 197                         pkcs7.GetASN1 (); // sign
 198                         return pkcs7.SignerInfo.Signature;
 199                 }
 200
 201                 public ASN1 TimestampRequest (byte[] signature)
 202                 {
 203                         PKCS7.ContentInfo ci = new PKCS7.ContentInfo (PKCS7.Oid.data);
 204                         ci.Content.Add (new ASN1 (0x04, signature));
 205                         return PKCS7.AlgorithmIdentifier (timestampCountersignature, ci.ASN1);
 206                 }
 207
 208                 public void ProcessTimestamp (byte[] response)
 209                 {
 210                         ASN1 ts = new ASN1 (Convert.FromBase64String (Encoding.ASCII.GetString (response)));
 211                         // first validate the received message
 212                         // TODO
 213
 214                         // add the supplied certificates inside our signature
 215                         for (int i=0; i < ts[1][0][3].Count; i++)
 216                                 pkcs7.Certificates.Add (new X509Certificate (ts[1][0][3][i].GetBytes ()));
 217
 218                         // add an unauthentified attribute to our signature
 219                         pkcs7.SignerInfo.UnauthenticatedAttributes.Add (Attribute (countersignature, ts[1][0][4][0]));
 220                 }
 221
 222                 public bool Sign (string fileName)
 223                 {
 224                         string hashAlgorithm = "MD5";
 225                         byte[] file = null;
 226
 227                         using (FileStream fs = new FileStream (fileName, FileMode.Open, FileAccess.Read, FileShare.Read)) {
 228                                 file = new byte [fs.Length];
 229                                 fs.Read (file, 0, file.Length);
 230                                 fs.Close ();
 231                         }
 232
 233                         // MZ - DOS header
 234                         if (BitConverterLE.ToUInt16 (file, 0) != 0x5A4D)
 235                                 return false;
 236
 237                         // find offset of PE header
 238                         int peOffset = BitConverterLE.ToInt32 (file, 60);
 239                         if (peOffset > file.Length)
 240                                 return false;
 241
 242                         // PE - NT header
 243                         if (BitConverterLE.ToUInt16 (file, peOffset) != 0x4550)
 244                                 return false;
 245
 246                         // IMAGE_DIRECTORY_ENTRY_SECURITY
 247                         int dirSecurityOffset = BitConverterLE.ToInt32 (file, peOffset + 152);
 248                         int dirSecuritySize = BitConverterLE.ToInt32 (file, peOffset + 156);
 249
 250                         if (dirSecuritySize > 8) {
 251                                 entry = new byte [dirSecuritySize - 8];
 252                                 Buffer.BlockCopy (file, dirSecurityOffset + 8, entry, 0, entry.Length);
 253                         }
 254                         else
 255                                 entry = null;
 256
 257                         HashAlgorithm hash = HashAlgorithm.Create (hashAlgorithm);
 258                         // 0 to 215 (216) then skip 4 (checksum)
 259                         int pe = peOffset + 88;
 260                         hash.TransformBlock (file, 0, pe, file, 0);
 261                         pe += 4;
 262                         // 220 to 279 (60) then skip 8 (IMAGE_DIRECTORY_ENTRY_SECURITY)
 263                         hash.TransformBlock (file, pe, 60, file, pe);
 264                         pe += 68;
 265                         // 288 to end of file
 266                         int n = file.Length - pe;
 267                         // minus any authenticode signature (with 8 bytes header)
 268                         if (dirSecurityOffset != 0)
 269                                 n -= (dirSecuritySize);
 270                         hash.TransformFinalBlock (file, pe, n);
 271
 272                         //
 273                         byte[] signature = Header (hash.Hash, hashAlgorithm);
 274                         if (timestamp != null) {
 275                                 ASN1 tsreq = TimestampRequest (signature);
 276                                 WebClient wc = new WebClient ();
 277                                 wc.Headers.Add ("Content-Type", "application/octet-stream");
 278                                 wc.Headers.Add ("Accept", "application/octet-stream");
 279                                 byte[] tsdata = Encoding.ASCII.GetBytes (Convert.ToBase64String (tsreq.GetBytes ()));
 280                                 byte[] tsres = wc.UploadData (timestamp.ToString (), tsdata);
 281                                 ProcessTimestamp (tsres);
 282                         }
 283                         PKCS7.ContentInfo sign = new PKCS7.ContentInfo (signedData);
 284                         sign.Content.Add (pkcs7.ASN1);
 285                         authenticode = sign.ASN1;
 286
 287                         byte[] asn = authenticode.GetBytes ();
 288 #if DEBUG
 289                         using (FileStream fs = File.Open (fileName + ".sig", FileMode.Create, FileAccess.Write)) {
 290                                 fs.Write (asn, 0, asn.Length);
 291                                 fs.Close ();
 292                         }
 293 #endif
 294                         // someday I may be sure enough to move this into DEBUG ;-)
 295                         File.Copy (fileName, fileName + ".bak", true);
 296
 297                         using (FileStream fs = File.Open (fileName, FileMode.Create, FileAccess.Write)) {
 298                                 int filesize = (dirSecurityOffset == 0) ? file.Length : dirSecurityOffset;
 299                                 // IMAGE_DIRECTORY_ENTRY_SECURITY (offset, size)
 300                                 byte[] data = BitConverterLE.GetBytes (filesize);
 301                                 file [peOffset + 152] = data [0];
 302                                 file [peOffset + 153] = data [1];
 303                                 file [peOffset + 154] = data [2];
 304                                 file [peOffset + 155] = data [3];
 305                                 int size = asn.Length + 8;
 306                                 // must be a multiple of 8 bytes
 307                                 int addsize = (size % 8);
 308                                 if (addsize > 0)
 309                                         addsize = 8 - addsize;
 310                                 size += addsize;
 311                                 data = BitConverterLE.GetBytes (size);          // header
 312                                 file [peOffset + 156] = data [0];
 313                                 file [peOffset + 157] = data [1];
 314                                 file [peOffset + 158] = data [2];
 315                                 file [peOffset + 159] = data [3];
 316                                 fs.Write (file, 0, filesize);
 317                                 fs.Write (data, 0, data.Length);                // length (again)
 318                                 data = BitConverterLE.GetBytes (0x00020200);    // magic
 319                                 fs.Write (data, 0, data.Length);
 320                                 fs.Write (asn, 0, asn.Length);
 321                                 // fill up
 322                                 byte[] fillup = new byte [addsize];
 323                                 fs.Write (fillup, 0, fillup.Length);
 324                                 fs.Close ();
 325                         }
 326                         return true;
 327                 }
 328
 329                 // in case we just want to timestamp the file
 330                 public bool Timestamp (string fileName)
 331                 {
 332                         return true;
 333                 }
 334         }
 335 }