2 // ASN1.cs: Abstract Syntax Notation 1 - micro-parser and generator
5 // Sebastien Pouliot <sebastien@ximian.com>
6 // Jesper Pedersen <jep@itplus.dk>
8 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
9 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
10 // (C) 2004 IT+ A/S (http://www.itplus.dk)
12 // Permission is hereby granted, free of charge, to any person obtaining
13 // a copy of this software and associated documentation files (the
14 // "Software"), to deal in the Software without restriction, including
15 // without limitation the rights to use, copy, modify, merge, publish,
16 // distribute, sublicense, and/or sell copies of the Software, and to
17 // permit persons to whom the Software is furnished to do so, subject to
18 // the following conditions:
20 // The above copyright notice and this permission notice shall be
21 // included in all copies or substantial portions of the Software.
23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
33 using System.Collections;
37 namespace Mono.Security {
40 // a. ITU ASN.1 standards (free download)
41 // http://www.itu.int/ITU-T/studygroups/com17/languages/
51 private byte[] m_aValue;
52 private ArrayList elist;
54 public ASN1 () : this (0x00, null) {}
56 public ASN1 (byte tag) : this (tag, null) {}
58 public ASN1 (byte tag, byte[] data)
64 public ASN1 (byte[] data)
69 int nLength = data [1];
73 nLenLength = nLength - 0x80;
75 for (int i = 0; i < nLenLength; i++) {
77 nLength += data [i + 2];
80 else if (nLength == 0x80) {
81 // undefined length encoding
82 throw new NotSupportedException ("Undefined length encoding.");
85 m_aValue = new byte [nLength];
86 Buffer.BlockCopy (data, (2 + nLenLength), m_aValue, 0, nLength);
88 if ((m_nTag & 0x20) == 0x20) {
89 int nStart = (2 + nLenLength);
90 Decode (data, ref nStart, data.Length);
103 get { return m_nTag; }
108 if (m_aValue != null)
109 return m_aValue.Length;
115 public byte[] Value {
117 if (m_aValue == null)
119 return (byte[]) m_aValue.Clone ();
123 m_aValue = (byte[]) value.Clone ();
127 private bool CompareArray (byte[] array1, byte[] array2)
129 bool bResult = (array1.Length == array2.Length);
131 for (int i = 0; i < array1.Length; i++) {
132 if (array1[i] != array2[i])
139 public bool Equals (byte[] asn1)
141 return CompareArray (this.GetBytes (), asn1);
144 public bool CompareValue (byte[] value)
146 return CompareArray (m_aValue, value);
149 public ASN1 Add (ASN1 asn1)
153 elist = new ArrayList ();
159 public virtual byte[] GetBytes ()
165 ArrayList al = new ArrayList ();
166 foreach (ASN1 a in elist) {
167 byte[] item = a.GetBytes ();
169 esize += item.Length;
171 val = new byte [esize];
173 for (int i=0; i < elist.Count; i++) {
174 byte[] item = (byte[]) al[i];
175 Buffer.BlockCopy (item, 0, val, pos, item.Length);
178 } else if (m_aValue != null) {
186 int nLength = val.Length;
187 // special for length > 127
189 if (nLength <= Byte.MaxValue) {
190 der = new byte [3 + nLength];
191 Buffer.BlockCopy (val, 0, der, 3, nLength);
193 der[2] = (byte)(nLength);
195 else if (nLength <= UInt16.MaxValue) {
196 der = new byte [4 + nLength];
197 Buffer.BlockCopy (val, 0, der, 4, nLength);
199 der[2] = (byte)(nLength >> 8);
200 der[3] = (byte)(nLength);
202 else if (nLength <= 0xFFFFFF) {
204 der = new byte [5 + nLength];
205 Buffer.BlockCopy (val, 0, der, 5, nLength);
207 der [2] = (byte)(nLength >> 16);
208 der [3] = (byte)(nLength >> 8);
209 der [4] = (byte)(nLength);
212 // max (Length is an integer) 32 bits
213 der = new byte [6 + nLength];
214 Buffer.BlockCopy (val, 0, der, 6, nLength);
216 der [2] = (byte)(nLength >> 24);
217 der [3] = (byte)(nLength >> 16);
218 der [4] = (byte)(nLength >> 8);
219 der [5] = (byte)(nLength);
223 // basic case (no encoding)
224 der = new byte [2 + nLength];
225 Buffer.BlockCopy (val, 0, der, 2, nLength);
226 nLengthLen = nLength;
228 if (m_aValue == null)
235 der[1] = (byte)nLengthLen;
241 protected void Decode (byte[] asn1, ref int anPos, int anLength)
247 // minimum is 2 bytes (tag + length of 0)
248 while (anPos < anLength - 1) {
249 DecodeTLV (asn1, ref anPos, out nTag, out nLength, out aValue);
250 // sometimes we get trailing 0
254 ASN1 elm = Add (new ASN1 (nTag, aValue));
256 if ((nTag & 0x20) == 0x20) {
257 int nConstructedPos = anPos;
258 elm.Decode (asn1, ref nConstructedPos, nConstructedPos + nLength);
260 anPos += nLength; // value length
264 // TLV : Tag - Length - Value
265 protected void DecodeTLV (byte[] asn1, ref int pos, out byte tag, out int length, out byte[] content)
268 length = asn1 [pos++];
270 // special case where L contains the Length of the Length + 0x80
271 if ((length & 0x80) == 0x80) {
272 int nLengthLen = length & 0x7F;
274 for (int i = 0; i < nLengthLen; i++)
275 length = length * 256 + asn1 [pos++];
278 content = new byte [length];
279 Buffer.BlockCopy (asn1, pos, content, 0, length);
282 public ASN1 this [int index] {
285 if ((elist == null) || (index >= elist.Count))
287 return (ASN1) elist [index];
289 catch (ArgumentOutOfRangeException) {
295 public ASN1 Element (int index, byte anTag)
298 if ((elist == null) || (index >= elist.Count))
301 ASN1 elm = (ASN1) elist [index];
302 if (elm.Tag == anTag)
307 catch (ArgumentOutOfRangeException) {
312 public override string ToString()
314 StringBuilder hexLine = new StringBuilder ();
317 hexLine.AppendFormat ("Tag: {0} {1}", m_nTag.ToString ("X2"), Environment.NewLine);
320 hexLine.AppendFormat ("Length: {0} {1}", Value.Length, Environment.NewLine);
323 hexLine.Append ("Value: ");
324 hexLine.Append (Environment.NewLine);
325 for (int i = 0; i < Value.Length; i++) {
326 hexLine.AppendFormat ("{0} ", Value [i].ToString ("X2"));
328 hexLine.AppendFormat (Environment.NewLine);
330 return hexLine.ToString ();
333 public void SaveToFile (string filename)
335 if (filename == null)
336 throw new ArgumentNullException ("filename");
338 using (FileStream fs = File.Create (filename)) {
339 byte[] data = GetBytes ();
340 fs.Write (data, 0, data.Length);