jellyfin/MediaBrowser.Server.Startup.Common/Cryptography/ASN1.cs
2016-11-10 23:25:21 -05:00

340 lines
8.1 KiB
C#

//
// ASN1.cs: Abstract Syntax Notation 1 - micro-parser and generator
//
// Authors:
// Sebastien Pouliot <sebastien@ximian.com>
// Jesper Pedersen <jep@itplus.dk>
//
// (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
// (C) 2004 IT+ A/S (http://www.itplus.dk)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections;
using System.IO;
using System.Text;
namespace Emby.Common.Implementations.Security {
// References:
// a. ITU ASN.1 standards (free download)
// http://www.itu.int/ITU-T/studygroups/com17/languages/
public class ASN1 {
private byte m_nTag;
private byte[] m_aValue;
private ArrayList elist;
public ASN1 () : this (0x00, null) {}
public ASN1 (byte tag) : this (tag, null) {}
public ASN1 (byte tag, byte[] data)
{
m_nTag = tag;
m_aValue = data;
}
public ASN1 (byte[] data)
{
m_nTag = data [0];
int nLenLength = 0;
int nLength = data [1];
if (nLength > 0x80) {
// composed length
nLenLength = nLength - 0x80;
nLength = 0;
for (int i = 0; i < nLenLength; i++) {
nLength *= 256;
nLength += data [i + 2];
}
}
else if (nLength == 0x80) {
// undefined length encoding
throw new NotSupportedException ("Undefined length encoding.");
}
m_aValue = new byte [nLength];
Buffer.BlockCopy (data, (2 + nLenLength), m_aValue, 0, nLength);
if ((m_nTag & 0x20) == 0x20) {
int nStart = (2 + nLenLength);
Decode (data, ref nStart, data.Length);
}
}
public int Count {
get {
if (elist == null)
return 0;
return elist.Count;
}
}
public byte Tag {
get { return m_nTag; }
}
public int Length {
get {
if (m_aValue != null)
return m_aValue.Length;
else
return 0;
}
}
public byte[] Value {
get {
if (m_aValue == null)
GetBytes ();
return (byte[]) m_aValue.Clone ();
}
set {
if (value != null)
m_aValue = (byte[]) value.Clone ();
}
}
private bool CompareArray (byte[] array1, byte[] array2)
{
bool bResult = (array1.Length == array2.Length);
if (bResult) {
for (int i = 0; i < array1.Length; i++) {
if (array1[i] != array2[i])
return false;
}
}
return bResult;
}
public bool Equals (byte[] asn1)
{
return CompareArray (this.GetBytes (), asn1);
}
public bool CompareValue (byte[] value)
{
return CompareArray (m_aValue, value);
}
public ASN1 Add (ASN1 asn1)
{
if (asn1 != null) {
if (elist == null)
elist = new ArrayList ();
elist.Add (asn1);
}
return asn1;
}
public virtual byte[] GetBytes ()
{
byte[] val = null;
if (Count > 0) {
int esize = 0;
ArrayList al = new ArrayList ();
foreach (ASN1 a in elist) {
byte[] item = a.GetBytes ();
al.Add (item);
esize += item.Length;
}
val = new byte [esize];
int pos = 0;
for (int i=0; i < elist.Count; i++) {
byte[] item = (byte[]) al[i];
Buffer.BlockCopy (item, 0, val, pos, item.Length);
pos += item.Length;
}
} else if (m_aValue != null) {
val = m_aValue;
}
byte[] der;
int nLengthLen = 0;
if (val != null) {
int nLength = val.Length;
// special for length > 127
if (nLength > 127) {
if (nLength <= Byte.MaxValue) {
der = new byte [3 + nLength];
Buffer.BlockCopy (val, 0, der, 3, nLength);
nLengthLen = 0x81;
der[2] = (byte)(nLength);
}
else if (nLength <= UInt16.MaxValue) {
der = new byte [4 + nLength];
Buffer.BlockCopy (val, 0, der, 4, nLength);
nLengthLen = 0x82;
der[2] = (byte)(nLength >> 8);
der[3] = (byte)(nLength);
}
else if (nLength <= 0xFFFFFF) {
// 24 bits
der = new byte [5 + nLength];
Buffer.BlockCopy (val, 0, der, 5, nLength);
nLengthLen = 0x83;
der [2] = (byte)(nLength >> 16);
der [3] = (byte)(nLength >> 8);
der [4] = (byte)(nLength);
}
else {
// max (Length is an integer) 32 bits
der = new byte [6 + nLength];
Buffer.BlockCopy (val, 0, der, 6, nLength);
nLengthLen = 0x84;
der [2] = (byte)(nLength >> 24);
der [3] = (byte)(nLength >> 16);
der [4] = (byte)(nLength >> 8);
der [5] = (byte)(nLength);
}
}
else {
// basic case (no encoding)
der = new byte [2 + nLength];
Buffer.BlockCopy (val, 0, der, 2, nLength);
nLengthLen = nLength;
}
if (m_aValue == null)
m_aValue = val;
}
else
der = new byte[2];
der[0] = m_nTag;
der[1] = (byte)nLengthLen;
return der;
}
// Note: Recursive
protected void Decode (byte[] asn1, ref int anPos, int anLength)
{
byte nTag;
int nLength;
byte[] aValue;
// minimum is 2 bytes (tag + length of 0)
while (anPos < anLength - 1) {
DecodeTLV (asn1, ref anPos, out nTag, out nLength, out aValue);
// sometimes we get trailing 0
if (nTag == 0)
continue;
ASN1 elm = Add (new ASN1 (nTag, aValue));
if ((nTag & 0x20) == 0x20) {
int nConstructedPos = anPos;
elm.Decode (asn1, ref nConstructedPos, nConstructedPos + nLength);
}
anPos += nLength; // value length
}
}
// TLV : Tag - Length - Value
protected void DecodeTLV (byte[] asn1, ref int pos, out byte tag, out int length, out byte[] content)
{
tag = asn1 [pos++];
length = asn1 [pos++];
// special case where L contains the Length of the Length + 0x80
if ((length & 0x80) == 0x80) {
int nLengthLen = length & 0x7F;
length = 0;
for (int i = 0; i < nLengthLen; i++)
length = length * 256 + asn1 [pos++];
}
content = new byte [length];
Buffer.BlockCopy (asn1, pos, content, 0, length);
}
public ASN1 this [int index] {
get {
try {
if ((elist == null) || (index >= elist.Count))
return null;
return (ASN1) elist [index];
}
catch (ArgumentOutOfRangeException) {
return null;
}
}
}
public ASN1 Element (int index, byte anTag)
{
try {
if ((elist == null) || (index >= elist.Count))
return null;
ASN1 elm = (ASN1) elist [index];
if (elm.Tag == anTag)
return elm;
else
return null;
}
catch (ArgumentOutOfRangeException) {
return null;
}
}
public override string ToString()
{
StringBuilder hexLine = new StringBuilder ();
// Add tag
hexLine.AppendFormat ("Tag: {0} {1}", m_nTag.ToString ("X2"), Environment.NewLine);
// Add length
hexLine.AppendFormat ("Length: {0} {1}", Value.Length, Environment.NewLine);
// Add value
hexLine.Append ("Value: ");
hexLine.Append (Environment.NewLine);
for (int i = 0; i < Value.Length; i++) {
hexLine.AppendFormat ("{0} ", Value [i].ToString ("X2"));
if ((i+1) % 16 == 0)
hexLine.AppendFormat (Environment.NewLine);
}
return hexLine.ToString ();
}
public void SaveToFile (string filename)
{
if (filename == null)
throw new ArgumentNullException ("filename");
using (FileStream fs = File.Create (filename)) {
byte[] data = GetBytes ();
fs.Write (data, 0, data.Length);
}
}
}
}