//
// This file is part of the source code distribution of SharpPrivacy.
// SharpPrivacy is an Open Source OpenPGP implementation and can be
// found at http://www.sharpprivacy.net
// It is released under Gnu General Public License and can be used
// and modified as long as the result is released under GPL too.
// For a copy of the GPL, please go to www.gnu.org/copyleft/gpl.html
//
// Packet.cs:
// This class provides static functions for handling packets, and
// defines the basic structure of a packet. All other packets extend
// this class.
//
// Author:
// Daniel Fabian (df@sharpprivacy.net)
//
//
// Version: 0.1.0 (initial release)
//
// Changelog:
// - 01.06.2003: Added this header for the first beta release.
//
// (C) 2003, Daniel Fabian
//
using System;
using System.Collections;
namespace SharpPrivacy.OpenPGP {
/// <summary>
/// <para>Representation of an OpenPGP Packet. All other packet
/// types extend this class.</para>
/// <para>The Packet class also provides a static helper function
/// to parse packets, regardless of there type.</para>
/// </summary>
/// <remarks>
/// Representation of an OpenPGP Packet. All other packet
/// types extend this class.</para>
/// <para>The Packet class also provides a static helper function
/// to parse packets, regardless of there type.</para>
/// </remarks>
public class Packet : object {
protected byte[] bHeader = new byte[2];
protected int lLength = 0;
protected byte[] bBody;
protected ContentTypes ctContent;
protected PacketFormats pfFormat;
protected bool bIsUpdated = false;
/// <summary>
/// Default Constructor - Initialises an empty OpenPGP
/// Packet.
/// </summary>
/// <remarks>No remarks</remarks>
public Packet() {
this.bHeader = new byte[0];
this.bBody = new byte[0];
this.bIsUpdated = true;
Format = PacketFormats.New;
}
/// <summary>
/// Creates the packet according to the parameters set
/// in the packet given as parameter
/// </summary>
/// <param name="pSource">A packet from which the parameters
/// are copied to this packet. </param>
/// <remarks>No remarks</remarks>
public Packet(Packet pSource) {
lLength = pSource.Length;
bBody = pSource.Body;
ctContent = pSource.Content;
pfFormat = pSource.Format;
bHeader = pSource.Header;
this.bIsUpdated = false;
}
public bool IsUpdated {
get {
return bIsUpdated;
}
}
/// <summary>
/// <para>Gives the exact type of the packet. This can be one
/// of the following:</para>
/// <list type="bullet">
/// <listheader>
/// <term>Packettypes</term>
/// </listheader>
/// <item><term> Public-Key Encrypted Session Key Packet</term></item>
/// <item><term> Signature Packet</term></item>
/// <item><term> Symmetric-Key Encrypted Session Key Packet</term></item>
/// <item><term> One-Pass Signature Packet</term></item>
/// <item><term> Secret Key Packet</term></item>
/// <item><term> Public Key Packet</term></item>
/// <item><term> Secret Subkey Packet</term></item>
/// <item><term> Compressed Data Packet</term></item>
/// <item><term> Symmetrically Encrypted Data Packet</term></item>
/// <item><term> Marker Packet</term></item>
/// <item><term> Literal Data Packet</term></item>
/// <item><term> Trust Packet</term></item>
/// <item><term> User ID Packet</term></item>
/// <item><term> Public Subkey Packet</term></item>
/// </list>
/// </summary>
/// <value>
/// <para>The exact type of the packet. This can be one
/// of the following:</para>
/// <list type="bullet">
/// <listheader>
/// <term>Packettypes</term>
/// </listheader>
/// <item><term> Public-Key Encrypted Session Key Packet</term></item>
/// <item><term> Signature Packet</term></item>
/// <item><term> Symmetric-Key Encrypted Session Key Packet</term></item>
/// <item><term> One-Pass Signature Packet</term></item>
/// <item><term> Secret Key Packet</term></item>
/// <item><term> Public Key Packet</term></item>
/// <item><term> Secret Subkey Packet</term></item>
/// <item><term> Compressed Data Packet</term></item>
/// <item><term> Symmetrically Encrypted Data Packet</term></item>
/// <item><term> Marker Packet</term></item>
/// <item><term> Literal Data Packet</term></item>
/// <item><term> Trust Packet</term></item>
/// <item><term> User ID Packet</term></item>
/// <item><term> Public Subkey Packet</term></item>
/// </list>
/// </value>
/// <remarks>No remarks</remarks>
public ContentTypes Content {
get {
return ctContent;
}
set {
this.bIsUpdated = true;
ctContent = value;
}
}
/// <summary>
/// Packetformat. Can be either newpacketformat or
/// oldpacketformat
/// </summary>
/// <value>Packetformat. Can be either newpacketformat or
/// oldpacketformat</value>
/// <remarks>No remarks</remarks>
public PacketFormats Format {
get {
return pfFormat;
}
set {
this.bIsUpdated = true;
pfFormat = value;
}
}
/// <summary>
/// Byte array that forms the header of the OpenPGP
/// Packet. This cannot be set directly, but you can
/// either set the headers parameters directly (like
/// packetformat) or you can use Packet.ParsePackets
/// to read packets from a byte buffer.
/// </summary>
/// <value>the header of the OpenPGP
/// Packet. This cannot be set directly, but you can
/// either set the headers parameters directly (like
/// packetformat) or you can use Packet.ParsePackets
/// to read packets from a byte buffer.</value>
/// <remarks>No remarks</remarks>
public byte[] Header {
get {
if (bIsUpdated)
CraftHeader();
return bHeader;
}
}
/// <summary>
/// Returns the total length of the packet (header length
/// + body length).
/// For obvious reasons, this is readonly.
/// </summary>
/// <value>the total length of the packet (header length
/// + body length).
/// For obvious reasons, this is readonly.</value>
/// <remarks>No remarks</remarks>
public int Length {
get {
return bBody.Length + bHeader.Length;
}
}
/// <summary>
/// Byte array that forms the body pf the OpenPGP
/// Packet.
/// </summary>
/// <value>the body pf the OpenPGP
/// Packet.</value>
/// <remarks>No remarks</remarks>
public byte[] Body {
get {
if (bIsUpdated)
this.CraftContent();
return bBody;
}
set {
this.bIsUpdated = true;
bBody = value;
lLength = bBody.Length;
}
}
/// <summary>
/// Returns a string representation of the packet. This is
/// a human readable formated representation that has nothing
/// to do with OpenPGP or RFC2440
/// </summary>
/// <returns>String representation of the packet.</returns>
/// <remarks>No remarks</remarks>
public override string ToString() {
string strReturn = "";
strReturn += "Packet Format: " + Format.ToString() + "\r\n";
return strReturn;
}
/// <summary>
/// Static function that makes parsing packets easy. Just give
/// a byte representation of a set of OpenPGP packets as
/// parameter, and the function returns an array of packets
/// that are the parsed OpenPGP packets.
/// </summary>
/// <param name="bBinaryData">A byte array containing a set
/// of OpenPGP packets</param>
/// <returns>Returns an array of packets</returns>
/// <remarks>No remarks</remarks>
public static Packet[] ParsePackets(byte[] bBinaryData) {
ArrayList alPackets = new ArrayList(100);
byte[] bTmpData = new byte[bBinaryData.Length];
Array.Copy(bBinaryData, bTmpData, bBinaryData.Length);
long iCurrentIndex = 0;
while (iCurrentIndex < bBinaryData.Length) {
Packet pTmpPacket = new Packet();
Packet pCurrentPacket = pTmpPacket.ParsePacket(bTmpData);
if (pCurrentPacket != null) {
iCurrentIndex += pCurrentPacket.Length;
if (pCurrentPacket.Content != ContentTypes.Marker) {
alPackets.Add(pCurrentPacket);
}
bTmpData = new byte[bTmpData.Length - pCurrentPacket.Length];
Array.Copy(bBinaryData, (int)iCurrentIndex, bTmpData, 0, bBinaryData.Length - (int)iCurrentIndex);
}
//MessageBox.Show("Parsed a " + pCurrentPacket.Content.ToString() + "Packet. Current Index: " + iCurrentIndex + "/" + bBinaryData.Length);
}
Packet[] pReturnPackets = new Packet[alPackets.Count];
IEnumerator iePacketEnum = alPackets.GetEnumerator();
int iCount = 0;
while (iePacketEnum.MoveNext()) {
if (iePacketEnum.Current is Packet) {
pReturnPackets[iCount++] = (Packet)iePacketEnum.Current;
}
}
return pReturnPackets;
}
/// <summary>
/// Static function that makes parsing packets easy. Just give
/// a Radix64 encoded representation of a set of OpenPGP packets
/// as parameter, and the function returns an array of packets
/// that are the parsed OpenPGP packets.
/// </summary>
/// <param name="strBase64Text">A string containing the Radix64
/// representation of a set of OpenPGP packets</param>
/// <returns>Returns an array of packets</returns>
/// <remarks>No remarks</remarks>
public static Packet[] ParsePackets(string strBase64Text) {
byte[] bData = Radix64.Decode(strBase64Text);
return ParsePackets(bData);
}
/// <summary>
/// Parses a single packet out of the given binary
/// data. Even if there are more than one packets in the byte
/// array, only the first packet is returned.
/// </summary>
/// <param name="bBinaryData">A byte array containing a set
/// of OpenPGP packets</param>
/// <returns>Returns an single OpenPGP packets</returns>
/// <remarks>No remarks</remarks>
public virtual Packet ParsePacket(byte[] bBinaryData) {
Packet pReturnPacket = new Packet();
if ((bBinaryData[0] & 0xC0) == 0xC0) {
pfFormat = PacketFormats.New;
} else if ((bBinaryData[0] & 0xC0) == 0x80) {
pfFormat = PacketFormats.Old;
} else {
throw(new ArgumentException("This is not a valid OpenPGP Packet"));
}
if (pfFormat == PacketFormats.New) {
int iBinaryDataPos = 2;
ctContent = (ContentTypes)(bBinaryData[0] & 0x3F);
lLength = bBinaryData[1];
bBody = new byte[0];
int iHeaderLength = 1;
//partial body lengths
while ((lLength > 223) && (lLength < 255)) {
iHeaderLength++;
int lPartialBody = 1 << ((int)(lLength & 0x1F));
int lOldLength = 0;
if (bBody.Length > 0) {
byte[] bOldBody = new byte[bBody.Length];
bBody.CopyTo(bOldBody, 0);
bBody = new byte[bOldBody.Length + lPartialBody];
bOldBody.CopyTo(bBody, 0);
lOldLength = bBody.Length;
} else {
bBody = new byte[lPartialBody];
}
Array.Copy(bBinaryData, iBinaryDataPos, bBody, lOldLength, lPartialBody);
lLength = bBinaryData[iBinaryDataPos + lPartialBody];
iBinaryDataPos += lPartialBody;
} //partial bodies must end with a normal header!
if (lLength < 192) {
iHeaderLength++;
bHeader = new byte[iHeaderLength];
if (bBody.Length == 0) {
Array.Copy(bBinaryData, 0, bHeader, 0, 2);
iBinaryDataPos = 1;
}
byte[] bOldBody = new byte[bBody.Length];
bBody.CopyTo(bOldBody, 0);
bBody = new byte[bOldBody.Length + lLength];
bOldBody.CopyTo(bBody, 0);
Array.Copy(bBinaryData, iBinaryDataPos + 1, bBody, bBody.Length - (int)lLength, (int)lLength);
} else if ((lLength > 191) && (lLength < 224)) {
iHeaderLength += 2;
bHeader = new byte[iHeaderLength];
if (bBody.Length == 0) {
Array.Copy(bBinaryData, 0, bHeader, 0, 3);
iBinaryDataPos = 1;
}
lLength = ((bBinaryData[iBinaryDataPos++] - 192) << 8) + bBinaryData[iBinaryDataPos++] + 192;
byte[] bOldBody = new byte[bBody.Length];
bBody.CopyTo(bOldBody, 0);
bBody = new byte[bOldBody.Length + lLength];
bOldBody.CopyTo(bBody, 0);
Array.Copy(bBinaryData, iBinaryDataPos, bBody, bBody.Length - (int)lLength, (int)lLength);
} else if (lLength == 255) {
iHeaderLength += 5;
bHeader = new byte[iHeaderLength];
if (bBody.Length == 0) {
Array.Copy(bBinaryData, 0, bHeader, 0, 6);
}
lLength = (bBinaryData[iBinaryDataPos++] << 24) ^ (bBinaryData[iBinaryDataPos++] << 16) ^
(bBinaryData[iBinaryDataPos++] << 8) ^ bBinaryData[iBinaryDataPos++];
byte[] bOldBody = new byte[bBody.Length];
bBody.CopyTo(bOldBody, 0);
bBody = new byte[bOldBody.Length + lLength];
bOldBody.CopyTo(bBody, 0);
Array.Copy(bBinaryData, iBinaryDataPos, bBody, bBody.Length - (int)lLength, (int)lLength);
}
} else {
ctContent = (ContentTypes)((bBinaryData[0] & 0x3C) >> 2);
switch (bBinaryData[0] & 0x03) {
case 0:
lLength = bBinaryData[1];
bHeader = new byte[2];
break;
case 1:
lLength = (bBinaryData[1] << 8) ^ (bBinaryData[2]);
bHeader = new byte[3];
break;
case 2:
lLength = (bBinaryData[1] << 16) ^ (bBinaryData[2] << 8) ^
(bBinaryData[3]);
bHeader = new byte[4];
break;
case 3:
throw new System.NotSupportedException("Packets of indetermined length are not supported due to security considerations!");
default:
throw new System.ApplicationException("This is not a valid Packet!");
}
bBody = new byte[lLength];
Array.Copy(bBinaryData, 0, bHeader, 0, bHeader.Length);
Array.Copy(bBinaryData, bHeader.Length, bBody, 0, (int)lLength);
}
this.bIsUpdated = false;
switch (ctContent) {
case ContentTypes.AsymSessionKey:
pReturnPacket = new AsymSessionKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.Compressed:
pReturnPacket = new CompressedDataPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.LiteralData:
pReturnPacket = new LiteralDataPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.Marker:
pReturnPacket = new Packet(this);
//We can savly ignore Marker packets!
//MessageBox.Show("This is a marker packet. It is not yet supported.");
break;
case ContentTypes.OnePassSignature:
pReturnPacket = new OnePassSignaturePacket(this);
//System.Windows.Forms.MessageBox.Show("This is a One Pass Signature Packet. It is not yet supported");
break;
//Content is Public Key Packet
case ContentTypes.PublicKey:
pReturnPacket = new PublicKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
//Content is Public Subkey Packet. Same format as Public Key Packet
case ContentTypes.PublicSubkey:
pReturnPacket = new PublicKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.SecretKey:
pReturnPacket = new SecretKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.SecretSubkey:
pReturnPacket = new SecretKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.Signature:
pReturnPacket = new SignaturePacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.SymEncrypted:
pReturnPacket = new SymmetricallyEncryptedDataPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.SymSessionKey:
pReturnPacket = new SymSessionKeyPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
case ContentTypes.Trust:
pReturnPacket = new Packet(this);
// TODO - Remove the messagebox
//System.Windows.Forms.MessageBox.Show("This is a Trust Packet. It is not yet supported");
break;
case ContentTypes.UserID:
pReturnPacket = new UserIDPacket(this);
pReturnPacket = pReturnPacket.ParsePacket(bBody);
break;
default:
pReturnPacket = new Packet(this);
// TODO - Remove the messagebox
System.Windows.Forms.MessageBox.Show("Sorry, but this is a packet I don't know about!");
break;
}
pReturnPacket.bIsUpdated = false;
return pReturnPacket;
}
/// <summary>
/// Generates the content of the packet. Here it is empty,
/// but every derived OpenPGP packet HAS to implement this
/// function.
/// </summary>
/// <remarks>No remarks</remarks>
protected virtual void CraftContent() {
}
/// <summary>
/// Generates the header of the packet according to the
/// parameters Format, Content and the length of the packet.
/// </summary>
/// <remarks>No remarks</remarks>
protected void CraftHeader() {
byte[] bData = new byte[0];
int iPos = 0;
if (Format == PacketFormats.New) {
if (bBody.Length < 192) {
bData = new byte[2];
bData[iPos++] = (byte)(0xC0 ^ (byte)Content);
bData[iPos++] = (byte)(bBody.Length & 0xFF);
} else if (bBody.Length < 8384) {
bData = new byte[3];
bData[iPos++] = (byte)(0xC0 ^ (byte)Content);
int iLen = bBody.Length - 192;
bData[iPos++] = (byte)(((iLen >> 8) & 0xFF) + 192);
bData[iPos++] = (byte)(iLen & 0xFF);
} else {
bData = new byte[6];
bData[iPos++] = (byte)(0xC0 ^ (byte)Content);
bData[iPos++] = 0xFF;
bData[iPos++] = (byte)((bBody.Length >> 24) & 0xFF);
bData[iPos++] = (byte)((bBody.Length >> 16) & 0xFF);
bData[iPos++] = (byte)((bBody.Length >> 8) & 0xFF);
bData[iPos++] = (byte)(bBody.Length & 0xFF);
}
} else {
if (bBody.Length <= 0xFF) {
bData = new byte[2];
bData[iPos++] = (byte)(0x80 ^ (byte)((byte)Content << 2) ^ 0);
bData[iPos++] = (byte)(bBody.Length & 0xFF);
} else if (bBody.Length <= 0xFFFF) {
bData = new byte[3];
bData[iPos++] = (byte)(0x80 ^ (byte)((byte)Content << 2) ^ 1);
bData[iPos++] = (byte)((bBody.Length >> 8) & 0xFF);
bData[iPos++] = (byte)(bBody.Length & 0xFF);
} else {
bData = new byte[5];
bData[iPos++] = (byte)(0x80 ^ (byte)((byte)Content << 2) ^ 2);
bData[iPos++] = (byte)((bBody.Length >> 24) & 0xFF);
bData[iPos++] = (byte)((bBody.Length >> 16) & 0xFF);
bData[iPos++] = (byte)((bBody.Length >> 8) & 0xFF);
bData[iPos++] = (byte)(bBody.Length & 0xFF);
}
}
bHeader = bData;
}
/// <summary>
/// Returns the OpenPGP encoded Packet as byte array.
/// </summary>
/// <returns>The encoded OpenPGP packet</returns>
/// <remarks>No remarks</remarks>
public byte[] Generate() {
if (IsUpdated) {
CraftContent();
CraftHeader();
}
this.bIsUpdated = false;
long lLength = bBody.Length + bHeader.Length;
byte[] bPacket = new byte[lLength];
Array.Copy(bHeader, bPacket, bHeader.Length);
Array.Copy(bBody, 0, bPacket, bHeader.Length, bBody.Length);
return bPacket;
}
}
}
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