ZipIOCentralDirectoryDigitalSignature.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Base / MS / Internal / IO / Zip / ZipIOCentralDirectoryDigitalSignature.cs / 1305600 / ZipIOCentralDirectoryDigitalSignature.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//-------------   *** WARNING ***
//-------------    This file is part of a legally monitored development project.
//-------------    Do not check in changes to this project.  Do not raid bugs on this
//-------------    code in the main PS database.  Do not contact the owner of this 
//-------------    code directly.  Contact the legal team at �ZSLegal� for assistance.
//-------------   *** WARNING *** 
//----------------------------------------------------------------------------- 

//----------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: 
//  This is an internal class that enables interactions with Zip archives 
//  for OPC scenarios
// 
// History:
//  11/19/2004: IgorBel: Initial creation.
//  09/14/2005: BruceMac: Disable creation of signatures and throw on parse if signature found:
//              If we encounter archive with encrypted and /or signed data we consider those as 
//              �invalid OPC packages�. Even in case when client application has never requested
//              read/write operations with the encrypted and/or signed area of the archive.  Motivations include: 
//              1. Security based 
//              2. It is inappropriate to silently ignore digital signatures because this may lead to users
//                 assuming that the signature has been validated when in fact it has not. 
//
//-----------------------------------------------------------------------------

using System; 
using System.IO;
using System.Diagnostics; 
using System.Collections; 
using System.Runtime.Serialization;
using System.Windows; 
using MS.Internal.WindowsBase;

namespace MS.Internal.IO.Zip
{ 
    internal class ZipIOCentralDirectoryDigitalSignature
    { 
#if false 
        internal static ZipIOCentralDirectoryDigitalSignature CreateNew()
         { 
            ZipIOCentralDirectoryDigitalSignature record = new ZipIOCentralDirectoryDigitalSignature ();

            return record;
        } 
#endif
        internal static ZipIOCentralDirectoryDigitalSignature ParseRecord(BinaryReader reader) 
        { 
            // this record is optional, so let's check for presence of signature rightaway
 
            //let's ensure we have at least enough data to cover _fixedMinimalRecordSize bytes of signature
            if ((reader.BaseStream.Length - reader.BaseStream.Position) < _fixedMinimalRecordSize)
            {
                return null; 
            }
 
            UInt32 signatureValue = reader.ReadUInt32(); 
            if (signatureValue != _signatureConstant)
            { 
                return null;
            }

            //at this point we can assume that Digital Signature Record is there 
            // Convention is to throw
            throw new NotSupportedException(SR.Get(SRID.ZipNotSupportedSignedArchive)); 
 
// Zeus PS 3: disable creation/parsing of zip archive digital signatures
#if ArchiveSignaturesEnabled 
            ZipIOCentralDirectoryDigitalSignature record = new ZipIOCentralDirectoryDigitalSignature ();

            record._signature = signatureValue;
            record._sizeOfData = reader.ReadUInt16(); 
            record._signatureData = reader.ReadBytes(record._sizeOfData );
 
            record.Validate(); 

            return record; 
#endif
        }

// Zeus PS 3: disable creation/parsing of zip archive digital signatures 
#if ArchiveSignaturesEnabled
        internal void Save(BinaryWriter writer) 
        { 
            writer.Write(_signatureConstant);
            writer.Write(_sizeOfData); 
            if (_sizeOfData > 0)
            {
                writer.Write(_signatureData , 0, _sizeOfData);
            } 

            writer.Flush(); 
        } 
        internal long Size
        { 
            get
            {
                return _fixedMinimalRecordSize + _sizeOfData;
            } 
        }
#endif 
 
        private ZipIOCentralDirectoryDigitalSignature()
        { 
        }

// Zeus PS 3: disable creation/parsing of zip archive digital signatures
#if ArchiveSignaturesEnabled 
        private void Validate ()
        { 
            if (_signature != _signatureConstant) 
            {
                throw new FileFormatException(SR.Get(SRID.CorruptedData)); 
            }

            if (_sizeOfData != _signatureData.Length)
            { 
                throw new FileFormatException(SR.Get(SRID.CorruptedData));
            } 
        } 
#endif
        private const long _fixedMinimalRecordSize = 6; 

        private const UInt32 _signatureConstant = 0x05054b50;

// Zeus PS 3: disable creation/parsing of zip archive digital signatures 
#if ArchiveSignaturesEnabled
        private UInt16 _sizeOfData; 
        private UInt32 _signature = _signatureConstant; 
        private byte[] _signatureData = null;
#endif 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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