2023-09-07 12:02:19 +04:00

379 lines
13 KiB
C#

//! \file ArcCSAF.cs
//! \date 2019 Jan 01
//! \brief Family Adv System resource archive.
//
// Copyright (C) 2019-2023 by morkt
//
// 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.Generic;
using System.ComponentModel.Composition;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using GameRes.Utility;
namespace GameRes.Formats.FamilyAdvSystem
{
[Serializable]
public class FamilyAdvScheme : ResourceScheme
{
public IDictionary<string, string> KnownKeys;
}
[Export(typeof(ArchiveFormat))]
public class CsafOpener : ArchiveFormat
{
public override string Tag { get { return "CSAF"; } }
public override string Description { get { return "Family Adv System resource archive"; } }
public override uint Signature { get { return 0x46415343; } } // 'CSAF'
public override bool IsHierarchic { get { return true; } }
public override bool CanWrite { get { return false; } }
public CsafOpener ()
{
Extensions = new string[] { "" };
}
static readonly string DefaultKey = "江ノ島の南";
static readonly byte[] DefaultIV = Encoding.ASCII.GetBytes ("FamilyAdvSystem ");
public override ArcFile TryOpen (ArcView file)
{
uint flags = file.View.ReadUInt32 (4);
if ((flags & 0x7FFFFFFF) != 0x10000)
return null;
int count = file.View.ReadInt32 (8);
if (!IsSaneCount (count))
return null;
bool is_encrypted = (flags >> 31) != 0;
uint index_size = (uint)((count * 24 + 31) & -4096) + 0xFE0u;
uint names_size = file.View.ReadUInt32 (12);
var arc_md5 = file.View.ReadBytes (0x10, 0x10);
var index = new byte[index_size + names_size];
CsafEncryption enc = null;
try
{
if (is_encrypted)
{
var key = QueryEncryptionKey (file);
file.View.Read (0x20, index, 0, index_size);
enc = new CsafEncryption (key, DefaultIV);
using (var decryptor = enc.CreateDecryptor (0))
using (var enc_names = file.CreateStream (0x20 + index_size, names_size))
using (var dec_names = new InputCryptoStream (enc_names, decryptor))
{
dec_names.Read (index, (int)index_size, (int)names_size);
}
}
else
{
file.View.Read (0x20, index, 0, index_size + names_size);
}
using (var md5 = MD5.Create())
{
var hash = md5.ComputeHash (index);
if (!hash.SequenceEqual (arc_md5))
return null;
int index_pos = 0x10;
int name_pos = (int)index_size;
var dir = new List<Entry> (count);
for (int i = 0; i < count; ++i)
{
int j;
for (j = name_pos; j+1 < index.Length; j += 2)
{
if (index[j] == 0 && index[j+1] == 0)
break;
}
int name_length = j - name_pos;
var name = Encoding.Unicode.GetString (index, name_pos, name_length);
// hash = md5.ComputeHash (index, name_pos, name_length); // == [index_pos-0x10]
name_pos += name_length + 10;
var entry = Create<Entry> (name);
entry.Offset = (long)index.ToUInt32 (index_pos) << 12;
entry.Size = index.ToUInt32 (index_pos+4);
index_pos += 0x18;
if (!entry.CheckPlacement (file.MaxOffset))
return null;
dir.Add (entry);
}
if (!is_encrypted)
return new ArcFile (file, this, dir);
var arc = new CsafArchive (file, this, dir, enc);
enc = null;
return arc;
}
}
finally
{
if (enc != null)
enc.Dispose();
}
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
if (0 == entry.Size)
return Stream.Null;
var carc = arc as CsafArchive;
if (null == carc)
return base.OpenEntry (arc, entry);
var input = new CsafStream (carc);
return new StreamRegion (input, entry.Offset, entry.Size);
}
internal string QueryEncryptionKey (ArcView file)
{
var title = FormatCatalog.Instance.LookupGame (file.Name);
if (string.IsNullOrEmpty (title))
return DefaultKey;
string key;
if (!KnownKeys.TryGetValue (title, out key))
return DefaultKey;
return key;
}
FamilyAdvScheme DefaultScheme = new FamilyAdvScheme { KnownKeys = new Dictionary<string, string>() };
internal IDictionary<string, string> KnownKeys { get { return DefaultScheme.KnownKeys; } }
public override ResourceScheme Scheme
{
get { return DefaultScheme; }
set { DefaultScheme = (FamilyAdvScheme)value; }
}
}
internal class CsafEncryption : IDisposable
{
Aes m_aes;
MD5 m_md5;
byte[] m_key;
byte[] m_iv;
public CsafEncryption (string password, byte[] iv)
{
m_md5 = MD5.Create();
m_aes = Aes.Create();
m_aes.Mode = CipherMode.CBC;
m_aes.Padding = PaddingMode.None;
m_key = InitKey (password);
m_iv = iv;
}
public ICryptoTransform CreateDecryptor (int block_num)
{
var block_key = GetBlockKey (block_num);
return m_aes.CreateDecryptor (block_key, m_iv);
}
byte[] InitKey (string pass_phrase)
{
var key = new byte[32];
if (!string.IsNullOrEmpty (pass_phrase))
{
var bytes = Encoding.Unicode.GetBytes (pass_phrase);
var hash = m_md5.ComputeHash (bytes);
Buffer.BlockCopy (hash, 0, key, 0, 16);
hash = m_md5.ComputeHash (bytes, 1, bytes.Length - 2);
Buffer.BlockCopy (hash, 0, key, 16, 16);
}
return key;
}
byte[] GetBlockKey (int block_num)
{
int offset = block_num / 8;
int shift = block_num & 7;
var key = new byte[32];
var buf = new byte[16];
for (int i = 0; i < 16; ++i)
{
buf[i] = Binary.RotByteL (m_key[(offset + i) & 0xF], shift);
}
var hash = m_md5.ComputeHash (buf, 0, 16);
Buffer.BlockCopy (hash, 0, key, 0, 16);
for (int i = 0; i < 16; ++i)
{
buf[i] = Binary.RotByteL (m_key[16 + ((offset + i) & 0xF)], shift);
}
hash = m_md5.ComputeHash (buf, 0, 16);
Buffer.BlockCopy (hash, 0, key, 16, 16);
return key;
}
#region IDisposable Members
bool m_disposed = false;
public void Dispose ()
{
if (!m_disposed)
{
m_aes.Dispose();
m_md5.Dispose();
m_disposed = true;
}
}
#endregion
}
internal class CsafArchive : ArcFile
{
public readonly CsafEncryption Encryption;
public CsafArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, CsafEncryption enc)
: base (arc, impl, dir)
{
Encryption = enc;
}
#region IDisposable Members
bool _csaf_disposed = false;
protected override void Dispose (bool disposing)
{
if (_csaf_disposed)
return;
if (disposing)
Encryption.Dispose();
_csaf_disposed = true;
base.Dispose (disposing);
}
#endregion
}
internal class CsafStream : Stream
{
readonly long m_length;
ArcView.Frame m_view;
CsafEncryption m_encryption;
long m_position = 0;
byte[] m_block = new byte[0x1000];
long m_block_start = 0;
int m_block_length = 0;
public override bool CanRead { get { return true; } }
public override bool CanSeek { get { return true; } }
public override bool CanWrite { get { return false; } }
public CsafStream (CsafArchive arc)
{
m_length = arc.File.MaxOffset;
m_view = arc.File.CreateFrame();
m_encryption = arc.Encryption;
}
public override int Read (byte[] buffer, int offset, int count)
{
int read = 0;
while (count > 0)
{
if (!(m_position >= m_block_start && m_position < m_block_start + m_block_length))
{
if (!ReadBlock())
break;
}
int block_pos = (int)m_position & 0xFFF;
int avail = Math.Min (count, m_block_length - block_pos);
Buffer.BlockCopy (m_block, block_pos, buffer, offset, avail);
m_position += avail;
offset += avail;
read += avail;
count -= avail;
}
return read;
}
bool ReadBlock ()
{
if (m_position >= m_length)
return false;
m_block_start = m_position & ~0xFFFL;
m_block_length = m_view.Read (m_block_start, m_block, 0, 0x1000);
if (m_block_length != 0x1000)
return false;
using (var decryptor = m_encryption.CreateDecryptor ((int)(m_block_start >> 12)))
using (var enc = new BinMemoryStream (m_block))
using (var dec = new InputCryptoStream (enc, decryptor))
dec.Read (m_block, 0, m_block_length);
return true;
}
#region IO.Stream members
public override long Length { get { return m_length; } }
public override long Position
{
get { return m_position; }
set { m_position = value; }
}
public override void Flush ()
{
}
public override long Seek (long offset, SeekOrigin origin)
{
if (SeekOrigin.Begin == origin)
Position = offset;
else if (SeekOrigin.Current == origin)
Position = m_position + offset;
else
Position = m_length + offset;
return m_position;
}
public override void SetLength (long length)
{
throw new NotSupportedException ("CsafStream.SetLength method is not supported");
}
public override void Write (byte[] buffer, int offset, int count)
{
throw new NotSupportedException ("CsafStream.Write method is not supported");
}
public override void WriteByte (byte value)
{
throw new NotSupportedException("CsafStream.WriteByte method is not supported");
}
#endregion
#region IDisposable Members
bool _disposed = false;
protected override void Dispose (bool disposing)
{
if (!_disposed)
{
if (disposing)
{
m_view.Dispose();
}
_disposed = true;
base.Dispose (disposing);
}
}
#endregion
}
}