public CpzArchive(ArcView arc, ArchiveFormat impl, ICollection <Entry> dir, CpzHeader header, Cpz5Decoder decoder, ArchiveKey key)
: base(arc, impl, dir)
{
Header = header;
Decoder = decoder;
Key = key;
}
public override ArcFile TryOpen(ArcView file)
{
if (null == KnownSchemes)
{
throw new OperationCanceledException("Outdated encryption schemes database");
}
var cpz = CpzHeader.Parse(file);
if (null == cpz)
{
return(null);
}
var index = file.View.ReadBytes(cpz.IndexOffset, cpz.IndexSize);
if (!cpz.VerifyIndex(index))
{
return(null);
}
int file_table_size = cpz.DirEntriesSize + cpz.FileEntriesSize;
if (cpz.IndexKeySize > 24)
{
var index_key = UnpackIndexKey(index, file_table_size, cpz.IndexKeySize);
for (int i = 0; i < file_table_size; ++i)
{
index[i] ^= index_key[(i + 3) % 0x3FF];
}
}
ArchiveKey arc_key = null;
if (cpz.Version > 6)
{
arc_key = FindArchiveKey(file.Name);
}
if (null == arc_key)
{
arc_key = new ArchiveKey();
}
var index_copy = new CowArray <byte> (index, 0, file_table_size).ToArray();
var cmvs_md5 = cpz.CmvsMd5.Clone() as uint[];
foreach (var scheme in KnownSchemes.Values.Where(s => s.Version == cpz.Version))
{
var arc = ReadIndex(file, scheme, cpz, index, arc_key);
if (null != arc)
{
return(arc);
}
// both CmvsMd5 and index was altered by ReadIndex in decryption attempt
Array.Copy(cmvs_md5, cpz.CmvsMd5, 4);
Array.Copy(index, index_copy, file_table_size);
}
throw new UnknownEncryptionScheme();
}
internal ArcFile ReadIndex(ArcView file, CmvsScheme scheme, CpzHeader cpz, byte[] index, ArchiveKey arc_key)
{
var cmvs_md5 = Cmvs.MD5.Create(scheme.Md5Variant);
cmvs_md5.Compute(cpz.CmvsMd5);
DecryptIndexStage1(index, cpz.MasterKey ^ 0x3795B39A, scheme);
var decoder = new Cpz5Decoder(scheme, cpz.MasterKey, cpz.CmvsMd5[1]);
decoder.Decode(index, 0, cpz.DirEntriesSize, 0x3A);
var key = new uint[4];
key[0] = cpz.CmvsMd5[0] ^ (cpz.MasterKey + 0x76A3BF29);
key[1] = cpz.CmvsMd5[1] ^ cpz.MasterKey;
key[2] = cpz.CmvsMd5[2] ^ (cpz.MasterKey + 0x10000000);
key[3] = cpz.CmvsMd5[3] ^ cpz.MasterKey;
DecryptIndexDirectory(index, cpz.DirEntriesSize, key, arc_key.IndexDirKey);
decoder.Init(cpz.MasterKey, cpz.CmvsMd5[2]);
uint base_offset = cpz.IndexOffset + cpz.IndexSize;
int dir_offset = 0;
var dir = new List <Entry>();
for (int i = 0; i < cpz.DirCount; ++i)
{
int dir_size = LittleEndian.ToInt32(index, dir_offset);
if (dir_size <= 0x10 || dir_size > index.Length)
{
return(null);
}
int file_count = LittleEndian.ToInt32(index, dir_offset + 4);
if (file_count >= 0x10000)
{
return(null);
}
int entries_offset = LittleEndian.ToInt32(index, dir_offset + 8);
uint dir_key = LittleEndian.ToUInt32(index, dir_offset + 0xC);
var dir_name = Binary.GetCString(index, dir_offset + 0x10, dir_size - 0x10);
int next_entries_offset;
if (i + 1 == cpz.DirCount)
{
next_entries_offset = cpz.FileEntriesSize;
}
else
{
next_entries_offset = LittleEndian.ToInt32(index, dir_offset + dir_size + 8);
}
int cur_entries_size = next_entries_offset - entries_offset;
if (cur_entries_size <= 0)
{
return(null);
}
int cur_offset = cpz.DirEntriesSize + entries_offset;
int cur_entries_end = cur_offset + cur_entries_size;
decoder.Decode(index, cur_offset, cur_entries_size, 0x7E);
for (int j = 0; j < 4; ++j)
{
key[j] = cpz.CmvsMd5[j] ^ (dir_key + scheme.DirKeyAddend[j]);
}
DecryptIndexEntry(index, cur_offset, cur_entries_size, key, scheme.IndexSeed, arc_key.IndexEntryKey);
bool is_root_dir = dir_name == "root";
dir.Capacity = dir.Count + file_count;
for (int j = 0; j < file_count; ++j)
{
int entry_size = LittleEndian.ToInt32(index, cur_offset);
if (entry_size > index.Length || entry_size <= cpz.EntryNameOffset)
{
return(null);
}
int name_offset = cur_offset + cpz.EntryNameOffset;
var name = Binary.GetCString(index, name_offset, cur_entries_end - name_offset);
if (!is_root_dir)
{
name = Path.Combine(dir_name, name);
}
var entry = FormatCatalog.Instance.Create <CpzEntry> (name);
entry.Offset = LittleEndian.ToInt64(index, cur_offset + 4) + base_offset;
entry.Size = LittleEndian.ToUInt32(index, cur_offset + 0xC);
int key_offset = cur_offset + 0x10;
if (cpz.IsLongSize)
{
key_offset += 4;
}
entry.CheckSum = LittleEndian.ToUInt32(index, key_offset);
entry.Key = LittleEndian.ToUInt32(index, key_offset + 4) + dir_key;
if (!entry.CheckPlacement(file.MaxOffset))
{
return(null);
}
dir.Add(entry);
cur_offset += entry_size;
}
dir_offset += dir_size;
}
if (cpz.IsEncrypted)
{
decoder.Init(cpz.CmvsMd5[3], cpz.MasterKey);
}
return(new CpzArchive(file, this, dir, cpz, decoder, arc_key));
}
