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another variant of AZSystem encrypted archives.

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This commit is contained in:
morkt
2016-05-27 12:16:12 +04:00
parent e69586a93b
commit 4479c1d417
2 changed files with 239 additions and 13 deletions
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247
ArcFormats/AZSys/ArcEncrypted.cs
View File

@@ -188,18 +188,21 @@ namespace GameRes.Formats.AZSys
return UnpackData (data);
}
Decrypt (data, entry.Offset, azarc.RegularKey);
if (data.Length > 0x14 && Binary.AsciiEqual (data, 0, "ASB\0"))
if (data.Length > 0x14 && Binary.AsciiEqual (data, 0, "ASB\0") && DecryptAsb (data))
{
return OpenAsb (data);
var asb = UnpackData (data, 0x10);
var header = new byte[0x10];
Buffer.BlockCopy (data, 0, header, 0, 0x10);
return new PrefixStream (header, asb);
}
return new MemoryStream (data);
}
Stream OpenAsb (byte[] data)
internal bool DecryptAsb (byte[] data)
{
int packed_size = LittleEndian.ToInt32 (data, 4);
if (packed_size <= 4 || packed_size > data.Length-0x10)
return new MemoryStream (data);
return false;
uint unpacked_size = LittleEndian.ToUInt32 (data, 8);
uint key = unpacked_size ^ 0x9E370001;
@@ -212,10 +215,7 @@ namespace GameRes.Formats.AZSys
*data32++ -= key;
}
}
var asb = UnpackData (data, 0x10);
var header = new byte[0x10];
Buffer.BlockCopy (data, 0, header, 0, 0x10);
return new PrefixStream (header, asb);
return true;
}
byte[] ReadSysenvSeed (ArcView file, Entry entry, uint key)
@@ -266,8 +266,18 @@ namespace GameRes.Formats.AZSys
if (checksum != Crc32.Compute (packed_index, 4, packed_index.Length-4))
throw new InvalidFormatException ("Index checksum mismatch");
}
uint base_offset = (uint)header.Length + index_length;
using (var input = new MemoryStream (packed_index, 4, packed_index.Length-4))
{
var dir = ParseIndex (input, count, header.Length + index_length, file.MaxOffset);
if (null == dir)
return null;
uint content_key = GetContentKey (file, dir, scheme);
return new AzArchive (file, this, dir, scheme.IndexKey, content_key);
}
}
internal List<Entry> ParseIndex (Stream input, int count, long base_offset, long max_offset)
{
using (var zstream = new ZLibStream (input, CompressionMode.Decompress))
using (var index = new BinaryReader (zstream))
{
@@ -287,12 +297,11 @@ namespace GameRes.Formats.AZSys
var entry = FormatCatalog.Instance.Create<Entry> (name);
entry.Offset = base_offset + offset;
entry.Size = size;
if (!entry.CheckPlacement (file.MaxOffset))
if (!entry.CheckPlacement (max_offset))
return null;
dir.Add (entry);
}
uint content_key = GetContentKey (file, dir, scheme);
return new AzArchive (file, this, dir, scheme.IndexKey, content_key);
return dir;
}
}
@@ -326,7 +335,7 @@ namespace GameRes.Formats.AZSys
}
else
{
var system_arc = VFS.CombinePath (Path.GetDirectoryName (file.Name), "system.arc");
var system_arc = VFS.CombinePath (VFS.GetDirectoryName (file.Name), "system.arc");
using (var arc = VFS.OpenView (system_arc))
{
var header = arc.View.ReadBytes (0, 0x30);
@@ -345,4 +354,216 @@ namespace GameRes.Formats.AZSys
return scheme.IndexKey;
}
}
[Export(typeof(ArchiveFormat))]
public class ArcIsaacEncryptedOpener : ArcEncryptedOpener
{
public override string Tag { get { return "ARC/AZ/ISAAC"; } }
public override string Description { get { return "AZ system encrypted resource archive"; } }
public override uint Signature { get { return 0; } }
public override bool IsHierarchic { get { return false; } }
public override bool CanCreate { get { return false; } }
public ArcIsaacEncryptedOpener ()
{
Extensions = new string[] { "arc" };
Signatures = new uint[] { 0 };
}
public override ArcFile TryOpen (ArcView file)
{
byte[] header_encrypted = file.View.ReadBytes (0, 0x30);
if (header_encrypted.Length < 0x30)
return null;
byte[] header = new byte[header_encrypted.Length];
Buffer.BlockCopy (header_encrypted, 0, header, 0, header.Length);
var cipher = new AzIsaacEncryption ((uint)file.MaxOffset);
cipher.Decrypt (header, 0, header.Length, 0);
if (!Binary.AsciiEqual (header, 0, "ARC\0"))
return null;
int ext_count = LittleEndian.ToInt32 (header, 4);
int count = LittleEndian.ToInt32 (header, 8);
uint index_length = LittleEndian.ToUInt32 (header, 12);
if (ext_count < 1 || ext_count > 8 || !IsSaneCount (count) || index_length >= file.MaxOffset)
return null;
var packed_index = file.View.ReadBytes (0x30, index_length);
if (packed_index.Length != index_length)
return null;
cipher.Decrypt (packed_index, 0, packed_index.Length, 0x30);
using (var input = new MemoryStream (packed_index))
{
var dir = ParseIndex (input, count, header.Length + index_length, file.MaxOffset);
if (null == dir)
return null;
return new ArcFile (file, this, dir);
}
}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
var cipher = new AzIsaacEncryption (entry.Size);
cipher.Decrypt (data, 0, data.Length, 0);
if (data.Length > 0x14 && Binary.AsciiEqual (data, 0, "ASB\0") && DecryptAsb (data))
{
var header = new byte[0x10];
Buffer.BlockCopy (data, 0, header, 0, 0x10);
Stream input = new MemoryStream (data, 0x10, data.Length-0x10);
input = new ZLibStream (input, CompressionMode.Decompress);
return new PrefixStream (header, input);
}
return new MemoryStream (data);
}
}
internal class AzIsaacEncryption
{
uint[] m_key = new uint[0x100];
public AzIsaacEncryption (uint seed)
{
var isaac = new Isaac64Cipher (seed);
for (int i = 0; i < m_key.Length; ++i)
{
m_key[i] = isaac.GetRand32();
}
}
public void Decrypt (byte[] data, int index, int length, ushort offset)
{
for (int i = 0; i < length; ++i)
{
data[index + i] ^= (byte)Binary.RotL (m_key[offset & 0xFF] ^ 0x1000193, offset >> 8);
++offset;
}
}
}
/// <summary>
/// ISAAC 64-bit pseudorandom number generator.
/// </summary>
internal class Isaac64Cipher
{
int m_count;
ulong[] m_entropy = new ulong[0x100];
ulong[] m_state = new ulong[0x100];
public Isaac64Cipher (uint seed)
{
unsafe
{
fixed (ulong* e = m_entropy)
{
uint* e32 = (uint*)e;
*e32 = seed ^ 0x9E370001u;
for (uint i = 1; i < 0x200u; ++i)
{
e32[i] = i - 0x61C88647u * (e32[i-1] ^ (e32[i-1] >> 30));
}
}
}
Init();
}
static void Mix (ref ulong a, ref ulong b, ref ulong c, ref ulong d, ref ulong e, ref ulong f, ref ulong g, ref ulong h)
{
a -= e; f ^= h >> 9; h += a;
b -= f; g ^= a << 9; a += b;
c -= g; h ^= b >> 23; b += c;
d -= h; a ^= c << 15; c += d;
e -= a; b ^= d >> 14; d += e;
f -= b; c ^= e << 20; e += f;
g -= c; d ^= f >> 17; f += g;
h -= d; e ^= g << 14; g += h;
}
ulong aa = 0, bb = 0, cc = 0;
void Init ()
{
int i;
ulong a, b, c, d, e, f, g, h;
aa = bb = cc = 0;
a = b = c = d = e = f = g = h = 0x9E3779B97F4A7C13ul;
for (i = 0; i < 4; ++i)
{
Mix (ref a, ref b, ref c, ref d, ref e, ref f, ref g, ref h);
}
for (i = 0; i < 0x100; i += 8)
{
a += m_entropy[i ]; b += m_entropy[i+1]; c += m_entropy[i+2]; d += m_entropy[i+3];
e += m_entropy[i+4]; f += m_entropy[i+5]; g += m_entropy[i+6]; h += m_entropy[i+7];
Mix (ref a, ref b, ref c, ref d, ref e, ref f, ref g, ref h);
m_state[i ] = a; m_state[i+1] = b; m_state[i+2] = c; m_state[i+3] = d;
m_state[i+4] = e; m_state[i+5] = f; m_state[i+6] = g; m_state[i+7] = h;
}
for (i = 0; i < 0x100; i += 8)
{
a += m_state[i ]; b += m_state[i+1]; c += m_state[i+2]; d += m_state[i+3];
e += m_state[i+4]; f += m_state[i+5]; g += m_state[i+6]; h += m_state[i+7];
Mix (ref a, ref b, ref c, ref d, ref e, ref f, ref g, ref h);
m_state[i ] = a; m_state[i+1] = b; m_state[i+2] = c; m_state[i+3] = d;
m_state[i+4] = e; m_state[i+5] = f; m_state[i+6] = g; m_state[i+7] = h;
}
Shuffle();
m_count = 0x100;
}
void RngStep (ulong mix, ref ulong a, ref ulong b, ref int m, ref int m2, ref int r)
{
ulong x = m_state[m];
a = mix + m_state[m2++];
ulong y = m_state[(x >> 3) & 0xFF] + a + b;
m_state[m++] = y;
m_entropy[r++] = b = m_state[(y >> 11) & 0xFF] + x;
}
void Shuffle ()
{
ulong a, b;
int m1 = 0;
int r = 0;
a = aa;
b = bb + (++cc);
int mend, m2;
mend = m2 = 0x80;
while (m1 < mend)
{
RngStep(~(a ^ (a << 21)), ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a >> 5) , ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a << 12) , ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a >> 33) , ref a, ref b, ref m1, ref m2, ref r);
}
m2 = 0;
while (m2 < mend)
{
RngStep(~(a ^ (a << 21)), ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a >> 5) , ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a << 12) , ref a, ref b, ref m1, ref m2, ref r);
RngStep( a ^ (a >> 33) , ref a, ref b, ref m1, ref m2, ref r);
}
bb = b;
aa = a;
}
public uint GetRand32 ()
{
if (0 == m_count--)
{
Shuffle();
m_count = 0xFF;
}
ulong num = m_entropy[m_count];
return (uint)num ^ (uint)(num >> 32);
}
}
}