public NCCHRegion(NCCHSection type, long offset, long size, long tid = 0)
{
this.Type = type;
this.Offset = offset;
this.Size = size;
if ((int)type < 4 && tid != 0)
{
BigInteger ctrAsBigInt = ((BigInteger)tid << 64 | (BigInteger)(int)type << 56);
this.CTRInt = ctrAsBigInt;
this.CTR = ctrAsBigInt.ToCTRBytes();
}
}
private byte[] getNcchAesCounter(NCCHHeader header, NCCHSection type) //Function based on code from ctrtool's source: https://github.com/Relys/Project_CTR
{
byte[] counter = new byte[16];
if (header.formatVersion == 2 || header.formatVersion == 0)
{
for (int i = 0; i < 8; ++i)
{
counter[i] = header.titleId[header.titleId.Length - 1 - i];
}
counter[8] = (byte)type;
}
else if (header.formatVersion == 1)
{
UInt32 x = 0;
switch (type)
{
case NCCHSection.ExHeader:
x = 0x200; //ExHeader is always 0x200 bytes into the NCCH
break;
case NCCHSection.ExeFS:
x = header.exefsOffset * MEDIAUNITSIZE;
break;
case NCCHSection.RomFS:
x = header.romfsOffset * MEDIAUNITSIZE;
break;
}
for (int i = 0; i < 8; ++i)
{
counter[i] = header.titleId[i];
}
counter[12] = (byte)((x >> 24) & 0xFF);
counter[13] = (byte)((x >> 16) & 0xFF);
counter[14] = (byte)((x >> 8) & 0xFF);
counter[15] = (byte)(x & 0xFF);
}
return(counter);
}
//Function based on code from ctrtool's source: https://github.com/Relys/Project_CTR
private byte[] getNcchAesCounter(NCCHHeader header, NCCHSection type)
{
byte[] counter = new byte[16];
if(header.formatVersion == 2 || header.formatVersion == 0)
{
for(int i = 0; i < 8; ++i)
{
counter[i] = header.titleId[header.titleId.Length - 1 - i];
}
counter[8] = (byte) type;
}
else if(header.formatVersion == 1)
{
UInt32 x = 0;
switch(type)
{
case NCCHSection.ExHeader:
x = 0x200; //ExHeader is always 0x200 bytes into the NCCH
break;
case NCCHSection.ExeFS:
x = header.exefsOffset * MEDIAUNITSIZE;
break;
case NCCHSection.RomFS:
x = header.romfsOffset * MEDIAUNITSIZE;
break;
}
for(int i = 0; i < 8; ++i)
{
counter[i] = header.titleId[i];
}
counter[12] = (byte) ((x >> 24) & 0xFF);
counter[13] = (byte) ((x >> 16) & 0xFF);
counter[14] = (byte) ((x >> 8) & 0xFF);
counter[15] = (byte) (x & 0xFF);
}
return counter;
}
private NCCHInfoEntry parseNCCHSection(NCCHHeader header, NCCHSection type, byte[] keyY, bool uses7xCrypto, bool usesSeedCrypto, bool print, string indent)
{
NCCHInfoEntry entry = new NCCHInfoEntry();
entry.keyY = keyY;
entry.reserved = 0x00000000;
entry.uses7xcrypto = (UInt32) (uses7xCrypto ? 0x00000001 : 0x00000000);
entry.uses9xcrypto = (UInt32) (usesSeedCrypto ? 0x00000001 : 0x00000000);
entry.outputname = new byte[112];
string sectionname;
uint offset;
uint sectionsize;
switch(type)
{
case NCCHSection.ExHeader:
sectionname = "ExHeader";
offset = 0x200; //Always 0x200
sectionsize = header.exhdrSize * MEDIAUNITSIZE;
break;
case NCCHSection.ExeFS:
sectionname = "ExeFS";
offset = header.exefsOffset * MEDIAUNITSIZE;
sectionsize = header.exefsSize * MEDIAUNITSIZE;
break;
case NCCHSection.RomFS:
sectionname = "RomFS";
offset = header.romfsOffset * MEDIAUNITSIZE;
sectionsize = header.romfsSize * MEDIAUNITSIZE;
break;
default:
Console.Error.WriteLine("Illegal NCCH Section type provided!");
Environment.Exit(1);
return entry; //Needed to compile
}
entry.counter = getNcchAesCounter(header, type);
entry.titleID = new byte[8];
Array.Copy(header.programId, 0, entry.titleID, 0, 8);
//Compute section size in MB, rounding up to the next MB
uint sectionMb = sectionsize / BYTES_PER_MEGABYTE; //Rounding down in this step
uint remainder = sectionsize % BYTES_PER_MEGABYTE;
if(remainder != 0)
{
++sectionMb;
}
entry.size = sectionMb;
if(print)
{
Console.WriteLine(String.Format(indent + "{0} offset: {1:X8}", sectionname, offset));
Console.WriteLine(String.Format(indent + "{0} counter: {1}", sectionname, ToHexString(entry.counter)));
Console.WriteLine(String.Format(indent + "{0} Megabytes(rounded up): {1}", sectionname, sectionMb));
}
//TODO
//return struct.pack('<16s16sIIIIQ', str(counter), str(keyY), sectionMb, 0, usesSeedCrypto, uses7xCrypto, titleId)
return entry;
}
public void ExtractSection(NCCHSection section, Stream outputStream, bool decrypt = true, bool close = true)
{
if (this.Info.Flags.UsesEncryption && this.Cryptor == null && decrypt == true)
{
throw new ArgumentException("This NCCH is encrypted, and no Crypto Engine was provided to perform decryption.");
}
if (!this.Regions.Any(region => region.Type == section))
{
throw new ArgumentException($"The requested section ({Enum.GetName(typeof(NCCHSection), section)}) was not found inside this NCCH.");
}
NCCHRegion region = this.Regions.Find(region => region.Type == section);
if (this.Info.Flags.UsesEncryption && decrypt && !NoCryptoSections.Contains(region.Type)) //if encrypted, user wants to decrypt, and the selected region is known to use encryption
{
Keyslot primaryKeyslot;
Keyslot secondaryKeyslot;
byte[] secondaryKeyY = new byte[16];
if (this.Info.Flags.UsesFixedKey)
{
primaryKeyslot = ((this.Info.TitleID & (0x10 << 32)) > 0) ? Keyslot.FixedSystemKey : Keyslot.ZeroKey;
secondaryKeyslot = primaryKeyslot;
}
else
{
primaryKeyslot = Keyslot.NCCH;
secondaryKeyslot = secondaryKeyslot = this.Info.Flags.CryptoMethod switch
{
0x00 => Keyslot.NCCH,
0x01 => Keyslot.NCCH70,
0x0A => Keyslot.NCCH93,
0x0B => Keyslot.NCCH96,
_ => throw new Exception("Could not determine crypto type. This should NOT happen.")
};
if (this.Info.Flags.UsesSeed)
{
this.Info.LoadSeed(this.SeedDB);
secondaryKeyY = this.Info.SeededKeyY;
}
else
{
secondaryKeyY = this.Info.KeyY;
}
}
this.Cryptor.SetKeyslot("y", (int)primaryKeyslot, this.Info.KeyY.ToUnsignedBigInt()); //load primary key into keyslot
this.Cryptor.SetKeyslot("y", (int)secondaryKeyslot, secondaryKeyY.ToUnsignedBigInt()); //load secondary key into keyslot
//decrypts based on section
switch (region.Type)
{
case NCCHSection.ExHeader:
Tools.CryptFileStreamPart(this.NCCHMemoryMappedFile, outputStream, new AesCtrCryptoTransform(this.Cryptor.NormalKey[(int)primaryKeyslot], region.CTR), region.Offset, region.Size, close);
break;
case NCCHSection.RomFS:
//uses secondary keyslot for it's entirety
Tools.CryptFileStreamPart(this.NCCHMemoryMappedFile, outputStream, new AesCtrCryptoTransform(this.Cryptor.NormalKey[(int)secondaryKeyslot], region.CTR), region.Offset, region.Size, close);
break;
case NCCHSection.ExeFS:
//can use two keyslots. because of this, I separated the ExeFS decryption into another method
ExtractExeFS(outputStream, region, secondaryKeyslot, close);
break;
}
}
else //just extract the raw section, because no crypto is used or the user did not request decryption
{
Tools.ExtractFileStreamPart(this.NCCHMemoryMappedFile, outputStream, region.Offset, region.Size, close);
}
}
private NCCHInfoEntry parseNCCHSection(NCCHHeader header, NCCHSection type, byte[] keyY, bool uses7xCrypto, bool usesSeedCrypto, bool print, string indent)
{
NCCHInfoEntry entry = new NCCHInfoEntry();
entry.keyY = keyY;
entry.reserved = 0x00000000;
entry.uses7xcrypto = (UInt32)(uses7xCrypto ? 0x00000001 : 0x00000000);
entry.uses9xcrypto = (UInt32)(usesSeedCrypto ? 0x00000001 : 0x00000000);
entry.outputname = new byte[112];
string sectionname;
uint offset;
uint sectionsize;
switch (type)
{
case NCCHSection.ExHeader:
sectionname = "ExHeader";
offset = 0x200; //Always 0x200
sectionsize = header.exhdrSize * MEDIAUNITSIZE;
break;
case NCCHSection.ExeFS:
sectionname = "ExeFS";
offset = header.exefsOffset * MEDIAUNITSIZE;
sectionsize = header.exefsSize * MEDIAUNITSIZE;
break;
case NCCHSection.RomFS:
sectionname = "RomFS";
offset = header.romfsOffset * MEDIAUNITSIZE;
sectionsize = header.romfsSize * MEDIAUNITSIZE;
break;
default:
Console.Error.WriteLine("Illegal NCCH Section type provided!");
Environment.Exit(1);
return(entry); //Needed to compile
}
entry.counter = getNcchAesCounter(header, type);
entry.titleID = new byte[8];
Array.Copy(header.programId, 0, entry.titleID, 0, 8);
//Compute section size in MB, rounding up to the next MB
uint sectionMb = sectionsize / BYTES_PER_MEGABYTE; //Rounding down in this step
uint remainder = sectionsize % BYTES_PER_MEGABYTE;
if (remainder != 0)
{
++sectionMb;
}
entry.size = sectionMb;
if (print)
{
Console.WriteLine(String.Format(indent + "{0} offset: {1:X8}", sectionname, offset));
Console.WriteLine(String.Format(indent + "{0} counter: {1}", sectionname, ToHexString(entry.counter)));
Console.WriteLine(String.Format(indent + "{0} Megabytes(rounded up): {1}", sectionname, sectionMb));
}
//TODO
//return struct.pack('<16s16sIIIIQ', str(counter), str(keyY), sectionMb, 0, usesSeedCrypto, uses7xCrypto, titleId)
return(entry);
}
