public static IStorage OpenStorage(this Nca nca, int index, IntegrityCheckLevel integrityCheckLevel,
bool openRaw)
{
if (openRaw)
{
return(nca.OpenRawStorage(index));
}
return(nca.OpenStorage(index, integrityCheckLevel));
}
public static IStorage OpenStorage(this Nca nca, NcaSectionType type, IntegrityCheckLevel integrityCheckLevel,
bool openRaw)
{
if (openRaw)
{
return(nca.OpenRawStorage(type));
}
return(nca.OpenStorage(type, integrityCheckLevel));
}
private static Validity ValidateCtrExDecryption(Nca nca, int index)
{
// The encryption subsection table in an AesCtrEx-encrypted partition contains the length of the entire partition.
// The encryption table is always located immediately following the partition data, so the offset value of the encryption
// table located in the NCA header should be the same as the size read from the encryption table.
Debug.Assert(nca.CanOpenSection(index));
NcaFsPatchInfo header = nca.Header.GetFsHeader(index).GetPatchInfo();
IStorage decryptedStorage = nca.OpenRawStorage(index);
Span <byte> buffer = stackalloc byte[sizeof(long)];
decryptedStorage.Read(buffer, header.EncryptionTreeOffset + 8);
long readDataSize = BinaryPrimitives.ReadInt64LittleEndian(buffer);
if (header.EncryptionTreeOffset != readDataSize)
{
return(Validity.Invalid);
}
return(Validity.Valid);
}
public static Validity ValidateSectionMasterHash(this Nca nca, int index)
{
if (!nca.SectionExists(index))
{
throw new ArgumentException(nameof(index), Messages.NcaSectionMissing);
}
if (!nca.CanOpenSection(index))
{
return(Validity.MissingKey);
}
NcaFsHeader header = nca.Header.GetFsHeader(index);
// The base data is needed to validate the hash, so use a trick involving the AES-CTR extended
// encryption table to check if the decryption is invalid.
// todo: If the patch replaces the data checked by the master hash, use that directly
if (header.IsPatchSection())
{
if (header.EncryptionType != NcaEncryptionType.AesCtrEx)
{
return(Validity.Unchecked);
}
Validity ctrExValidity = ValidateCtrExDecryption(nca, index);
return(ctrExValidity == Validity.Invalid ? Validity.Invalid : Validity.Unchecked);
}
byte[] expectedHash;
long offset;
long size;
switch (header.HashType)
{
case NcaHashType.Ivfc:
NcaFsIntegrityInfoIvfc ivfcInfo = header.GetIntegrityInfoIvfc();
expectedHash = ivfcInfo.MasterHash.ToArray();
offset = ivfcInfo.GetLevelOffset(0);
size = 1 << ivfcInfo.GetLevelBlockSize(0);
break;
case NcaHashType.Sha256:
NcaFsIntegrityInfoSha256 sha256Info = header.GetIntegrityInfoSha256();
expectedHash = sha256Info.MasterHash.ToArray();
offset = sha256Info.GetLevelOffset(0);
size = sha256Info.GetLevelSize(0);
break;
default:
return(Validity.Unchecked);
}
IStorage storage = nca.OpenRawStorage(index);
var data = new byte[size];
storage.Read(data, offset);
byte[] actualHash = Crypto.ComputeSha256(data, 0, data.Length);
if (Util.ArraysEqual(expectedHash, actualHash))
{
return(Validity.Valid);
}
return(Validity.Invalid);
}