SabreTools/NDecrypt
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Handle empty secure area, better

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This commit is contained in:
Matt Nadareski
2019-04-11 14:59:05 -07:00
parent 6fa8867f93
commit 5807d4ddc2
1 changed files with 28 additions and 8 deletions
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36
NDecrypt/Headers/NDSHeader.cs
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@@ -597,8 +597,13 @@ namespace NDecrypt.Headers
/// <param name="encrypt">True if we want to encrypt the partitions, false otherwise</param>
public void ProcessSecureArea(BinaryReader reader, BinaryWriter writer, bool encrypt)
{
bool isDecrypted = CheckIfDecrypted(reader);
if (encrypt ^ isDecrypted)
bool? isDecrypted = CheckIfDecrypted(reader);
if (isDecrypted == null)
{
Console.WriteLine("File has an empty secure area, cannot proceed");
return;
}
else if (encrypt ^ isDecrypted.Value)
{
Console.WriteLine("File is already " + (encrypt ? "encrypted" : "decrypted"));
return;
@@ -610,19 +615,34 @@ namespace NDecrypt.Headers
}
/// <summary>
/// Determine if the current file is already decrypted or not
/// Determine if the current file is already decrypted or not (or has an empty secure area)
/// </summary>
/// <param name="reader">BinaryReader representing the input stream</param>
/// <returns>True if the file has known values for a decrypted file, false otherwise</returns>
private bool CheckIfDecrypted(BinaryReader reader)
/// <returns>True if the file has known values for a decrypted file, null if it's empty, false otherwise</returns>
private bool? CheckIfDecrypted(BinaryReader reader)
{
reader.BaseStream.Seek(0x4000, SeekOrigin.Begin);
uint firstValue = reader.ReadUInt32();
uint secondValue = reader.ReadUInt32();
return ((firstValue == 0xE7FFDEFF) && (secondValue == 0xE7FFDEFF))
|| ((firstValue == 0xD0D48B67) && (secondValue == 0x39392F23)) // Incorrectly mastered value
|| ((firstValue == 0x00000000) && (secondValue == 0x00000000)); // Empty secure area
// Empty secure area standard
if (firstValue == 0 && secondValue == 0)
return null;
// Improperly decrypted empty secure area
else if (firstValue == 0xE386C397 && secondValue == 0x82775B7E)
return true;
// Improperly encrypted empty secure area
else if (firstValue == 0x4BCE88BE && secondValue == 0xD3662DD1)
return false;
// Properly decrypte nonstandard value
else if (firstValue == 0xD0D48B67 && secondValue == 0x39392F23)
return true;
// Standard decryption values
return (firstValue == 0xE7FFDEFF && secondValue == 0xE7FFDEFF);
}
/// <summary>