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Some fixes

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- Rename offset variables
- Alloc buffer outside the loop
- Read CRC32 checksum outside the loop
- Get rid of a local variable
This commit is contained in:
de4dot 2012-12-13 14:03:31 +01:00
parent 7e9e691ef3
commit bf7c0d58d2
1 changed files with 14 additions and 14 deletions
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28
de4dot.code/deobfuscators/ILProtector/MethodsDecrypter.cs
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@ -169,11 +169,11 @@ namespace de4dot.code.deobfuscators.ILProtector {
public static DecrypterV106 create(IBinaryReader reader) {
try {
int keyXorOffs2 = (ReadByteAt(reader, 0) ^ ReadByteAt(reader, 2)) + 2;
reader.Position = keyXorOffs2 + (ReadByteAt(reader, 1) ^ ReadByteAt(reader, keyXorOffs2));
int keyXorOffs7 = (ReadByteAt(reader, 0) ^ ReadByteAt(reader, 2)) + 2;
reader.Position = keyXorOffs7 + (ReadByteAt(reader, 1) ^ ReadByteAt(reader, keyXorOffs7));
int sha1DataLen = reader.Read7BitEncodedInt32() + 0x80;
int keyXorOffs1 = (int)reader.Position;
int keyXorOffs6 = (int)reader.Position;
int encryptedOffs = (int)reader.Position + sha1DataLen;
var sha1Data = reader.ReadBytes(sha1DataLen);
uint crc32 = CRC32.checksum(sha1Data);
@ -184,8 +184,8 @@ namespace de4dot.code.deobfuscators.ILProtector {
return null;
var key0 = DeobUtils.sha1Sum(sha1Data); // 1.0.6.0
var key6 = getKey(reader, key0, keyXorOffs1); // 1.0.6.6
var key7 = getKey(reader, key0, keyXorOffs2); // 1.0.6.7
var key6 = getKey(reader, key0, keyXorOffs6); // 1.0.6.6
var key7 = getKey(reader, key0, keyXorOffs7); // 1.0.6.7
return new DecrypterV106(key0, key6, key7, encryptedOffs);
}
catch (IOException) {
@ -196,27 +196,27 @@ namespace de4dot.code.deobfuscators.ILProtector {
static byte[] getKey(IBinaryReader reader, byte[] sha1Sum, int offs) {
var key = (byte[])sha1Sum.Clone();
reader.Position = offs;
for (int i = 0; i < key.Length; i++) {
byte b = reader.ReadByte();
key[i] ^= b;
}
for (int i = 0; i < key.Length; i++)
key[i] ^= reader.ReadByte();
return key;
}
static byte ReadByteAt(IBinaryReader reader, int offs) {
reader.Position = offs;
byte b = reader.ReadByte();
return b;
return reader.ReadByte();
}
public override byte[] getMethodsData(EmbeddedResource resource) {
var reader = resource.Data;
reader.Position = startOffset;
var decrypted = new byte[reader.Read7BitEncodedUInt32()];
uint origCrc32 = reader.ReadUInt32();
long pos = reader.Position;
var keys = new byte[][] { decryptionKey, decryptionKey6, decryptionKey7 };
foreach (var key in keys) {
try {
reader.Position = startOffset;
var decrypted = new byte[reader.Read7BitEncodedUInt32()];
uint origCrc32 = reader.ReadUInt32();
reader.Position = pos;
decompress(decrypted, reader, key, decryptionKeyMod);
uint crc32 = CRC32.checksum(decrypted);
if (crc32 == origCrc32)