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Merge pull request #532 from wheremyfoodat/crypto

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Fix AES-CTR decryption for non-NCCHKey0 games
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wheremyfoodat 2024-07-11 19:54:31 +00:00 • committed by GitHub
commit 83dabc2737
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GPG key ID: B5690EEEBB952194
2 changed files with 18 additions and 6 deletions
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2
include/loader/ncch.hpp
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@ -60,6 +60,8 @@ struct NCCH {
CodeSetInfo text, data, rodata;
FSInfo partitionInfo;
std::optional<Crypto::AESKey> primaryKey, secondaryKey;
// Contents of the .code file in the ExeFS
std::vector<u8> codeFile;
// Contains of the cart's save data

22
src/core/loader/ncch.cpp
View file

@ -29,6 +29,9 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
smdh.clear();
partitionInfo = info;
primaryKey = {};
secondaryKey = {};
size = u64(*(u32*)&header[0x104]) * mediaUnit; // TODO: Maybe don't type pun because big endian will break
exheaderSize = *(u32*)&header[0x180];
@ -78,11 +81,11 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
if (!primaryResult.first || !secondaryResult.first) {
gotCryptoKeys = false;
} else {
Crypto::AESKey primaryKey = primaryResult.second;
Crypto::AESKey secondaryKey = secondaryResult.second;
primaryKey = primaryResult.second;
secondaryKey = secondaryResult.second;
EncryptionInfo encryptionInfoTmp;
encryptionInfoTmp.normalKey = primaryKey;
encryptionInfoTmp.normalKey = *primaryKey;
encryptionInfoTmp.initialCounter.fill(0);
for (std::size_t i = 1; i <= sizeof(std::uint64_t) - 1; i++) {
@ -94,7 +97,7 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
encryptionInfoTmp.initialCounter[8] = 2;
exeFS.encryptionInfo = encryptionInfoTmp;
encryptionInfoTmp.normalKey = secondaryKey;
encryptionInfoTmp.normalKey = *secondaryKey;
encryptionInfoTmp.initialCounter[8] = 3;
romFS.encryptionInfo = encryptionInfoTmp;
}
@ -201,13 +204,20 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
Helpers::panic("Second code file in a single NCCH partition. What should this do?\n");
}
// All files in ExeFS use the same IV, though .code uses the secondary key for decryption
// whereas .icon/.banner use the primary key.
FSInfo info = exeFS;
if (encrypted && secondaryKey.has_value() && info.encryptionInfo.has_value()) {
info.encryptionInfo->normalKey = *secondaryKey;
}
if (compressCode) {
std::vector<u8> tmp;
tmp.resize(fileSize);
// A file offset of 0 means our file is located right after the ExeFS header
// So in the ROM, files are located at (file offset + exeFS offset + exeFS header size)
readFromFile(file, exeFS, tmp.data(), fileOffset + exeFSHeaderSize, fileSize);
readFromFile(file, info, tmp.data(), fileOffset + exeFSHeaderSize, fileSize);
// Decompress .code file from the tmp vector to the "code" vector
if (!CartLZ77::decompress(codeFile, tmp)) {
@ -216,7 +226,7 @@ bool NCCH::loadFromHeader(Crypto::AESEngine &aesEngine, IOFile& file, const FSIn
}
} else {
codeFile.resize(fileSize);
readFromFile(file, exeFS, codeFile.data(), fileOffset + exeFSHeaderSize, fileSize);
readFromFile(file, info, codeFile.data(), fileOffset + exeFSHeaderSize, fileSize);
}
} else if (std::strcmp(name, "icon") == 0) {
// Parse icon file to extract region info and more in the future (logo, etc)