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fs: utilities for hac2l to print gc headers

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This commit is contained in:
Michael Scire
2022-03-14 14:26:45 -07:00
committed by SciresM
parent 2d984822c6
commit c35114bacc
15 changed files with 893 additions and 3 deletions
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41
libraries/libstratosphere/source/gc/impl/gc_gc_crypto.cpp
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@@ -132,4 +132,45 @@ namespace ams::gc::impl {
R_SUCCEED();
}
Result GcCrypto::DecryptCardInitialData(void *dst, size_t dst_size, const void *initial_data, size_t data_size, size_t kek_index) {
/* Check pre-conditions. */
R_UNLESS(data_size == sizeof(CardInitialData), fs::ResultGameCardPreconditionViolation());
R_UNLESS(kek_index < GcTitleKeyKekIndexMax, fs::ResultGameCardPreconditionViolation());
/* Verify the kek is preset. */
const void * const kek = EmbeddedDataHolder::s_titlekey_keks[kek_index];
{
u8 zeros[GcAesKeyLength] = {};
R_UNLESS(!crypto::IsSameBytes(kek, zeros, sizeof(zeros)), fs::ResultGameCardPreconditionViolation());
}
/*Generate the key. */
u8 key[GcAesKeyLength];
{
crypto::AesDecryptor128 aes;
aes.Initialize(kek, GcAesKeyLength);
aes.DecryptBlock(key, sizeof(key), initial_data, 0x10);
}
/* Get data buffer as type. */
const auto * const data = static_cast<const CardInitialData *>(initial_data);
R_UNLESS(dst_size == sizeof(data->payload.auth_data), fs::ResultGameCardPreconditionViolation());
/* Verify padding is all-zero. */
bool any_nonzero = false;
for (size_t i = 0; i < util::size(data->padding); ++i) {
any_nonzero |= data->padding[i] != 0;
}
R_UNLESS(!any_nonzero, fs::ResultGameCardInitialNotFilledWithZero());
/* Decrypt the auth data. */
u8 mac[sizeof(data->payload.auth_mac)];
crypto::DecryptAes128Ccm(dst, dst_size, mac, sizeof(mac), key, GcAesKeyLength, data->payload.auth_nonce, sizeof(data->payload.auth_nonce), data->payload.auth_data, sizeof(data->payload.auth_data), nullptr, 0, sizeof(mac));
/* Check the mac. */
R_UNLESS(crypto::IsSameBytes(mac, data->payload.auth_mac, sizeof(mac)), fs::ResultGameCardKekIndexMismatch());
R_SUCCEED();
}
}