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Merge pull request #920 from DarkLordZach/titlekey

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content_archive: Add support for titlekey cryptography
This commit is contained in:
bunnei 2018-08-07 17:01:25 -04:00 committed by GitHub
commit b9829a05be
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 39 additions and 7 deletions
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44
src/core/file_sys/content_archive.cpp
View file

@ -76,12 +76,17 @@ bool IsValidNCA(const NCAHeader& header) {
return header.magic == Common::MakeMagic('N', 'C', 'A', '3');
}
boost::optional<Core::Crypto::Key128> NCA::GetKeyAreaKey(NCASectionCryptoType type) const {
u8 NCA::GetCryptoRevision() const {
u8 master_key_id = header.crypto_type;
if (header.crypto_type_2 > master_key_id)
master_key_id = header.crypto_type_2;
if (master_key_id > 0)
--master_key_id;
return master_key_id;
}
boost::optional<Core::Crypto::Key128> NCA::GetKeyAreaKey(NCASectionCryptoType type) const {
const auto master_key_id = GetCryptoRevision();
if (!keys.HasKey(Core::Crypto::S128KeyType::KeyArea, master_key_id, header.key_index))
return boost::none;
@ -108,33 +113,58 @@ boost::optional<Core::Crypto::Key128> NCA::GetKeyAreaKey(NCASectionCryptoType ty
return out;
}
VirtualFile NCA::Decrypt(NCASectionHeader header, VirtualFile in, u64 starting_offset) const {
boost::optional<Core::Crypto::Key128> NCA::GetTitlekey() const {
const auto master_key_id = GetCryptoRevision();
u128 rights_id{};
memcpy(rights_id.data(), header.rights_id.data(), 16);
if (rights_id == u128{})
return boost::none;
auto titlekey = keys.GetKey(Core::Crypto::S128KeyType::Titlekey, rights_id[1], rights_id[0]);
if (titlekey == Core::Crypto::Key128{})
return boost::none;
Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(
keys.GetKey(Core::Crypto::S128KeyType::Titlekek, master_key_id), Core::Crypto::Mode::ECB);
cipher.Transcode(titlekey.data(), titlekey.size(), titlekey.data(), Core::Crypto::Op::Decrypt);
return titlekey;
}
VirtualFile NCA::Decrypt(NCASectionHeader s_header, VirtualFile in, u64 starting_offset) const {
if (!encrypted)
return in;
switch (header.raw.header.crypto_type) {
switch (s_header.raw.header.crypto_type) {
case NCASectionCryptoType::NONE:
LOG_DEBUG(Crypto, "called with mode=NONE");
return in;
case NCASectionCryptoType::CTR:
LOG_DEBUG(Crypto, "called with mode=CTR, starting_offset={:016X}", starting_offset);
{
const auto key = GetKeyAreaKey(NCASectionCryptoType::CTR);
boost::optional<Core::Crypto::Key128> key = boost::none;
if (std::find_if_not(header.rights_id.begin(), header.rights_id.end(),
[](char c) { return c == 0; }) == header.rights_id.end()) {
key = GetKeyAreaKey(NCASectionCryptoType::CTR);
} else {
key = GetTitlekey();
}
if (key == boost::none)
return nullptr;
auto out = std::make_shared<Core::Crypto::CTREncryptionLayer>(
std::move(in), key.value(), starting_offset);
std::vector<u8> iv(16);
for (u8 i = 0; i < 8; ++i)
iv[i] = header.raw.section_ctr[0x8 - i - 1];
iv[i] = s_header.raw.section_ctr[0x8 - i - 1];
out->SetIV(iv);
return std::static_pointer_cast<VfsFile>(out);
}
case NCASectionCryptoType::XTS:
// TODO(DarkLordZach): Implement XTSEncryptionLayer and title key encryption.
// TODO(DarkLordZach): Implement XTSEncryptionLayer.
default:
LOG_ERROR(Crypto, "called with unhandled crypto type={:02X}",
static_cast<u8>(header.raw.header.crypto_type));
static_cast<u8>(s_header.raw.header.crypto_type));
return nullptr;
}
}

2
src/core/file_sys/content_archive.h
View file

@ -95,7 +95,9 @@ protected:
bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) override;
private:
u8 GetCryptoRevision() const;
boost::optional<Core::Crypto::Key128> GetKeyAreaKey(NCASectionCryptoType type) const;
boost::optional<Core::Crypto::Key128> GetTitlekey() const;
VirtualFile Decrypt(NCASectionHeader header, VirtualFile in, u64 starting_offset) const;
std::vector<VirtualDir> dirs;