crypto: Eliminate magic constants

4 files changed, 38 insertions, 32 deletions

diff --git a/src/core/crypto/key_manager.cpp b/src/core/crypto/key_manager.cpp
index 994ac4eec..acf635a65 100644
--- a/src/core/crypto/key_manager.cpp
+++ b/src/core/crypto/key_manager.cpp
@@ -102,7 +102,7 @@ Loader::ResultStatus DeriveSDKeys(std::array<Key256, 2>& sd_keys, const KeyManag
 
     AESCipher<Key128> cipher(sd_kek, Mode::ECB);
     for (size_t i = 0; i < 2; ++i) {
-        for (size_t j = 0; j < 0x20; ++j)
+        for (size_t j = 0; j < sd_key_sources[i].size(); ++j)
             sd_key_sources[i][j] ^= sd_seed[j & 0xF];
         cipher.Transcode(sd_key_sources[i].data(), sd_key_sources[i].size(), sd_keys[i].data(),
                          Op::Decrypt);
diff --git a/src/core/crypto/xts_encryption_layer.cpp b/src/core/crypto/xts_encryption_layer.cpp
index 431099580..c6e5df1ce 100644
--- a/src/core/crypto/xts_encryption_layer.cpp
+++ b/src/core/crypto/xts_encryption_layer.cpp
@@ -8,6 +8,8 @@
 
 namespace Core::Crypto {
 
+constexpr u64 XTS_SECTOR_SIZE = 0x4000;
+
 XTSEncryptionLayer::XTSEncryptionLayer(FileSys::VirtualFile base_, Key256 key_)
     : EncryptionLayer(std::move(base_)), cipher(key_, Mode::XTS) {}
 
@@ -17,34 +19,35 @@ size_t XTSEncryptionLayer::Read(u8* data, size_t length, size_t offset) const {
 
     const auto sector_offset = offset & 0x3FFF;
     if (sector_offset == 0) {
-        if (length % 0x4000 == 0) {
+        if (length % XTS_SECTOR_SIZE == 0) {
             std::vector<u8> raw = base->ReadBytes(length, offset);
-            cipher.XTSTranscode(raw.data(), raw.size(), data, offset / 0x4000, 0x4000, Op::Decrypt);
+            cipher.XTSTranscode(raw.data(), raw.size(), data, offset / XTS_SECTOR_SIZE,
+                                XTS_SECTOR_SIZE, Op::Decrypt);
             return raw.size();
         }
-        if (length > 0x4000) {
-            const auto rem = length % 0x4000;
+        if (length > XTS_SECTOR_SIZE) {
+            const auto rem = length % XTS_SECTOR_SIZE;
             const auto read = length - rem;
             return Read(data, read, offset) + Read(data + read, rem, offset + read);
         }
-        std::vector<u8> buffer = base->ReadBytes(0x4000, offset);
-        if (buffer.size() < 0x4000)
-            buffer.resize(0x4000);
-        cipher.XTSTranscode(buffer.data(), buffer.size(), buffer.data(), offset / 0x4000, 0x4000,
-                            Op::Decrypt);
+        std::vector<u8> buffer = base->ReadBytes(XTS_SECTOR_SIZE, offset);
+        if (buffer.size() < XTS_SECTOR_SIZE)
+            buffer.resize(XTS_SECTOR_SIZE);
+        cipher.XTSTranscode(buffer.data(), buffer.size(), buffer.data(), offset / XTS_SECTOR_SIZE,
+                            XTS_SECTOR_SIZE, Op::Decrypt);
         std::memcpy(data, buffer.data(), std::min(buffer.size(), length));
         return std::min(buffer.size(), length);
     }
 
     // offset does not fall on block boundary (0x4000)
     std::vector<u8> block = base->ReadBytes(0x4000, offset - sector_offset);
-    if (block.size() < 0x4000)
-        block.resize(0x4000);
-    cipher.XTSTranscode(block.data(), block.size(), block.data(), (offset - sector_offset) / 0x4000,
-                        0x4000, Op::Decrypt);
-    const size_t read = 0x4000 - sector_offset;
+    if (block.size() < XTS_SECTOR_SIZE)
+        block.resize(XTS_SECTOR_SIZE);
+    cipher.XTSTranscode(block.data(), block.size(), block.data(),
+                        (offset - sector_offset) / XTS_SECTOR_SIZE, XTS_SECTOR_SIZE, Op::Decrypt);
+    const size_t read = XTS_SECTOR_SIZE - sector_offset;
 
-    if (length + sector_offset < 0x4000) {
+    if (length + sector_offset < XTS_SECTOR_SIZE) {
         std::memcpy(data, block.data() + sector_offset, std::min<u64>(length, read));
         return std::min<u64>(length, read);
     }
diff --git a/src/core/file_sys/xts_archive.cpp b/src/core/file_sys/xts_archive.cpp
index 54be31916..605c1a283 100644
--- a/src/core/file_sys/xts_archive.cpp
+++ b/src/core/file_sys/xts_archive.cpp
@@ -19,6 +19,8 @@
 
 namespace FileSys {
 
+constexpr u64 NAX_HEADER_PADDING_SIZE = 0x4000;
+
 template <typename SourceData, typename SourceKey, typename Destination>
 static bool CalculateHMAC256(Destination* out, const SourceKey* key, size_t key_length,
                              const SourceData* data, size_t data_length) {
@@ -67,14 +69,14 @@ NAX::NAX(VirtualFile file_, std::array<u8, 0x10> nca_id)
                                Common::HexArrayToString(nca_id, false)));
 }
 
-Loader::ResultStatus NAX::Parse(std::string path) {
+Loader::ResultStatus NAX::Parse(std::string_view path) {
     if (file->ReadObject(header.get()) != sizeof(NAXHeader))
         return Loader::ResultStatus::ErrorBadNAXHeader;
 
     if (header->magic != Common::MakeMagic('N', 'A', 'X', '0'))
         return Loader::ResultStatus::ErrorBadNAXHeader;
 
-    if (file->GetSize() < 0x4000 + header->file_size)
+    if (file->GetSize() < NAX_HEADER_PADDING_SIZE + header->file_size)
         return Loader::ResultStatus::ErrorIncorrectNAXFileSize;
 
     keys.DeriveSDSeedLazy();
@@ -87,14 +89,14 @@ Loader::ResultStatus NAX::Parse(std::string path) {
     const auto enc_keys = header->key_area;
 
     size_t i = 0;
-    for (; i < 2; ++i) {
+    for (; i < sd_keys.size(); ++i) {
         std::array<Core::Crypto::Key128, 2> nax_keys{};
-        if (!CalculateHMAC256(nax_keys.data(), sd_keys[i].data(), 0x10, path.c_str(),
+        if (!CalculateHMAC256(nax_keys.data(), sd_keys[i].data(), 0x10, std::string(path).c_str(),
                               path.size())) {
             return Loader::ResultStatus::ErrorNAXKeyHMACFailed;
         }
 
-        for (size_t j = 0; j < 2; ++j) {
+        for (size_t j = 0; j < nax_keys.size(); ++j) {
             Core::Crypto::AESCipher<Core::Crypto::Key128> cipher(nax_keys[j],
                                                                  Core::Crypto::Mode::ECB);
             cipher.Transcode(enc_keys[j].data(), 0x10, header->key_area[j].data(),
@@ -117,28 +119,29 @@ Loader::ResultStatus NAX::Parse(std::string path) {
     type = static_cast<NAXContentType>(i);
 
     Core::Crypto::Key256 final_key{};
-    memcpy(final_key.data(), &header->key_area, 0x20);
-    const auto enc_file = std::make_shared<OffsetVfsFile>(file, header->file_size, 0x4000);
+    std::memcpy(final_key.data(), &header->key_area, final_key.size());
+    const auto enc_file =
+        std::make_shared<OffsetVfsFile>(file, header->file_size, NAX_HEADER_PADDING_SIZE);
     dec_file = std::make_shared<Core::Crypto::XTSEncryptionLayer>(enc_file, final_key);
 
     return Loader::ResultStatus::Success;
 }
 
-Loader::ResultStatus NAX::GetStatus() {
+Loader::ResultStatus NAX::GetStatus() const {
     return status;
 }
 
-VirtualFile NAX::GetDecrypted() {
+VirtualFile NAX::GetDecrypted() const {
     return dec_file;
 }
 
-std::shared_ptr<NCA> NAX::AsNCA() {
+std::shared_ptr<NCA> NAX::AsNCA() const {
     if (type == NAXContentType::NCA)
         return std::make_shared<NCA>(GetDecrypted());
     return nullptr;
 }
 
-NAXContentType NAX::GetContentType() {
+NAXContentType NAX::GetContentType() const {
     return type;
 }
 
diff --git a/src/core/file_sys/xts_archive.h b/src/core/file_sys/xts_archive.h
index 4e44f634a..5249ad026 100644
--- a/src/core/file_sys/xts_archive.h
+++ b/src/core/file_sys/xts_archive.h
@@ -33,13 +33,13 @@ public:
     explicit NAX(VirtualFile file);
     explicit NAX(VirtualFile file, std::array<u8, 0x10> nca_id);
 
-    Loader::ResultStatus GetStatus();
+    Loader::ResultStatus GetStatus() const;
 
-    VirtualFile GetDecrypted();
+    VirtualFile GetDecrypted() const;
 
-    std::shared_ptr<NCA> AsNCA();
+    std::shared_ptr<NCA> AsNCA() const;
 
-    NAXContentType GetContentType();
+    NAXContentType GetContentType() const;
 
     std::vector<std::shared_ptr<VfsFile>> GetFiles() const override;
 
@@ -53,7 +53,7 @@ protected:
     bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) override;
 
 private:
-    Loader::ResultStatus Parse(std::string path);
+    Loader::ResultStatus Parse(std::string_view path);
 
     std::unique_ptr<NAXHeader> header;