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authorZach Hilman <zachhilman@gmail.com>2018-08-16 23:01:32 +0200
committerZach Hilman <zachhilman@gmail.com>2018-08-23 17:52:44 +0200
commitc4845df3d4b9fc3fc19dd936af87090ffb3fbdf2 (patch)
tree7bca82326831ee20fc73a4fb2d609825cce8fad3 /src/core/crypto/xts_encryption_layer.cpp
parentaes_util: Make XTSTranscode stricter about sizes (diff)
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Diffstat (limited to 'src/core/crypto/xts_encryption_layer.cpp')
-rw-r--r--src/core/crypto/xts_encryption_layer.cpp54
1 files changed, 54 insertions, 0 deletions
diff --git a/src/core/crypto/xts_encryption_layer.cpp b/src/core/crypto/xts_encryption_layer.cpp
new file mode 100644
index 000000000..431099580
--- /dev/null
+++ b/src/core/crypto/xts_encryption_layer.cpp
@@ -0,0 +1,54 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cstring>
+#include "common/assert.h"
+#include "core/crypto/xts_encryption_layer.h"
+
+namespace Core::Crypto {
+
+XTSEncryptionLayer::XTSEncryptionLayer(FileSys::VirtualFile base_, Key256 key_)
+ : EncryptionLayer(std::move(base_)), cipher(key_, Mode::XTS) {}
+
+size_t XTSEncryptionLayer::Read(u8* data, size_t length, size_t offset) const {
+ if (length == 0)
+ return 0;
+
+ const auto sector_offset = offset & 0x3FFF;
+ if (sector_offset == 0) {
+ if (length % 0x4000 == 0) {
+ std::vector<u8> raw = base->ReadBytes(length, offset);
+ cipher.XTSTranscode(raw.data(), raw.size(), data, offset / 0x4000, 0x4000, Op::Decrypt);
+ return raw.size();
+ }
+ if (length > 0x4000) {
+ const auto rem = length % 0x4000;
+ 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::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 (length + sector_offset < 0x4000) {
+ std::memcpy(data, block.data() + sector_offset, std::min<u64>(length, read));
+ return std::min<u64>(length, read);
+ }
+ std::memcpy(data, block.data() + sector_offset, read);
+ return read + Read(data + read, length - read, offset + read);
+}
+} // namespace Core::Crypto