35 lines
1.5 KiB
C++
35 lines
1.5 KiB
C++
#include "RandomPadding.h"
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#include "../logging/logging.h"
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#include "../random/Random.h"
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using boost::optional;
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using namespace cpputils::logging;
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namespace cpputils {
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Data RandomPadding::add(const Data &data, size_t targetSize) {
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uint32_t size = data.size();
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if (size >= targetSize - sizeof(size)) {
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throw std::runtime_error("Data too large. We should increase padding target size.");
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}
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Data randomData = Random::PseudoRandom().get(targetSize-sizeof(size)-size);
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ASSERT(sizeof(size) + size + randomData.size() == targetSize, "Calculated size of randomData incorrectly");
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Data result(targetSize);
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std::memcpy(reinterpret_cast<char*>(result.data()), &size, sizeof(size));
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std::memcpy(reinterpret_cast<char*>(result.dataOffset(sizeof(size))), reinterpret_cast<const char*>(data.data()), size);
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std::memcpy(reinterpret_cast<char*>(result.dataOffset(sizeof(size)+size)), reinterpret_cast<const char*>(randomData.data()), randomData.size());
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return result;
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}
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optional<Data> RandomPadding::remove(const Data &data) {
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uint32_t size;
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std::memcpy(&size, reinterpret_cast<const char*>(data.data()), sizeof(size));
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if(sizeof(size) + size >= data.size()) {
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LOG(ERROR, "Config file is invalid: Invalid padding.");
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return boost::none;
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};
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Data result(size);
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std::memcpy(reinterpret_cast<char*>(result.data()), reinterpret_cast<const char*>(data.dataOffset(sizeof(size))), size);
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return std::move(result);
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}
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}
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