mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 01:22:43 +00:00
3f3f45580a
Each of these strings would previously rely on StringView's char const* constructor overload, which would call __builtin_strlen on the string. Since we now have operator ""sv, we can replace these with much simpler versions. This opens the door to being able to remove StringView(char const*). No functional changes.
130 lines
3.8 KiB
C++
130 lines
3.8 KiB
C++
/*
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* Copyright (c) 2020, Ali Mohammad Pur <mpfard@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/StringBuilder.h>
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#include <AK/StringView.h>
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#include <LibCrypto/Cipher/Mode/Mode.h>
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#ifndef KERNEL
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# include <AK/String.h>
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#endif
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namespace Crypto {
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namespace Cipher {
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template<typename T>
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class CBC : public Mode<T> {
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public:
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constexpr static size_t IVSizeInBits = 128;
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virtual ~CBC() = default;
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template<typename... Args>
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explicit constexpr CBC<T>(Args... args)
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: Mode<T>(args...)
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{
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}
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#ifndef KERNEL
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virtual String class_name() const override
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{
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StringBuilder builder;
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builder.append(this->cipher().class_name());
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builder.append("_CBC"sv);
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return builder.build();
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}
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#endif
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virtual size_t IV_length() const override
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{
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return IVSizeInBits / 8;
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}
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virtual void encrypt(ReadonlyBytes in, Bytes& out, ReadonlyBytes ivec = {}, Bytes* ivec_out = nullptr) override
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{
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auto length = in.size();
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if (length == 0)
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return;
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auto& cipher = this->cipher();
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// FIXME: We should have two of these encrypt/decrypt functions that
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// we SFINAE out based on whether the Cipher mode needs an ivec
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VERIFY(!ivec.is_empty());
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ReadonlyBytes iv = ivec;
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m_cipher_block.set_padding_mode(cipher.padding_mode());
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size_t offset { 0 };
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auto block_size = cipher.block_size();
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while (length >= block_size) {
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m_cipher_block.overwrite(in.slice(offset, block_size));
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m_cipher_block.apply_initialization_vector(iv);
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cipher.encrypt_block(m_cipher_block, m_cipher_block);
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VERIFY(offset + block_size <= out.size());
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__builtin_memcpy(out.offset(offset), m_cipher_block.bytes().data(), block_size);
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iv = out.slice(offset);
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length -= block_size;
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offset += block_size;
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}
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if (length > 0) {
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m_cipher_block.overwrite(in.slice(offset, length));
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m_cipher_block.apply_initialization_vector(iv);
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cipher.encrypt_block(m_cipher_block, m_cipher_block);
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VERIFY(offset + block_size <= out.size());
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__builtin_memcpy(out.offset(offset), m_cipher_block.bytes().data(), block_size);
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iv = out.slice(offset);
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}
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if (ivec_out)
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__builtin_memcpy(ivec_out->data(), iv.data(), min(IV_length(), ivec_out->size()));
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}
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virtual void decrypt(ReadonlyBytes in, Bytes& out, ReadonlyBytes ivec = {}) override
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{
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auto length = in.size();
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if (length == 0)
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return;
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auto& cipher = this->cipher();
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VERIFY(!ivec.is_empty());
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ReadonlyBytes iv = ivec;
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auto block_size = cipher.block_size();
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// if the data is not aligned, it's not correct encrypted data
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// FIXME (ponder): Should we simply decrypt as much as we can?
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VERIFY(length % block_size == 0);
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m_cipher_block.set_padding_mode(cipher.padding_mode());
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size_t offset { 0 };
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while (length > 0) {
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auto slice = in.slice(offset);
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m_cipher_block.overwrite(slice.data(), block_size);
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cipher.decrypt_block(m_cipher_block, m_cipher_block);
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m_cipher_block.apply_initialization_vector(iv);
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auto decrypted = m_cipher_block.bytes();
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VERIFY(offset + decrypted.size() <= out.size());
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__builtin_memcpy(out.offset(offset), decrypted.data(), decrypted.size());
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iv = slice;
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length -= block_size;
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offset += block_size;
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}
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out = out.slice(0, offset);
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this->prune_padding(out);
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}
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private:
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typename T::BlockType m_cipher_block {};
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};
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}
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}
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