Libraries: Move to Userland/Libraries/

Userland/Libraries/LibCrypto/Cipher/Mode/CBC.h

@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2020, Ali Mohammad Pur <ali.mpfard@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/String.h>
+#include <AK/StringBuilder.h>
+#include <AK/StringView.h>
+#include <LibCrypto/Cipher/Mode/Mode.h>
+
+namespace Crypto {
+namespace Cipher {
+
+template<typename T>
+class CBC : public Mode<T> {
+public:
+    constexpr static size_t IVSizeInBits = 128;
+
+    virtual ~CBC() { }
+    template<typename... Args>
+    explicit constexpr CBC<T>(Args... args)
+        : Mode<T>(args...)
+    {
+    }
+
+    virtual String class_name() const override
+    {
+        StringBuilder builder;
+        builder.append(this->cipher().class_name());
+        builder.append("_CBC");
+        return builder.build();
+    }
+
+    virtual size_t IV_length() const override { return IVSizeInBits / 8; }
+
+    virtual void encrypt(ReadonlyBytes in, Bytes& out, ReadonlyBytes ivec = {}, Bytes* ivec_out = nullptr) override
+    {
+        auto length = in.size();
+        if (length == 0)
+            return;
+
+        auto& cipher = this->cipher();
+
+        // FIXME: We should have two of these encrypt/decrypt functions that
+        //        we SFINAE out based on whether the Cipher mode needs an ivec
+        ASSERT(!ivec.is_empty());
+        const auto* iv = ivec.data();
+
+        m_cipher_block.set_padding_mode(cipher.padding_mode());
+        size_t offset { 0 };
+        auto block_size = cipher.block_size();
+
+        while (length >= block_size) {
+            m_cipher_block.overwrite(in.slice(offset, block_size));
+            m_cipher_block.apply_initialization_vector(iv);
+            cipher.encrypt_block(m_cipher_block, m_cipher_block);
+            ASSERT(offset + block_size <= out.size());
+            __builtin_memcpy(out.offset(offset), m_cipher_block.bytes().data(), block_size);
+            iv = out.offset(offset);
+            length -= block_size;
+            offset += block_size;
+        }
+
+        if (length > 0) {
+            m_cipher_block.overwrite(in.slice(offset, length));
+            m_cipher_block.apply_initialization_vector(iv);
+            cipher.encrypt_block(m_cipher_block, m_cipher_block);
+            ASSERT(offset + block_size <= out.size());
+            __builtin_memcpy(out.offset(offset), m_cipher_block.bytes().data(), block_size);
+            iv = out.offset(offset);
+        }
+
+        if (ivec_out)
+            __builtin_memcpy(ivec_out->data(), iv, min(IV_length(), ivec_out->size()));
+    }
+
+    virtual void decrypt(ReadonlyBytes in, Bytes& out, ReadonlyBytes ivec = {}) override
+    {
+        auto length = in.size();
+        if (length == 0)
+            return;
+
+        auto& cipher = this->cipher();
+
+        ASSERT(!ivec.is_empty());
+        const auto* iv = ivec.data();
+
+        auto block_size = cipher.block_size();
+
+        // if the data is not aligned, it's not correct encrypted data
+        // FIXME (ponder): Should we simply decrypt as much as we can?
+        ASSERT(length % block_size == 0);
+
+        m_cipher_block.set_padding_mode(cipher.padding_mode());
+        size_t offset { 0 };
+
+        while (length > 0) {
+            auto* slice = in.offset(offset);
+            m_cipher_block.overwrite(slice, block_size);
+            cipher.decrypt_block(m_cipher_block, m_cipher_block);
+            m_cipher_block.apply_initialization_vector(iv);
+            auto decrypted = m_cipher_block.bytes();
+            ASSERT(offset + decrypted.size() <= out.size());
+            __builtin_memcpy(out.offset(offset), decrypted.data(), decrypted.size());
+            iv = slice;
+            length -= block_size;
+            offset += block_size;
+        }
+        out = out.slice(0, offset);
+        this->prune_padding(out);
+    }
+
+private:
+    typename T::BlockType m_cipher_block {};
+};
+
+}
+
+}