Encrypt certificate reports before uploading to HTTP URLs

crypto/aead_openssl.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "crypto/aead_openssl.h"
+
+#if defined(USE_OPENSSL)
+
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+#include <string>
+
+#include "base/strings/string_util.h"
+#include "crypto/openssl_util.h"
+#include "crypto/symmetric_key.h"
+
+namespace crypto {
+
+Aead::Aead(const std::string* key) : key_(key) {
+  EnsureOpenSSLInit();
+  DCHECK_EQ(KeyLength(), key->size());
+}
+
+Aead::~Aead() {
+}
+
+bool Aead::Seal(const base::StringPiece& plaintext,
+                const base::StringPiece& nonce,
+                std::string* ciphertext) {
+  DCHECK_EQ(NonceLength(), nonce.size());
+  const EVP_AEAD* aead = EVP_aead_aes_128_ctr_hmac_sha256();
+  EVP_AEAD_CTX ctx;
+
+  if (!EVP_AEAD_CTX_init(&ctx, aead,
+                         reinterpret_cast<const uint8*>(key_->data()),
+                         key_->size(), EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr)) {
+    return false;
+  }
+
+  std::string result;
+  const size_t max_output_length =
+      EVP_AEAD_max_overhead(aead) + plaintext.size();
+  size_t output_length;
+  uint8* out_ptr =
+      reinterpret_cast<uint8*>(WriteInto(&result, max_output_length + 1));
+
+  if (!EVP_AEAD_CTX_seal(&ctx, out_ptr, &output_length, max_output_length,
+                         reinterpret_cast<const uint8*>(nonce.data()),
+                         nonce.size(),
+                         reinterpret_cast<const uint8*>(plaintext.data()),
+                         plaintext.size(), nullptr, 0)) {
+    EVP_AEAD_CTX_cleanup(&ctx);
+    return false;
+  }
+
+  DCHECK_LE(output_length, max_output_length);
+  result.resize(output_length);
+
+  ciphertext->swap(result);
+  EVP_AEAD_CTX_cleanup(&ctx);
+
+  return true;
+}
+
+bool Aead::Open(const base::StringPiece& ciphertext,
+                const base::StringPiece& nonce,
+                std::string* plaintext) {
+  const EVP_AEAD* aead = EVP_aead_aes_128_ctr_hmac_sha256();
+  EVP_AEAD_CTX ctx;
+
+  if (!EVP_AEAD_CTX_init(&ctx, aead,
+                         reinterpret_cast<const uint8*>(key_->data()),
+                         key_->size(), EVP_AEAD_DEFAULT_TAG_LENGTH, nullptr)) {
+    return false;
+  }
+
+  std::string result;
+  const size_t max_output_length = ciphertext.size();
+  size_t output_length;
+  uint8* out_ptr =
+      reinterpret_cast<uint8*>(WriteInto(&result, max_output_length + 1));
+
+  if (!EVP_AEAD_CTX_open(&ctx, out_ptr, &output_length, max_output_length,
+                         reinterpret_cast<const uint8*>(nonce.data()),
+                         nonce.size(),
+                         reinterpret_cast<const uint8*>(ciphertext.data()),
+                         ciphertext.size(), nullptr, 0)) {
+    EVP_AEAD_CTX_cleanup(&ctx);
+    return false;
+  }
+
+  DCHECK_LE(output_length, max_output_length);
+  result.resize(output_length);
+
+  plaintext->swap(result);
+  EVP_AEAD_CTX_cleanup(&ctx);
+
+  return true;
+}
+
+size_t Aead::KeyLength() {
+  return EVP_AEAD_key_length(EVP_aead_aes_128_ctr_hmac_sha256());
+}
+
+size_t Aead::NonceLength() {
+  return EVP_AEAD_nonce_length(EVP_aead_aes_128_ctr_hmac_sha256());
+}
+
+}  // namespace
+
+#endif