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/basictypes.h"
+#include "base/strings/string_util.h"
+#include "crypto/openssl_util.h"
+
+namespace crypto {
+
+Aead::Aead(AeadAlgorithm algorithm) : key_(nullptr) {
+  EnsureOpenSSLInit();
+  switch (algorithm) {
+    case AES_128_CTR_HMAC_SHA256:
+      aead_ = EVP_aead_aes_128_ctr_hmac_sha256();
+      break;
+  }
+}
+
+Aead::~Aead() {
+}
+
+void Aead::Init(const std::string* key) {
+  DCHECK(!key_);
+  DCHECK_EQ(KeyLength(), key->size());
+  key_ = key;
+}
+
+bool Aead::Seal(const base::StringPiece& plaintext,
+                const base::StringPiece& nonce,
+                const base::StringPiece& additional_data,
+                std::string* ciphertext) const {
+  DCHECK(key_);
+  DCHECK_EQ(NonceLength(), nonce.size());
+  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(),
+          reinterpret_cast<const uint8*>(additional_data.data()),
+          additional_data.size())) {
+    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,
+                const base::StringPiece& additional_data,
+                std::string* plaintext) const {
+  DCHECK(key_);
+  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(),
+          reinterpret_cast<const uint8*>(additional_data.data()),
+          additional_data.size())) {
+    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() const {
+  return EVP_AEAD_key_length(aead_);
+}
+
+size_t Aead::NonceLength() const {
+  return EVP_AEAD_nonce_length(aead_);
+}
+
+}  // namespace
+
+#endif