Update monet.

crypto/encryptor_openssl.cc

+// Copyright (c) 2011 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/encryptor.h"
+
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "crypto/openssl_util.h"
+#include "crypto/symmetric_key.h"
+
+namespace crypto {
+
+namespace {
+
+const EVP_CIPHER* GetCipherForKey(SymmetricKey* key) {
+  switch (key->key().length()) {
+    case 16: return EVP_aes_128_cbc();
+    case 32: return EVP_aes_256_cbc();
+    default: return NULL;
+  }
+}
+
+// On destruction this class will cleanup the ctx, and also clear the OpenSSL
+// ERR stack as a convenience.
+class ScopedCipherCTX {
+ public:
+  explicit ScopedCipherCTX() {
+    EVP_CIPHER_CTX_init(&ctx_);
+  }
+  ~ScopedCipherCTX() {
+    EVP_CIPHER_CTX_cleanup(&ctx_);
+    ClearOpenSSLERRStack(FROM_HERE);
+  }
+  EVP_CIPHER_CTX* get() { return &ctx_; }
+
+ private:
+  EVP_CIPHER_CTX ctx_;
+};
+
+}  // namespace
+
+Encryptor::Encryptor()
+    : key_(NULL),
+      mode_(CBC) {
+}
+
+Encryptor::~Encryptor() {
+}
+
+bool Encryptor::Init(SymmetricKey* key,
+                     Mode mode,
+                     const base::StringPiece& iv) {
+  DCHECK(key);
+  DCHECK(mode == CBC || mode == CTR);
+
+  EnsureOpenSSLInit();
+  if (mode == CBC && iv.size() != AES_BLOCK_SIZE)
+    return false;
+
+  if (GetCipherForKey(key) == NULL)
+    return false;
+
+  key_ = key;
+  mode_ = mode;
+  iv.CopyToString(&iv_);
+  return true;
+}
+
+bool Encryptor::Encrypt(const base::StringPiece& plaintext,
+                        std::string* ciphertext) {
+  CHECK(!plaintext.empty() || (mode_ == CBC));
+  return (mode_ == CTR) ?
+      CryptCTR(true, plaintext, ciphertext) :
+      Crypt(true, plaintext, ciphertext);
+}
+
+bool Encryptor::Decrypt(const base::StringPiece& ciphertext,
+                        std::string* plaintext) {
+  CHECK(!ciphertext.empty());
+  return (mode_ == CTR) ?
+      CryptCTR(false, ciphertext, plaintext) :
+      Crypt(false, ciphertext, plaintext);
+}
+
+bool Encryptor::Crypt(bool do_encrypt,
+                      const base::StringPiece& input,
+                      std::string* output) {
+  DCHECK(key_);  // Must call Init() before En/De-crypt.
+  // Work on the result in a local variable, and then only transfer it to
+  // |output| on success to ensure no partial data is returned.
+  std::string result;
+  output->clear();
+
+  const EVP_CIPHER* cipher = GetCipherForKey(key_);
+  DCHECK(cipher);  // Already handled in Init();
+
+  const std::string& key = key_->key();
+  DCHECK_EQ(EVP_CIPHER_iv_length(cipher), iv_.length());
+  DCHECK_EQ(EVP_CIPHER_key_length(cipher), key.length());
+
+  ScopedCipherCTX ctx;
+  if (!EVP_CipherInit_ex(ctx.get(), cipher, NULL,
+                         reinterpret_cast<const uint8*>(key.data()),
+                         reinterpret_cast<const uint8*>(iv_.data()),
+                         do_encrypt))
+    return false;
+
+  // When encrypting, add another block size of space to allow for any padding.
+  const size_t output_size = input.size() + (do_encrypt ? iv_.size() : 0);
+  CHECK_GT(output_size, 0u);
+  CHECK_GT(output_size + 1, input.size());
+  uint8* out_ptr =
+      reinterpret_cast<uint8*>(base::WriteInto(&result, output_size + 1));
+  int out_len;
+  if (!EVP_CipherUpdate(ctx.get(), out_ptr, &out_len,
+                        reinterpret_cast<const uint8*>(input.data()),
+                        input.length()))
+    return false;
+
+  // Write out the final block plus padding (if any) to the end of the data
+  // just written.
+  int tail_len;
+  if (!EVP_CipherFinal_ex(ctx.get(), out_ptr + out_len, &tail_len))
+    return false;
+
+  out_len += tail_len;
+  DCHECK_LE(out_len, static_cast<int>(output_size));
+  result.resize(out_len);
+
+  output->swap(result);
+  return true;
+}
+
+bool Encryptor::CryptCTR(bool do_encrypt,
+                         const base::StringPiece& input,
+                         std::string* output) {
+  if (!counter_.get()) {
+    LOG(ERROR) << "Counter value not set in CTR mode.";
+    return false;
+  }
+
+  AES_KEY aes_key;
+  if (AES_set_encrypt_key(reinterpret_cast<const uint8*>(key_->key().data()),
+                          key_->key().size() * 8, &aes_key) != 0) {
+    return false;
+  }
+
+  const size_t out_size = input.size();
+  CHECK_GT(out_size, 0u);
+  CHECK_GT(out_size + 1, input.size());
+
+  std::string result;
+  uint8* out_ptr =
+      reinterpret_cast<uint8*>(base::WriteInto(&result, out_size + 1));
+
+  uint8_t ivec[AES_BLOCK_SIZE] = { 0 };
+  uint8_t ecount_buf[AES_BLOCK_SIZE] = { 0 };
+  unsigned int block_offset = 0;
+
+  counter_->Write(ivec);
+
+  AES_ctr128_encrypt(reinterpret_cast<const uint8*>(input.data()), out_ptr,
+                     input.size(), &aes_key, ivec, ecount_buf, &block_offset);
+
+  // AES_ctr128_encrypt() updates |ivec|. Update the |counter_| here.
+  SetCounter(base::StringPiece(reinterpret_cast<const char*>(ivec),
+                               AES_BLOCK_SIZE));
+
+  output->swap(result);
+  return true;
+}
+
+}  // namespace crypto