Add ChaCha20Poly1305Encrypter, based on

net/quic/crypto/aes_128_gcm_12_encrypter_openssl.cc

 // Copyright (c) 2013 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 "net/quic/crypto/aes_128_gcm_12_encrypter.h"
 
-#include <openssl/err.h>
 #include <openssl/evp.h>
-#include <string.h>
-
-#include "base/memory/scoped_ptr.h"
-
-using base::StringPiece;
 
 namespace net {
 
 namespace {
 
 const size_t kKeySize = 16;
 const size_t kNoncePrefixSize = 4;
-const size_t kAESNonceSize = 12;
-
-void ClearOpenSslErrors() {
-#ifdef NDEBUG
-  while (ERR_get_error()) {}
-#else
-  while (long error = ERR_get_error()) {
-    char buf[120];
-    ERR_error_string_n(error, buf, arraysize(buf));
-    DLOG(ERROR) << "OpenSSL error: " << buf;
-  }
-#endif
-}
 
 }  // namespace
 
-Aes128Gcm12Encrypter::Aes128Gcm12Encrypter() {}
+Aes128Gcm12Encrypter::Aes128Gcm12Encrypter()
+    : AeadBaseEncrypter(EVP_aead_aes_128_gcm(), kKeySize, kAuthTagSize,
+                        kNoncePrefixSize) {
+  COMPILE_ASSERT(kKeySize <= kMaxKeySize, key_size_too_big);
+  COMPILE_ASSERT(kNoncePrefixSize <= kMaxNoncePrefixSize,
+                 nonce_prefix_size_too_big);
+}
 
 Aes128Gcm12Encrypter::~Aes128Gcm12Encrypter() {}
 
-bool Aes128Gcm12Encrypter::SetKey(StringPiece key) {
-  DCHECK_EQ(key.size(), sizeof(key_));
-  if (key.size() != sizeof(key_)) {
-    return false;
-  }
-  memcpy(key_, key.data(), key.size());
-
-  EVP_AEAD_CTX_cleanup(ctx_.get());
-
-  if (!EVP_AEAD_CTX_init(ctx_.get(), EVP_aead_aes_128_gcm(), key_,
-                         sizeof(key_), kAuthTagSize, NULL)) {
-    ClearOpenSslErrors();
-    return false;
-  }
-
-  return true;
-}
-
-bool Aes128Gcm12Encrypter::SetNoncePrefix(StringPiece nonce_prefix) {
-  DCHECK_EQ(nonce_prefix.size(), kNoncePrefixSize);
-  if (nonce_prefix.size() != kNoncePrefixSize) {
-    return false;
-  }
-  COMPILE_ASSERT(sizeof(nonce_prefix_) == kNoncePrefixSize, bad_nonce_length);
-  memcpy(nonce_prefix_, nonce_prefix.data(), nonce_prefix.size());
-  return true;
-}
-
-bool Aes128Gcm12Encrypter::Encrypt(StringPiece nonce,
-                                   StringPiece associated_data,
-                                   StringPiece plaintext,
-                                   unsigned char* output) {
-  if (nonce.size() != kNoncePrefixSize + sizeof(QuicPacketSequenceNumber)) {
-    return false;
-  }
-
-  ssize_t len = EVP_AEAD_CTX_seal(
-      ctx_.get(), output, plaintext.size() + kAuthTagSize,
-      reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(),
-      reinterpret_cast<const uint8_t*>(plaintext.data()), plaintext.size(),
-      reinterpret_cast<const uint8_t*>(associated_data.data()),
-      associated_data.size());
-
-  if (len < 0) {
-    ClearOpenSslErrors();
-    return false;
-  }
-
-  return true;
-}
-
-QuicData* Aes128Gcm12Encrypter::EncryptPacket(
-    QuicPacketSequenceNumber sequence_number,
-    StringPiece associated_data,
-    StringPiece plaintext) {
-  size_t ciphertext_size = GetCiphertextSize(plaintext.length());
-  scoped_ptr<char[]> ciphertext(new char[ciphertext_size]);
-
-  // TODO(ianswett): Introduce a check to ensure that we don't encrypt with the
-  // same sequence number twice.
-  uint8 nonce[kNoncePrefixSize + sizeof(sequence_number)];
-  COMPILE_ASSERT(sizeof(nonce) == kAESNonceSize, bad_sequence_number_size);
-  memcpy(nonce, nonce_prefix_, kNoncePrefixSize);
-  memcpy(nonce + kNoncePrefixSize, &sequence_number, sizeof(sequence_number));
-  if (!Encrypt(StringPiece(reinterpret_cast<char*>(nonce), sizeof(nonce)),
-               associated_data, plaintext,
-               reinterpret_cast<unsigned char*>(ciphertext.get()))) {
-    return NULL;
-  }
-
-  return new QuicData(ciphertext.release(), ciphertext_size, true);
-}
-
-size_t Aes128Gcm12Encrypter::GetKeySize() const { return kKeySize; }
-
-size_t Aes128Gcm12Encrypter::GetNoncePrefixSize() const {
-  return kNoncePrefixSize;
-}
-
-size_t Aes128Gcm12Encrypter::GetMaxPlaintextSize(size_t ciphertext_size) const {
-  return ciphertext_size - kAuthTagSize;
-}
-
-// An AEAD_AES_128_GCM_12 ciphertext is exactly 12 bytes longer than its
-// corresponding plaintext.
-size_t Aes128Gcm12Encrypter::GetCiphertextSize(size_t plaintext_size) const {
-  return plaintext_size + kAuthTagSize;
-}
-
-StringPiece Aes128Gcm12Encrypter::GetKey() const {
-  return StringPiece(reinterpret_cast<const char*>(key_), sizeof(key_));
-}
-
-StringPiece Aes128Gcm12Encrypter::GetNoncePrefix() const {
-  return StringPiece(reinterpret_cast<const char*>(nonce_prefix_),
-                     kNoncePrefixSize);
-}
-
 }  // namespace net