Add ChaCha20Poly1305Encrypter, based on

net/quic/crypto/aes_128_gcm_12_decrypter_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_decrypter.h"
 
-#include <openssl/err.h>
 #include <openssl/evp.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;
 
 }  // namespace
 
-Aes128Gcm12Decrypter::Aes128Gcm12Decrypter() {}
+Aes128Gcm12Decrypter::Aes128Gcm12Decrypter()
+    : AeadBaseDecrypter(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);
+}
 
 Aes128Gcm12Decrypter::~Aes128Gcm12Decrypter() {}
 
-// static
-bool Aes128Gcm12Decrypter::IsSupported() { return true; }
-
-bool Aes128Gcm12Decrypter::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)) {
-    // Clear OpenSSL error stack.
-    while (ERR_get_error()) {}
-    return false;
-  }
-
-  return true;
-}
-
-bool Aes128Gcm12Decrypter::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 Aes128Gcm12Decrypter::Decrypt(StringPiece nonce,
-                                   StringPiece associated_data,
-                                   StringPiece ciphertext,
-                                   uint8* output,
-                                   size_t* output_length) {
-  if (ciphertext.length() < kAuthTagSize ||
-      nonce.size() != kNoncePrefixSize + sizeof(QuicPacketSequenceNumber)) {
-    return false;
-  }
-
-  ssize_t len = EVP_AEAD_CTX_open(
-      ctx_.get(), output, ciphertext.size(),
-      reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(),
-      reinterpret_cast<const uint8_t*>(ciphertext.data()), ciphertext.size(),
-      reinterpret_cast<const uint8_t*>(associated_data.data()),
-      associated_data.size());
-
-  if (len < 0) {
-    // Clear OpenSSL error stack.
-    while (ERR_get_error()) {}
-    return false;
-  }
-
-  *output_length = len;
-  return true;
-}
-
-QuicData* Aes128Gcm12Decrypter::DecryptPacket(
-    QuicPacketSequenceNumber sequence_number,
-    StringPiece associated_data,
-    StringPiece ciphertext) {
-  if (ciphertext.length() < kAuthTagSize) {
-    return NULL;
-  }
-  size_t plaintext_size = ciphertext.length();
-  scoped_ptr<char[]> plaintext(new char[plaintext_size]);
-
-  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 (!Decrypt(StringPiece(reinterpret_cast<char*>(nonce), sizeof(nonce)),
-               associated_data, ciphertext,
-               reinterpret_cast<uint8*>(plaintext.get()),
-               &plaintext_size)) {
-    return NULL;
-  }
-  return new QuicData(plaintext.release(), plaintext_size, true);
-}
-
-StringPiece Aes128Gcm12Decrypter::GetKey() const {
-  return StringPiece(reinterpret_cast<const char*>(key_), sizeof(key_));
-}
-
-StringPiece Aes128Gcm12Decrypter::GetNoncePrefix() const {
-  return StringPiece(reinterpret_cast<const char*>(nonce_prefix_),
-                     kNoncePrefixSize);
-}
-
 }  // namespace net