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// Copyright (c) 2012 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 "remoting/protocol/v2_authenticator.h"
#include "base/base64.h"
#include "base/logging.h"
#include "crypto/rsa_private_key.h"
#include "remoting/base/constants.h"
#include "remoting/protocol/ssl_hmac_channel_authenticator.h"
#include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
using crypto::P224EncryptedKeyExchange;
#if defined(_WIN32) && defined(GetMessage)
#undef GetMessage
#endif
namespace remoting {
namespace protocol {
namespace {
const buzz::StaticQName kEkeTag = { kChromotingXmlNamespace,
"eke-message" };
const buzz::StaticQName kCertificateTag = { kChromotingXmlNamespace,
"certificate" };
} // namespace
// static
bool V2Authenticator::IsEkeMessage(const buzz::XmlElement* message) {
return message->FirstNamed(kEkeTag) != NULL;
}
// static
scoped_ptr<Authenticator> V2Authenticator::CreateForClient(
const std::string& shared_secret,
Authenticator::State initial_state) {
return scoped_ptr<Authenticator>(new V2Authenticator(
P224EncryptedKeyExchange::kPeerTypeClient, shared_secret, initial_state));
}
// static
scoped_ptr<Authenticator> V2Authenticator::CreateForHost(
const std::string& local_cert,
const crypto::RSAPrivateKey& local_private_key,
const std::string& shared_secret,
Authenticator::State initial_state) {
scoped_ptr<V2Authenticator> result(new V2Authenticator(
P224EncryptedKeyExchange::kPeerTypeServer, shared_secret, initial_state));
result->local_cert_ = local_cert;
result->local_private_key_.reset(local_private_key.Copy());
return scoped_ptr<Authenticator>(result.Pass());
}
V2Authenticator::V2Authenticator(
crypto::P224EncryptedKeyExchange::PeerType type,
const std::string& shared_secret,
Authenticator::State initial_state)
: certificate_sent_(false),
key_exchange_impl_(type, shared_secret),
state_(initial_state),
rejection_reason_(INVALID_CREDENTIALS) {
pending_messages_.push(key_exchange_impl_.GetMessage());
}
V2Authenticator::~V2Authenticator() {
}
Authenticator::State V2Authenticator::state() const {
if (state_ == ACCEPTED && !pending_messages_.empty())
return MESSAGE_READY;
return state_;
}
Authenticator::RejectionReason V2Authenticator::rejection_reason() const {
DCHECK_EQ(state(), REJECTED);
return rejection_reason_;
}
void V2Authenticator::ProcessMessage(const buzz::XmlElement* message) {
DCHECK_EQ(state(), WAITING_MESSAGE);
// Parse the certificate.
std::string base64_cert = message->TextNamed(kCertificateTag);
if (!base64_cert.empty()) {
if (!base::Base64Decode(base64_cert, &remote_cert_)) {
LOG(WARNING) << "Failed to decode certificate received from the peer.";
remote_cert_.clear();
}
}
// Client always expect certificate in the first message.
if (!is_host_side() && remote_cert_.empty()) {
LOG(WARNING) << "No valid host certificate.";
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
return;
}
const buzz::XmlElement* eke_element = message->FirstNamed(kEkeTag);
if (!eke_element) {
LOG(WARNING) << "No eke-message found.";
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
return;
}
for (; eke_element; eke_element = eke_element->NextNamed(kEkeTag)) {
std::string base64_message = eke_element->BodyText();
std::string spake_message;
if (base64_message.empty() ||
!base::Base64Decode(base64_message, &spake_message)) {
LOG(WARNING) << "Failed to decode auth message received from the peer.";
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
return;
}
P224EncryptedKeyExchange::Result result =
key_exchange_impl_.ProcessMessage(spake_message);
switch (result) {
case P224EncryptedKeyExchange::kResultPending:
pending_messages_.push(key_exchange_impl_.GetMessage());
break;
case P224EncryptedKeyExchange::kResultFailed:
state_ = REJECTED;
rejection_reason_ = INVALID_CREDENTIALS;
return;
case P224EncryptedKeyExchange::kResultSuccess:
auth_key_ = key_exchange_impl_.GetKey();
state_ = ACCEPTED;
return;
}
}
state_ = MESSAGE_READY;
}
scoped_ptr<buzz::XmlElement> V2Authenticator::GetNextMessage() {
DCHECK_EQ(state(), MESSAGE_READY);
scoped_ptr<buzz::XmlElement> message = CreateEmptyAuthenticatorMessage();
DCHECK(!pending_messages_.empty());
while (!pending_messages_.empty()) {
const std::string& spake_message = pending_messages_.front();
std::string base64_message;
if (!base::Base64Encode(spake_message, &base64_message)) {
LOG(DFATAL) << "Cannot perform base64 encode on certificate";
continue;
}
buzz::XmlElement* eke_tag = new buzz::XmlElement(kEkeTag);
eke_tag->SetBodyText(base64_message);
message->AddElement(eke_tag);
pending_messages_.pop();
}
if (!local_cert_.empty() && !certificate_sent_) {
buzz::XmlElement* certificate_tag = new buzz::XmlElement(kCertificateTag);
std::string base64_cert;
if (!base::Base64Encode(local_cert_, &base64_cert)) {
LOG(DFATAL) << "Cannot perform base64 encode on certificate";
}
certificate_tag->SetBodyText(base64_cert);
message->AddElement(certificate_tag);
certificate_sent_ = true;
}
if (state_ != ACCEPTED) {
state_ = WAITING_MESSAGE;
}
return message.Pass();
}
scoped_ptr<ChannelAuthenticator>
V2Authenticator::CreateChannelAuthenticator() const {
DCHECK_EQ(state(), ACCEPTED);
CHECK(!auth_key_.empty());
if (is_host_side()) {
return scoped_ptr<ChannelAuthenticator>(
SslHmacChannelAuthenticator::CreateForHost(
local_cert_, local_private_key_.get(), auth_key_).Pass());
} else {
return scoped_ptr<ChannelAuthenticator>(
SslHmacChannelAuthenticator::CreateForClient(
remote_cert_, auth_key_).Pass());
}
}
bool V2Authenticator::is_host_side() const {
return local_private_key_.get() != NULL;
}
} // namespace protocol
} // namespace remoting
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