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// Copyright 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 "remoting/protocol/negotiating_host_authenticator.h"
#include <algorithm>
#include <sstream>
#include <utility>
#include "base/bind.h"
#include "base/callback.h"
#include "base/logging.h"
#include "base/strings/string_split.h"
#include "remoting/base/rsa_key_pair.h"
#include "remoting/protocol/channel_authenticator.h"
#include "remoting/protocol/pairing_host_authenticator.h"
#include "remoting/protocol/pairing_registry.h"
#include "remoting/protocol/spake2_authenticator.h"
#include "remoting/protocol/token_validator.h"
#include "remoting/protocol/v2_authenticator.h"
#include "third_party/webrtc/libjingle/xmllite/xmlelement.h"
namespace remoting {
namespace protocol {
NegotiatingHostAuthenticator::NegotiatingHostAuthenticator(
const std::string& local_id,
const std::string& remote_id,
const std::string& local_cert,
scoped_refptr<RsaKeyPair> key_pair)
: NegotiatingAuthenticatorBase(WAITING_MESSAGE),
local_id_(local_id),
remote_id_(remote_id),
local_cert_(local_cert),
local_key_pair_(key_pair) {}
// static
scoped_ptr<NegotiatingHostAuthenticator>
NegotiatingHostAuthenticator::CreateWithSharedSecret(
const std::string& local_id,
const std::string& remote_id,
const std::string& local_cert,
scoped_refptr<RsaKeyPair> key_pair,
const std::string& shared_secret_hash,
scoped_refptr<PairingRegistry> pairing_registry) {
scoped_ptr<NegotiatingHostAuthenticator> result(
new NegotiatingHostAuthenticator(local_id, remote_id, local_cert,
key_pair));
result->shared_secret_hash_ = shared_secret_hash;
result->pairing_registry_ = pairing_registry;
result->AddMethod(Method::SHARED_SECRET_SPAKE2_CURVE25519);
result->AddMethod(Method::SHARED_SECRET_SPAKE2_P224);
if (pairing_registry.get()) {
result->AddMethod(Method::PAIRED_SPAKE2_CURVE25519);
result->AddMethod(Method::PAIRED_SPAKE2_P224);
}
return result;
}
// static
scoped_ptr<NegotiatingHostAuthenticator>
NegotiatingHostAuthenticator::CreateWithThirdPartyAuth(
const std::string& local_id,
const std::string& remote_id,
const std::string& local_cert,
scoped_refptr<RsaKeyPair> key_pair,
scoped_refptr<TokenValidatorFactory> token_validator_factory) {
scoped_ptr<NegotiatingHostAuthenticator> result(
new NegotiatingHostAuthenticator(local_id, remote_id, local_cert,
key_pair));
result->token_validator_factory_ = token_validator_factory;
result->AddMethod(Method::THIRD_PARTY_SPAKE2_CURVE25519);
result->AddMethod(Method::THIRD_PARTY_SPAKE2_P224);
return result;
}
NegotiatingHostAuthenticator::~NegotiatingHostAuthenticator() {}
void NegotiatingHostAuthenticator::ProcessMessage(
const buzz::XmlElement* message,
const base::Closure& resume_callback) {
DCHECK_EQ(state(), WAITING_MESSAGE);
state_ = PROCESSING_MESSAGE;
const buzz::XmlElement* pairing_tag = message->FirstNamed(kPairingInfoTag);
if (pairing_tag) {
client_id_ = pairing_tag->Attr(kClientIdAttribute);
}
std::string method_attr = message->Attr(kMethodAttributeQName);
Method method = ParseMethodString(method_attr);
// If the host has already chosen a method, it can't be changed by the client.
if (current_method_ != Method::INVALID && method != current_method_) {
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
resume_callback.Run();
return;
}
// If the client did not specify a preferred auth method, or specified an
// unknown or unsupported method, then select the first known method from
// the supported-methods attribute.
if (method == Method::INVALID ||
std::find(methods_.begin(), methods_.end(), method) == methods_.end()) {
method = Method::INVALID;
std::string supported_methods_attr =
message->Attr(kSupportedMethodsAttributeQName);
if (supported_methods_attr.empty()) {
// Message contains neither method nor supported-methods attributes.
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
resume_callback.Run();
return;
}
// Find the first mutually-supported method in the client's list of
// supported-methods.
for (const std::string& method_str :
base::SplitString(supported_methods_attr,
std::string(1, kSupportedMethodsSeparator),
base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
Method list_value = ParseMethodString(method_str);
if (list_value != Method::INVALID &&
std::find(methods_.begin(), methods_.end(), list_value) !=
methods_.end()) {
// Found common method.
method = list_value;
break;
}
}
if (method == Method::INVALID) {
// Failed to find a common auth method.
state_ = REJECTED;
rejection_reason_ = PROTOCOL_ERROR;
resume_callback.Run();
return;
}
// Drop the current message because we've chosen a different method.
current_method_ = method;
CreateAuthenticator(MESSAGE_READY,
base::Bind(&NegotiatingHostAuthenticator::UpdateState,
base::Unretained(this), resume_callback));
return;
}
// If the client specified a supported method, and the host hasn't chosen a
// method yet, use the client's preferred method and process the message.
if (current_method_ == Method::INVALID) {
current_method_ = method;
// Copy the message since the authenticator may process it asynchronously.
CreateAuthenticator(
WAITING_MESSAGE,
base::Bind(&NegotiatingAuthenticatorBase::ProcessMessageInternal,
base::Unretained(this),
base::Owned(new buzz::XmlElement(*message)),
resume_callback));
return;
}
// If the client is using the host's current method, just process the message.
ProcessMessageInternal(message, resume_callback);
}
scoped_ptr<buzz::XmlElement> NegotiatingHostAuthenticator::GetNextMessage() {
return GetNextMessageInternal();
}
void NegotiatingHostAuthenticator::CreateAuthenticator(
Authenticator::State preferred_initial_state,
const base::Closure& resume_callback) {
DCHECK(current_method_ != Method::INVALID);
switch(current_method_) {
case Method::INVALID:
NOTREACHED();
break;
case Method::THIRD_PARTY_SPAKE2_P224:
current_authenticator_.reset(new ThirdPartyHostAuthenticator(
base::Bind(&V2Authenticator::CreateForHost, local_cert_,
local_key_pair_),
token_validator_factory_->CreateTokenValidator(local_id_,
remote_id_)));
resume_callback.Run();
break;
case Method::THIRD_PARTY_SPAKE2_CURVE25519:
current_authenticator_.reset(new ThirdPartyHostAuthenticator(
base::Bind(&Spake2Authenticator::CreateForHost, local_id_, remote_id_,
local_cert_, local_key_pair_),
token_validator_factory_->CreateTokenValidator(local_id_,
remote_id_)));
resume_callback.Run();
break;
case Method::PAIRED_SPAKE2_P224: {
PairingHostAuthenticator* pairing_authenticator =
new PairingHostAuthenticator(
pairing_registry_, base::Bind(&V2Authenticator::CreateForHost,
local_cert_, local_key_pair_),
shared_secret_hash_);
current_authenticator_.reset(pairing_authenticator);
pairing_authenticator->Initialize(client_id_, preferred_initial_state,
resume_callback);
break;
}
case Method::PAIRED_SPAKE2_CURVE25519: {
PairingHostAuthenticator* pairing_authenticator =
new PairingHostAuthenticator(
pairing_registry_,
base::Bind(&Spake2Authenticator::CreateForHost, local_id_,
remote_id_, local_cert_, local_key_pair_),
shared_secret_hash_);
current_authenticator_.reset(pairing_authenticator);
pairing_authenticator->Initialize(client_id_, preferred_initial_state,
resume_callback);
break;
}
case Method::SHARED_SECRET_SPAKE2_CURVE25519:
current_authenticator_ = Spake2Authenticator::CreateForHost(
local_id_, remote_id_, local_cert_, local_key_pair_,
shared_secret_hash_, preferred_initial_state);
resume_callback.Run();
break;
case Method::SHARED_SECRET_SPAKE2_P224:
current_authenticator_ = V2Authenticator::CreateForHost(
local_cert_, local_key_pair_, shared_secret_hash_,
preferred_initial_state);
resume_callback.Run();
break;
}
}
} // namespace protocol
} // namespace remoting
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