1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "remoting/protocol/negotiating_client_authenticator.h"
#include <memory>
#include <sstream>
#include <utility>
#include "base/check_op.h"
#include "base/containers/contains.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/location.h"
#include "base/memory/ptr_util.h"
#include "base/notreached.h"
#include "base/strings/string_split.h"
#include "remoting/protocol/auth_util.h"
#include "remoting/protocol/channel_authenticator.h"
#include "remoting/protocol/host_authentication_config.h"
#include "remoting/protocol/pairing_client_authenticator.h"
#include "remoting/protocol/spake2_authenticator.h"
#include "third_party/libjingle_xmpp/xmllite/xmlelement.h"
namespace remoting::protocol {
NegotiatingClientAuthenticator::NegotiatingClientAuthenticator(
const std::string& local_id,
const std::string& remote_id,
const ClientAuthenticationConfig& config)
: NegotiatingAuthenticatorBase(MESSAGE_READY),
local_id_(local_id),
remote_id_(remote_id),
config_(config) {
AddMethod(AuthenticationMethod::PAIRED_SPAKE2_CURVE25519);
AddMethod(AuthenticationMethod::SHARED_SECRET_SPAKE2_CURVE25519);
}
NegotiatingClientAuthenticator::~NegotiatingClientAuthenticator() = default;
void NegotiatingClientAuthenticator::ProcessMessage(
const jingle_xmpp::XmlElement* message,
base::OnceClosure resume_callback) {
DCHECK_EQ(state(), WAITING_MESSAGE);
state_ = PROCESSING_MESSAGE;
std::string method_attr = message->Attr(kMethodAttributeQName);
AuthenticationMethod method = ParseAuthenticationMethodString(method_attr);
// The host picked a method different from the one the client had selected.
if (method != current_method_) {
if (method_set_by_host_) {
state_ = REJECTED;
rejection_reason_ = RejectionReason::INVALID_STATE;
rejection_details_ = RejectionDetails(
"The host must not change methods after it has picked one.");
std::move(resume_callback).Run();
return;
}
if (method == AuthenticationMethod::INVALID ||
!base::Contains(methods_, method)) {
state_ = REJECTED;
rejection_reason_ = RejectionReason::INVALID_STATE;
rejection_details_ = RejectionDetails(
"The host must pick a method that is valid and supported by the "
"client.");
std::move(resume_callback).Run();
return;
}
current_method_ = method;
method_set_by_host_ = true;
// Copy the message since the authenticator may process it asynchronously.
CreateAuthenticatorForCurrentMethod(
WAITING_MESSAGE,
base::BindOnce(&NegotiatingAuthenticatorBase::ProcessMessageInternal,
base::Unretained(this),
base::Owned(new jingle_xmpp::XmlElement(*message)),
std::move(resume_callback)));
return;
}
ProcessMessageInternal(message, std::move(resume_callback));
}
std::unique_ptr<jingle_xmpp::XmlElement>
NegotiatingClientAuthenticator::GetNextMessage() {
DCHECK_EQ(state(), MESSAGE_READY);
// This is the first message to the host, send a list of supported methods.
if (current_method_ == AuthenticationMethod::INVALID) {
// If no authentication method has been chosen, see if we can optimistically
// choose one.
std::unique_ptr<jingle_xmpp::XmlElement> result;
if (current_authenticator_) {
DCHECK(current_authenticator_->state() == MESSAGE_READY);
result = GetNextMessageInternal();
} else {
result = CreateEmptyAuthenticatorMessage();
}
if (is_paired()) {
// If the client is paired with the host then attach pairing client_id to
// the message.
jingle_xmpp::XmlElement* pairing_tag =
new jingle_xmpp::XmlElement(kPairingInfoTag);
result->AddElement(pairing_tag);
pairing_tag->AddAttr(kClientIdAttribute, config_.pairing_client_id);
}
// Include a list of supported methods.
std::string supported_methods;
for (AuthenticationMethod method : methods_) {
if (!supported_methods.empty()) {
supported_methods += kSupportedMethodsSeparator;
}
supported_methods += AuthenticationMethodToString(method);
}
result->AddAttr(kSupportedMethodsAttributeQName, supported_methods);
state_ = WAITING_MESSAGE;
return result;
}
return GetNextMessageInternal();
}
void NegotiatingClientAuthenticator::CreateAuthenticatorForCurrentMethod(
Authenticator::State preferred_initial_state,
base::OnceClosure resume_callback) {
DCHECK_EQ(state(), PROCESSING_MESSAGE);
DCHECK(current_method_ != AuthenticationMethod::INVALID);
switch (current_method_) {
case AuthenticationMethod::INVALID:
NOTREACHED();
case AuthenticationMethod::PAIRED_SPAKE2_CURVE25519: {
PairingClientAuthenticator* pairing_authenticator =
new PairingClientAuthenticator(
config_,
base::BindRepeating(&Spake2Authenticator::CreateForClient,
local_id_, remote_id_));
current_authenticator_ = base::WrapUnique(pairing_authenticator);
pairing_authenticator->Start(preferred_initial_state,
std::move(resume_callback));
break;
}
case AuthenticationMethod::SHARED_SECRET_SPAKE2_CURVE25519:
config_.fetch_secret_callback.Run(
false,
base::BindRepeating(
&NegotiatingClientAuthenticator::CreateSharedSecretAuthenticator,
weak_factory_.GetWeakPtr(), preferred_initial_state,
base::Passed(std::move(resume_callback))));
break;
case AuthenticationMethod::CLOUD_SESSION_AUTHZ_SPAKE2_CURVE25519:
case AuthenticationMethod::CORP_SESSION_AUTHZ_SPAKE2_CURVE25519:
NOTREACHED();
}
ChainStateChangeAfterAcceptedWithUnderlying(*current_authenticator_);
}
void NegotiatingClientAuthenticator::CreateSharedSecretAuthenticator(
Authenticator::State initial_state,
base::OnceClosure resume_callback,
const std::string& shared_secret) {
std::string shared_secret_hash =
GetSharedSecretHash(config_.host_id, shared_secret);
current_authenticator_ = Spake2Authenticator::CreateForClient(
local_id_, remote_id_, shared_secret_hash, initial_state);
std::move(resume_callback).Run();
}
bool NegotiatingClientAuthenticator::is_paired() {
return !config_.pairing_client_id.empty() && !config_.pairing_secret.empty();
}
} // namespace remoting::protocol
|
