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1 // Copyright 2016 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "remoting/host/security_key/gnubby_auth_handler.h" | |
6 | |
7 #include <stdint.h> | |
8 #include <unistd.h> | |
9 | |
10 #include <memory> | |
11 | |
12 #include "base/bind.h" | |
13 #include "base/files/file_util.h" | |
14 #include "base/lazy_instance.h" | |
15 #include "base/logging.h" | |
16 #include "base/stl_util.h" | |
17 #include "base/threading/thread_checker.h" | |
18 #include "base/threading/thread_restrictions.h" | |
19 #include "base/values.h" | |
20 #include "net/base/completion_callback.h" | |
21 #include "net/base/net_errors.h" | |
22 #include "net/socket/stream_socket.h" | |
23 #include "net/socket/unix_domain_server_socket_posix.h" | |
24 #include "remoting/base/logging.h" | |
25 #include "remoting/host/security_key/gnubby_socket.h" | |
26 | |
27 namespace { | |
28 | |
29 const int64_t kDefaultRequestTimeoutSeconds = 60; | |
30 | |
31 // The name of the socket to listen for gnubby requests on. | |
32 base::LazyInstance<base::FilePath>::Leaky g_gnubby_socket_name = | |
33 LAZY_INSTANCE_INITIALIZER; | |
34 | |
35 // Socket authentication function that only allows connections from callers with | |
36 // the current uid. | |
37 bool MatchUid(const net::UnixDomainServerSocket::Credentials& credentials) { | |
38 bool allowed = credentials.user_id == getuid(); | |
39 if (!allowed) | |
40 HOST_LOG << "Refused socket connection from uid " << credentials.user_id; | |
41 return allowed; | |
42 } | |
43 | |
44 // Returns the command code (the first byte of the data) if it exists, or -1 if | |
45 // the data is empty. | |
46 unsigned int GetCommandCode(const std::string& data) { | |
47 return data.empty() ? -1 : static_cast<unsigned int>(data[0]); | |
48 } | |
49 | |
50 } // namespace | |
51 | |
52 namespace remoting { | |
53 | |
54 class GnubbyAuthHandlerLinux : public GnubbyAuthHandler { | |
55 public: | |
56 GnubbyAuthHandlerLinux(); | |
57 ~GnubbyAuthHandlerLinux() override; | |
58 | |
59 private: | |
60 typedef std::map<int, GnubbySocket*> ActiveSockets; | |
61 | |
62 // GnubbyAuthHandler interface. | |
63 void CreateGnubbyConnection() override; | |
64 bool IsValidConnectionId(int gnubby_connection_id) const override; | |
65 void SendClientResponse(int gnubby_connection_id, | |
66 const std::string& response) override; | |
67 void SendErrorAndCloseConnection(int gnubby_connection_id) override; | |
68 void SetSendMessageCallback(const SendMessageCallback& callback) override; | |
69 size_t GetActiveConnectionCountForTest() const override; | |
70 void SetRequestTimeoutForTest(base::TimeDelta timeout) override; | |
71 | |
72 // Starts listening for connection. | |
73 void DoAccept(); | |
74 | |
75 // Called when a connection is accepted. | |
76 void OnAccepted(int result); | |
77 | |
78 // Called when a GnubbySocket has done reading. | |
79 void OnReadComplete(int gnubby_connection_id); | |
80 | |
81 // Gets an active socket iterator for |gnubby_connection_id|. | |
82 ActiveSockets::const_iterator GetSocketForConnectionId( | |
83 int gnubby_connection_id) const; | |
84 | |
85 // Send an error and closes an active socket. | |
86 void SendErrorAndCloseActiveSocket(const ActiveSockets::const_iterator& iter); | |
87 | |
88 // A request timed out. | |
89 void RequestTimedOut(int gnubby_connection_id); | |
90 | |
91 // Ensures GnubbyAuthHandlerLinux methods are called on the same thread. | |
92 base::ThreadChecker thread_checker_; | |
93 | |
94 // Socket used to listen for authorization requests. | |
95 std::unique_ptr<net::UnixDomainServerSocket> auth_socket_; | |
96 | |
97 // A temporary holder for an accepted connection. | |
98 std::unique_ptr<net::StreamSocket> accept_socket_; | |
99 | |
100 // Used to pass gnubby extension messages to the client. | |
101 SendMessageCallback send_message_callback_; | |
102 | |
103 // The last assigned gnubby connection id. | |
104 int last_connection_id_; | |
105 | |
106 // Sockets by connection id used to process gnubbyd requests. | |
107 ActiveSockets active_sockets_; | |
108 | |
109 // Timeout used for a request. | |
110 base::TimeDelta request_timeout_; | |
111 | |
112 DISALLOW_COPY_AND_ASSIGN(GnubbyAuthHandlerLinux); | |
113 }; | |
114 | |
115 std::unique_ptr<GnubbyAuthHandler> GnubbyAuthHandler::Create( | |
116 ClientSessionDetails* client_session_details, | |
117 const SendMessageCallback& send_message_callback) { | |
118 std::unique_ptr<GnubbyAuthHandler> auth_handler(new GnubbyAuthHandlerLinux()); | |
119 auth_handler->SetSendMessageCallback(send_message_callback); | |
120 return auth_handler; | |
121 } | |
122 | |
123 void GnubbyAuthHandler::SetGnubbySocketName( | |
124 const base::FilePath& gnubby_socket_name) { | |
125 g_gnubby_socket_name.Get() = gnubby_socket_name; | |
126 } | |
127 | |
128 GnubbyAuthHandlerLinux::GnubbyAuthHandlerLinux() | |
129 : last_connection_id_(0), | |
130 request_timeout_( | |
131 base::TimeDelta::FromSeconds(kDefaultRequestTimeoutSeconds)) {} | |
132 | |
133 GnubbyAuthHandlerLinux::~GnubbyAuthHandlerLinux() { | |
134 STLDeleteValues(&active_sockets_); | |
135 } | |
136 | |
137 void GnubbyAuthHandlerLinux::CreateGnubbyConnection() { | |
138 DCHECK(thread_checker_.CalledOnValidThread()); | |
139 DCHECK(!g_gnubby_socket_name.Get().empty()); | |
140 | |
141 { | |
142 // DeleteFile() is a blocking operation, but so is creation of the unix | |
143 // socket below. Consider moving this class to a different thread if this | |
144 // causes any problems. See crbug.com/509807. | |
145 // TODO(joedow): Since this code now runs as a host extension, we should | |
146 // perform our IO on a separate thread: crbug.com/591739 | |
147 base::ThreadRestrictions::ScopedAllowIO allow_io; | |
148 | |
149 // If the file already exists, a socket in use error is returned. | |
150 base::DeleteFile(g_gnubby_socket_name.Get(), false); | |
151 } | |
152 | |
153 HOST_LOG << "Listening for gnubby requests on " | |
154 << g_gnubby_socket_name.Get().value(); | |
155 | |
156 auth_socket_.reset( | |
157 new net::UnixDomainServerSocket(base::Bind(MatchUid), false)); | |
158 int rv = auth_socket_->BindAndListen(g_gnubby_socket_name.Get().value(), | |
159 /*backlog=*/1); | |
160 if (rv != net::OK) { | |
161 LOG(ERROR) << "Failed to open socket for gnubby requests: '" << rv << "'"; | |
162 return; | |
163 } | |
164 DoAccept(); | |
165 } | |
166 | |
167 bool GnubbyAuthHandlerLinux::IsValidConnectionId( | |
168 int gnubby_connection_id) const { | |
169 return GetSocketForConnectionId(gnubby_connection_id) != | |
170 active_sockets_.end(); | |
171 } | |
172 | |
173 void GnubbyAuthHandlerLinux::SendClientResponse(int gnubby_connection_id, | |
174 const std::string& response) { | |
175 ActiveSockets::const_iterator iter = | |
176 GetSocketForConnectionId(gnubby_connection_id); | |
177 if (iter != active_sockets_.end()) { | |
178 iter->second->SendResponse(response); | |
179 } else { | |
180 LOG(WARNING) << "Unknown gnubby-auth data connection: '" | |
181 << gnubby_connection_id << "'"; | |
182 } | |
183 } | |
184 | |
185 void GnubbyAuthHandlerLinux::SendErrorAndCloseConnection( | |
186 int gnubby_connection_id) { | |
187 ActiveSockets::const_iterator iter = | |
188 GetSocketForConnectionId(gnubby_connection_id); | |
189 if (iter != active_sockets_.end()) { | |
190 HOST_LOG << "Sending gnubby error"; | |
191 SendErrorAndCloseActiveSocket(iter); | |
192 } else { | |
193 LOG(WARNING) << "Unknown gnubby-auth data connection: '" | |
194 << gnubby_connection_id << "'"; | |
195 } | |
196 } | |
197 | |
198 void GnubbyAuthHandlerLinux::SetSendMessageCallback( | |
199 const SendMessageCallback& callback) { | |
200 send_message_callback_ = callback; | |
201 } | |
202 | |
203 size_t GnubbyAuthHandlerLinux::GetActiveConnectionCountForTest() const { | |
204 return active_sockets_.size(); | |
205 } | |
206 | |
207 void GnubbyAuthHandlerLinux::SetRequestTimeoutForTest(base::TimeDelta timeout) { | |
208 request_timeout_ = timeout; | |
209 } | |
210 | |
211 void GnubbyAuthHandlerLinux::DoAccept() { | |
212 int result = auth_socket_->Accept( | |
213 &accept_socket_, | |
214 base::Bind(&GnubbyAuthHandlerLinux::OnAccepted, base::Unretained(this))); | |
215 if (result != net::ERR_IO_PENDING) | |
216 OnAccepted(result); | |
217 } | |
218 | |
219 void GnubbyAuthHandlerLinux::OnAccepted(int result) { | |
220 DCHECK(thread_checker_.CalledOnValidThread()); | |
221 DCHECK_NE(net::ERR_IO_PENDING, result); | |
222 | |
223 if (result < 0) { | |
224 LOG(ERROR) << "Error in accepting a new connection"; | |
225 return; | |
226 } | |
227 | |
228 int gnubby_connection_id = ++last_connection_id_; | |
229 GnubbySocket* socket = new GnubbySocket( | |
230 std::move(accept_socket_), request_timeout_, | |
231 base::Bind(&GnubbyAuthHandlerLinux::RequestTimedOut, | |
232 base::Unretained(this), gnubby_connection_id)); | |
233 active_sockets_[gnubby_connection_id] = socket; | |
234 socket->StartReadingRequest( | |
235 base::Bind(&GnubbyAuthHandlerLinux::OnReadComplete, | |
236 base::Unretained(this), gnubby_connection_id)); | |
237 | |
238 // Continue accepting new connections. | |
239 DoAccept(); | |
240 } | |
241 | |
242 void GnubbyAuthHandlerLinux::OnReadComplete(int gnubby_connection_id) { | |
243 DCHECK(thread_checker_.CalledOnValidThread()); | |
244 | |
245 ActiveSockets::const_iterator iter = | |
246 active_sockets_.find(gnubby_connection_id); | |
247 DCHECK(iter != active_sockets_.end()); | |
248 std::string request_data; | |
249 if (!iter->second->GetAndClearRequestData(&request_data)) { | |
250 SendErrorAndCloseActiveSocket(iter); | |
251 return; | |
252 } | |
253 | |
254 HOST_LOG << "Received gnubby request: " << GetCommandCode(request_data); | |
255 send_message_callback_.Run(gnubby_connection_id, request_data); | |
256 | |
257 iter->second->StartReadingRequest( | |
258 base::Bind(&GnubbyAuthHandlerLinux::OnReadComplete, | |
259 base::Unretained(this), gnubby_connection_id)); | |
260 } | |
261 | |
262 GnubbyAuthHandlerLinux::ActiveSockets::const_iterator | |
263 GnubbyAuthHandlerLinux::GetSocketForConnectionId( | |
264 int gnubby_connection_id) const { | |
265 return active_sockets_.find(gnubby_connection_id); | |
266 } | |
267 | |
268 void GnubbyAuthHandlerLinux::SendErrorAndCloseActiveSocket( | |
269 const ActiveSockets::const_iterator& iter) { | |
270 iter->second->SendSshError(); | |
271 delete iter->second; | |
272 active_sockets_.erase(iter); | |
273 } | |
274 | |
275 void GnubbyAuthHandlerLinux::RequestTimedOut(int gnubby_connection_id) { | |
276 HOST_LOG << "Gnubby request timed out"; | |
277 ActiveSockets::const_iterator iter = | |
278 active_sockets_.find(gnubby_connection_id); | |
279 if (iter != active_sockets_.end()) | |
280 SendErrorAndCloseActiveSocket(iter); | |
281 } | |
282 | |
283 } // namespace remoting | |
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