1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.server.hdmi;
18 
19 import android.hardware.hdmi.HdmiDeviceInfo;
20 import android.util.SparseArray;
21 
22 /**
23  * A helper class to validates {@link HdmiCecMessage}.
24  */
25 public class HdmiCecMessageValidator {
26     private static final String TAG = "HdmiCecMessageValidator";
27 
28     static final int OK = 0;
29     static final int ERROR_SOURCE = 1;
30     static final int ERROR_DESTINATION = 2;
31     static final int ERROR_PARAMETER = 3;
32     static final int ERROR_PARAMETER_SHORT = 4;
33 
34     private final HdmiControlService mService;
35 
36     interface ParameterValidator {
37         /**
38          * @return errorCode errorCode can be {@link #OK}, {@link #ERROR_PARAMETER} or
39          *         {@link #ERROR_PARAMETER_SHORT}.
40          */
isValid(byte[] params)41         int isValid(byte[] params);
42     }
43 
44     // Only the direct addressing is allowed.
45     private static final int DEST_DIRECT = 1 << 0;
46     // Only the broadcast addressing is allowed.
47     private static final int DEST_BROADCAST = 1 << 1;
48     // Both the direct and the broadcast addressing are allowed.
49     private static final int DEST_ALL = DEST_DIRECT | DEST_BROADCAST;
50     // True if the messages from address 15 (unregistered) are allowed.
51     private static final int SRC_UNREGISTERED = 1 << 2;
52 
53     private static class ValidationInfo {
54         public final ParameterValidator parameterValidator;
55         public final int addressType;
56 
ValidationInfo(ParameterValidator validator, int type)57         public ValidationInfo(ParameterValidator validator, int type) {
58             parameterValidator = validator;
59             addressType = type;
60         }
61     }
62 
63     final SparseArray<ValidationInfo> mValidationInfo = new SparseArray<>();
64 
HdmiCecMessageValidator(HdmiControlService service)65     public HdmiCecMessageValidator(HdmiControlService service) {
66         mService = service;
67 
68         // Messages related to the physical address.
69         PhysicalAddressValidator physicalAddressValidator = new PhysicalAddressValidator();
70         addValidationInfo(Constants.MESSAGE_ACTIVE_SOURCE,
71                 physicalAddressValidator, DEST_BROADCAST | SRC_UNREGISTERED);
72         addValidationInfo(Constants.MESSAGE_INACTIVE_SOURCE, physicalAddressValidator, DEST_DIRECT);
73         addValidationInfo(Constants.MESSAGE_REPORT_PHYSICAL_ADDRESS,
74                 new ReportPhysicalAddressValidator(), DEST_BROADCAST | SRC_UNREGISTERED);
75         addValidationInfo(Constants.MESSAGE_ROUTING_CHANGE,
76                 new RoutingChangeValidator(), DEST_BROADCAST | SRC_UNREGISTERED);
77         addValidationInfo(Constants.MESSAGE_ROUTING_INFORMATION,
78                 physicalAddressValidator, DEST_BROADCAST | SRC_UNREGISTERED);
79         addValidationInfo(Constants.MESSAGE_SET_STREAM_PATH,
80                 physicalAddressValidator, DEST_BROADCAST);
81         addValidationInfo(Constants.MESSAGE_SYSTEM_AUDIO_MODE_REQUEST,
82                 new SystemAudioModeRequestValidator(), DEST_DIRECT);
83 
84         // Messages have no parameter.
85         FixedLengthValidator noneValidator = new FixedLengthValidator(0);
86         addValidationInfo(Constants.MESSAGE_ABORT, noneValidator, DEST_DIRECT);
87         addValidationInfo(Constants.MESSAGE_GET_CEC_VERSION, noneValidator, DEST_DIRECT);
88         addValidationInfo(Constants.MESSAGE_GET_MENU_LANGUAGE,
89                 noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
90         addValidationInfo(Constants.MESSAGE_GIVE_AUDIO_STATUS, noneValidator, DEST_DIRECT);
91         addValidationInfo(Constants.MESSAGE_GIVE_DEVICE_POWER_STATUS, noneValidator, DEST_DIRECT);
92         addValidationInfo(Constants.MESSAGE_GIVE_DEVICE_VENDOR_ID,
93                 noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
94         addValidationInfo(Constants.MESSAGE_GIVE_OSD_NAME, noneValidator, DEST_DIRECT);
95         addValidationInfo(Constants.MESSAGE_GIVE_PHYSICAL_ADDRESS,
96                 noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
97         addValidationInfo(Constants.MESSAGE_GIVE_SYSTEM_AUDIO_MODE_STATUS,
98                 noneValidator, DEST_DIRECT);
99         addValidationInfo(Constants.MESSAGE_IMAGE_VIEW_ON, noneValidator, DEST_DIRECT);
100         addValidationInfo(Constants.MESSAGE_INITIATE_ARC, noneValidator, DEST_DIRECT);
101         addValidationInfo(Constants.MESSAGE_RECORD_OFF, noneValidator, DEST_DIRECT);
102         addValidationInfo(Constants.MESSAGE_RECORD_TV_SCREEN, noneValidator, DEST_DIRECT);
103         addValidationInfo(Constants.MESSAGE_REPORT_ARC_INITIATED, noneValidator, DEST_DIRECT);
104         addValidationInfo(Constants.MESSAGE_REPORT_ARC_TERMINATED, noneValidator, DEST_DIRECT);
105         addValidationInfo(Constants.MESSAGE_REQUEST_ARC_INITIATION, noneValidator, DEST_DIRECT);
106         addValidationInfo(Constants.MESSAGE_REQUEST_ARC_TERMINATION, noneValidator, DEST_DIRECT);
107         addValidationInfo(Constants.MESSAGE_REQUEST_ACTIVE_SOURCE,
108                 noneValidator, DEST_BROADCAST | SRC_UNREGISTERED);
109         addValidationInfo(Constants.MESSAGE_STANDBY, noneValidator, DEST_ALL | SRC_UNREGISTERED);
110         addValidationInfo(Constants.MESSAGE_TERMINATE_ARC, noneValidator, DEST_DIRECT);
111         addValidationInfo(Constants.MESSAGE_TEXT_VIEW_ON, noneValidator, DEST_DIRECT);
112         addValidationInfo(Constants.MESSAGE_TUNER_STEP_DECREMENT, noneValidator, DEST_DIRECT);
113         addValidationInfo(Constants.MESSAGE_TUNER_STEP_INCREMENT, noneValidator, DEST_DIRECT);
114         addValidationInfo(Constants.MESSAGE_USER_CONTROL_RELEASED, noneValidator, DEST_DIRECT);
115         addValidationInfo(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_UP, noneValidator, DEST_ALL);
116 
117         // TODO: Validate more than length for the following messages.
118 
119         // Messages for the One Touch Record.
120         FixedLengthValidator oneByteValidator = new FixedLengthValidator(1);
121         addValidationInfo(Constants.MESSAGE_RECORD_ON,
122                 new VariableLengthValidator(1, 8), DEST_DIRECT);
123         addValidationInfo(Constants.MESSAGE_RECORD_STATUS, oneByteValidator, DEST_DIRECT);
124 
125         // TODO: Handle messages for the Timer Programming.
126 
127         // Messages for the System Information.
128         addValidationInfo(Constants.MESSAGE_CEC_VERSION, oneByteValidator, DEST_DIRECT);
129         addValidationInfo(Constants.MESSAGE_SET_MENU_LANGUAGE,
130                 new FixedLengthValidator(3), DEST_BROADCAST);
131 
132         // TODO: Handle messages for the Deck Control.
133 
134         // TODO: Handle messages for the Tuner Control.
135 
136         // Messages for the Vendor Specific Commands.
137         VariableLengthValidator maxLengthValidator = new VariableLengthValidator(0, 14);
138         addValidationInfo(Constants.MESSAGE_DEVICE_VENDOR_ID,
139                 new FixedLengthValidator(3), DEST_BROADCAST);
140         // Allow unregistered source for all vendor specific commands, because we don't know
141         // how to use the commands at this moment.
142         addValidationInfo(Constants.MESSAGE_VENDOR_COMMAND,
143                 new VariableLengthValidator(1, 14), DEST_DIRECT | SRC_UNREGISTERED);
144         addValidationInfo(Constants.MESSAGE_VENDOR_COMMAND_WITH_ID,
145                 new VariableLengthValidator(4, 14), DEST_ALL | SRC_UNREGISTERED);
146         addValidationInfo(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_DOWN,
147                 maxLengthValidator, DEST_ALL | SRC_UNREGISTERED);
148 
149         // Messages for the OSD.
150         addValidationInfo(Constants.MESSAGE_SET_OSD_STRING, maxLengthValidator, DEST_DIRECT);
151         addValidationInfo(Constants.MESSAGE_SET_OSD_NAME, maxLengthValidator, DEST_DIRECT);
152 
153         // Messages for the Device Menu Control.
154         addValidationInfo(Constants.MESSAGE_MENU_REQUEST, oneByteValidator, DEST_DIRECT);
155         addValidationInfo(Constants.MESSAGE_MENU_STATUS, oneByteValidator, DEST_DIRECT);
156 
157         // Messages for the Remote Control Passthrough.
158         // TODO: Parse the first parameter and determine if it can have the next parameter.
159         addValidationInfo(Constants.MESSAGE_USER_CONTROL_PRESSED,
160                 new VariableLengthValidator(1, 2), DEST_DIRECT);
161 
162         // Messages for the Power Status.
163         addValidationInfo(Constants.MESSAGE_REPORT_POWER_STATUS, oneByteValidator, DEST_DIRECT);
164 
165         // Messages for the General Protocol.
166         addValidationInfo(Constants.MESSAGE_FEATURE_ABORT,
167                 new FixedLengthValidator(2), DEST_DIRECT);
168 
169         // Messages for the System Audio Control.
170         addValidationInfo(Constants.MESSAGE_REPORT_AUDIO_STATUS, oneByteValidator, DEST_DIRECT);
171         addValidationInfo(Constants.MESSAGE_REPORT_SHORT_AUDIO_DESCRIPTOR,
172                 new FixedLengthValidator(3), DEST_DIRECT);
173         addValidationInfo(Constants.MESSAGE_REQUEST_SHORT_AUDIO_DESCRIPTOR,
174                 oneByteValidator, DEST_DIRECT);
175         addValidationInfo(Constants.MESSAGE_SET_SYSTEM_AUDIO_MODE, oneByteValidator, DEST_ALL);
176         addValidationInfo(Constants.MESSAGE_SYSTEM_AUDIO_MODE_STATUS,
177                 oneByteValidator, DEST_DIRECT);
178 
179         // Messages for the Audio Rate Control.
180         addValidationInfo(Constants.MESSAGE_SET_AUDIO_RATE, oneByteValidator, DEST_DIRECT);
181 
182         // All Messages for the ARC have no parameters.
183 
184         // Messages for the Capability Discovery and Control.
185         addValidationInfo(Constants.MESSAGE_CDC_MESSAGE, maxLengthValidator,
186                 DEST_BROADCAST | SRC_UNREGISTERED);
187     }
188 
addValidationInfo(int opcode, ParameterValidator validator, int addrType)189     private void addValidationInfo(int opcode, ParameterValidator validator, int addrType) {
190         mValidationInfo.append(opcode, new ValidationInfo(validator, addrType));
191     }
192 
isValid(HdmiCecMessage message)193     int isValid(HdmiCecMessage message) {
194         int opcode = message.getOpcode();
195         ValidationInfo info = mValidationInfo.get(opcode);
196         if (info == null) {
197             HdmiLogger.warning("No validation information for the message: " + message);
198             return OK;
199         }
200 
201         // Check the source field.
202         if (message.getSource() == Constants.ADDR_UNREGISTERED &&
203                 (info.addressType & SRC_UNREGISTERED) == 0) {
204             HdmiLogger.warning("Unexpected source: " + message);
205             return ERROR_SOURCE;
206         }
207         // Check the destination field.
208         if (message.getDestination() == Constants.ADDR_BROADCAST) {
209             if ((info.addressType & DEST_BROADCAST) == 0) {
210                 HdmiLogger.warning("Unexpected broadcast message: " + message);
211                 return ERROR_DESTINATION;
212             }
213         } else {  // Direct addressing.
214             if ((info.addressType & DEST_DIRECT) == 0) {
215                 HdmiLogger.warning("Unexpected direct message: " + message);
216                 return ERROR_DESTINATION;
217             }
218         }
219 
220         // Check the parameter type.
221         int errorCode = info.parameterValidator.isValid(message.getParams());
222         if (errorCode != OK) {
223             HdmiLogger.warning("Unexpected parameters: " + message);
224             return errorCode;
225         }
226         return OK;
227     }
228 
229     private static class FixedLengthValidator implements ParameterValidator {
230         private final int mLength;
231 
FixedLengthValidator(int length)232         public FixedLengthValidator(int length) {
233             mLength = length;
234         }
235 
236         @Override
isValid(byte[] params)237         public int isValid(byte[] params) {
238             // If the length is longer than expected, we assume it's OK since the parameter can be
239             // extended in the future version.
240             return params.length < mLength ? ERROR_PARAMETER_SHORT : OK;
241         }
242     }
243 
244     private static class VariableLengthValidator implements ParameterValidator {
245         private final int mMinLength;
246         private final int mMaxLength;
247 
VariableLengthValidator(int minLength, int maxLength)248         public VariableLengthValidator(int minLength, int maxLength) {
249             mMinLength = minLength;
250             mMaxLength = maxLength;
251         }
252 
253         @Override
isValid(byte[] params)254         public int isValid(byte[] params) {
255             return params.length < mMinLength ? ERROR_PARAMETER_SHORT : OK;
256         }
257     }
258 
isValidPhysicalAddress(byte[] params, int offset)259     private boolean isValidPhysicalAddress(byte[] params, int offset) {
260         // TODO: Add more logic like validating 1.0.1.0.
261 
262         if (!mService.isTvDevice()) {
263             // If the device is not TV, we can't convert path to port-id, so stop here.
264             return true;
265         }
266         int path = HdmiUtils.twoBytesToInt(params, offset);
267         if (path != Constants.INVALID_PHYSICAL_ADDRESS && path == mService.getPhysicalAddress()) {
268             return true;
269         }
270         int portId = mService.pathToPortId(path);
271         if (portId == Constants.INVALID_PORT_ID) {
272             return false;
273         }
274         return true;
275     }
276 
277     /**
278      * Check if the given type is valid. A valid type is one of the actual logical device types
279      * defined in the standard ({@link HdmiDeviceInfo#DEVICE_TV},
280      * {@link HdmiDeviceInfo#DEVICE_PLAYBACK}, {@link HdmiDeviceInfo#DEVICE_TUNER},
281      * {@link HdmiDeviceInfo#DEVICE_RECORDER}, and {@link HdmiDeviceInfo#DEVICE_AUDIO_SYSTEM}).
282      *
283      * @param type device type
284      * @return true if the given type is valid
285      */
isValidType(int type)286     static boolean isValidType(int type) {
287         return (HdmiDeviceInfo.DEVICE_TV <= type
288                 && type <= HdmiDeviceInfo.DEVICE_VIDEO_PROCESSOR)
289                 && type != HdmiDeviceInfo.DEVICE_RESERVED;
290     }
291 
toErrorCode(boolean success)292     private static int toErrorCode(boolean success) {
293         return success ? OK : ERROR_PARAMETER;
294     }
295 
296     private class PhysicalAddressValidator implements ParameterValidator {
297         @Override
isValid(byte[] params)298         public int isValid(byte[] params) {
299             if (params.length < 2) {
300                 return ERROR_PARAMETER_SHORT;
301             }
302             return toErrorCode(isValidPhysicalAddress(params, 0));
303         }
304     }
305 
306     private class SystemAudioModeRequestValidator extends PhysicalAddressValidator {
307         @Override
isValid(byte[] params)308         public int isValid(byte[] params) {
309             // TV can send <System Audio Mode Request> with no parameters to terminate system audio.
310             if (params.length == 0) {
311                 return OK;
312             }
313             return super.isValid(params);
314         }
315     }
316 
317     private class ReportPhysicalAddressValidator implements ParameterValidator {
318         @Override
isValid(byte[] params)319         public int isValid(byte[] params) {
320             if (params.length < 3) {
321                 return ERROR_PARAMETER_SHORT;
322             }
323             return toErrorCode(isValidPhysicalAddress(params, 0) && isValidType(params[2]));
324         }
325     }
326 
327     private class RoutingChangeValidator implements ParameterValidator {
328         @Override
isValid(byte[] params)329         public int isValid(byte[] params) {
330             if (params.length < 4) {
331                 return ERROR_PARAMETER_SHORT;
332             }
333             return toErrorCode(
334                     isValidPhysicalAddress(params, 0) && isValidPhysicalAddress(params, 2));
335         }
336     }
337 }
338