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
17package com.android.server.hdmi;
18
19import android.hardware.hdmi.HdmiDeviceInfo;
20import android.util.SparseArray;
21
22/**
23 * A helper class to validates {@link HdmiCecMessage}.
24 */
25public final 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         */
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
57        public ValidationInfo(ParameterValidator validator, int type) {
58            parameterValidator = validator;
59            addressType = type;
60        }
61    }
62
63    final SparseArray<ValidationInfo> mValidationInfo = new SparseArray<>();
64
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
189    private void addValidationInfo(int opcode, ParameterValidator validator, int addrType) {
190        mValidationInfo.append(opcode, new ValidationInfo(validator, addrType));
191    }
192
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
232        public FixedLengthValidator(int length) {
233            mLength = length;
234        }
235
236        @Override
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
248        public VariableLengthValidator(int minLength, int maxLength) {
249            mMinLength = minLength;
250            mMaxLength = maxLength;
251        }
252
253        @Override
254        public int isValid(byte[] params) {
255            return params.length < mMinLength ? ERROR_PARAMETER_SHORT : OK;
256        }
257    }
258
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     */
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
292    private static int toErrorCode(boolean success) {
293        return success ? OK : ERROR_PARAMETER;
294    }
295
296    private class PhysicalAddressValidator implements ParameterValidator {
297        @Override
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
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
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
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