HdmiCecMessageValidator.java revision 4c212897813d6c23b2e7ffba4a4c01e13a41b1fa 
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
33    private final HdmiControlService mService;
34
35    interface ParameterValidator {
36        boolean isValid(byte[] params);
37    }
38
39    // Only the direct addressing is allowed.
40    private static final int DEST_DIRECT = 1 << 0;
41    // Only the broadcast addressing is allowed.
42    private static final int DEST_BROADCAST = 1 << 1;
43    // Both the direct and the broadcast addressing are allowed.
44    private static final int DEST_ALL = DEST_DIRECT | DEST_BROADCAST;
45    // True if the messages from address 15 (unregistered) are allowed.
46    private static final int SRC_UNREGISTERED = 1 << 2;
47
48    private static class ValidationInfo {
49        public final ParameterValidator parameterValidator;
50        public final int addressType;
51
52        public ValidationInfo(ParameterValidator validator, int type) {
53            parameterValidator = validator;
54            addressType = type;
55        }
56    }
57
58    final SparseArray<ValidationInfo> mValidationInfo = new SparseArray<>();
59
60    public HdmiCecMessageValidator(HdmiControlService service) {
61        mService = service;
62
63        // Messages related to the physical address.
64        PhysicalAddressValidator physicalAddressValidator = new PhysicalAddressValidator();
65        addValidationInfo(Constants.MESSAGE_ACTIVE_SOURCE,
66                physicalAddressValidator, DEST_BROADCAST | SRC_UNREGISTERED);
67        addValidationInfo(Constants.MESSAGE_INACTIVE_SOURCE, physicalAddressValidator, DEST_DIRECT);
68        addValidationInfo(Constants.MESSAGE_REPORT_PHYSICAL_ADDRESS,
69                new ReportPhysicalAddressValidator(), DEST_BROADCAST | SRC_UNREGISTERED);
70        addValidationInfo(Constants.MESSAGE_ROUTING_CHANGE,
71                new RoutingChangeValidator(), DEST_BROADCAST | SRC_UNREGISTERED);
72        addValidationInfo(Constants.MESSAGE_ROUTING_INFORMATION,
73                physicalAddressValidator, DEST_BROADCAST | SRC_UNREGISTERED);
74        addValidationInfo(Constants.MESSAGE_SET_STREAM_PATH,
75                physicalAddressValidator, DEST_BROADCAST);
76        addValidationInfo(Constants.MESSAGE_SYSTEM_AUDIO_MODE_REQUEST,
77                physicalAddressValidator, DEST_DIRECT);
78
79        // Messages have no parameter.
80        FixedLengthValidator noneValidator = new FixedLengthValidator(0);
81        addValidationInfo(Constants.MESSAGE_ABORT, noneValidator, DEST_DIRECT);
82        addValidationInfo(Constants.MESSAGE_GET_CEC_VERSION, noneValidator, DEST_DIRECT);
83        addValidationInfo(Constants.MESSAGE_GET_MENU_LANGUAGE,
84                noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
85        addValidationInfo(Constants.MESSAGE_GIVE_AUDIO_STATUS, noneValidator, DEST_DIRECT);
86        addValidationInfo(Constants.MESSAGE_GIVE_DEVICE_POWER_STATUS, noneValidator, DEST_DIRECT);
87        addValidationInfo(Constants.MESSAGE_GIVE_DEVICE_VENDOR_ID,
88                noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
89        addValidationInfo(Constants.MESSAGE_GIVE_OSD_NAME, noneValidator, DEST_DIRECT);
90        addValidationInfo(Constants.MESSAGE_GIVE_PHYSICAL_ADDRESS,
91                noneValidator, DEST_DIRECT | SRC_UNREGISTERED);
92        addValidationInfo(Constants.MESSAGE_GIVE_SYSTEM_AUDIO_MODE_STATUS,
93                noneValidator, DEST_DIRECT);
94        addValidationInfo(Constants.MESSAGE_IMAGE_VIEW_ON, noneValidator, DEST_DIRECT);
95        addValidationInfo(Constants.MESSAGE_INITIATE_ARC, noneValidator, DEST_DIRECT);
96        addValidationInfo(Constants.MESSAGE_RECORD_OFF, noneValidator, DEST_DIRECT);
97        addValidationInfo(Constants.MESSAGE_RECORD_TV_SCREEN, noneValidator, DEST_DIRECT);
98        addValidationInfo(Constants.MESSAGE_REPORT_ARC_INITIATED, noneValidator, DEST_DIRECT);
99        addValidationInfo(Constants.MESSAGE_REPORT_ARC_TERMINATED, noneValidator, DEST_DIRECT);
100        addValidationInfo(Constants.MESSAGE_REQUEST_ARC_INITIATION, noneValidator, DEST_DIRECT);
101        addValidationInfo(Constants.MESSAGE_REQUEST_ARC_TERMINATION, noneValidator, DEST_DIRECT);
102        addValidationInfo(Constants.MESSAGE_REQUEST_ACTIVE_SOURCE,
103                noneValidator, DEST_BROADCAST | SRC_UNREGISTERED);
104        addValidationInfo(Constants.MESSAGE_STANDBY, noneValidator, DEST_ALL | SRC_UNREGISTERED);
105        addValidationInfo(Constants.MESSAGE_TERMINATE_ARC, noneValidator, DEST_DIRECT);
106        addValidationInfo(Constants.MESSAGE_TEXT_VIEW_ON, noneValidator, DEST_DIRECT);
107        addValidationInfo(Constants.MESSAGE_TUNER_STEP_DECREMENT, noneValidator, DEST_DIRECT);
108        addValidationInfo(Constants.MESSAGE_TUNER_STEP_INCREMENT, noneValidator, DEST_DIRECT);
109        addValidationInfo(Constants.MESSAGE_USER_CONTROL_RELEASED, noneValidator, DEST_DIRECT);
110        addValidationInfo(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_UP, noneValidator, DEST_ALL);
111
112        // TODO: Validate more than length for the following messages.
113
114        // Messages for the One Touch Record.
115        FixedLengthValidator oneByteValidator = new FixedLengthValidator(1);
116        addValidationInfo(Constants.MESSAGE_RECORD_ON,
117                new VariableLengthValidator(1, 8), DEST_DIRECT);
118        addValidationInfo(Constants.MESSAGE_RECORD_STATUS, oneByteValidator, DEST_DIRECT);
119
120        // TODO: Handle messages for the Timer Programming.
121
122        // Messages for the System Information.
123        addValidationInfo(Constants.MESSAGE_CEC_VERSION, oneByteValidator, DEST_DIRECT);
124        addValidationInfo(Constants.MESSAGE_SET_MENU_LANGUAGE,
125                new FixedLengthValidator(3), DEST_BROADCAST);
126
127        // TODO: Handle messages for the Deck Control.
128
129        // TODO: Handle messages for the Tuner Control.
130
131        // Messages for the Vendor Specific Commands.
132        VariableLengthValidator maxLengthValidator = new VariableLengthValidator(0, 14);
133        addValidationInfo(Constants.MESSAGE_DEVICE_VENDOR_ID,
134                new FixedLengthValidator(3), DEST_BROADCAST);
135        // Allow unregistered source for all vendor specific commands, because we don't know
136        // how to use the commands at this moment.
137        addValidationInfo(Constants.MESSAGE_VENDOR_COMMAND,
138                maxLengthValidator, DEST_DIRECT | SRC_UNREGISTERED);
139        addValidationInfo(Constants.MESSAGE_VENDOR_COMMAND_WITH_ID,
140                maxLengthValidator, DEST_ALL | SRC_UNREGISTERED);
141        addValidationInfo(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_DOWN,
142                maxLengthValidator, DEST_ALL | SRC_UNREGISTERED);
143
144        // Messages for the OSD.
145        addValidationInfo(Constants.MESSAGE_SET_OSD_STRING, maxLengthValidator, DEST_DIRECT);
146        addValidationInfo(Constants.MESSAGE_SET_OSD_NAME, maxLengthValidator, DEST_DIRECT);
147
148        // TODO: Handle messages for the Device Menu Control.
149
150        // Messages for the Remote Control Passthrough.
151        // TODO: Parse the first parameter and determine if it can have the next parameter.
152        addValidationInfo(Constants.MESSAGE_USER_CONTROL_PRESSED,
153                new VariableLengthValidator(1, 2), DEST_DIRECT);
154
155        // Messages for the Power Status.
156        addValidationInfo(Constants.MESSAGE_REPORT_POWER_STATUS, oneByteValidator, DEST_DIRECT);
157
158        // Messages for the General Protocol.
159        addValidationInfo(Constants.MESSAGE_FEATURE_ABORT,
160                new FixedLengthValidator(2), DEST_DIRECT);
161
162        // Messages for the System Audio Control.
163        addValidationInfo(Constants.MESSAGE_REPORT_AUDIO_STATUS, oneByteValidator, DEST_DIRECT);
164        addValidationInfo(Constants.MESSAGE_REPORT_SHORT_AUDIO_DESCRIPTOR,
165                new FixedLengthValidator(3), DEST_DIRECT);
166        addValidationInfo(Constants.MESSAGE_REQUEST_SHORT_AUDIO_DESCRIPTOR,
167                oneByteValidator, DEST_DIRECT);
168        addValidationInfo(Constants.MESSAGE_SET_SYSTEM_AUDIO_MODE, oneByteValidator, DEST_ALL);
169        addValidationInfo(Constants.MESSAGE_SYSTEM_AUDIO_MODE_STATUS,
170                oneByteValidator, DEST_DIRECT);
171
172        // Messages for the Audio Rate Control.
173        addValidationInfo(Constants.MESSAGE_SET_AUDIO_RATE, oneByteValidator, DEST_DIRECT);
174
175        // All Messages for the ARC have no parameters.
176
177        // Messages for the Capability Discovery and Control.
178        addValidationInfo(Constants.MESSAGE_CDC_MESSAGE, maxLengthValidator,
179                DEST_BROADCAST | SRC_UNREGISTERED);
180    }
181
182    private void addValidationInfo(int opcode, ParameterValidator validator, int addrType) {
183        mValidationInfo.append(opcode, new ValidationInfo(validator, addrType));
184    }
185
186    int isValid(HdmiCecMessage message) {
187        int opcode = message.getOpcode();
188        ValidationInfo info = mValidationInfo.get(opcode);
189        if (info == null) {
190            HdmiLogger.warning("No validation information for the message: " + message);
191            return OK;
192        }
193
194        // Check the source field.
195        if (message.getSource() == Constants.ADDR_UNREGISTERED &&
196                (info.addressType & SRC_UNREGISTERED) == 0) {
197            HdmiLogger.warning("Unexpected source: " + message);
198            return ERROR_SOURCE;
199        }
200        // Check the destination field.
201        if (message.getDestination() == Constants.ADDR_BROADCAST) {
202            if ((info.addressType & DEST_BROADCAST) == 0) {
203                HdmiLogger.warning("Unexpected broadcast message: " + message);
204                return ERROR_DESTINATION;
205            }
206        } else {  // Direct addressing.
207            if ((info.addressType & DEST_DIRECT) == 0) {
208                HdmiLogger.warning("Unexpected direct message: " + message);
209                return ERROR_DESTINATION;
210            }
211        }
212
213        // Check the parameter type.
214        if (!info.parameterValidator.isValid(message.getParams())) {
215            HdmiLogger.warning("Unexpected parameters: " + message);
216            return ERROR_PARAMETER;
217        }
218        return OK;
219    }
220
221    private static class FixedLengthValidator implements ParameterValidator {
222        private final int mLength;
223
224        public FixedLengthValidator(int length) {
225            mLength = length;
226        }
227
228        @Override
229        public boolean isValid(byte[] params) {
230            return params.length == mLength;
231        }
232    }
233
234    private static class VariableLengthValidator implements ParameterValidator {
235        private final int mMinLength;
236        private final int mMaxLength;
237
238        public VariableLengthValidator(int minLength, int maxLength) {
239            mMinLength = minLength;
240            mMaxLength = maxLength;
241        }
242
243        @Override
244        public boolean isValid(byte[] params) {
245            return params.length >= mMinLength && params.length <= mMaxLength;
246        }
247    }
248
249    private boolean isValidPhysicalAddress(byte[] params, int offset) {
250        // TODO: Add more logic like validating 1.0.1.0.
251
252        if (!mService.isTvDevice()) {
253            // If the device is not TV, we can't convert path to port-id, so stop here.
254            return true;
255        }
256        int path = HdmiUtils.twoBytesToInt(params, offset);
257        if (path != Constants.INVALID_PHYSICAL_ADDRESS && path == mService.getPhysicalAddress()) {
258            return true;
259        }
260        int portId = mService.pathToPortId(path);
261        if (portId == Constants.INVALID_PORT_ID) {
262            return false;
263        }
264        return true;
265    }
266
267    /**
268     * Check if the given type is valid. A valid type is one of the actual logical device types
269     * defined in the standard ({@link HdmiDeviceInfo#DEVICE_TV},
270     * {@link HdmiDeviceInfo#DEVICE_PLAYBACK}, {@link HdmiDeviceInfo#DEVICE_TUNER},
271     * {@link HdmiDeviceInfo#DEVICE_RECORDER}, and
272     * {@link HdmiDeviceInfo#DEVICE_AUDIO_SYSTEM}).
273     *
274     * @param type device type
275     * @return true if the given type is valid
276     */
277    static boolean isValidType(int type) {
278        return (HdmiDeviceInfo.DEVICE_TV <= type
279                && type <= HdmiDeviceInfo.DEVICE_VIDEO_PROCESSOR)
280                && type != HdmiDeviceInfo.DEVICE_RESERVED;
281    }
282
283    private class PhysicalAddressValidator implements ParameterValidator {
284        @Override
285        public boolean isValid(byte[] params) {
286            if (params.length != 2) {
287                return false;
288            }
289            return isValidPhysicalAddress(params, 0);
290        }
291    }
292
293    private class ReportPhysicalAddressValidator implements ParameterValidator {
294        @Override
295        public boolean isValid(byte[] params) {
296            if (params.length != 3) {
297                return false;
298            }
299            return isValidPhysicalAddress(params, 0) && isValidType(params[2]);
300        }
301    }
302
303    private class RoutingChangeValidator implements ParameterValidator {
304        @Override
305        public boolean isValid(byte[] params) {
306            if (params.length != 4) {
307                return false;
308            }
309            return isValidPhysicalAddress(params, 0) && isValidPhysicalAddress(params, 2);
310        }
311    }
312}
313