Home | History | Annotate | Download | only in hdmi 
      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 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