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 
     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         // Messages for the Device Menu Control.
    149         addValidationInfo(Constants.MESSAGE_MENU_REQUEST, oneByteValidator, DEST_DIRECT);
    150         addValidationInfo(Constants.MESSAGE_MENU_STATUS, oneByteValidator, DEST_DIRECT);
    151 
    152         // Messages for the Remote Control Passthrough.
    153         // TODO: Parse the first parameter and determine if it can have the next parameter.
    154         addValidationInfo(Constants.MESSAGE_USER_CONTROL_PRESSED,
    155                 new VariableLengthValidator(1, 2), DEST_DIRECT);
    156 
    157         // Messages for the Power Status.
    158         addValidationInfo(Constants.MESSAGE_REPORT_POWER_STATUS, oneByteValidator, DEST_DIRECT);
    159 
    160         // Messages for the General Protocol.
    161         addValidationInfo(Constants.MESSAGE_FEATURE_ABORT,
    162                 new FixedLengthValidator(2), DEST_DIRECT);
    163 
    164         // Messages for the System Audio Control.
    165         addValidationInfo(Constants.MESSAGE_REPORT_AUDIO_STATUS, oneByteValidator, DEST_DIRECT);
    166         addValidationInfo(Constants.MESSAGE_REPORT_SHORT_AUDIO_DESCRIPTOR,
    167                 new FixedLengthValidator(3), DEST_DIRECT);
    168         addValidationInfo(Constants.MESSAGE_REQUEST_SHORT_AUDIO_DESCRIPTOR,
    169                 oneByteValidator, DEST_DIRECT);
    170         addValidationInfo(Constants.MESSAGE_SET_SYSTEM_AUDIO_MODE, oneByteValidator, DEST_ALL);
    171         addValidationInfo(Constants.MESSAGE_SYSTEM_AUDIO_MODE_STATUS,
    172                 oneByteValidator, DEST_DIRECT);
    173 
    174         // Messages for the Audio Rate Control.
    175         addValidationInfo(Constants.MESSAGE_SET_AUDIO_RATE, oneByteValidator, DEST_DIRECT);
    176 
    177         // All Messages for the ARC have no parameters.
    178 
    179         // Messages for the Capability Discovery and Control.
    180         addValidationInfo(Constants.MESSAGE_CDC_MESSAGE, maxLengthValidator,
    181                 DEST_BROADCAST | SRC_UNREGISTERED);
    182     }
    183 
    184     private void addValidationInfo(int opcode, ParameterValidator validator, int addrType) {
    185         mValidationInfo.append(opcode, new ValidationInfo(validator, addrType));
    186     }
    187 
    188     int isValid(HdmiCecMessage message) {
    189         int opcode = message.getOpcode();
    190         ValidationInfo info = mValidationInfo.get(opcode);
    191         if (info == null) {
    192             HdmiLogger.warning("No validation information for the message: " + message);
    193             return OK;
    194         }
    195 
    196         // Check the source field.
    197         if (message.getSource() == Constants.ADDR_UNREGISTERED &&
    198                 (info.addressType & SRC_UNREGISTERED) == 0) {
    199             HdmiLogger.warning("Unexpected source: " + message);
    200             return ERROR_SOURCE;
    201         }
    202         // Check the destination field.
    203         if (message.getDestination() == Constants.ADDR_BROADCAST) {
    204             if ((info.addressType & DEST_BROADCAST) == 0) {
    205                 HdmiLogger.warning("Unexpected broadcast message: " + message);
    206                 return ERROR_DESTINATION;
    207             }
    208         } else {  // Direct addressing.
    209             if ((info.addressType & DEST_DIRECT) == 0) {
    210                 HdmiLogger.warning("Unexpected direct message: " + message);
    211                 return ERROR_DESTINATION;
    212             }
    213         }
    214 
    215         // Check the parameter type.
    216         if (!info.parameterValidator.isValid(message.getParams())) {
    217             HdmiLogger.warning("Unexpected parameters: " + message);
    218             return ERROR_PARAMETER;
    219         }
    220         return OK;
    221     }
    222 
    223     private static class FixedLengthValidator implements ParameterValidator {
    224         private final int mLength;
    225 
    226         public FixedLengthValidator(int length) {
    227             mLength = length;
    228         }
    229 
    230         @Override
    231         public boolean isValid(byte[] params) {
    232             return params.length == mLength;
    233         }
    234     }
    235 
    236     private static class VariableLengthValidator implements ParameterValidator {
    237         private final int mMinLength;
    238         private final int mMaxLength;
    239 
    240         public VariableLengthValidator(int minLength, int maxLength) {
    241             mMinLength = minLength;
    242             mMaxLength = maxLength;
    243         }
    244 
    245         @Override
    246         public boolean isValid(byte[] params) {
    247             return params.length >= mMinLength && params.length <= mMaxLength;
    248         }
    249     }
    250 
    251     private boolean isValidPhysicalAddress(byte[] params, int offset) {
    252         // TODO: Add more logic like validating 1.0.1.0.
    253 
    254         if (!mService.isTvDevice()) {
    255             // If the device is not TV, we can't convert path to port-id, so stop here.
    256             return true;
    257         }
    258         int path = HdmiUtils.twoBytesToInt(params, offset);
    259         if (path != Constants.INVALID_PHYSICAL_ADDRESS && path == mService.getPhysicalAddress()) {
    260             return true;
    261         }
    262         int portId = mService.pathToPortId(path);
    263         if (portId == Constants.INVALID_PORT_ID) {
    264             return false;
    265         }
    266         return true;
    267     }
    268 
    269     /**
    270      * Check if the given type is valid. A valid type is one of the actual logical device types
    271      * defined in the standard ({@link HdmiDeviceInfo#DEVICE_TV},
    272      * {@link HdmiDeviceInfo#DEVICE_PLAYBACK}, {@link HdmiDeviceInfo#DEVICE_TUNER},
    273      * {@link HdmiDeviceInfo#DEVICE_RECORDER}, and
    274      * {@link HdmiDeviceInfo#DEVICE_AUDIO_SYSTEM}).
    275      *
    276      * @param type device type
    277      * @return true if the given type is valid
    278      */
    279     static boolean isValidType(int type) {
    280         return (HdmiDeviceInfo.DEVICE_TV <= type
    281                 && type <= HdmiDeviceInfo.DEVICE_VIDEO_PROCESSOR)
    282                 && type != HdmiDeviceInfo.DEVICE_RESERVED;
    283     }
    284 
    285     private class PhysicalAddressValidator implements ParameterValidator {
    286         @Override
    287         public boolean isValid(byte[] params) {
    288             if (params.length != 2) {
    289                 return false;
    290             }
    291             return isValidPhysicalAddress(params, 0);
    292         }
    293     }
    294 
    295     private class ReportPhysicalAddressValidator implements ParameterValidator {
    296         @Override
    297         public boolean isValid(byte[] params) {
    298             if (params.length != 3) {
    299                 return false;
    300             }
    301             return isValidPhysicalAddress(params, 0) && isValidType(params[2]);
    302         }
    303     }
    304 
    305     private class RoutingChangeValidator implements ParameterValidator {
    306         @Override
    307         public boolean isValid(byte[] params) {
    308             if (params.length != 4) {
    309                 return false;
    310             }
    311             return isValidPhysicalAddress(params, 0) && isValidPhysicalAddress(params, 2);
    312         }
    313     }
    314 }
    315