Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5985c85b authored by Shraddha Basantwani's avatar Shraddha Basantwani
Browse files

CEC : Add ASCII validator for CEC messages 

Test: atest HdmiCecMessageValidatorTest
Bug: 170811408
Change-Id: Ie74822a660e1b360d694629b90497b0a6f5ddcb1
parent 8fafabfe

services/core/java/com/android/server/hdmi/HdmiCecMessageValidator.java

+51 −2
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ public class HdmiCecMessageValidator { 
        FixedLengthValidator oneByteValidator = new FixedLengthValidator(1);

        addValidationInfo(Constants.MESSAGE_CEC_VERSION, oneByteValidator, DEST_DIRECT);

        addValidationInfo(Constants.MESSAGE_SET_MENU_LANGUAGE,

                new FixedLengthValidator(3), DEST_BROADCAST);

                new AsciiValidator(3), DEST_BROADCAST);



        // TODO: Handle messages for the Deck Control.
@@ -149,7 +149,7 @@ public class HdmiCecMessageValidator { 


        // Messages for the OSD.

        addValidationInfo(Constants.MESSAGE_SET_OSD_STRING, maxLengthValidator, DEST_DIRECT);

        addValidationInfo(Constants.MESSAGE_SET_OSD_NAME, maxLengthValidator, DEST_DIRECT);

        addValidationInfo(Constants.MESSAGE_SET_OSD_NAME, new AsciiValidator(1, 14), DEST_DIRECT);



        // Messages for the Device Menu Control.

        addValidationInfo(Constants.MESSAGE_MENU_REQUEST, oneByteValidator, DEST_DIRECT);
@@ -299,6 +299,25 @@ public class HdmiCecMessageValidator { 
        return (value >= min && value <= max);

    }



    /**

     * Check if the given params has valid ASCII characters.

     * A valid ASCII character is a printable character. It should fall within range description

     * defined in CEC 1.4 Specification : Operand Descriptions (Section 17)

     *

     * @param params parameter consisting of string

     * @param offset Start offset of string

     * @param maxLength Maximum length of string to be evaluated

     * @return true if the given type is valid

     */

    private boolean isValidAsciiString(byte[] params, int offset, int maxLength) {

        for (int i = offset; i < params.length && i < maxLength; i++) {

            if (!isWithinRange(params[i], 0x20, 0x7E)) {

                return false;

            }

        }

        return true;

    }



    private class PhysicalAddressValidator implements ParameterValidator {

        @Override

        public int isValid(byte[] params) {
@@ -359,4 +378,34 @@ public class HdmiCecMessageValidator { 
                            || params[0] == 0x1F);

        }

    }



    /**

     * Check if the given parameters represents printable characters.

     * A valid parameter should lie within the range description of ASCII defined in CEC 1.4

     * Specification : Operand Descriptions (Section 17)

     */

    private class AsciiValidator implements ParameterValidator {

        private final int mMinLength;

        private final int mMaxLength;



        AsciiValidator(int length) {

            mMinLength = length;

            mMaxLength = length;

        }



        AsciiValidator(int minLength, int maxLength) {

            mMinLength = minLength;

            mMaxLength = maxLength;

        }



        @Override

        public int isValid(byte[] params) {

            // If the length is longer than expected, we assume it's OK since the parameter can be

            // extended in the future version.

            if (params.length < mMinLength) {

                return ERROR_PARAMETER_SHORT;

            }

            return toErrorCode(isValidAsciiString(params, 0, mMaxLength));

        }

    }

}

services/tests/servicestests/src/com/android/server/hdmi/HdmiCecMessageValidatorTest.java

+23 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
package com.android.server.hdmi;



import static com.android.server.hdmi.HdmiCecMessageValidator.ERROR_DESTINATION;

import static com.android.server.hdmi.HdmiCecMessageValidator.ERROR_PARAMETER;

import static com.android.server.hdmi.HdmiCecMessageValidator.ERROR_PARAMETER_SHORT;

import static com.android.server.hdmi.HdmiCecMessageValidator.ERROR_SOURCE;

import static com.android.server.hdmi.HdmiCecMessageValidator.OK;
@@ -71,6 +72,28 @@ public class HdmiCecMessageValidatorTest { 
        assertMessageValidity("04:90").isEqualTo(ERROR_PARAMETER_SHORT);

    }



    @Test

    public void isValid_setMenuLanguage() {

        assertMessageValidity("4F:32:53:50:41").isEqualTo(OK);

        assertMessageValidity("0F:32:45:4E:47:8C:49:D3:48").isEqualTo(OK);



        assertMessageValidity("40:32:53:50:41").isEqualTo(ERROR_DESTINATION);

        assertMessageValidity("F0:32").isEqualTo(ERROR_SOURCE);

        assertMessageValidity("4F:32:45:55").isEqualTo(ERROR_PARAMETER_SHORT);

        assertMessageValidity("4F:32:19:7F:83").isEqualTo(ERROR_PARAMETER);

    }



    @Test

    public void isValid_setOsdName() {

        assertMessageValidity("40:47:4C:69:76:69:6E:67:52:6F:6F:6D:54:56").isEqualTo(OK);

        assertMessageValidity("40:47:54:56").isEqualTo(OK);



        assertMessageValidity("4F:47:54:56").isEqualTo(ERROR_DESTINATION);

        assertMessageValidity("F0:47:54:56").isEqualTo(ERROR_SOURCE);

        assertMessageValidity("40:47").isEqualTo(ERROR_PARAMETER_SHORT);

        assertMessageValidity("40:47:4C:69:7F").isEqualTo(ERROR_PARAMETER);

    }



    private IntegerSubject assertMessageValidity(String message) {

        return assertThat(mHdmiCecMessageValidator.isValid(buildMessage(message)));

    }