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Commit 3ce1db0b authored by Shraddha Basantwani's avatar Shraddha Basantwani
Browse files

CEC : Add OSD String Validator for CEC Messages 

Test: atest HdmiCecMessageValidatorTest
Bug: 170811408
Change-Id: Id53a8305b5b5339881f46a891fa20cc5f4d50094
parent 5985c85b

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

+34 −1
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ public class HdmiCecMessageValidator { 
                maxLengthValidator, DEST_ALL | SRC_UNREGISTERED);



        // Messages for the OSD.

        addValidationInfo(Constants.MESSAGE_SET_OSD_STRING, maxLengthValidator, DEST_DIRECT);

        addValidationInfo(Constants.MESSAGE_SET_OSD_STRING, new OsdStringValidator(), DEST_DIRECT);

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



        // Messages for the Device Menu Control.
@@ -299,6 +299,18 @@ public class HdmiCecMessageValidator { 
        return (value >= min && value <= max);

    }



    /**

     * Check if the given value is a valid Display Control. A valid value is one which falls within

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

     *

     * @param value Display Control

     * @return true if the Display Control is valid

     */

    private boolean isValidDisplayControl(int value) {

        value = value & 0xFF;

        return (value == 0x00 || value == 0x40 || value == 0x80 || value == 0xC0);

    }



    /**

     * Check if the given params has valid ASCII characters.

     * A valid ASCII character is a printable character. It should fall within range description
@@ -408,4 +420,25 @@ public class HdmiCecMessageValidator { 
            return toErrorCode(isValidAsciiString(params, 0, mMaxLength));

        }

    }



    /**

     * Check if the given parameters is valid OSD String.

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

     * Specification : Operand Descriptions (Section 17)

     */

    private class OsdStringValidator implements ParameterValidator {

        @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 < 2) {

                return ERROR_PARAMETER_SHORT;

            }

            return toErrorCode(

                    // Display Control

                    isValidDisplayControl(params[0])

                    // OSD String

                    && isValidAsciiString(params, 1, 14));

        }

    }

}

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

+16 −0
Original line number Diff line number Diff line
@@ -83,6 +83,22 @@ public class HdmiCecMessageValidatorTest { 
        assertMessageValidity("4F:32:19:7F:83").isEqualTo(ERROR_PARAMETER);

    }



    @Test

    public void isValid_setOsdString() {

        assertMessageValidity("40:64:80:41").isEqualTo(OK);

        // Even though the parameter string in this message is longer than 14 bytes, it is accepted

        // as this parameter might be extended in future versions.

        assertMessageValidity("04:64:00:4C:69:76:69:6E:67:52:6F:6F:6D:20:54:56:C4").isEqualTo(OK);



        assertMessageValidity("4F:64:40:41").isEqualTo(ERROR_DESTINATION);

        assertMessageValidity("F0:64:C0:41").isEqualTo(ERROR_SOURCE);

        assertMessageValidity("40:64:00").isEqualTo(ERROR_PARAMETER_SHORT);

        // Invalid Display Control

        assertMessageValidity("40:64:20:4C:69:76").isEqualTo(ERROR_PARAMETER);

        // Invalid ASCII characters

        assertMessageValidity("40:64:40:4C:69:7F").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);