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Commit 874d8163 authored by sandeepbandaru's avatar sandeepbandaru
Browse files

Adding method to check if a Parcel has any Binders marshalled in it. 

This is an extension to the existing `hasFileDescriptors` method, both of which are "Active Objects" of a sort and allow writes across processes.
This check would be useful to perform validations on Bundle entries or
any Parcelable type if it only contains non-active objects and can be
essentially treated read only without having to inspect the marshalled
parcel object.

Test: TODO
Bug: 316589195
API-Coverage-Bug: 323147058
Change-Id: I1fd8c8a27e3e7b90df8fefb0fe77bbad908db6b6
parent dc6f83dd

core/java/android/os/Parcel.java

+32 −0
Original line number Diff line number Diff line
@@ -475,6 +475,10 @@ public final class Parcel { 
    private static native boolean nativeHasFileDescriptors(long nativePtr);

    private static native boolean nativeHasFileDescriptorsInRange(

            long nativePtr, int offset, int length);



    private static native boolean nativeHasBinders(long nativePtr);

    private static native boolean nativeHasBindersInRange(

            long nativePtr, int offset, int length);

    @RavenwoodThrow

    private static native void nativeWriteInterfaceToken(long nativePtr, String interfaceName);

    @RavenwoodThrow
@@ -969,6 +973,34 @@ public final class Parcel { 
        return false;

    }



    /**

     * Report whether the parcel contains any marshalled IBinder objects.

     *

     * @throws UnsupportedOperationException if binder kernel driver was disabled or if method was

     *                                       invoked in case of Binder RPC protocol.

     * @hide

     */

    public boolean hasBinders() {

        return nativeHasBinders(mNativePtr);

    }



    /**

     * Report whether the parcel contains any marshalled {@link IBinder} objects in the range

     * defined by {@code offset} and {@code length}.

     *

     * @param offset The offset from which the range starts. Should be between 0 and

     *               {@link #dataSize()}.

     * @param length The length of the range. Should be between 0 and {@link #dataSize()} - {@code

     *               offset}.

     * @return whether there are binders in the range or not.

     * @throws IllegalArgumentException if the parameters are out of the permitted ranges.

     *

     * @hide

     */

    public boolean hasBinders(int offset, int length) {

        return nativeHasBindersInRange(mNativePtr, offset, length);

    }



    /**

     * Store or read an IBinder interface token in the parcel at the current

     * {@link #dataPosition}. This is used to validate that the marshalled

core/jni/android_os_Parcel.cpp

+34 −1
Original line number Diff line number Diff line
@@ -661,6 +661,35 @@ static void android_os_Parcel_appendFrom(JNIEnv* env, jclass clazz, jlong thisNa 
    return;

}



static jboolean android_os_Parcel_hasBinders(JNIEnv* env, jclass clazz, jlong nativePtr) {

    Parcel* parcel = reinterpret_cast<Parcel*>(nativePtr);

    if (parcel != NULL) {

        bool result;

        status_t err = parcel->hasBinders(&result);

        if (err != NO_ERROR) {

            signalExceptionForError(env, clazz, err);

            return JNI_FALSE;

        }

        return result ? JNI_TRUE : JNI_FALSE;

    }

    return JNI_FALSE;

}



static jboolean android_os_Parcel_hasBindersInRange(JNIEnv* env, jclass clazz, jlong nativePtr,

                                                    jint offset, jint length) {

    Parcel* parcel = reinterpret_cast<Parcel*>(nativePtr);

    if (parcel != NULL) {

        bool result;

        status_t err = parcel->hasBindersInRange(offset, length, &result);

        if (err != NO_ERROR) {

            signalExceptionForError(env, clazz, err);

            return JNI_FALSE;

        }

        return result ? JNI_TRUE : JNI_FALSE;

    }

    return JNI_FALSE;

}



static jboolean android_os_Parcel_hasFileDescriptors(jlong nativePtr)

{

    jboolean ret = JNI_FALSE;
@@ -806,7 +835,7 @@ static jboolean android_os_Parcel_replaceCallingWorkSourceUid(jlong nativePtr, j 
}



// ----------------------------------------------------------------------------



// clang-format off

static const JNINativeMethod gParcelMethods[] = {

    // @CriticalNative

    {"nativeMarkSensitive",       "(J)V", (void*)android_os_Parcel_markSensitive},
@@ -886,6 +915,9 @@ static const JNINativeMethod gParcelMethods[] = { 
    // @CriticalNative

    {"nativeHasFileDescriptors",  "(J)Z", (void*)android_os_Parcel_hasFileDescriptors},

    {"nativeHasFileDescriptorsInRange",  "(JII)Z", (void*)android_os_Parcel_hasFileDescriptorsInRange},



    {"nativeHasBinders",  "(J)Z", (void*)android_os_Parcel_hasBinders},

    {"nativeHasBindersInRange",  "(JII)Z", (void*)android_os_Parcel_hasBindersInRange},

    {"nativeWriteInterfaceToken", "(JLjava/lang/String;)V", (void*)android_os_Parcel_writeInterfaceToken},

    {"nativeEnforceInterface",    "(JLjava/lang/String;)V", (void*)android_os_Parcel_enforceInterface},
@@ -900,6 +932,7 @@ static const JNINativeMethod gParcelMethods[] = { 
    // @CriticalNative

    {"nativeReplaceCallingWorkSourceUid", "(JI)Z", (void*)android_os_Parcel_replaceCallingWorkSourceUid},

};

// clang-format on



const char* const kParcelPathName = "android/os/Parcel";

core/tests/coretests/src/android/os/ParcelTest.java

+26 −0
Original line number Diff line number Diff line
@@ -347,4 +347,30 @@ public class ParcelTest { 
        p.recycle();

        Binder.setIsDirectlyHandlingTransactionOverride(false);

    }



    @Test

    @IgnoreUnderRavenwood(blockedBy = Parcel.class)

    public void testHasBinders_AfterWritingBinderToParcel() {

        Binder binder = new Binder();

        Parcel pA = Parcel.obtain();

        int iA = pA.dataPosition();

        pA.writeInt(13);

        assertFalse(pA.hasBinders());

        pA.writeStrongBinder(binder);

        assertTrue(pA.hasBinders());

    }





    @Test

    @IgnoreUnderRavenwood(blockedBy = Parcel.class)

    public void testHasBindersInRange_AfterWritingBinderToParcel() {

        Binder binder = new Binder();

        Parcel pA = Parcel.obtain();

        pA.writeInt(13);



        int binderStartPos = pA.dataPosition();

        pA.writeStrongBinder(binder);

        int binderEndPos = pA.dataPosition();

        assertTrue(pA.hasBinders(binderStartPos, binderEndPos - binderStartPos));

    }

}

ravenwood/runtime-helper-src/framework/com/android/platform/test/ravenwood/nativesubstitution/Parcel_host.java

+12 −0
Original line number Diff line number Diff line
@@ -383,9 +383,21 @@ public class Parcel_host { 
        // Assume false for now, because we don't support writing FDs yet.

        return false;

    }



    public static boolean nativeHasFileDescriptorsInRange(

            long nativePtr, int offset, int length) {

        // Assume false for now, because we don't support writing FDs yet.

        return false;

    }



    public static boolean nativeHasBinders(long nativePtr) {

        // Assume false for now, because we don't support adding binders.

        return false;

    }



    public static boolean nativeHasBindersInRange(

            long nativePtr, int offset, int length) {

        // Assume false for now, because we don't support writing FDs yet.

        return false;

    }

}