spoofing signatures only for system apps

    <!-- @hide Allows an application to change the package signature as

	 seen by applications -->

    <permission android:name="android.permission.FAKE_PACKAGE_SIGNATURE"

        android:protectionLevel="dangerous"

        android:protectionLevel="signatureOrSystem"

        android:label="@string/permlab_fakePackageSignature"

        android:description="@string/permdesc_fakePackageSignature" />