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Commit d0d1e688 authored by Robert Wu's avatar Robert Wu
Browse files

MIDI: Check MIDI permission before parsing XML 

MidiService is parsing the XML of installed packages.
This is relatively expensive.

This CL changes it so permissions and flags are checked first.

This CL also adds additional null checks.

Bug: 315203699
Test: atest MidiEchoTest
Change-Id: I57e332f2afdcc54cc67986b8a8b2941ee1899c26
parent 0edd8471

services/midi/java/com/android/server/midi/MidiService.java

+40 −17
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ import android.content.ServiceConnection; 
import android.content.pm.ApplicationInfo;

import android.content.pm.PackageInfo;

import android.content.pm.PackageManager;

import android.content.pm.PackageManager.Property;

import android.content.pm.ResolveInfo;

import android.content.pm.ServiceInfo;

import android.content.res.Resources;
@@ -1396,16 +1397,20 @@ public class MidiService extends IMidiManager.Stub { 
        XmlResourceParser parser = null;



        try {

            parser = serviceInfo.loadXmlMetaData(mPackageManager,

                    MidiDeviceService.SERVICE_INTERFACE);

            if (parser == null) return;

            if (serviceInfo == null) {

                Log.w(TAG, "Skipping null service info");

                return;

            }



            // ignore virtual device servers that do not require the correct permission

            if (!android.Manifest.permission.BIND_MIDI_DEVICE_SERVICE.equals(

                    serviceInfo.permission)) {

                Log.w(TAG, "Skipping MIDI device service " + serviceInfo.packageName

                        + ": it does not require the permission "

                        + android.Manifest.permission.BIND_MIDI_DEVICE_SERVICE);

                return;

            }

            parser = serviceInfo.loadXmlMetaData(mPackageManager,

                    MidiDeviceService.SERVICE_INTERFACE);

            if (parser == null) {

                Log.w(TAG, "loading xml metadata failed");

                return;

            }
@@ -1533,21 +1538,14 @@ public class MidiService extends IMidiManager.Stub { 
        XmlResourceParser parser = null;



        try {

            ComponentName componentName = new ComponentName(serviceInfo.packageName,

                    serviceInfo.name);

            int resId = mPackageManager.getProperty(MidiUmpDeviceService.SERVICE_INTERFACE,

                    componentName).getResourceId();

            Resources resources = mPackageManager.getResourcesForApplication(

                    serviceInfo.packageName);

            parser = resources.getXml(resId);

            if (parser == null) return;

            if (serviceInfo == null) {

                Log.w(TAG, "Skipping null service info");

                return;

            }



            // ignore virtual device servers that do not require the correct permission

            if (!android.Manifest.permission.BIND_MIDI_DEVICE_SERVICE.equals(

                    serviceInfo.permission)) {

                Log.w(TAG, "Skipping MIDI device service " + serviceInfo.packageName

                        + ": it does not require the permission "

                        + android.Manifest.permission.BIND_MIDI_DEVICE_SERVICE);

                return;

            }
@@ -1557,6 +1555,31 @@ public class MidiService extends IMidiManager.Stub { 
                return;

            }



            ComponentName componentName = new ComponentName(serviceInfo.packageName,

                    serviceInfo.name);

            Property property = mPackageManager.getProperty(MidiUmpDeviceService.SERVICE_INTERFACE,

                    componentName);

            if (property == null) {

                Log.w(TAG, "Getting MidiUmpDeviceService property failed");

                return;

            }

            int resId = property.getResourceId();

            if (resId == 0) {

                Log.w(TAG, "Getting MidiUmpDeviceService resourceId failed");

                return;

            }

            Resources resources = mPackageManager.getResourcesForApplication(

                    serviceInfo.packageName);

            if (resources == null) {

                Log.w(TAG, "Getting resource failed " + serviceInfo.packageName);

                return;

            }

            parser = resources.getXml(resId);

            if (parser == null) {

                Log.w(TAG, "Getting XML failed " + resId);

                return;

            }



            Bundle properties = null;

            int numPorts = 0;

            boolean isPrivate = false;