Enforce MediaButtonReceiver extracted component name matches session package name

This change makes sure that the extracted component name in a
MediaButtonReceiverHolder matches the Media Session owner's package
name. This avoids incorrectly routing media button events and potential
security issues.

Bug: 244312001
Bug: 238177121
Test: atest CtsMediaBetterTogetherTestCases
Change-Id: Ifac9cf53889222e31d18c14c1e096ee68c0a346c
(cherry picked from commit 185c3e2523)
Merged-In: Ifac9cf53889222e31d18c14c1e096ee68c0a346c

media/java/android/media/session/ISession.aidl

@@ -35,7 +35,7 @@ interface ISession {
     ISessionController getController();
     void setFlags(int flags);
     void setActive(boolean active);
-    void setMediaButtonReceiver(in PendingIntent mbr, String sessionPackageName);
+    void setMediaButtonReceiver(in PendingIntent mbr);
     void setMediaButtonBroadcastReceiver(in ComponentName broadcastReceiver);
     void setLaunchPendingIntent(in PendingIntent pi);
     void destroySession();

media/java/android/media/session/MediaSession.java

@@ -286,7 +286,7 @@ public final class MediaSession {
     @Deprecated
     public void setMediaButtonReceiver(@Nullable PendingIntent mbr) {
         try {
-            mBinder.setMediaButtonReceiver(mbr, mContext.getPackageName());
+            mBinder.setMediaButtonReceiver(mbr);
         } catch (RemoteException e) {
             Log.wtf(TAG, "Failure in setMediaButtonReceiver.", e);
         }

services/core/java/com/android/server/media/MediaButtonReceiverHolder.java

@@ -18,6 +18,7 @@ package com.android.server.media;
 
 import android.annotation.IntDef;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.app.BroadcastOptions;
 import android.app.PendingIntent;
 import android.content.ComponentName;
@@ -37,6 +38,7 @@ import android.view.KeyEvent;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -102,15 +104,19 @@ final class MediaButtonReceiverHolder {
     }
 
     /**
-     * Creates a new instance.
+     * Creates a new instance from a {@link PendingIntent}.
+     *
+     * <p>This method assumes the session package name has been validated and effectively belongs to
+     * the media session's owner.
      *
-     * @param context context
      * @param userId userId
-     * @param pendingIntent pending intent
-     * @return Can be {@code null} if pending intent was null.
+     * @param pendingIntent pending intent that will receive media button events
+     * @param sessionPackageName package name of media session owner
+     * @return {@link MediaButtonReceiverHolder} instance or {@code null} if pending intent was
+     *     null.
      */
-    public static MediaButtonReceiverHolder create(Context context, int userId,
-            PendingIntent pendingIntent, String sessionPackageName) {
+    public static MediaButtonReceiverHolder create(
+            int userId, @Nullable PendingIntent pendingIntent, String sessionPackageName) {
         if (pendingIntent == null) {
             return null;
         }
@@ -312,7 +318,7 @@ final class MediaButtonReceiverHolder {
     }
 
     private static ComponentName getComponentName(PendingIntent pendingIntent, int componentType) {
-        List<ResolveInfo> resolveInfos = null;
+        List<ResolveInfo> resolveInfos = Collections.emptyList();
         switch (componentType) {
             case COMPONENT_TYPE_ACTIVITY:
                 resolveInfos = pendingIntent.queryIntentComponents(
@@ -330,32 +336,37 @@ final class MediaButtonReceiverHolder {
                         PACKAGE_MANAGER_COMMON_FLAGS | PackageManager.GET_RECEIVERS);
                 break;
         }
-        if (resolveInfos != null && !resolveInfos.isEmpty()) {
-            return createComponentName(resolveInfos.get(0));
+
+        for (ResolveInfo resolveInfo : resolveInfos) {
+            ComponentInfo componentInfo = getComponentInfo(resolveInfo);
+            if (componentInfo != null && TextUtils.equals(componentInfo.packageName,
+                    pendingIntent.getCreatorPackage())
+                    && componentInfo.packageName != null && componentInfo.name != null) {
+                return new ComponentName(componentInfo.packageName, componentInfo.name);
+            }
         }
+
         return null;
     }
 
-    private static ComponentName createComponentName(ResolveInfo resolveInfo) {
-        if (resolveInfo == null) {
-            return null;
-        }
-        ComponentInfo componentInfo;
+    /**
+     * Retrieves the {@link ComponentInfo} from a {@link ResolveInfo} instance. Similar to {@link
+     * ResolveInfo#getComponentInfo()}, but returns {@code null} if this {@link ResolveInfo} points
+     * to a content provider.
+     *
+     * @param resolveInfo Where to extract the {@link ComponentInfo} from.
+     * @return Either a non-null {@link ResolveInfo#activityInfo} or {@link
+     *     ResolveInfo#serviceInfo}. Otherwise {@code null} if {@link ResolveInfo#providerInfo} is
+     *     not {@code null}.
+     */
+    private static ComponentInfo getComponentInfo(@NonNull ResolveInfo resolveInfo) {
         // Code borrowed from ResolveInfo#getComponentInfo().
         if (resolveInfo.activityInfo != null) {
-            componentInfo = resolveInfo.activityInfo;
+            return resolveInfo.activityInfo;
         } else if (resolveInfo.serviceInfo != null) {
-            componentInfo = resolveInfo.serviceInfo;
+            return resolveInfo.serviceInfo;
         } else {
-            // We're not interested in content provider.
-            return null;
-        }
-        // Code borrowed from ComponentInfo#getComponentName().
-        try {
-            return new ComponentName(componentInfo.packageName, componentInfo.name);
-        } catch (IllegalArgumentException | NullPointerException e) {
-            // This may be happen if resolveActivity() end up with matching multiple activities.
-            // see PackageManager#resolveActivity().
+            // We're not interested in content providers.
             return null;
         }
     }

services/core/java/com/android/server/media/MediaSessionRecord.java

@@ -933,8 +933,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR
         }
 
         @Override
-        public void setMediaButtonReceiver(PendingIntent pi, String sessionPackageName)
-                throws RemoteException {
+        public void setMediaButtonReceiver(PendingIntent pi) throws RemoteException {
             final long token = Binder.clearCallingIdentity();
             try {
                 if ((mPolicies & MediaSessionPolicyProvider.SESSION_POLICY_IGNORE_BUTTON_RECEIVER)
@@ -942,7 +941,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR
                     return;
                 }
                 mMediaButtonReceiverHolder =
-                        MediaButtonReceiverHolder.create(mContext, mUserId, pi, sessionPackageName);
+                        MediaButtonReceiverHolder.create(mUserId, pi, mPackageName);
                 mService.onMediaButtonReceiverChanged(MediaSessionRecord.this);
             } finally {
                 Binder.restoreCallingIdentity(token);

services/core/java/com/android/server/media/MediaSessionService.java

@@ -2229,9 +2229,9 @@ public class MediaSessionService extends SystemService implements Monitor {
                     PendingIntent pi = mCustomMediaKeyDispatcher.getMediaButtonReceiver(keyEvent,
                             uid, asSystemService);
                     if (pi != null) {
-                        mediaButtonReceiverHolder = MediaButtonReceiverHolder.create(mContext,
-                                mCurrentFullUserRecord.mFullUserId, pi,
-                                /* sessionPackageName= */ "");
+                        mediaButtonReceiverHolder =
+                                MediaButtonReceiverHolder.create(
+                                        mCurrentFullUserRecord.mFullUserId, pi, "");
                     }
                 }
             }