带android:sharedUserId=“android.uid.system” 发送广播时，会出现 Sending non-protected broadcast 异常提醒；
原因： Ams在发送广播时，对于systemApp(系统应用)，会要求发送广播必须是声明在frameworks\base\core\res\AndroidManifest.xml里面的protected-broadcast。这是为了提醒 系统应用开发者要将 broadcast 添加到protected-broadcast，因为非 protexted-broadcast 广播是可以被三方应用发送的。定义为 proected-broadcast 可以避免三方垃圾应用也发送这些广播来捣蛋。
查找问题
首先去搜索问题出现的位置 ,去AndroidXRef网站搜索下
定位到frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java
类中，在checkBroadcastFromSystem中抛出该异常。
checkBroadcastFromSytem是用于检测系统应用发出的广播是否安全，如果发出的广播不安全，就会抛出no-protected broadcast异常，提醒系统应用开发者。
为什么要有这个机制？
这是为了提醒 系统应用开发者去将 broadcast添加为protected-broadcast，因为非 protected-broadcast 广播是可以被三方应用发送的。 而定义为 proected-broadcast 就能防止恶意的三方应用模仿系统应用去发出该广播。
private void checkBroadcastFromSystem(Intent intent, ProcessRecord callerApp,
String callerPackage, int callingUid, boolean isProtectedBroadcast, List receivers) {
if ((intent.getFlags() & Intent.FLAG_RECEIVER_FROM_SHELL) != 0) {
// Don't yell about broadcasts sent via shell
return;
}
final String action = intent.getAction();
if (isProtectedBroadcast
|| Intent.ACTION_CLOSE_SYSTEM_DIALOGS.equals(action)
|| Intent.ACTION_DISMISS_KEYBOARD_SHORTCUTS.equals(action)
|| Intent.ACTION_MEDIA_BUTTON.equals(action)
|| Intent.ACTION_MEDIA_SCANNER_SCAN_FILE.equals(action)
|| Intent.ACTION_SHOW_KEYBOARD_SHORTCUTS.equals(action)
|| Intent.ACTION_MASTER_CLEAR.equals(action)
|| Intent.ACTION_FACTORY_RESET.equals(action)
|| AppWidgetManager.ACTION_APPWIDGET_CONFIGURE.equals(action)
|| AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)
|| LocationManager.HIGH_POWER_REQUEST_CHANGE_ACTION.equals(action)
|| TelephonyIntents.ACTION_REQUEST_OMADM_CONFIGURATION_UPDATE.equals(action)
|| SuggestionSpan.ACTION_SUGGESTION_PICKED.equals(action)
|| AudioEffect.ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION.equals(action)
|| AudioEffect.ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION.equals(action)) {
// Broadcast is either protected, or it's a public action that
// we've relaxed, so it's fine for system internals to send.
return;
}
// This broadcast may be a problem... but there are often system components that
// want to send an internal broadcast to themselves, which is annoying to have to
// explicitly list each action as a protected broadcast, so we will check for that
// one safe case and allow it: an explicit broadcast, only being received by something
// that has protected itself.
if (intent.getPackage() != null || intent.getComponent() != null) {
if (receivers == null || receivers.size() == 0) {
// Intent is explicit and there's no receivers.
// This happens, e.g. , when a system component sends a broadcast to
// its own runtime receiver, and there's no manifest receivers for it,
// because this method is called twice for each broadcast,
// for runtime receivers and manifest receivers and the later check would find
// no receivers.
return;
}
boolean allProtected = true;
for (int i = receivers.size()-1; i >= 0; i--) {
Object target = receivers.get(i);
if (target instanceof ResolveInfo) {
ResolveInfo ri = (ResolveInfo)target;
if (ri.activityInfo.exported && ri.activityInfo.permission == null) {
allProtected = false;
break;
}
} else {
BroadcastFilter bf = (BroadcastFilter)target;
if (bf.requiredPermission == null) {
allProtected = false;
break;
}
}
}
if (allProtected) {
// All safe!
return;
}
}
// The vast majority of broadcasts sent from system internals
// should be protected to avoid security holes, so yell loudly
// to ensure we examine these cases.
if (callerApp != null) {
Log.wtf(TAG, "Sending non-protected broadcast " + action
+ " from system " + callerApp.toShortString() + " pkg " + callerPackage,
new Throwable());
} else {
Log.wtf(TAG, "Sending non-protected broadcast " + action
+ " from system uid " + UserHandle.formatUid(callingUid)
+ " pkg " + callerPackage,
new Throwable());
}
}
如上代码， 对于广播，checkBroadcastFromSystem方法有三种检测。
如果Action 是Shell 发出的，则直接返回，不发出警告 如果Action 是protected-broadcast广播或一些指定的Action,不发出警告 如果Action 是指定了包名或者Compononent信息，只有特定应用能接收，则当所有receiver 均根据receiverPermisson 对权限进行了顾虑，则不发出警告
如果系统应用不满足以上三种情况，则发送公共广播时会被警告
如何解决 non-protected broadcast警告
从系统源码层面
1.在checkBroadcastFromSystem 处修改
if (isProtectedBroadcast
|| Intent.ACTION_CLOSE_SYSTEM_DIALOGS.equals(action)
|| Intent.ACTION_DISMISS_KEYBOARD_SHORTCUTS.equals(action)
|| Intent.ACTION_MEDIA_BUTTON.equals(action)
|| Intent.ACTION_MEDIA_SCANNER_SCAN_FILE.equals(action)
|| Intent.ACTION_SHOW_KEYBOARD_SHORTCUTS.equals(action)
|| Intent.ACTION_MASTER_CLEAR.equals(action)
|| Intent.ACTION_FACTORY_RESET.equals(action)
|| AppWidgetManager.ACTION_APPWIDGET_CONFIGURE.equals(action)
|| AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action)
|| LocationManager.HIGH_POWER_REQUEST_CHANGE_ACTION.equals(action)
|| TelephonyIntents.ACTION_REQUEST_OMADM_CONFIGURATION_UPDATE.equals(action)
|| SuggestionSpan.ACTION_SUGGESTION_PICKED.equals(action)
|| AudioEffect.ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION.equals(action)
|| AudioEffect.ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION.equals(action)) {
// Broadcast is either protected, or it's a public action that
// we've relaxed, so it's fine for system internals to send.
return;
}
复制代码
2.在/frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#isProtectedBroadcast方法处修改
3.在/frameworks/base/core/res/AndroidManifest.xml 处增加 protected-broadcast 标签
在应用层面修改
在系统应用的 AndroidManifest.xml 处增加 protected-broadcast 标签,且apk放在 /system/priv-app 目录下 指定接收者.获取所有接收该广播的ResolveInfo，发送广播。
参考文章
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