android 权限控制_android defaultpermissiongrantpolicy

android6 的权限分为几个级别，普通的第三方应用一般会用到 normal dangerous 。系统应用可能会用到 signature|system signature|privileged signature,详细的信息在Manifest中定义

vim frameworks/base/core/res/AndroidManifest.xml

其中，只有定义为dangerous 的才会要求”检查权限”，normal级别的，只要在应用的Manifest中有声明，就会自动允许。所以一般开发者要重地关注dangerous的权限.
“检查权限” 是这样的，

1，如果设备运行的是 Android 5.1（API 级别 22）或更低版本，并且应用的 targetSdkVersion 是 22 或更低版本，则系统会在安装时要求用户授予权限
2，targetSdkVersion>=23 && 设备系统是android6+。需要动态申请
3，动态申请 之后，用户会允许或者拒绝，拒绝的话，就不能使用相关功能，强行调用的话，会抛出SerurityException

dangerous的权限有：

参考 https://developer.android.com/guide/topics/security/permissions.html#normal-dangerous

好了，游戏规则就是这样。从应用开发者来说，github上也有不少辅助的第三方库，直接拿来用就可以了。颗粒度的控制权限，当然对用户来说是好事。

背景介绍完

不过每开一个app就要弹窗授权什么的，我觉得有点麻烦，所以先看看源码，改一下这个部分的功能。

以静默安装应用为例

vim ./frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

@Override
public void installPackageAsUser(String originPath, IPackageInstallObserver2 observer,
        int installFlags, String installerPackageName, VerificationParams verificationParams,
        String packageAbiOverride, int userId) {
    mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INSTALL_PACKAGES, null);

    final int callingUid = Binder.getCallingUid();
    enforceCrossUserPermission(callingUid, userId, true, true, "installPackageAsUser");
    // ...
}
1
2
3
4
5
6
7
8
9
10

enforceCrossUserPermission 里面调用了

mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INTERACT_ACROSS_USERS_FULL, message);

绕了几圈，最后是在ActivityManager.java 中落地

vim ./frameworks/base/core/java/android/app/ActivityManager.java

/** @hide */
public static int checkComponentPermission(String permission, int uid,
        int owningUid, boolean exported) {
    // Root, system server get to do everything.
    final int appId = UserHandle.getAppId(uid);
    if (appId == Process.ROOT_UID || appId == Process.SYSTEM_UID) {
        return PackageManager.PERMISSION_GRANTED;
    }
    // Isolated processes don't get any permissions.
    if (UserHandle.isIsolated(uid)) {
        return PackageManager.PERMISSION_DENIED;
    }
    // If there is a uid that owns whatever is being accessed, it has
    // blanket access to it regardless of the permissions it requires.
    if (owningUid >= 0 && UserHandle.isSameApp(uid, owningUid)) {
        return PackageManager.PERMISSION_GRANTED;
    }
    // If the target is not exported, then nobody else can get to it.
    if (!exported) {
        /*
        RuntimeException here = new RuntimeException("here");
        here.fillInStackTrace();
        Slog.w(TAG, "Permission denied: checkComponentPermission() owningUid=" + owningUid,
                here);
        */
        return PackageManager.PERMISSION_DENIED;
    }
    if (permission == null) {
        return PackageManager.PERMISSION_GRANTED;
    }
    try {
        return AppGlobals.getPackageManager()
                .checkUidPermission(permission, uid);
    } catch (RemoteException e) {
        // Should never happen, but if it does... deny!
        Slog.e(TAG, "PackageManager is dead?!?", e);
    }
    return PackageManager.PERMISSION_DENIED;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

vim ./frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

@Override
public int checkUidPermission(String permName, int uid) {
    final int userId = UserHandle.getUserId(uid);

    if (!sUserManager.exists(userId)) {
        return PackageManager.PERMISSION_DENIED;
    }

    synchronized (mPackages) {
        Object obj = mSettings.getUserIdLPr(UserHandle.getAppId(uid));
        if (obj != null) {
            final SettingBase ps = (SettingBase) obj;
            final PermissionsState permissionsState = ps.getPermissionsState();
            if (permissionsState.hasPermission(permName, userId)) {
                return PackageManager.PERMISSION_GRANTED;
            }
            // Special case: ACCESS_FINE_LOCATION permission includes ACCESS_COARSE_LOCATION
            if (Manifest.permission.ACCESS_COARSE_LOCATION.equals(permName) && permissionsState
                    .hasPermission(Manifest.permission.ACCESS_FINE_LOCATION, userId)) {
                return PackageManager.PERMISSION_GRANTED;
            }
        } else {
            ArraySet<String> perms = mSystemPermissions.get(uid);
            if (perms != null) {
                if (perms.contains(permName)) {
                    return PackageManager.PERMISSION_GRANTED;
                }
                if (Manifest.permission.ACCESS_COARSE_LOCATION.equals(permName) && perms
                        .contains(Manifest.permission.ACCESS_FINE_LOCATION)) {
                    return PackageManager.PERMISSION_GRANTED;
                }
            }
        }
    }

    return PackageManager.PERMISSION_DENIED;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37

细节代码完

弄通了之后就动手改一下，一开始改的是frameworks/base/core/res/AndroidManifest.xml 一开始，改掉了 STORAGE ，把READ_EXTERNAL_STORAGE、WRITE_EXTERNAL_STORAGE 的级别都变成了normal，然后存储权限就默认赋予了（PERMISSION_GRANTED）， 之后就不会弹窗了。

再改了 SMS 然后系统就起不来了

adb connect 192.168.0.67 && adb shell logcat

报这个错误

09-20 16:16:25.907  5653  5653 E AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: main
09-20 16:16:25.907  5653  5653 E AndroidRuntime: java.lang.SecurityException: Permission android.permission.READ_SMS is not a changeable permission type
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.pm.PackageManagerService.enforceDeclaredAsUsedAndRuntimeOrDevelopmentPermission(PackageManagerService.java:3468)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.pm.PackageManagerService.grantRuntimePermission(PackageManagerService.java:3501)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.pm.DefaultPermissionGrantPolicy.grantRuntimePermissionsLPw(DefaultPermissionGrantPolicy.java:828)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.pm.DefaultPermissionGrantPolicy.grantDefaultPermissionsToDefaultSmsAppLPr(DefaultPermissionGrantPolicy.java:616)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.pm.PackageManagerService$PackageManagerInternalImpl.grantDefaultPermissionsToDefaultSmsApp(PackageManagerService.java:17006)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.telecom.TelecomLoaderService$TelecomServiceConnection.onServiceConnected(TelecomLoaderService.java:86)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1223)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1240)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at android.os.Handler.handleCallback(Handler.java:739)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at android.os.Handler.dispatchMessage(Handler.java:95)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at android.os.Looper.loop(Looper.java:148)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.SystemServer.run(SystemServer.java:283)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.server.SystemServer.main(SystemServer.java:168)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at java.lang.reflect.Method.invoke(Native Method)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:745)
09-20 16:16:25.907  5653  5653 E AndroidRuntime:    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:635)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

目测是 PackageManagerService.java 抛异常，SystemServer起不来，然后就不停的重启。

待续