android - 普通开发人员如何尝试isPermissionRevokedByPolicy()？

API级别23已添加 isPermissionRevokedByPolicy() on PackageManager 。如果某个包“通过策略”被阻止了所请求的权限，则应该返回false:



开发人员是否可以做一些事情，以使isPermissionRevokedByPolicy()为某些打包/许可组合返回false，而无需经历整个Android for Work的恶作剧集？

最佳答案

当然，我可能错了，但是不幸的是，简短的答案似乎是“不，没有”。

扩展一些的答案:
这是ApplicationPackageManager的代码:

@Override
public boolean isPermissionRevokedByPolicy(String permName, String pkgName) {
    try {
        return mPM.isPermissionRevokedByPolicy(permName, pkgName, mContext.getUserId());
    } catch (RemoteException e) {
        throw new RuntimeException("Package manager has died", e);
    }
}

其中mPM-

private final IPackageManager mPM;

它是在构造函数中初始化的，该构造函数由ContextImpl.getPackageManager()调用:

@Override
public PackageManager getPackageManager() {
    if (mPackageManager != null) {
        return mPackageManager;
    }

    IPackageManager pm = ActivityThread.getPackageManager();
    if (pm != null) {
        // Doesn't matter if we make more than one instance.
        return (mPackageManager = new ApplicationPackageManager(this, pm));
    }

    return null;
}

(source code)

更深入地研究ActivityThread.getPackageManager():

public static IPackageManager getPackageManager() {
    if (sPackageManager != null) {
        //Slog.v("PackageManager", "returning cur default = " + sPackageManager);
        return sPackageManager;
    }
    IBinder b = ServiceManager.getService("package");
    //Slog.v("PackageManager", "default service binder = " + b);
    sPackageManager = IPackageManager.Stub.asInterface(b);
    //Slog.v("PackageManager", "default service = " + sPackageManager);
    return sPackageManager;
}

(source code)

我为查找isPermissionRevokedByPolicy btw的实际实现所做的所有这些步骤。然后，我必须找到谁扩展了IPackageManager.Stub-它是PackageManagerService(source code)。

所以这是实际的实现:

@Override
public boolean isPermissionRevokedByPolicy(String permission, String packageName, int userId) {
    if (UserHandle.getCallingUserId() != userId) {
        mContext.enforceCallingPermission(
                android.Manifest.permission.INTERACT_ACROSS_USERS_FULL,
                "isPermissionRevokedByPolicy for user " + userId);
    }
    if (checkPermission(permission, packageName, userId)
            == PackageManager.PERMISSION_GRANTED) {
        return false;
    }
    final long identity = Binder.clearCallingIdentity();
    try {
        final int flags = getPermissionFlags(permission, packageName, userId);
        return (flags & PackageManager.FLAG_PERMISSION_POLICY_FIXED) != 0;
    } finally {
        Binder.restoreCallingIdentity(identity);
    }
}

要潜在地“伪造”特定权限的状态，您需要破解checkPermission和getPermissionFlags方法。恐怕，问题是，至少在没有反射的情况下，没有明显的方法如何使用覆盖的PackageManagerService来填充ApplicationPackageManager。