Enforce VPN control "permission" with an actual permission.
The current implementation uses a whitelist of package names. Use a
system|signature permission instead of rolling our own security and
add that permission to the existing set of whitelisted packages
(SystemUI and VpnDialogs).
In addition to being less of a security risk (using well-known methods
like Context.enforceCallingPermission rather than manually querying
PackageManager and checking UIDs for package names), this enables
other system-privileged apps to control VPN as needed per the below
bug.
Bug: 18327583
Change-Id: I38617965c40d62cf1ac28e3cb382c0877fb1275d
diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index 83756aa..03c05ec 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -23,6 +23,7 @@
import static android.system.OsConstants.AF_INET;
import static android.system.OsConstants.AF_INET6;
+import android.Manifest;
import android.app.AppGlobals;
import android.app.AppOpsManager;
import android.app.PendingIntent;
@@ -739,31 +740,7 @@
};
private void enforceControlPermission() {
- // System user is allowed to control VPN.
- if (Binder.getCallingUid() == Process.SYSTEM_UID) {
- return;
- }
- int appId = UserHandle.getAppId(Binder.getCallingUid());
- final long token = Binder.clearCallingIdentity();
- try {
- // System VPN dialogs are also allowed to control VPN.
- PackageManager pm = mContext.getPackageManager();
- ApplicationInfo app = pm.getApplicationInfo(VpnConfig.DIALOGS_PACKAGE, 0);
- if (((app.flags & ApplicationInfo.FLAG_SYSTEM) != 0) && (appId == app.uid)) {
- return;
- }
- // SystemUI dialogs are also allowed to control VPN.
- ApplicationInfo sysUiApp = pm.getApplicationInfo("com.android.systemui", 0);
- if (((sysUiApp.flags & ApplicationInfo.FLAG_SYSTEM) != 0) && (appId == sysUiApp.uid)) {
- return;
- }
- } catch (Exception e) {
- // ignore
- } finally {
- Binder.restoreCallingIdentity(token);
- }
-
- throw new SecurityException("Unauthorized Caller");
+ mContext.enforceCallingPermission(Manifest.permission.CONTROL_VPN, "Unauthorized Caller");
}
private class Connection implements ServiceConnection {