Fix bugs when system apps reclaim permissions.

Recently we started letting system apps always take precedence over
third-party apps when defining permissions.  This change fixes that
logic to claim the permission immediately, instead of delaying until
after the next reboot.  (Permissions are always reevaluated after
each install.)

We also tighten the constraints slightly to prevent two system
apps from fighting over a permission definition; the first system
app to claim the permission wins.

Bug: 17526617
Change-Id: I49686407f5e99322bc511795c653c5d702becd9d

diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 75fef27..00bb908 100644 (file)
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -201,6 +201,7 @@ import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
@@ -5940,25 +5941,26 @@ public class PackageManagerService extends IPackageManager.Stub {
                 p.group = mPermissionGroups.get(p.info.group);
                 if (p.info.group == null || p.group != null) {
                     BasePermission bp = permissionMap.get(p.info.name);
+
+                    // Allow system apps to redefine non-system permissions
+                    if (bp != null && !Objects.equals(bp.sourcePackage, p.info.packageName)) {
+                        final boolean currentOwnerIsSystem = (bp.perm != null
+                                && isSystemApp(bp.perm.owner));
+                        if (isSystemApp(p.owner) && !currentOwnerIsSystem) {
+                            String msg = "New decl " + p.owner + " of permission  "
+                                    + p.info.name + " is system; overriding " + bp.sourcePackage;
+                            reportSettingsProblem(Log.WARN, msg);
+                            bp = null;
+                        }
+                    }
+
                     if (bp == null) {
                         bp = new BasePermission(p.info.name, p.info.packageName,
                                 BasePermission.TYPE_NORMAL);
                         permissionMap.put(p.info.name, bp);
                     }
+
                     if (bp.perm == null) {
-                        if (bp.sourcePackage != null
-                                && !bp.sourcePackage.equals(p.info.packageName)) {
-                            // If this is a permission that was formerly defined by a non-system
-                            // app, but is now defined by a system app (following an upgrade),
-                            // discard the previous declaration and consider the system's to be
-                            // canonical.
-                            if (isSystemApp(p.owner)) {
-                                String msg = "New decl " + p.owner + " of permission  "
-                                        + p.info.name + " is system";
-                                reportSettingsProblem(Log.WARN, msg);
-                                bp.sourcePackage = null;
-                            }
-                        }
                         if (bp.sourcePackage == null
                                 || bp.sourcePackage.equals(p.info.packageName)) {
                             BasePermission tree = findPermissionTreeLP(p.info.name);
@@ -5967,6 +5969,7 @@ public class PackageManagerService extends IPackageManager.Stub {
                                 bp.packageSetting = pkgSetting;
                                 bp.perm = p;
                                 bp.uid = pkg.applicationInfo.uid;
+                                bp.sourcePackage = p.info.packageName;
                                 if ((parseFlags&PackageParser.PARSE_CHATTY) != 0) {
                                     if (r == null) {
                                         r = new StringBuilder(256);