DO NOT MERGE Fix intent filter priorities

Since this is a backport, there is only one rule that guards intent
filter priorities:
1) Updates will NOT be granted a priority greater than the priority
   defined on the system image.

Bug: 27450489
Change-Id: Ifcec4d7a59e684331399abc41eea1bd6876155a4

2 files changed, 266 insertions, 19 deletions

diff --git a/core/java/android/content/IntentFilter.java b/core/java/android/content/IntentFilter.java
index 3a17e23..ed5dfa5 100644
--- a/core/java/android/content/IntentFilter.java
+++ b/core/java/android/content/IntentFilter.java
@@ -883,6 +883,15 @@ public class IntentFilter implements Parcelable {
             return true;
         }
 
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof AuthorityEntry) {
+                final AuthorityEntry other = (AuthorityEntry)obj;
+                return match(other);
+            }
+            return false;
+        }
+
         /**
          * Determine whether this AuthorityEntry matches the given data Uri.
          * <em>Note that this comparison is case-sensitive, unlike formal
@@ -917,7 +926,7 @@ public class IntentFilter implements Parcelable {
             }
             return MATCH_CATEGORY_HOST;
         }
-    };
+    }
 
     /**
      * Add a new Intent data "scheme specific part" to match against.  The filter must
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index c1d091b..7654cc9 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -297,6 +297,7 @@ public class PackageManagerService extends IPackageManager.Stub {
     private static final boolean DEBUG_PACKAGE_SCANNING = false;
     private static final boolean DEBUG_VERIFY = false;
     private static final boolean DEBUG_DEXOPT = false;
+    private static final boolean DEBUG_FILTERS = false;
     private static final boolean DEBUG_ABI_SELECTION = false;
 
     static final boolean CLEAR_RUNTIME_PERMISSIONS_ON_UPGRADE = false;
@@ -8744,6 +8745,255 @@ public class PackageManagerService extends IPackageManager.Stub {
             return super.queryIntentFromList(intent, resolvedType, defaultOnly, listCut, userId);
         }
 
+        /**
+         * Finds a privileged activity that matches the specified activity names.
+         */
+        private PackageParser.Activity findMatchingActivity(
+                List<PackageParser.Activity> activityList, ActivityInfo activityInfo) {
+            for (PackageParser.Activity sysActivity : activityList) {
+                if (sysActivity.info.name.equals(activityInfo.name)) {
+                    return sysActivity;
+                }
+                if (sysActivity.info.name.equals(activityInfo.targetActivity)) {
+                    return sysActivity;
+                }
+                if (sysActivity.info.targetActivity != null) {
+                    if (sysActivity.info.targetActivity.equals(activityInfo.name)) {
+                        return sysActivity;
+                    }
+                    if (sysActivity.info.targetActivity.equals(activityInfo.targetActivity)) {
+                        return sysActivity;
+                    }
+                }
+            }
+            return null;
+        }
+
+        public class IterGenerator<E> {
+            public Iterator<E> generate(ActivityIntentInfo info) {
+                return null;
+            }
+        }
+
+        public class ActionIterGenerator extends IterGenerator<String> {
+            @Override
+            public Iterator<String> generate(ActivityIntentInfo info) {
+                return info.actionsIterator();
+            }
+        }
+
+        public class CategoriesIterGenerator extends IterGenerator<String> {
+            @Override
+            public Iterator<String> generate(ActivityIntentInfo info) {
+                return info.categoriesIterator();
+            }
+        }
+
+        public class SchemesIterGenerator extends IterGenerator<String> {
+            @Override
+            public Iterator<String> generate(ActivityIntentInfo info) {
+                return info.schemesIterator();
+            }
+        }
+
+        public class AuthoritiesIterGenerator extends IterGenerator<IntentFilter.AuthorityEntry> {
+            @Override
+            public Iterator<IntentFilter.AuthorityEntry> generate(ActivityIntentInfo info) {
+                return info.authoritiesIterator();
+            }
+        }
+
+        /**
+         * <em>WARNING</em> for performance reasons, the passed in intentList WILL BE
+         * MODIFIED. Do not pass in a list that should not be changed.
+         */
+        private <T> void getIntentListSubset(List<ActivityIntentInfo> intentList,
+                IterGenerator<T> generator, Iterator<T> searchIterator) {
+            // loop through the set of actions; every one must be found in the intent filter
+            while (searchIterator.hasNext()) {
+                // we must have at least one filter in the list to consider a match
+                if (intentList.size() == 0) {
+                    break;
+                }
+
+                final T searchAction = searchIterator.next();
+
+                // loop through the set of intent filters
+                final Iterator<ActivityIntentInfo> intentIter = intentList.iterator();
+                while (intentIter.hasNext()) {
+                    final ActivityIntentInfo intentInfo = intentIter.next();
+                    boolean selectionFound = false;
+
+                    // loop through the intent filter's selection criteria; at least one
+                    // of them must match the searched criteria
+                    final Iterator<T> intentSelectionIter = generator.generate(intentInfo);
+                    while (intentSelectionIter != null && intentSelectionIter.hasNext()) {
+                        final T intentSelection = intentSelectionIter.next();
+                        if (intentSelection != null && intentSelection.equals(searchAction)) {
+                            selectionFound = true;
+                            break;
+                        }
+                    }
+
+                    // the selection criteria wasn't found in this filter's set; this filter
+                    // is not a potential match
+                    if (!selectionFound) {
+                        intentIter.remove();
+                    }
+                }
+            }
+        }
+
+        /**
+         * Adjusts the priority of the given intent filter according to policy.
+         * <p>
+         * <ul>
+         * <li>The priority for unbundled updates to system applications is capped to the
+         *      priority defined on the system partition</li>
+         * </ul>
+         */
+        private void adjustPriority(
+                List<PackageParser.Activity> systemActivities, ActivityIntentInfo intent) {
+            // nothing to do; priority is fine as-is
+            if (intent.getPriority() <= 0) {
+                return;
+            }
+
+            final ActivityInfo activityInfo = intent.activity.info;
+            final ApplicationInfo applicationInfo = activityInfo.applicationInfo;
+
+            final boolean systemApp = applicationInfo.isSystemApp();
+            if (!systemApp) {
+                // non-system applications can never define a priority >0
+                Slog.w(TAG, "Non-system app; cap priority to 0;"
+                        + " package: " + applicationInfo.packageName
+                        + " activity: " + intent.activity.className
+                        + " origPrio: " + intent.getPriority());
+                intent.setPriority(0);
+                return;
+            }
+
+            if (systemActivities == null) {
+                // the system package is not disabled; we're parsing the system partition
+                // apps on the system image get whatever priority they request
+                return;
+            }
+
+            // system app unbundled update ... try to find the same activity
+            final PackageParser.Activity foundActivity =
+                    findMatchingActivity(systemActivities, activityInfo);
+            if (foundActivity == null) {
+                // this is a new activity; it cannot obtain >0 priority
+                if (DEBUG_FILTERS) {
+                    Slog.i(TAG, "New activity; cap priority to 0;"
+                            + " package: " + applicationInfo.packageName
+                            + " activity: " + intent.activity.className
+                            + " origPrio: " + intent.getPriority());
+                }
+                intent.setPriority(0);
+                return;
+            }
+
+            // found activity, now check for filter equivalence
+
+            // a shallow copy is enough; we modify the list, not its contents
+            final List<ActivityIntentInfo> intentListCopy =
+                    new ArrayList<>(foundActivity.intents);
+            final List<ActivityIntentInfo> foundFilters = findFilters(intent);
+
+            // find matching action subsets
+            final Iterator<String> actionsIterator = intent.actionsIterator();
+            if (actionsIterator != null) {
+                getIntentListSubset(
+                        intentListCopy, new ActionIterGenerator(), actionsIterator);
+                if (intentListCopy.size() == 0) {
+                    // no more intents to match; we're not equivalent
+                    if (DEBUG_FILTERS) {
+                        Slog.i(TAG, "Mismatched action; cap priority to 0;"
+                                + " package: " + applicationInfo.packageName
+                                + " activity: " + intent.activity.className
+                                + " origPrio: " + intent.getPriority());
+                    }
+                    intent.setPriority(0);
+                    return;
+                }
+            }
+
+            // find matching category subsets
+            final Iterator<String> categoriesIterator = intent.categoriesIterator();
+            if (categoriesIterator != null) {
+                getIntentListSubset(intentListCopy, new CategoriesIterGenerator(),
+                        categoriesIterator);
+                if (intentListCopy.size() == 0) {
+                    // no more intents to match; we're not equivalent
+                    if (DEBUG_FILTERS) {
+                        Slog.i(TAG, "Mismatched category; cap priority to 0;"
+                                + " package: " + applicationInfo.packageName
+                                + " activity: " + intent.activity.className
+                                + " origPrio: " + intent.getPriority());
+                    }
+                    intent.setPriority(0);
+                    return;
+                }
+            }
+
+            // find matching schemes subsets
+            final Iterator<String> schemesIterator = intent.schemesIterator();
+            if (schemesIterator != null) {
+                getIntentListSubset(intentListCopy, new SchemesIterGenerator(),
+                        schemesIterator);
+                if (intentListCopy.size() == 0) {
+                    // no more intents to match; we're not equivalent
+                    if (DEBUG_FILTERS) {
+                        Slog.i(TAG, "Mismatched scheme; cap priority to 0;"
+                                + " package: " + applicationInfo.packageName
+                                + " activity: " + intent.activity.className
+                                + " origPrio: " + intent.getPriority());
+                    }
+                    intent.setPriority(0);
+                    return;
+                }
+            }
+
+            // find matching authorities subsets
+            final Iterator<IntentFilter.AuthorityEntry>
+                    authoritiesIterator = intent.authoritiesIterator();
+            if (authoritiesIterator != null) {
+                getIntentListSubset(intentListCopy,
+                        new AuthoritiesIterGenerator(),
+                        authoritiesIterator);
+                if (intentListCopy.size() == 0) {
+                    // no more intents to match; we're not equivalent
+                    if (DEBUG_FILTERS) {
+                        Slog.i(TAG, "Mismatched authority; cap priority to 0;"
+                                + " package: " + applicationInfo.packageName
+                                + " activity: " + intent.activity.className
+                                + " origPrio: " + intent.getPriority());
+                    }
+                    intent.setPriority(0);
+                    return;
+                }
+            }
+
+            // we found matching filter(s); app gets the max priority of all intents
+            int cappedPriority = 0;
+            for (int i = intentListCopy.size() - 1; i >= 0; --i) {
+                cappedPriority = Math.max(cappedPriority, intentListCopy.get(i).getPriority());
+            }
+            if (intent.getPriority() > cappedPriority) {
+                if (DEBUG_FILTERS) {
+                    Slog.i(TAG, "Found matching filter(s);"
+                            + " cap priority to " + cappedPriority + ";"
+                            + " package: " + applicationInfo.packageName
+                            + " activity: " + intent.activity.className
+                            + " origPrio: " + intent.getPriority());
+                }
+                intent.setPriority(cappedPriority);
+                return;
+            }
+            // all this for nothing; the requested priority was <= what was on the system
+        }
+
         public final void addActivity(PackageParser.Activity a, String type) {
             final boolean systemApp = a.info.applicationInfo.isSystemApp();
             mActivities.put(a.getComponentName(), a);
@@ -8756,10 +9006,12 @@ public class PackageManagerService extends IPackageManager.Stub {
             final int NI = a.intents.size();
             for (int j=0; j<NI; j++) {
                 PackageParser.ActivityIntentInfo intent = a.intents.get(j);
-                if (!systemApp && intent.getPriority() > 0 && "activity".equals(type)) {
-                    intent.setPriority(0);
-                    Log.w(TAG, "Package " + a.info.applicationInfo.packageName + " has activity "
-                            + a.className + " with priority > 0, forcing to 0");
+                if ("activity".equals(type)) {
+                    final PackageSetting ps =
+                            mSettings.getDisabledSystemPkgLPr(intent.activity.info.packageName);
+                    final List<PackageParser.Activity> systemActivities =
+                            ps != null && ps.pkg != null ? ps.pkg.activities : null;
+                    adjustPriority(systemActivities, intent);
                 }
                 if (DEBUG_SHOW_INFO) {
                     Log.v(TAG, "    IntentFilter:");
@@ -8913,18 +9165,6 @@ public class PackageManagerService extends IPackageManager.Stub {
             out.println();
         }
 
-//        List<ResolveInfo> filterEnabled(List<ResolveInfo> resolveInfoList) {
-//            final Iterator<ResolveInfo> i = resolveInfoList.iterator();
-//            final List<ResolveInfo> retList = Lists.newArrayList();
-//            while (i.hasNext()) {
-//                final ResolveInfo resolveInfo = i.next();
-//                if (isEnabledLP(resolveInfo.activityInfo)) {
-//                    retList.add(resolveInfo);
-//                }
-//            }
-//            return retList;
-//        }
-
         // Keys are String (activity class name), values are Activity.
         private final ArrayMap<ComponentName, PackageParser.Activity> mActivities
                 = new ArrayMap<ComponentName, PackageParser.Activity>();
@@ -10974,8 +11214,6 @@ public class PackageManagerService extends IPackageManager.Stub {
          * Called after the source arguments are copied. This is used mostly for
          * MoveParams when it needs to read the source file to put it in the
          * destination.
-         *
-         * @return
          */
         int doPostCopy(int uid) {
             return PackageManager.INSTALL_SUCCEEDED;