Split permissions inherit state from their parents

The old hack to grant permissions on upgrade was removed. The new code
applies to
- platfrom upgrade
- initial package installation
- package update

Inheriting the grant state is the default behavior for split permissions.
Special cases will be added later.

Also make sure to revoke the permission once the app declares that it is
aware of the permission.

Test: atest CtsPermissionTestCases:SplitPermissionTest
Change-Id: Ie51971530607f0b585cf7a3e11b01b11a28e1de9
diff --git a/services/core/java/com/android/server/pm/permission/PermissionManagerService.java b/services/core/java/com/android/server/pm/permission/PermissionManagerService.java
index d52bd64..af05a79 100644
--- a/services/core/java/com/android/server/pm/permission/PermissionManagerService.java
+++ b/services/core/java/com/android/server/pm/permission/PermissionManagerService.java
@@ -18,8 +18,25 @@
 
 import static android.Manifest.permission.READ_EXTERNAL_STORAGE;
 import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;
+import static android.app.AppOpsManager.MODE_ALLOWED;
+import static android.app.AppOpsManager.MODE_DEFAULT;
+import static android.app.AppOpsManager.MODE_ERRORED;
+import static android.app.AppOpsManager.MODE_FOREGROUND;
+import static android.app.AppOpsManager.MODE_IGNORED;
+import static android.app.AppOpsManager.OP_NONE;
+import static android.app.AppOpsManager.permissionToOp;
+import static android.app.AppOpsManager.permissionToOpCode;
+import static android.content.pm.ApplicationInfo.PRIVATE_FLAG_PRIVILEGED;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_GRANTED_BY_DEFAULT;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_POLICY_FIXED;
 import static android.content.pm.PackageManager.FLAG_PERMISSION_REVIEW_REQUIRED;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_REVOKE_WHEN_REQUESTED;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_SYSTEM_FIXED;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_USER_FIXED;
+import static android.content.pm.PackageManager.FLAG_PERMISSION_USER_SET;
 import static android.os.Trace.TRACE_TAG_PACKAGE_MANAGER;
+import static android.os.UserHandle.getAppId;
+import static android.os.UserHandle.getUid;
 
 import static com.android.server.pm.PackageManagerService.DEBUG_INSTALL;
 import static com.android.server.pm.PackageManagerService.DEBUG_PACKAGE_SCANNING;
@@ -30,6 +47,9 @@
 import android.Manifest;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.UserIdInt;
+import android.app.AppOpsManager;
+import android.app.AppOpsManagerInternal;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManagerInternal;
@@ -49,6 +69,7 @@
 import android.os.UserManagerInternal;
 import android.os.storage.StorageManager;
 import android.os.storage.StorageManagerInternal;
+import android.permission.PermissionManager;
 import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.ArraySet;
@@ -832,7 +853,8 @@
                 }
 
                 if (DEBUG_PERMISSIONS) {
-                    Slog.i(TAG, "Granting permission " + perm + " to package " + pkg.packageName);
+                    Slog.i(TAG, "Considering granting permission " + perm + " to package "
+                            + pkg.packageName);
                 }
 
                 if (grant != GRANT_DENIED) {
@@ -1021,6 +1043,11 @@
                 // changed.
                 ps.setInstallPermissionsFixed(true);
             }
+
+            updatedUserIds = revokePermissionsNoLongerImplicitLocked(permissionsState, pkg,
+                    updatedUserIds);
+            updatedUserIds = setInitialGrantForNewImplicitPermissionsLocked(origPermissions,
+                    permissionsState, pkg, updatedUserIds);
         }
 
         // Persist the runtime permissions state for users with changes. If permissions
@@ -1031,6 +1058,299 @@
         }
     }
 
+    /**
+     * Set app op for a app-op related to a permission.
+     *
+     * @param permission The permission the app-op belongs to
+     * @param pkg The package the permission belongs to
+     * @param userId The user to be changed
+     * @param mode The new mode to set
+     */
+    private void setAppOpMode(@NonNull String permission, @NonNull PackageParser.Package pkg,
+            @UserIdInt int userId, int mode) {
+        AppOpsManagerInternal appOpsInternal = LocalServices.getService(
+                AppOpsManagerInternal.class);
+
+        appOpsInternal.setMode(permissionToOpCode(permission),
+                getUid(userId, getAppId(pkg.applicationInfo.uid)), pkg.packageName, mode,
+                (pkg.applicationInfo.privateFlags & PRIVATE_FLAG_PRIVILEGED) != 0);
+    }
+
+    /**
+     * Revoke permissions that are not implicit anymore and that have
+     * {@link PackageManager#FLAG_PERMISSION_REVOKE_WHEN_REQUESTED} set.
+     *
+     * @param ps The state of the permissions of the package
+     * @param pkg The package that is currently looked at
+     * @param updatedUserIds a list of user ids that needs to be amended if the permission state
+     *                       for a user is changed.
+     *
+     * @return The updated value of the {@code updatedUserIds} parameter
+     */
+    private @NonNull int[] revokePermissionsNoLongerImplicitLocked(
+            @NonNull PermissionsState ps, @NonNull PackageParser.Package pkg,
+            @NonNull int[] updatedUserIds) {
+        AppOpsManager appOpsManager = mContext.getSystemService(AppOpsManager.class);
+
+        String pkgName = pkg.packageName;
+
+        int[] users = UserManagerService.getInstance().getUserIds();
+        int numUsers = users.length;
+        for (int i = 0; i < numUsers; i++) {
+            int userId = users[i];
+
+            for (String permission : ps.getPermissions(userId)) {
+                if (!pkg.implicitPermissions.contains(permission)) {
+                    if (!ps.hasInstallPermission(permission)) {
+                        int flags = ps.getRuntimePermissionState(permission, userId).getFlags();
+
+                        if ((flags & FLAG_PERMISSION_REVOKE_WHEN_REQUESTED) != 0) {
+                            BasePermission bp = mSettings.getPermissionLocked(permission);
+
+                            ps.updatePermissionFlags(bp, userId,
+                                    FLAG_PERMISSION_REVOKE_WHEN_REQUESTED
+                                            | FLAG_PERMISSION_USER_FIXED | FLAG_PERMISSION_USER_SET,
+                                    0);
+                            updatedUserIds = ArrayUtils.appendInt(updatedUserIds,
+                                    userId);
+
+                            if ((flags & (FLAG_PERMISSION_GRANTED_BY_DEFAULT
+                                    | FLAG_PERMISSION_POLICY_FIXED | FLAG_PERMISSION_SYSTEM_FIXED))
+                                    == 0) {
+                                if (pkg.applicationInfo.targetSdkVersion < Build.VERSION_CODES.M) {
+                                    if (permissionToOpCode(permission) != OP_NONE) {
+                                        setAppOpMode(permission, pkg, userId, MODE_IGNORED);
+
+                                        if (DEBUG_PERMISSIONS) {
+                                            Slog.i(TAG, "Revoking app-op "
+                                                    + permissionToOp(permission) + " for " + pkgName
+                                                    + " as it is now requested");
+                                        }
+                                    }
+                                } else {
+                                    int revokeOpSuccess = ps.revokeRuntimePermission(bp, userId);
+                                    if (revokeOpSuccess
+                                            != PermissionsState.PERMISSION_OPERATION_FAILURE) {
+
+                                        if (DEBUG_PERMISSIONS) {
+                                            Slog.i(TAG, "Revoking runtime permission " + permission
+                                                    + " for " + pkgName
+                                                    + " as it is now requested");
+                                        }
+                                    }
+                                }
+
+                                List<String> fgPerms = mBackgroundPermissions.get(permission);
+                                if (fgPerms != null) {
+                                    int numFgPerms = fgPerms.size();
+                                    for (int fgPermNum = 0; fgPermNum < numFgPerms; fgPermNum++) {
+                                        String fgPerm = fgPerms.get(fgPermNum);
+
+                                        int mode = appOpsManager.unsafeCheckOpRaw(
+                                                permissionToOp(fgPerm),
+                                                getUid(userId, getAppId(pkg.applicationInfo.uid)),
+                                                pkgName);
+
+                                        if (mode == MODE_ALLOWED) {
+                                            setAppOpMode(fgPerm, pkg, userId, MODE_FOREGROUND);
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        return updatedUserIds;
+    }
+
+    /**
+     * {@code newPerm} is newly added; Inherit the state from {@code sourcePerms}.
+     *
+     * <p>A single new permission can be split off from several source permissions. In this case
+     * the most leniant state is inherited.
+     *
+     * <p>Warning: This does not handle foreground / background permissions
+     *
+     * @param sourcePerms The permissions to inherit from
+     * @param newPerm The permission to inherit to
+     * @param ps The permission state of the package
+     * @param pkg The package requesting the permissions
+     * @param userId The user the permission belongs to
+     */
+    private void inheritPermissionStateToNewImplicitPermissionLocked(
+            @NonNull ArraySet<String> sourcePerms, @NonNull String newPerm,
+            @NonNull PermissionsState ps, @NonNull PackageParser.Package pkg,
+            @UserIdInt int userId) {
+        AppOpsManager appOpsManager = mContext.getSystemService(AppOpsManager.class);
+        String pkgName = pkg.packageName;
+
+        if (pkg.applicationInfo.targetSdkVersion < Build.VERSION_CODES.M) {
+            if (permissionToOp(newPerm) != null) {
+                int mostLenientSourceMode = MODE_ERRORED;
+
+                // Find most lenient source permission state.
+                int numSourcePerms = sourcePerms.size();
+                for (int i = 0; i < numSourcePerms; i++) {
+                    String sourcePerm = sourcePerms.valueAt(i);
+
+                    if (ps.hasRuntimePermission(sourcePerm, userId)) {
+                        String sourceOp = permissionToOp(sourcePerm);
+
+                        if (sourceOp != null) {
+                            int mode = appOpsManager.unsafeCheckOpRaw(sourceOp,
+                                    getUid(userId, getAppId(pkg.applicationInfo.uid)), pkgName);
+
+                            if (mode == MODE_FOREGROUND) {
+                                throw new IllegalArgumentException("split permission" + sourcePerm
+                                        + " has app-op state " + AppOpsManager.MODE_NAMES[mode]);
+                            }
+
+                            // Leniency order: allowed > ignored > default
+                            if (mode == MODE_ALLOWED) {
+                                mostLenientSourceMode = MODE_ALLOWED;
+                                break;
+                            } else if (mode == MODE_IGNORED) {
+                                mostLenientSourceMode = MODE_IGNORED;
+                            } else if (mode == MODE_DEFAULT
+                                    && mostLenientSourceMode != MODE_IGNORED) {
+                                mostLenientSourceMode = MODE_DEFAULT;
+                            }
+                        }
+                    }
+                }
+
+                if (mostLenientSourceMode != MODE_ERRORED) {
+                    if (DEBUG_PERMISSIONS) {
+                        Slog.i(TAG, newPerm + " inherits app-ops state " + mostLenientSourceMode
+                                + " from " + sourcePerms + " for " + pkgName);
+                    }
+
+                    setAppOpMode(newPerm, pkg, userId, mostLenientSourceMode);
+                }
+            }
+        } else {
+            boolean isGranted = false;
+
+            int numSourcePerm = sourcePerms.size();
+            for (int i = 0; i < numSourcePerm; i++) {
+                String sourcePerm = sourcePerms.valueAt(i);
+                if (ps.hasRuntimePermission(sourcePerm, userId)
+                        && ps.getRuntimePermissionState(sourcePerm, userId).isGranted()) {
+                    isGranted = true;
+                    break;
+                }
+            }
+
+            if (isGranted) {
+                if (DEBUG_PERMISSIONS) {
+                    Slog.i(TAG, newPerm + " inherits runtime perm grant from " + sourcePerms
+                            + " for " + pkgName);
+                }
+
+                ps.grantRuntimePermission(mSettings.getPermissionLocked(newPerm), userId);
+            }
+        }
+    }
+
+    /**
+     * Set the state of a implicit permission that is seen for the first time.
+     *
+     * @param origPs The permission state of the package before the split
+     * @param ps The new permission state
+     * @param pkg The package the permission belongs to
+     * @param updatedUserIds List of users for which the permission state has already been changed
+     *
+     * @return  List of users for which the permission state has been changed
+     */
+    private @NonNull int[] setInitialGrantForNewImplicitPermissionsLocked(
+            @NonNull PermissionsState origPs,
+            @NonNull PermissionsState ps, @NonNull PackageParser.Package pkg,
+            @NonNull int[] updatedUserIds) {
+        String pkgName = pkg.packageName;
+        ArraySet<String> newImplicitPermissions = new ArraySet<>();
+
+        int numRequestedPerms = pkg.requestedPermissions.size();
+        for (int i = 0; i < numRequestedPerms; i++) {
+            BasePermission bp = mSettings.getPermissionLocked(pkg.requestedPermissions.get(i));
+            if (bp != null) {
+                String perm = bp.getName();
+
+                if (!origPs.hasRequestedPermission(perm) && pkg.implicitPermissions.contains(
+                        perm)) {
+                    newImplicitPermissions.add(perm);
+
+                    if (DEBUG_PERMISSIONS) {
+                        Slog.i(TAG, perm + " is newly added for " + pkgName);
+                    }
+                }
+            }
+        }
+
+        ArrayMap<String, ArraySet<String>> newToSplitPerms = new ArrayMap<>();
+
+        int numSplitPerms = PermissionManager.SPLIT_PERMISSIONS.size();
+        for (int splitPermNum = 0; splitPermNum < numSplitPerms; splitPermNum++) {
+            PermissionManager.SplitPermissionInfo spi =
+                    PermissionManager.SPLIT_PERMISSIONS.get(splitPermNum);
+
+            List<String> newPerms = spi.getNewPermissions();
+            int numNewPerms = newPerms.size();
+            for (int newPermNum = 0; newPermNum < numNewPerms; newPermNum++) {
+                String newPerm = newPerms.get(newPermNum);
+
+                ArraySet<String> splitPerms = newToSplitPerms.get(newPerm);
+                if (splitPerms == null) {
+                    splitPerms = new ArraySet<>();
+                    newToSplitPerms.put(newPerm, splitPerms);
+                }
+
+                splitPerms.add(spi.getSplitPermission());
+            }
+        }
+
+        int numNewImplicitPerms = newImplicitPermissions.size();
+        for (int newImplicitPermNum = 0; newImplicitPermNum < numNewImplicitPerms;
+                newImplicitPermNum++) {
+            String newPerm = newImplicitPermissions.valueAt(newImplicitPermNum);
+            ArraySet<String> sourcePerms = newToSplitPerms.get(newPerm);
+
+            if (sourcePerms != null) {
+                if (!ps.hasInstallPermission(newPerm)) {
+                    BasePermission bp = mSettings.getPermissionLocked(newPerm);
+
+                    int[] users = UserManagerService.getInstance().getUserIds();
+                    int numUsers = users.length;
+                    for (int userNum = 0; userNum < numUsers; userNum++) {
+                        int userId = users[userNum];
+
+                        ps.updatePermissionFlags(bp, userId,
+                                FLAG_PERMISSION_REVOKE_WHEN_REQUESTED,
+                                FLAG_PERMISSION_REVOKE_WHEN_REQUESTED);
+                        updatedUserIds = ArrayUtils.appendInt(updatedUserIds, userId);
+
+                        if (!origPs.hasRequestedPermission(sourcePerms)) {
+                            // Both permissions are new, do nothing
+                            if (DEBUG_PERMISSIONS) {
+                                Slog.i(TAG, newPerm + " does not inherit from " + sourcePerms
+                                        + " for " + pkgName + " as split permission is also new");
+                            }
+
+                            break;
+                        } else {
+                            inheritPermissionStateToNewImplicitPermissionLocked(sourcePerms,
+                                    newPerm, ps, pkg, userId);
+                        }
+                    }
+                }
+            }
+        }
+
+        return updatedUserIds;
+    }
+
     private boolean isNewPlatformPermissionForPackage(String perm, PackageParser.Package pkg) {
         boolean allowed = false;
         final int NP = PackageParser.NEW_PERMISSIONS.length;