16683: Check that remote cluster id is presumed valid, add test

[arvados.git] / services / api / app / models / link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index 808489e1c2b93084e40e85deb04a3b1aa3a06b45..bf107f575cc39c03637d12001a3c7639106815b9 100644 (file)
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -1,14 +1,21 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
 class Link < ArvadosModel
   include HasUuid
   include KindAndEtag
   include CommonApiTemplate
-  serialize :properties, Hash
+
+  # Posgresql JSONB columns should NOT be declared as serialized, Rails 5
+  # already know how to properly treat them.
+  attribute :properties, :jsonbHash, default: {}
+
   before_create :permission_to_attach_to_objects
   before_update :permission_to_attach_to_objects
   after_update :maybe_invalidate_permissions_cache
   after_create :maybe_invalidate_permissions_cache
   after_destroy :maybe_invalidate_permissions_cache
-  attr_accessor :head_kind, :tail_kind
   validate :name_links_are_obsolete
 
   api_accessible :user, extend: :common do |t|
@@ -21,11 +28,6 @@ class Link < ArvadosModel
     t.add :properties
   end
 
-  def properties
-    @properties ||= Hash.new
-    super
-  end
-
   def head_kind
     if k = ArvadosModel::resource_class_for_uuid(head_uuid)
       k.kind
@@ -40,6 +42,28 @@ class Link < ArvadosModel
 
   protected
 
+  def check_readable_uuid attr, attr_value
+    if attr == 'tail_uuid' &&
+       !attr_value.nil? &&
+       self.link_class == 'permission' &&
+       attr_value[0..4] != Rails.configuration.ClusterID &&
+       ApiClientAuthorization.remote_host(uuid_prefix: attr_value[0..4]) &&
+       ArvadosModel::resource_class_for_uuid(attr_value) == User
+      # Permission link tail is a remote user (the user permissions
+      # are being granted to), so bypass the standard check that a
+      # referenced object uuid is readable by current user.
+      #
+      # We could do a call to the remote cluster to check if the user
+      # in tail_uuid exists.  This would detect copy-and-paste errors,
+      # but add another way for the request to fail, and I don't think
+      # it would improve security.  It doesn't seem to be worth the
+      # complexity tradeoff.
+      true
+    else
+      super
+    end
+  end
+
   def permission_to_attach_to_objects
     # Anonymous users cannot write links
     return false if !current_user
@@ -50,8 +74,17 @@ class Link < ArvadosModel
     # Administrators can grant permissions
     return true if current_user.is_admin
 
-    # All users can grant permissions on objects they own or can manage
     head_obj = ArvadosModel.find_by_uuid(head_uuid)
+
+    if head_obj.nil?
+      errors.add(:head_uuid, "does not exist")
+      return false
+    end
+
+    # No permission links can be pointed to past collection versions
+    return false if head_obj.is_a?(Collection) && head_obj.current_version_uuid != head_uuid
+
+    # All users can grant permissions on objects they own or can manage
     return true if current_user.can?(manage: head_obj)
 
     # Default = deny.
@@ -80,8 +113,9 @@ class Link < ArvadosModel
   end
 
   # A user is permitted to create, update or modify a permission link
-  # if and only if they have "manage" permission on the destination
-  # object.
+  # if and only if they have "manage" permission on the object
+  # indicated by the permission link's head_uuid.
+  #
   # All other links are treated as regular ArvadosModel objects.
   #
   def ensure_owner_uuid_is_permitted
@@ -95,15 +129,4 @@ class Link < ArvadosModel
       super
     end
   end
-
-  # A user can give all other users permissions on projects.
-  def skip_uuid_read_permission_check
-    skipped_attrs = super
-    if link_class == "permission" and
-        (ArvadosModel.resource_class_for_uuid(head_uuid) == Group) and
-        (ArvadosModel.resource_class_for_uuid(tail_uuid) == User)
-      skipped_attrs << "tail_uuid"
-    end
-    skipped_attrs
-  end
 end