X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/f8743ac8fa1ed9dc8c7c4f7a23803ffe8721cfa6..6430b728cbce69b56adc01432fc9351088724efd:/services/api/app/models/link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index af3918551e..24872b21ec 100644
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -9,7 +9,7 @@ class Link < ArvadosModel
   after_create :maybe_invalidate_permissions_cache
   after_destroy :maybe_invalidate_permissions_cache
   attr_accessor :head_kind, :tail_kind
-  validate :name_link_has_valid_name
+  validate :name_links_are_obsolete
 
   api_accessible :user, extend: :common do |t|
     t.add :tail_uuid
@@ -50,22 +50,9 @@ class Link < ArvadosModel
     # Administrators can grant permissions
     return true if current_user.is_admin
 
-    # All users can grant permissions on objects they own
-    head_obj = self.class.
-      resource_class_for_uuid(self.head_uuid).
-      where('uuid=?',head_uuid).
-      first
-    if head_obj
-      return true if head_obj.owner_uuid == current_user.uuid
-    end
-
-    # Users with "can_grant" permission on an object can grant
-    # permissions on that object
-    has_grant_permission = self.class.
-      where('link_class=? AND name=? AND tail_uuid=? AND head_uuid=?',
-            'permission', 'can_grant', current_user.uuid, self.head_uuid).
-      count > 0
-    return true if has_grant_permission
+    # All users can grant permissions on objects they own or can manage
+    head_obj = ArvadosModel.find_by_uuid(head_uuid)
+    return true if current_user.can?(manage: head_obj)
 
     # Default = deny.
     false
@@ -79,17 +66,35 @@ class Link < ArvadosModel
       # permissions for head_uuid and tail_uuid, and invalidate the
       # cache for only those users. (This would require a browseable
       # cache.)
-      User.invalidate_permissions_cache
+      User.invalidate_permissions_cache db_current_time.to_i
     end
   end
 
-  def name_link_has_valid_name
+  def name_links_are_obsolete
     if link_class == 'name'
-      unless name.is_a? String and !name.empty?
-        errors.add('name', 'must be a non-empty string')
-      end
+      errors.add('name', 'Name links are obsolete')
+      false
     else
       true
     end
   end
+
+  # A user is permitted to create, update or modify a permission link
+  # 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
+    if link_class == 'permission'
+      ob = ArvadosModel.find_by_uuid(head_uuid)
+      raise PermissionDeniedError unless current_user.can?(manage: ob)
+      # All permission links should be owned by the system user.
+      self.owner_uuid = system_user_uuid
+      return true
+    else
+      super
+    end
+  end
+
 end