X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/24b1ca4bf401b6701055ad0df4160a9fc1aacd7b..cfe9b58cc374794df00910b7708ffa245aaf03bf:/services/api/app/models/link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index 60a94c7e23..83043a56d1 100644
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -43,6 +43,28 @@ 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
@@ -63,7 +85,7 @@ class Link < ArvadosModel
         return false
       end
       if tail_obj.group_class != "role"
-        errors.add(:tail_uuid, "must be a role, was #{tail_obj.group_class}")
+        errors.add(:tail_uuid, "must be a user or role, was group with group_class #{tail_obj.group_class}")
         return false
       end
     elsif rsc_class != User
@@ -76,6 +98,11 @@ class Link < ArvadosModel
 
     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
     if head_obj.is_a?(Collection) && head_obj.current_version_uuid != head_uuid
       errors.add(:head_uuid, "cannot point to a past version of a collection")
@@ -109,12 +136,14 @@ class Link < ArvadosModel
   def call_update_permissions
     if self.link_class == 'permission'
       update_permissions tail_uuid, head_uuid, PERM_LEVEL[name], self.uuid
+      current_user.forget_cached_group_perms
     end
   end
 
   def clear_permissions
     if self.link_class == 'permission'
       update_permissions tail_uuid, head_uuid, REVOKE_PERM, self.uuid
+      current_user.forget_cached_group_perms
     end
   end