X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/6ba9fdc006d023fe1a56cd28fb87a54dff5265d8..bad73626c4208fb95ac8e3d9503fc4482f936cb3:/services/api/app/models/link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index 33e18b296b..83043a56d1 100644
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -12,8 +12,8 @@ class Link < ArvadosModel
   attribute :properties, :jsonbHash, default: {}
 
   validate :name_links_are_obsolete
-  before_create :permission_to_attach_to_objects
-  before_update :permission_to_attach_to_objects
+  validate :permission_to_attach_to_objects
+  before_update :restrict_alter_permissions
   after_update :call_update_permissions
   after_create :call_update_permissions
   before_destroy :clear_permissions
@@ -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
@@ -50,13 +72,42 @@ class Link < ArvadosModel
     # All users can write links that don't affect permissions
     return true if self.link_class != 'permission'
 
+    if PERM_LEVEL[self.name].nil?
+      errors.add(:name, "is invalid permission, must be one of 'can_read', 'can_write', 'can_manage', 'can_login'")
+      return false
+    end
+
+    rsc_class = ArvadosModel::resource_class_for_uuid tail_uuid
+    if rsc_class == Group
+      tail_obj = Group.find_by_uuid(tail_uuid)
+      if tail_obj.nil?
+        errors.add(:tail_uuid, "does not exist")
+        return false
+      end
+      if tail_obj.group_class != "role"
+        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
+      errors.add(:tail_uuid, "must be a user or role")
+      return false
+    end
+
     # Administrators can grant permissions
     return true if current_user.is_admin
 
     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
+    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")
+      return false
+    end
 
     # All users can grant permissions on objects they own or can manage
     return true if current_user.can?(manage: head_obj)
@@ -65,6 +116,16 @@ class Link < ArvadosModel
     false
   end
 
+  def restrict_alter_permissions
+    return true if self.link_class != 'permission' && self.link_class_was != 'permission'
+
+    return true if current_user.andand.uuid == system_user.uuid
+
+    if link_class_changed? || tail_uuid_changed? || head_uuid_changed?
+      raise "Can only alter permission link level"
+    end
+  end
+
   PERM_LEVEL = {
     'can_read' => 1,
     'can_login' => 1,
@@ -74,19 +135,21 @@ class Link < ArvadosModel
 
   def call_update_permissions
     if self.link_class == 'permission'
-      update_permissions tail_uuid, head_uuid, PERM_LEVEL[name]
+      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, 0
+      update_permissions tail_uuid, head_uuid, REVOKE_PERM, self.uuid
+      current_user.forget_cached_group_perms
     end
   end
 
   def check_permissions
     if self.link_class == 'permission'
-      #check_permissions_against_full_refresh
+      check_permissions_against_full_refresh
     end
   end