X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/ccce5e8ad71ed2e50ecd57c0f73f1aaafc468539..f2574ec2e4ddef03c9504cd58741e73426ea1b17:/services/api/app/models/arvados_model.rb

diff --git a/services/api/app/models/arvados_model.rb b/services/api/app/models/arvados_model.rb
index 4f06f054a3..4a717c4658 100644
--- a/services/api/app/models/arvados_model.rb
+++ b/services/api/app/models/arvados_model.rb
@@ -1,4 +1,5 @@
-require 'assign_uuid'
+require 'has_uuid'
+
 class ArvadosModel < ActiveRecord::Base
   self.abstract_class = true
 
@@ -9,10 +10,11 @@ class ArvadosModel < ActiveRecord::Base
   attr_protected :modified_by_client_uuid
   attr_protected :modified_at
   after_initialize :log_start_state
-  before_create :ensure_permission_to_create
-  before_update :ensure_permission_to_update
+  before_save :ensure_permission_to_save
+  before_save :ensure_owner_uuid_is_permitted
+  before_save :ensure_ownership_path_leads_to_user
+  before_destroy :ensure_owner_uuid_is_permitted
   before_destroy :ensure_permission_to_destroy
-
   before_create :update_modified_by_fields
   before_update :maybe_update_modified_by_fields
   after_create :log_create
@@ -22,7 +24,10 @@ class ArvadosModel < ActiveRecord::Base
   validate :normalize_collection_uuids
   validate :ensure_valid_uuids
 
-  has_many :permissions, :foreign_key => :head_uuid, :class_name => 'Link', :primary_key => :uuid, :conditions => "link_class = 'permission'"
+  # Note: This only returns permission links. It does not account for
+  # permissions obtained via user.is_admin or
+  # user.uuid==object.owner_uuid.
+  has_many :permissions, :foreign_key => :head_uuid, :class_name => 'Link', :primary_key => :uuid, :conditions => "link_class = 'permission'", dependent: :destroy
 
   class PermissionDeniedError < StandardError
     def http_status
@@ -59,6 +64,24 @@ class ArvadosModel < ActiveRecord::Base
     self.columns.select { |col| col.name == attr.to_s }.first
   end
 
+  # Return nil if current user is not allowed to see the list of
+  # writers. Otherwise, return a list of user_ and group_uuids with
+  # write permission. (If not returning nil, current_user is always in
+  # the list because can_manage permission is needed to see the list
+  # of writers.)
+  def writable_by
+    unless (owner_uuid == current_user.uuid or
+            current_user.is_admin or
+            current_user.groups_i_can(:manage).index(owner_uuid))
+      return nil
+    end
+    [owner_uuid, current_user.uuid] + permissions.collect do |p|
+      if ['can_write', 'can_manage'].index p.name
+        p.tail_uuid
+      end
+    end.compact.uniq
+  end
+
   # Return a query with read permissions restricted to the union of of the
   # permissions of the members of users_list, i.e. if something is readable by
   # any user in users_list, it will be readable in the query returned by this
@@ -130,16 +153,71 @@ class ArvadosModel < ActiveRecord::Base
 
   protected
 
-  def ensure_permission_to_create
-    raise PermissionDeniedError unless permission_to_create
+  def ensure_ownership_path_leads_to_user
+    if new_record? or owner_uuid_changed?
+      uuid_in_path = {owner_uuid => true, uuid => true}
+      x = owner_uuid
+      while (owner_class = self.class.resource_class_for_uuid(x)) != User
+        begin
+          if x == uuid
+            # Test for cycles with the new version, not the DB contents
+            x = owner_uuid
+          elsif !owner_class.respond_to? :find_by_uuid
+            raise ActiveRecord::RecordNotFound.new
+          else
+            x = owner_class.find_by_uuid(x).owner_uuid
+          end
+        rescue ActiveRecord::RecordNotFound => e
+          errors.add :owner_uuid, "is not owned by any user: #{e}"
+          return false
+        end
+        if uuid_in_path[x]
+          if x == owner_uuid
+            errors.add :owner_uuid, "would create an ownership cycle"
+          else
+            errors.add :owner_uuid, "has an ownership cycle"
+          end
+          return false
+        end
+        uuid_in_path[x] = true
+      end
+    end
+    true
   end
 
-  def permission_to_create
-    current_user.andand.is_active
+  def ensure_owner_uuid_is_permitted
+    raise PermissionDeniedError if !current_user
+    self.owner_uuid ||= current_user.uuid
+    if self.owner_uuid_changed?
+      if current_user.uuid == self.owner_uuid or
+          current_user.can? write: self.owner_uuid
+        # current_user is, or has :write permission on, the new owner
+      else
+        logger.warn "User #{current_user.uuid} tried to change owner_uuid of #{self.class.to_s} #{self.uuid} to #{self.owner_uuid} but does not have permission to write to #{self.owner_uuid}"
+        raise PermissionDeniedError
+      end
+    end
+    if new_record?
+      return true
+    elsif current_user.uuid == self.owner_uuid_was or
+        current_user.uuid == self.uuid or
+        current_user.can? write: self.owner_uuid_was
+      # current user is, or has :write permission on, the previous owner
+      return true
+    else
+      logger.warn "User #{current_user.uuid} tried to modify #{self.class.to_s} #{self.uuid} but does not have permission to write #{self.owner_uuid_was}"
+      raise PermissionDeniedError
+    end
   end
 
-  def ensure_permission_to_update
-    raise PermissionDeniedError unless permission_to_update
+  def ensure_permission_to_save
+    unless (new_record? ? permission_to_create : permission_to_update)
+      raise PermissionDeniedError
+    end
+  end
+
+  def permission_to_create
+    current_user.andand.is_active
   end
 
   def permission_to_update
@@ -156,24 +234,7 @@ class ArvadosModel < ActiveRecord::Base
       logger.warn "User #{current_user.uuid} tried to change uuid of #{self.class.to_s} #{self.uuid_was} to #{self.uuid}"
       return false
     end
-    if self.owner_uuid_changed?
-      if current_user.uuid == self.owner_uuid or
-          current_user.can? write: self.owner_uuid
-        # current_user is, or has :write permission on, the new owner
-      else
-        logger.warn "User #{current_user.uuid} tried to change owner_uuid of #{self.class.to_s} #{self.uuid} to #{self.owner_uuid} but does not have permission to write to #{self.owner_uuid}"
-        return false
-      end
-    end
-    if current_user.uuid == self.owner_uuid_was or
-        current_user.uuid == self.uuid or
-        current_user.can? write: self.owner_uuid_was
-      # current user is, or has :write permission on, the previous owner
-      return true
-    else
-      logger.warn "User #{current_user.uuid} tried to modify #{self.class.to_s} #{self.uuid} but does not have permission to write #{self.owner_uuid_was}"
-      return false
-    end
+    return true
   end
 
   def ensure_permission_to_destroy
@@ -186,6 +247,7 @@ class ArvadosModel < ActiveRecord::Base
 
   def maybe_update_modified_by_fields
     update_modified_by_fields if self.changed? or self.new_record?
+    true
   end
 
   def update_modified_by_fields
@@ -194,6 +256,7 @@ class ArvadosModel < ActiveRecord::Base
     self.modified_at = Time.now
     self.modified_by_user_uuid = current_user ? current_user.uuid : nil
     self.modified_by_client_uuid = current_api_client ? current_api_client.uuid : nil
+    true
   end
 
   def ensure_serialized_attribute_type