security: detect object containment violations at the IR level

It is more efficient to check for object containment violations at the IR
level instead of in the protocol handlers.  OStatus containment is especially
a tricky situation, as the containment rules don't match those of IR and
ActivityPub.

Accordingly, we just always do a final containment check at the IR level
before the object is added to the IR object graph.
This commit is contained in:
Ariadne Conill 2019-07-14 17:47:08 +00:00
parent 93701c3399
commit 739bbe0d3b
3 changed files with 40 additions and 0 deletions

View file

@ -48,6 +48,9 @@ defmodule Pleroma.Object.Containment do
end
end
def contain_origin(id, %{"attributedTo" => actor} = params),
do: contain_origin(id, Map.put(params, "actor", actor))
def contain_origin_from_id(_id, %{"id" => nil}), do: :error
def contain_origin_from_id(id, %{"id" => other_id} = _params) do
@ -60,4 +63,9 @@ defmodule Pleroma.Object.Containment do
:error
end
end
def contain_child(%{"object" => %{"id" => id, "attributedTo" => _} = object}),
do: contain_origin(id, object)
def contain_child(_), do: :ok
end

View file

@ -8,6 +8,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
alias Pleroma.Conversation
alias Pleroma.Notification
alias Pleroma.Object
alias Pleroma.Object.Containment
alias Pleroma.Object.Fetcher
alias Pleroma.Pagination
alias Pleroma.Repo
@ -126,6 +127,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
{:ok, map} <- MRF.filter(map),
{recipients, _, _} = get_recipients(map),
{:fake, false, map, recipients} <- {:fake, fake, map, recipients},
:ok <- Containment.contain_child(map),
{:ok, map, object} <- insert_full_object(map) do
{:ok, activity} =
Repo.insert(%Activity{

View file

@ -68,4 +68,34 @@ defmodule Pleroma.Object.ContainmentTest do
"[error] Could not decode user at fetch https://n1u.moe/users/rye, {:error, :error}"
end
end
describe "containment of children" do
test "contain_child() catches spoofing attempts" do
data = %{
"id" => "http://example.com/whatever",
"type" => "Create",
"object" => %{
"id" => "http://example.net/~alyssa/activities/1234",
"attributedTo" => "http://example.org/~alyssa"
},
"actor" => "http://example.com/~bob"
}
:error = Containment.contain_child(data)
end
test "contain_child() allows correct origins" do
data = %{
"id" => "http://example.org/~alyssa/activities/5678",
"type" => "Create",
"object" => %{
"id" => "http://example.org/~alyssa/activities/1234",
"attributedTo" => "http://example.org/~alyssa"
},
"actor" => "http://example.org/~alyssa"
}
:ok = Containment.contain_child(data)
end
end
end