fix(api): isolate sensitive idempotency responses

lib/pleroma/web/admin_api/controllers/user_controller.ex

@@ -152,6 +152,13 @@ defmodule Pleroma.Web.AdminAPI.UserController do
         } = conn,
         _
       ) do
+    conn =
+      if Enum.any?(users, fn user -> Map.get(user, :password) in ["", nil] end) do
+        put_private(conn, :skip_idempotency_cache, true)
+      else
+        conn
+      end
+
     multi =
       users
       |> Enum.map(fn %{nickname: nickname, email: email} = attrs ->

lib/pleroma/web/plugs/idempotency_plug.ex

@@ -6,6 +6,8 @@ defmodule Pleroma.Web.Plugs.IdempotencyPlug do
   import Phoenix.Controller, only: [json: 2]
   import Plug.Conn
 
+  alias Pleroma.Config
+
   @behaviour Plug
 
   @cachex Pleroma.Config.get([:cachex, :provider], Cachex)
@@ -27,9 +29,11 @@ defmodule Pleroma.Web.Plugs.IdempotencyPlug do
   def call(conn, _), do: conn
 
   def process_request(conn, key) do
-    case @cachex.get(:idempotency_cache, key) do
+    cache_key = {conn.method, conn.request_path, actor_key(conn), key}
+
+    case @cachex.get(:idempotency_cache, cache_key) do
       {:ok, nil} ->
-        cache_resposnse(conn, key)
+        cache_resposnse(conn, key, cache_key)
 
       {:ok, record} ->
         send_cached(conn, key, record)
@@ -39,18 +43,48 @@ defmodule Pleroma.Web.Plugs.IdempotencyPlug do
     end
   end
 
-  defp cache_resposnse(conn, key) do
-    register_before_send(conn, fn conn ->
-      [request_id] = get_resp_header(conn, "x-request-id")
-      content_type = get_content_type(conn)
+  defp cache_resposnse(conn, key, cache_key) do
+    register_before_send(conn, &maybe_cache_response(&1, key, cache_key))
+  end
 
-      record = {request_id, content_type, conn.status, conn.resp_body}
-      {:ok, _} = @cachex.put(:idempotency_cache, key, record)
+  defp maybe_cache_response(
+         %{private: %{skip_idempotency_cache: true}} = conn,
+         _key,
+         _cache_key
+       ),
+       do: conn
 
-      conn
-      |> put_resp_header("idempotency-key", key)
-      |> put_resp_header("x-original-request-id", request_id)
-    end)
+  defp maybe_cache_response(conn, key, cache_key) do
+    [request_id] = get_resp_header(conn, "x-request-id")
+    content_type = get_content_type(conn)
+
+    record = {request_id, content_type, conn.status, conn.resp_body}
+    {:ok, _} = @cachex.put(:idempotency_cache, cache_key, record)
+
+    conn
+    |> put_resp_header("idempotency-key", key)
+    |> put_resp_header("x-original-request-id", request_id)
+  end
+
+  defp actor_key(%{assigns: assigns}) do
+    {principal_key(assigns), token_key(assigns[:token]), staff_privileges()}
+  end
+
+  defp principal_key(%{user: %{id: id} = user}) do
+    {:user, id, Map.get(user, :is_admin), Map.get(user, :is_moderator)}
+  end
+
+  defp principal_key(%{app: %{id: id}}), do: {:app, id}
+  defp principal_key(_assigns), do: nil
+
+  defp token_key(%{id: id} = token), do: {id, token |> Map.get(:scopes, []) |> Enum.sort()}
+  defp token_key(_token), do: nil
+
+  defp staff_privileges do
+    {
+      Config.get([:instance, :admin_privileges], []) |> Enum.sort(),
+      Config.get([:instance, :moderator_privileges], []) |> Enum.sort()
+    }
   end
 
   defp send_cached(conn, key, record) do

test/pleroma/web/admin_api/controllers/user_controller_test.exs

@@ -238,6 +238,51 @@ defmodule Pleroma.Web.AdminAPI.UserControllerTest do
       assert Repo.aggregate(Pleroma.PasswordResetToken, :count) == 0
     end
 
+    test "Password reset links are not cached by idempotency key", %{conn: conn} do
+      idempotency_key = Ecto.UUID.generate()
+
+      request = fn conn ->
+        conn
+        |> put_req_header("accept", "application/json")
+        |> put_req_header("content-type", "application/json")
+        |> put_req_header("idempotency-key", idempotency_key)
+        |> post("/api/pleroma/admin/users", %{
+          "users" => [%{"nickname" => "lain", "email" => "lain@example.org"}]
+        })
+      end
+
+      assert [%{"data" => %{"password_reset_link" => _link}}] =
+               conn |> request.() |> json_response(200)
+
+      second_conn = request.(conn)
+
+      assert [_error] = json_response(second_conn, 409)
+      refute get_resp_header(second_conn, "idempotent-replayed") == ["true"]
+    end
+
+    test "Explicit-password responses remain idempotent", %{conn: conn} do
+      idempotency_key = Ecto.UUID.generate()
+
+      request = fn conn ->
+        conn
+        |> put_req_header("accept", "application/json")
+        |> put_req_header("content-type", "application/json")
+        |> put_req_header("idempotency-key", idempotency_key)
+        |> post("/api/pleroma/admin/users", %{
+          "users" => [
+            %{"nickname" => "lain", "email" => "lain@example.org", "password" => "test"}
+          ]
+        })
+      end
+
+      assert [_account] = conn |> request.() |> json_response(200)
+
+      second_conn = request.(conn)
+
+      assert [_account] = json_response(second_conn, 200)
+      assert get_resp_header(second_conn, "idempotent-replayed") == ["true"]
+    end
+
     test "Duplicate nicknames in a batch return a conflict", %{conn: conn} do
       conn =
         conn

test/pleroma/web/plugs/idempotency_plug_test.exs

@@ -70,6 +70,139 @@ defmodule Pleroma.Web.Plugs.IdempotencyPlugTest do
     assert [^key] = Conn.get_resp_header(conn, "idempotency-key")
   end
 
+  test "does not cache responses marked as sensitive" do
+    key = Ecto.UUID.generate()
+
+    :post
+    |> conn("/cofe")
+    |> put_req_header("idempotency-key", key)
+    |> Conn.put_resp_header("x-request-id", "sensitive-request")
+    |> Conn.put_resp_content_type("application/json")
+    |> IdempotencyPlug.call([])
+    |> Conn.put_private(:skip_idempotency_cache, true)
+    |> Conn.send_resp(200, "secret")
+
+    conn =
+      :post
+      |> conn("/cofe")
+      |> put_req_header("idempotency-key", key)
+      |> Conn.put_resp_header("x-request-id", "second-request")
+      |> Conn.put_resp_content_type("application/json")
+      |> IdempotencyPlug.call([])
+
+    refute conn.halted
+    refute conn.resp_body
+  end
+
+  test "does not replay legacy unscoped cache entries" do
+    key = Ecto.UUID.generate()
+    record = {"legacy-request", "application/json", 200, "secret"}
+    assert {:ok, true} = Cachex.put(:idempotency_cache, key, record)
+
+    conn =
+      :post
+      |> conn("/cofe")
+      |> put_req_header("idempotency-key", key)
+      |> Conn.put_resp_header("x-request-id", "new-request")
+      |> Conn.put_resp_content_type("application/json")
+      |> IdempotencyPlug.call([])
+
+    refute conn.halted
+    refute conn.resp_body
+  end
+
+  test "scopes cached responses to the route and authenticated actor" do
+    key = Ecto.UUID.generate()
+
+    :post
+    |> conn("/cofe")
+    |> Conn.assign(:user, %{id: "user-one", is_admin: false, is_moderator: false})
+    |> put_req_header("idempotency-key", key)
+    |> Conn.put_resp_header("x-request-id", "original-request")
+    |> Conn.put_resp_content_type("application/json")
+    |> IdempotencyPlug.call([])
+    |> Conn.send_resp(200, "one")
+
+    for {path, user} <- [
+          {"/tea", %{id: "user-one", is_admin: false, is_moderator: false}},
+          {"/cofe", %{id: "user-two", is_admin: false, is_moderator: false}},
+          {"/cofe", %{id: "user-one", is_admin: true, is_moderator: false}}
+        ] do
+      conn =
+        :post
+        |> conn(path)
+        |> Conn.assign(:user, user)
+        |> put_req_header("idempotency-key", key)
+        |> Conn.put_resp_header("x-request-id", Ecto.UUID.generate())
+        |> Conn.put_resp_content_type("application/json")
+        |> IdempotencyPlug.call([])
+
+      refute conn.halted
+      refute conn.resp_body
+    end
+  end
+
+  test "scopes cached responses to the OAuth application and token" do
+    key = Ecto.UUID.generate()
+
+    :post
+    |> conn("/cofe")
+    |> Conn.assign(:app, %{id: "app-one"})
+    |> Conn.assign(:token, %{id: "token-one", scopes: ["write"]})
+    |> put_req_header("idempotency-key", key)
+    |> Conn.put_resp_header("x-request-id", "original-request")
+    |> Conn.put_resp_content_type("application/json")
+    |> IdempotencyPlug.call([])
+    |> Conn.send_resp(200, "one")
+
+    for {app, token} <- [
+          {%{id: "app-two"}, %{id: "token-two", scopes: ["write"]}},
+          {%{id: "app-one"}, %{id: "token-two", scopes: ["write"]}},
+          {%{id: "app-one"}, %{id: "token-one", scopes: ["read"]}}
+        ] do
+      conn =
+        :post
+        |> conn("/cofe")
+        |> Conn.assign(:app, app)
+        |> Conn.assign(:token, token)
+        |> put_req_header("idempotency-key", key)
+        |> Conn.put_resp_header("x-request-id", Ecto.UUID.generate())
+        |> Conn.put_resp_content_type("application/json")
+        |> IdempotencyPlug.call([])
+
+      refute conn.halted
+      refute conn.resp_body
+    end
+  end
+
+  test "scopes cached responses to configured staff privileges" do
+    key = Ecto.UUID.generate()
+    clear_config([:instance, :admin_privileges], [:users_delete])
+
+    :post
+    |> conn("/cofe")
+    |> Conn.assign(:user, %{id: "admin", is_admin: true, is_moderator: false})
+    |> put_req_header("idempotency-key", key)
+    |> Conn.put_resp_header("x-request-id", "original-request")
+    |> Conn.put_resp_content_type("application/json")
+    |> IdempotencyPlug.call([])
+    |> Conn.send_resp(200, "one")
+
+    clear_config([:instance, :admin_privileges], [])
+
+    conn =
+      :post
+      |> conn("/cofe")
+      |> Conn.assign(:user, %{id: "admin", is_admin: true, is_moderator: false})
+      |> put_req_header("idempotency-key", key)
+      |> Conn.put_resp_header("x-request-id", "second-request")
+      |> Conn.put_resp_content_type("application/json")
+      |> IdempotencyPlug.call([])
+
+    refute conn.halted
+    refute conn.resp_body
+  end
+
   test "passes conn downstream if idempotency is not present in headers" do
     orig_request_id = "test4"
     body = "testing"