5 files changed, 146 insertions, 29 deletions

diff --git a/lib/pleroma/web/oauth/app.ex b/lib/pleroma/web/oauth/app.ex
index bccc2ac96..ddcdb1871 100644
--- a/lib/pleroma/web/oauth/app.ex
+++ b/lib/pleroma/web/oauth/app.ex
@@ -7,6 +7,7 @@ defmodule Pleroma.Web.OAuth.App do
   import Ecto.Changeset
 
   @type t :: %__MODULE__{}
+
   schema "apps" do
     field(:client_name, :string)
     field(:redirect_uris, :string)
diff --git a/lib/pleroma/web/oauth/authorization.ex b/lib/pleroma/web/oauth/authorization.ex
index ca3901cc4..b47688de1 100644
--- a/lib/pleroma/web/oauth/authorization.ex
+++ b/lib/pleroma/web/oauth/authorization.ex
@@ -14,6 +14,7 @@ defmodule Pleroma.Web.OAuth.Authorization do
   import Ecto.Query
 
   @type t :: %__MODULE__{}
+
   schema "oauth_authorizations" do
     field(:token, :string)
     field(:scopes, {:array, :string}, default: [])
@@ -25,28 +26,45 @@ defmodule Pleroma.Web.OAuth.Authorization do
     timestamps()
   end
 
+  @spec create_authorization(App.t(), User.t() | %{}, [String.t()] | nil) ::
+          {:ok, Authorization.t()} | {:error, Changeset.t()}
   def create_authorization(%App{} = app, %User{} = user, scopes \\ nil) do
-    scopes = scopes || app.scopes
-    token = :crypto.strong_rand_bytes(32) |> Base.url_encode64(padding: false)
-
-    authorization = %Authorization{
-      token: token,
-      used: false,
+    %{
+      scopes: scopes || app.scopes,
       user_id: user.id,
-      app_id: app.id,
-      scopes: scopes,
-      valid_until: NaiveDateTime.add(NaiveDateTime.utc_now(), 60 * 10)
+      app_id: app.id
     }
+    |> create_changeset()
+    |> Repo.insert()
+  end
+
+  @spec create_changeset(map()) :: Changeset.t()
+  def create_changeset(attrs \\ %{}) do
+    %Authorization{}
+    |> cast(attrs, [:user_id, :app_id, :scopes, :valid_until])
+    |> validate_required([:app_id, :scopes])
+    |> add_token()
+    |> add_lifetime()
+  end
+
+  defp add_token(changeset) do
+    token = :crypto.strong_rand_bytes(32) |> Base.url_encode64(padding: false)
+    put_change(changeset, :token, token)
+  end
 
-    Repo.insert(authorization)
+  defp add_lifetime(changeset) do
+    put_change(changeset, :valid_until, NaiveDateTime.add(NaiveDateTime.utc_now(), 60 * 10))
   end
 
+  @spec use_changeset(Authtorizatiton.t(), map()) :: Changeset.t()
   def use_changeset(%Authorization{} = auth, params) do
     auth
     |> cast(params, [:used])
     |> validate_required([:used])
   end
 
+  @spec use_token(Authorization.t()) ::
+          {:ok, Authorization.t()} | {:error, Changeset.t()} | {:error, String.t()}
   def use_token(%Authorization{used: false, valid_until: valid_until} = auth) do
     if NaiveDateTime.diff(NaiveDateTime.utc_now(), valid_until) < 0 do
       Repo.update(use_changeset(auth, %{used: true}))
@@ -57,6 +75,7 @@ defmodule Pleroma.Web.OAuth.Authorization do
 
   def use_token(%Authorization{used: true}), do: {:error, "already used"}
 
+  @spec delete_user_authorizations(User.t()) :: {integer(), any()}
   def delete_user_authorizations(%User{id: user_id}) do
     from(
       a in Pleroma.Web.OAuth.Authorization,
diff --git a/lib/pleroma/web/oauth/oauth_controller.ex b/lib/pleroma/web/oauth/oauth_controller.ex
index e3c01217d..4ee8339e2 100644
--- a/lib/pleroma/web/oauth/oauth_controller.ex
+++ b/lib/pleroma/web/oauth/oauth_controller.ex
@@ -15,8 +15,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
   alias Pleroma.Web.OAuth.Token
   alias Pleroma.Web.OAuth.Token.Strategy.RefreshToken
   alias Pleroma.Web.OAuth.Token.Strategy.Revoke, as: RevokeToken
-
-  import Pleroma.Web.ControllerHelper, only: [oauth_scopes: 2]
+  alias Pleroma.Web.OAuth.Scopes
 
   if Pleroma.Config.oauth_consumer_enabled?(), do: plug(Ueberauth)
 
@@ -57,7 +56,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
   defp do_authorize(conn, params) do
     app = Repo.get_by(App, client_id: params["client_id"])
     available_scopes = (app && app.scopes) || []
-    scopes = oauth_scopes(params, nil) || available_scopes
+    scopes = Scopes.fetch_scopes(params, available_scopes)
 
     # Note: `params` might differ from `conn.params`; use `@params` not `@conn.params` in template
     render(conn, Authenticator.auth_template(), %{
@@ -113,7 +112,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
 
   defp handle_create_authorization_error(
          conn,
-         {scopes_issue, _},
+         {:error, scopes_issue},
          %{"authorization" => _} = params
        )
        when scopes_issue in [:unsupported_scopes, :missing_scopes] do
@@ -184,9 +183,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
          %App{} = app <- get_app_from_request(conn, params),
          {:auth_active, true} <- {:auth_active, User.auth_active?(user)},
          {:user_active, true} <- {:user_active, !user.info.deactivated},
-         scopes <- oauth_scopes(params, app.scopes),
-         [] <- scopes -- app.scopes,
-         true <- Enum.any?(scopes),
+         {:ok, scopes} <- validate_scopes(app, params),
          {:ok, auth} <- Authorization.create_authorization(app, user, scopes),
          {:ok, token} <- Token.exchange_token(app, auth) do
       json(conn, response_token(user, token))
@@ -221,6 +218,28 @@ defmodule Pleroma.Web.OAuth.OAuthController do
     token_exchange(conn, params)
   end
 
+  def token_exchange(conn, %{"grant_type" => "client_credentials"} = params) do
+    with %App{} = app <- get_app_from_request(conn, params),
+         {:ok, auth} <- Authorization.create_authorization(app, %User{}),
+         {:ok, token} <- Token.exchange_token(app, auth),
+         {:ok, inserted_at} <- DateTime.from_naive(token.inserted_at, "Etc/UTC") do
+      response = %{
+        token_type: "Bearer",
+        access_token: token.token,
+        refresh_token: token.refresh_token,
+        created_at: DateTime.to_unix(inserted_at),
+        expires_in: 60 * 10,
+        scope: Enum.join(token.scopes, " ")
+      }
+
+      json(conn, response)
+    else
+      _error ->
+        put_status(conn, 400)
+        |> json(%{error: "Invalid credentials"})
+    end
+  end
+
   # Bad request
   def token_exchange(conn, params), do: bad_request(conn, params)
 
@@ -247,14 +266,15 @@ defmodule Pleroma.Web.OAuth.OAuthController do
   @doc "Prepares OAuth request to provider for Ueberauth"
   def prepare_request(conn, %{"provider" => provider, "authorization" => auth_attrs}) do
     scope =
-      oauth_scopes(auth_attrs, [])
-      |> Enum.join(" ")
+      auth_attrs
+      |> Scopes.fetch_scopes([])
+      |> Scopes.to_string()
 
     state =
       auth_attrs
       |> Map.delete("scopes")
       |> Map.put("scope", scope)
-      |> Poison.encode!()
+      |> Jason.encode!()
 
     params =
       auth_attrs
@@ -318,7 +338,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
   end
 
   defp callback_params(%{"state" => state} = params) do
-    Map.merge(params, Poison.decode!(state))
+    Map.merge(params, Jason.decode!(state))
   end
 
   def registration_details(conn, %{"authorization" => auth_attrs}) do
@@ -326,7 +346,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
       client_id: auth_attrs["client_id"],
       redirect_uri: auth_attrs["redirect_uri"],
       state: auth_attrs["state"],
-      scopes: oauth_scopes(auth_attrs, []),
+      scopes: Scopes.fetch_scopes(auth_attrs, []),
       nickname: auth_attrs["nickname"],
       email: auth_attrs["email"]
     })
@@ -401,10 +421,7 @@ defmodule Pleroma.Web.OAuth.OAuthController do
            {:get_user, (user && {:ok, user}) || Authenticator.get_user(conn)},
          %App{} = app <- Repo.get_by(App, client_id: client_id),
          true <- redirect_uri in String.split(app.redirect_uris),
-         scopes <- oauth_scopes(auth_attrs, []),
-         {:unsupported_scopes, []} <- {:unsupported_scopes, scopes -- app.scopes},
-         # Note: `scope` param is intentionally not optional in this context
-         {:missing_scopes, false} <- {:missing_scopes, scopes == []},
+         {:ok, scopes} <- validate_scopes(app, auth_attrs),
          {:auth_active, true} <- {:auth_active, User.auth_active?(user)} do
       Authorization.create_authorization(app, user, scopes)
     end
@@ -458,4 +475,12 @@ defmodule Pleroma.Web.OAuth.OAuthController do
     }
     |> Map.merge(opts)
   end
+
+  @spec validate_scopes(App.t(), map()) ::
+          {:ok, list()} | {:error, :missing_scopes | :unsupported_scopes}
+  defp validate_scopes(app, params) do
+    params
+    |> Scopes.fetch_scopes(app.scopes)
+    |> Scopes.validates(app.scopes)
+  end
 end
diff --git a/lib/pleroma/web/oauth/scopes.ex b/lib/pleroma/web/oauth/scopes.ex
new file mode 100644
index 000000000..ad9dfb260
--- /dev/null
+++ b/lib/pleroma/web/oauth/scopes.ex
@@ -0,0 +1,67 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.OAuth.Scopes do
+  @moduledoc """
+  Functions for dealing with scopes.
+  """
+
+  @doc """
+  Fetch scopes from requiest params.
+
+  Note: `scopes` is used by Mastodon — supporting it but sticking to
+  OAuth's standard `scope` wherever we control it
+  """
+  @spec fetch_scopes(map(), list()) :: list()
+  def fetch_scopes(params, default) do
+    parse_scopes(params["scope"] || params["scopes"], default)
+  end
+
+  def parse_scopes(scopes, _default) when is_list(scopes) do
+    Enum.filter(scopes, &(&1 not in [nil, ""]))
+  end
+
+  def parse_scopes(scopes, default) when is_binary(scopes) do
+    scopes
+    |> to_list
+    |> parse_scopes(default)
+  end
+
+  def parse_scopes(_, default) do
+    default
+  end
+
+  @doc """
+  Convert scopes string to list
+  """
+  @spec to_list(binary()) :: [binary()]
+  def to_list(nil), do: []
+
+  def to_list(str) do
+    str
+    |> String.trim()
+    |> String.split(~r/[\s,]+/)
+  end
+
+  @doc """
+  Convert scopes list to string
+  """
+  @spec to_string(list()) :: binary()
+  def to_string(scopes), do: Enum.join(scopes, " ")
+
+  @doc """
+  Validates scopes.
+  """
+  @spec validates(list() | nil, list()) ::
+          {:ok, list()} | {:error, :missing_scopes | :unsupported_scopes}
+  def validates([], _app_scopes), do: {:error, :missing_scopes}
+  def validates(nil, _app_scopes), do: {:error, :missing_scopes}
+
+  def validates(scopes, app_scopes) do
+    case scopes -- app_scopes do
+      [] -> {:ok, scopes}
+      _ -> {:error, :unsupported_scopes}
+    end
+  end
+end
diff --git a/lib/pleroma/web/oauth/token.ex b/lib/pleroma/web/oauth/token.ex
index 4e5d1d118..ef047d565 100644
--- a/lib/pleroma/web/oauth/token.ex
+++ b/lib/pleroma/web/oauth/token.ex
@@ -45,12 +45,16 @@ defmodule Pleroma.Web.OAuth.Token do
     |> Repo.find_resource()
   end
 
+  @spec exchange_token(App.t(), Authorization.t()) ::
+          {:ok, Token.t()} | {:error, Changeset.t()}
   def exchange_token(app, auth) do
     with {:ok, auth} <- Authorization.use_token(auth),
          true <- auth.app_id == app.id do
+      user = if auth.user_id, do: User.get_cached_by_id(auth.user_id), else: %User{}
+
       create_token(
         app,
-        User.get_cached_by_id(auth.user_id),
+        user,
         %{scopes: auth.scopes}
       )
     end
@@ -81,12 +85,13 @@ defmodule Pleroma.Web.OAuth.Token do
     |> validate_required([:valid_until])
   end
 
+  @spec create_token(App.t(), User.t(), map()) :: {:ok, Token} | {:error, Changeset.t()}
   def create_token(%App{} = app, %User{} = user, attrs \\ %{}) do
     %__MODULE__{user_id: user.id, app_id: app.id}
     |> cast(%{scopes: attrs[:scopes] || app.scopes}, [:scopes])
-    |> validate_required([:scopes, :user_id, :app_id])
+    |> validate_required([:scopes, :app_id])
     |> put_valid_until(attrs)
-    |> put_token
+    |> put_token()
     |> put_refresh_token(attrs)
     |> Repo.insert()
   end