diff --git a/config/config.exs b/config/config.exs index 11ee220e7..34b516e02 100644 --- a/config/config.exs +++ b/config/config.exs @@ -12,7 +12,7 @@ config :pleroma, Pleroma.Repo, types: Pleroma.PostgresTypes config :pleroma, Pleroma.Captcha, enabled: false, - seconds_retained: 180, + seconds_valid: 60, method: Pleroma.Captcha.Kocaptcha config :pleroma, Pleroma.Captcha.Kocaptcha, endpoint: "https://captcha.kotobank.ch" diff --git a/config/test.exs b/config/test.exs index 51aace407..67ed4737f 100644 --- a/config/test.exs +++ b/config/test.exs @@ -9,7 +9,8 @@ config :pleroma, Pleroma.Web.Endpoint, # Disable captha for tests config :pleroma, Pleroma.Captcha, - enabled: true, + # It should not be enabled for automatic tests + enabled: false, # A fake captcha service for tests method: Pleroma.Captcha.Mock diff --git a/docs/config.md b/docs/config.md index f4bcae3fd..1c3219efe 100644 --- a/docs/config.md +++ b/docs/config.md @@ -172,7 +172,7 @@ Web Push Notifications configuration. You can use the mix task `mix web_push.gen ## Pleroma.Captcha * `enabled`: Whether the captcha should be shown on registration * `method`: The method/service to use for captcha -* `seconds_retained`: The time in seconds for which the captcha is valid (stored in the cache) +* `seconds_valid`: The time in seconds for which the captcha is valid ### Pleroma.Captcha.Kocaptcha Kocaptcha is a very simple captcha service with a single API endpoint, diff --git a/lib/pleroma/application.ex b/lib/pleroma/application.ex index 4542ed623..cb3e6b69b 100644 --- a/lib/pleroma/application.ex +++ b/lib/pleroma/application.ex @@ -32,6 +32,16 @@ defmodule Pleroma.Application do worker( Cachex, [ + :used_captcha_cache, + [ + ttl_interval: :timer.seconds(Pleroma.Config.get!([Pleroma.Captcha, :seconds_valid])) + ] + ], + id: :cachex_used_captcha_cache + ), + worker( + Cachex, + [ :user_cache, [ default_ttl: 25000, diff --git a/lib/pleroma/captcha/captcha.ex b/lib/pleroma/captcha/captcha.ex index 133a9fd68..0207bcbea 100644 --- a/lib/pleroma/captcha/captcha.ex +++ b/lib/pleroma/captcha/captcha.ex @@ -3,9 +3,11 @@ # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Captcha do - use GenServer + alias Plug.Crypto.KeyGenerator + alias Plug.Crypto.MessageEncryptor + alias Calendar.DateTime - @ets_options [:ordered_set, :private, :named_table, {:read_concurrency, true}] + use GenServer @doc false def start_link() do @@ -14,14 +16,6 @@ defmodule Pleroma.Captcha do @doc false def init(_) do - # Create a ETS table to store captchas - ets_name = Module.concat(method(), Ets) - ^ets_name = :ets.new(Module.concat(method(), Ets), @ets_options) - - # Clean up old captchas every few minutes - seconds_retained = Pleroma.Config.get!([__MODULE__, :seconds_retained]) - Process.send_after(self(), :cleanup, 1000 * seconds_retained) - {:ok, nil} end @@ -35,8 +29,8 @@ defmodule Pleroma.Captcha do @doc """ Ask the configured captcha service to validate the captcha """ - def validate(token, captcha) do - GenServer.call(__MODULE__, {:validate, token, captcha}) + def validate(token, captcha, answer_data) do + GenServer.call(__MODULE__, {:validate, token, captcha, answer_data}) end @doc false @@ -46,24 +40,71 @@ defmodule Pleroma.Captcha do if !enabled do {:reply, %{type: :none}, state} else - {:reply, method().new(), state} + new_captcha = method().new() + + secret_key_base = Pleroma.Config.get!([Pleroma.Web.Endpoint, :secret_key_base]) + + # This make salt a little different for two keys + token = new_captcha[:token] + secret = KeyGenerator.generate(secret_key_base, token <> "_encrypt") + sign_secret = KeyGenerator.generate(secret_key_base, token <> "_sign") + # Basicallty copy what Phoenix.Token does here, add the time to + # the actual data and make it a binary to then encrypt it + encrypted_captcha_answer = + %{ + at: DateTime.now_utc(), + answer_data: new_captcha[:answer_data] + } + |> :erlang.term_to_binary() + |> MessageEncryptor.encrypt(secret, sign_secret) + + { + :reply, + # Repalce the answer with the encrypted answer + %{new_captcha | answer_data: encrypted_captcha_answer}, + state + } end end @doc false - def handle_call({:validate, token, captcha}, _from, state) do - {:reply, method().validate(token, captcha), state} - end + def handle_call({:validate, token, captcha, answer_data}, _from, state) do + secret_key_base = Pleroma.Config.get!([Pleroma.Web.Endpoint, :secret_key_base]) + secret = KeyGenerator.generate(secret_key_base, token <> "_encrypt") + sign_secret = KeyGenerator.generate(secret_key_base, token <> "_sign") - @doc false - def handle_info(:cleanup, state) do - :ok = method().cleanup() + # If the time found is less than (current_time - seconds_valid), then the time has already passed. + # Later we check that the time found is more than the presumed invalidatation time, that means + # that the data is still valid and the captcha can be checked + seconds_valid = Pleroma.Config.get!([Pleroma.Captcha, :seconds_valid]) + valid_if_after = DateTime.subtract!(DateTime.now_utc(), seconds_valid) - seconds_retained = Pleroma.Config.get!([__MODULE__, :seconds_retained]) - # Schedule the next clenup - Process.send_after(self(), :cleanup, 1000 * seconds_retained) + result = + with {:ok, data} <- MessageEncryptor.decrypt(answer_data, secret, sign_secret), + %{at: at, answer_data: answer_md5} <- :erlang.binary_to_term(data) do + try do + if DateTime.before?(at, valid_if_after), do: throw({:error, "CAPTCHA expired"}) - {:noreply, state} + if not is_nil(Cachex.get!(:used_captcha_cache, token)), + do: throw({:error, "CAPTCHA already used"}) + + res = method().validate(token, captcha, answer_md5) + # Throw if an error occurs + if res != :ok, do: throw(res) + + # Mark this captcha as used + {:ok, _} = + Cachex.put(:used_captcha_cache, token, true, ttl: :timer.seconds(seconds_valid)) + + :ok + catch + :throw, e -> e + end + else + _ -> {:error, "Invalid answer data"} + end + + {:reply, result, state} end defp method, do: Pleroma.Config.get!([__MODULE__, :method]) diff --git a/lib/pleroma/captcha/captcha_service.ex b/lib/pleroma/captcha/captcha_service.ex index a820751a8..8d27c04f1 100644 --- a/lib/pleroma/captcha/captcha_service.ex +++ b/lib/pleroma/captcha/captcha_service.ex @@ -8,9 +8,14 @@ defmodule Pleroma.Captcha.Service do Returns: - Service-specific data for using the newly created captcha + Type/Name of the service, the token to identify the captcha, + the data of the answer and service-specific data to use the newly created captcha """ - @callback new() :: map + @callback new() :: %{ + type: atom(), + token: String.t(), + answer_data: any() + } @doc """ Validated the provided captcha solution. @@ -18,15 +23,15 @@ defmodule Pleroma.Captcha.Service do Arguments: * `token` the captcha is associated with * `captcha` solution of the captcha to validate + * `answer_data` is the data needed to validate the answer (presumably encrypted) Returns: `true` if captcha is valid, `false` if not """ - @callback validate(token :: String.t(), captcha :: String.t()) :: boolean - - @doc """ - This function is called periodically to clean up old captchas - """ - @callback cleanup() :: :ok + @callback validate( + token :: String.t(), + captcha :: String.t(), + answer_data :: any() + ) :: :ok | {:error, String.t()} end diff --git a/lib/pleroma/captcha/kocaptcha.ex b/lib/pleroma/captcha/kocaptcha.ex index 66f9ce754..34a611492 100644 --- a/lib/pleroma/captcha/kocaptcha.ex +++ b/lib/pleroma/captcha/kocaptcha.ex @@ -3,13 +3,9 @@ # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Captcha.Kocaptcha do - alias Calendar.DateTime - alias Pleroma.Captcha.Service @behaviour Service - @ets __MODULE__.Ets - @impl Service def new() do endpoint = Pleroma.Config.get!([__MODULE__, :endpoint]) @@ -21,51 +17,21 @@ defmodule Pleroma.Captcha.Kocaptcha do {:ok, res} -> json_resp = Poison.decode!(res.body) - token = json_resp["token"] - - true = - :ets.insert( - @ets, - {token, json_resp["md5"], DateTime.now_utc() |> DateTime.Format.unix()} - ) - - %{type: :kocaptcha, token: token, url: endpoint <> json_resp["url"]} - end - end - - @impl Service - def validate(token, captcha) do - with false <- is_nil(captcha), - [{^token, saved_md5, _}] <- :ets.lookup(@ets, token), - true <- :crypto.hash(:md5, captcha) |> Base.encode16() == String.upcase(saved_md5) do - # Clear the saved value - :ets.delete(@ets, token) - - true - else - _ -> false - end - end - - @impl Service - def cleanup() do - seconds_retained = Pleroma.Config.get!([Pleroma.Captcha, :seconds_retained]) - # If the time in ETS is less than current_time - seconds_retained, then the time has - # already passed - delete_after = - DateTime.subtract!(DateTime.now_utc(), seconds_retained) |> DateTime.Format.unix() - - :ets.select_delete( - @ets, - [ - { - {:_, :_, :"$1"}, - [{:<, :"$1", {:const, delete_after}}], - [true] + %{ + type: :kocaptcha, + token: json_resp["token"], + url: endpoint <> json_resp["url"], + answer_data: json_resp["md5"] } - ] - ) + end + end - :ok + @impl Service + def validate(_token, captcha, answer_data) do + # Here the token is unsed, because the unencrypted captcha answer is just passed to method + if not is_nil(captcha) and + :crypto.hash(:md5, captcha) |> Base.encode16() == String.upcase(answer_data), + do: :ok, + else: {:error, "Invalid CAPTCHA"} end end diff --git a/lib/pleroma/web/twitter_api/twitter_api.ex b/lib/pleroma/web/twitter_api/twitter_api.ex index 0aa4a8d23..ecf81d492 100644 --- a/lib/pleroma/web/twitter_api/twitter_api.ex +++ b/lib/pleroma/web/twitter_api/twitter_api.ex @@ -140,22 +140,28 @@ defmodule Pleroma.Web.TwitterAPI.TwitterAPI do password: params["password"], password_confirmation: params["confirm"], captcha_solution: params["captcha_solution"], - captcha_token: params["captcha_token"] + captcha_token: params["captcha_token"], + captcha_answer_data: params["captcha_answer_data"] } captcha_enabled = Pleroma.Config.get([Pleroma.Captcha, :enabled]) # true if captcha is disabled or enabled and valid, false otherwise captcha_ok = if !captcha_enabled do - true + :ok else - Pleroma.Captcha.validate(params[:captcha_token], params[:captcha_solution]) + Pleroma.Captcha.validate( + params[:captcha_token], + params[:captcha_solution], + params[:captcha_answer_data] + ) end # Captcha invalid - if not captcha_ok do + if captcha_ok != :ok do + {:error, error} = captcha_ok # I have no idea how this error handling works - {:error, %{error: Jason.encode!(%{captcha: ["Invalid CAPTCHA"]})}} + {:error, %{error: Jason.encode!(%{captcha: [error]})}} else registrations_open = Pleroma.Config.get([:instance, :registrations_open]) diff --git a/test/captcha_test.exs b/test/captcha_test.exs index 7f559ac72..7ca9a4607 100644 --- a/test/captcha_test.exs +++ b/test/captcha_test.exs @@ -29,16 +29,18 @@ defmodule Pleroma.CaptchaTest do end test "new and validate" do - assert Kocaptcha.new() == %{ - type: :kocaptcha, - token: "afa1815e14e29355e6c8f6b143a39fa2", - url: "https://captcha.kotobank.ch/captchas/afa1815e14e29355e6c8f6b143a39fa2.png" - } + new = Kocaptcha.new() + assert new[:type] == :kocaptcha + assert new[:token] == "afa1815e14e29355e6c8f6b143a39fa2" + + assert new[:url] == + "https://captcha.kotobank.ch/captchas/afa1815e14e29355e6c8f6b143a39fa2.png" assert Kocaptcha.validate( - "afa1815e14e29355e6c8f6b143a39fa2", - "7oEy8c" - ) + new[:token], + "7oEy8c", + new[:answer_data] + ) == :ok end end end diff --git a/test/support/captcha_mock.ex b/test/support/captcha_mock.ex index 3ab02916f..9061f2b45 100644 --- a/test/support/captcha_mock.ex +++ b/test/support/captcha_mock.ex @@ -10,8 +10,5 @@ defmodule Pleroma.Captcha.Mock do def new(), do: %{type: :mock} @impl Service - def validate(_token, _captcha), do: true - - @impl Service - def cleanup(), do: :ok + def validate(_token, _captcha, _data), do: :ok end