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"
# 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
## 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,
supervisor(Pleroma.Repo, []),
worker(Pleroma.Emoji, []),
worker(Pleroma.Captcha, []),
+ worker(
+ Cachex,
+ [
+ :used_captcha_cache,
+ [
+ ttl_interval: :timer.seconds(Pleroma.Config.get!([Pleroma.Captcha, :seconds_valid]))
+ ]
+ ],
+ id: :cachex_used_captcha_cache
+ ),
worker(
Cachex,
[
# 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
@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
@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
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)
+
+ 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"})
+
+ 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))
- seconds_retained = Pleroma.Config.get!([__MODULE__, :seconds_retained])
- # Schedule the next clenup
- Process.send_after(self(), :cleanup, 1000 * seconds_retained)
+ :ok
+ catch
+ :throw, e -> e
+ end
+ else
+ _ -> {:error, "Invalid answer data"}
+ end
- {:noreply, state}
+ {:reply, result, state}
end
defp method, do: Pleroma.Config.get!([__MODULE__, :method])
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.
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
# 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])
{: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
+ %{
+ type: :kocaptcha,
+ token: json_resp["token"],
+ url: endpoint <> json_resp["url"],
+ answer_data: json_resp["md5"]
+ }
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]
- }
- ]
- )
-
- :ok
+ 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
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])
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
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
projects / akkoma / commitdiff