74 lines
2.6 KiB
Elixir
74 lines
2.6 KiB
Elixir
defmodule Pleroma.Captcha.Kocaptcha do
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alias Plug.Crypto.KeyGenerator
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alias Plug.Crypto.MessageEncryptor
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alias Calendar.DateTime
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alias Pleroma.Captcha.Service
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@behaviour Service
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@impl Service
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def new() do
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endpoint = Pleroma.Config.get!([__MODULE__, :endpoint])
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case Tesla.get(endpoint <> "/new") do
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{:error, _} ->
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%{error: "Kocaptcha service unavailable"}
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{:ok, res} ->
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json_resp = Poison.decode!(res.body)
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token = json_resp["token"]
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answer_md5 = json_resp["md5"]
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secret_key_base = Pleroma.Config.get!([Pleroma.Web.Endpoint, :secret_key_base])
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# This make salt a little different for two keys
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secret = KeyGenerator.generate(secret_key_base, token <> "_encrypt")
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sign_secret = KeyGenerator.generate(secret_key_base, token <> "_sign")
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# Basicallty copy what Phoenix.Token does here, add the time to
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# the actual data and make it a binary to then encrypt it
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encrypted_captcha_answer =
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%{
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at: DateTime.now_utc(),
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answer_md5: answer_md5
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}
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|> :erlang.term_to_binary()
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|> MessageEncryptor.encrypt(secret, sign_secret)
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%{
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type: :kocaptcha,
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token: token,
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url: endpoint <> json_resp["url"],
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answer_data: encrypted_captcha_answer
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}
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end
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end
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@impl Service
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def validate(token, captcha, answer_data) do
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secret_key_base = Pleroma.Config.get!([Pleroma.Web.Endpoint, :secret_key_base])
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secret = KeyGenerator.generate(secret_key_base, token <> "_encrypt")
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sign_secret = KeyGenerator.generate(secret_key_base, token <> "_sign")
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# If the time found is less than (current_time - seconds_valid), then the time has already passed.
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# Later we check that the time found is more than the presumed invalidatation time, that means
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# that the data is still valid and the captcha can be checked
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seconds_valid = Pleroma.Config.get!([Pleroma.Captcha, :seconds_valid])
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valid_if_after = DateTime.subtract!(DateTime.now_utc(), seconds_valid)
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with {:ok, data} <- MessageEncryptor.decrypt(answer_data, secret, sign_secret),
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%{at: at, answer_md5: answer_md5} <- :erlang.binary_to_term(data) do
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if DateTime.after?(at, valid_if_after) do
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if not is_nil(captcha) and
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:crypto.hash(:md5, captcha) |> Base.encode16() == String.upcase(answer_md5),
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do: :ok,
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else: {:error, "Invalid CAPTCHA"}
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else
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{:error, "CAPTCHA expired"}
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end
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else
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_ -> {:error, "Invalid answer data"}
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end
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end
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end
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