-defmodule Pleroma.Web.MediaProxy do
- @base64_opts [padding: false]
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
- def url(nil), do: nil
+defmodule Pleroma.Web.MediaProxy do
+ alias Pleroma.Config
+ alias Pleroma.Web
- def url(""), do: nil
+ @base64_opts [padding: false]
- def url(url = "/" <> _), do: url
+ def url(url) when is_nil(url) or url == "", do: nil
+ def url("/" <> _ = url), do: url
def url(url) do
- config = Application.get_env(:pleroma, :media_proxy, [])
-
- if !Keyword.get(config, :enabled, false) or String.starts_with?(url, Pleroma.Web.base_url()) do
+ if disabled?() or local?(url) or whitelisted?(url) do
url
else
- secret = Application.get_env(:pleroma, Pleroma.Web.Endpoint)[:secret_key_base]
+ encode_url(url)
+ end
+ end
- # The URL is url-decoded and encoded again to ensure it is correctly encoded and not twice.
- base64 =
- url
- |> URI.decode()
- |> URI.encode()
- |> Base.url_encode64(@base64_opts)
+ defp disabled?, do: !Config.get([:media_proxy, :enabled], false)
- sig = :crypto.hmac(:sha, secret, base64)
- sig64 = sig |> Base.url_encode64(@base64_opts)
+ defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
- build_url(sig64, base64, filename(url))
- end
+ defp whitelisted?(url) do
+ %{host: domain} = URI.parse(url)
+
+ Enum.any?(Config.get([:media_proxy, :whitelist]), fn pattern ->
+ String.equivalent?(domain, pattern)
+ end)
end
- def decode_url(sig, url) do
- secret = Application.get_env(:pleroma, Pleroma.Web.Endpoint)[:secret_key_base]
- sig = Base.url_decode64!(sig, @base64_opts)
- local_sig = :crypto.hmac(:sha, secret, url)
+ def encode_url(url) do
+ base64 = Base.url_encode64(url, @base64_opts)
+
+ sig64 =
+ base64
+ |> signed_url
+ |> Base.url_encode64(@base64_opts)
+
+ build_url(sig64, base64, filename(url))
+ end
- if local_sig == sig do
+ def decode_url(sig, url) do
+ with {:ok, sig} <- Base.url_decode64(sig, @base64_opts),
+ signature when signature == sig <- signed_url(url) do
{:ok, Base.url_decode64!(url, @base64_opts)}
else
- {:error, :invalid_signature}
+ _ -> {:error, :invalid_signature}
end
end
+ defp signed_url(url) do
+ :crypto.hmac(:sha, Config.get([Web.Endpoint, :secret_key_base]), url)
+ end
+
def filename(url_or_path) do
if path = URI.parse(url_or_path).path, do: Path.basename(path)
end
def build_url(sig_base64, url_base64, filename \\ nil) do
[
- Pleroma.Config.get([:media_proxy, :base_url], Pleroma.Web.base_url()),
+ Pleroma.Config.get([:media_proxy, :base_url], Web.base_url()),
"proxy",
sig_base64,
url_base64,
filename
]
- |> Enum.filter(fn value -> value end)
+ |> Enum.filter(& &1)
|> Path.join()
end
end