# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.MediaProxy do
- @base64_opts [padding: false]
-
- def url(nil), do: nil
+ alias Pleroma.Config
+ alias Pleroma.Web
- def url(""), do: nil
+ @base64_opts [padding: false]
+ def url(url) when is_nil(url) or url == "", do: nil
def url("/" <> _ = url), do: url
def url(url) do
- if !enabled?() or local?(url) or whitelisted?(url) do
+ if disabled?() or local?(url) or whitelisted?(url) do
url
else
encode_url(url)
end
end
- defp enabled?, do: Pleroma.Config.get([:media_proxy, :enabled], false)
+ defp disabled?, do: !Config.get([:media_proxy, :enabled], false)
defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
defp whitelisted?(url) do
%{host: domain} = URI.parse(url)
- Enum.any?(Pleroma.Config.get([:media_proxy, :whitelist]), fn pattern ->
+ Enum.any?(Config.get([:media_proxy, :whitelist]), fn pattern ->
String.equivalent?(domain, pattern)
end)
end
def encode_url(url) do
- secret = Pleroma.Config.get([Pleroma.Web.Endpoint, :secret_key_base])
-
- # Must preserve `%2F` for compatibility with S3
- # https://git.pleroma.social/pleroma/pleroma/issues/580
- replacement = get_replacement(url, ":2F:")
+ base64 = Base.url_encode64(url, @base64_opts)
- # The URL is url-decoded and encoded again to ensure it is correctly encoded and not twice.
- base64 =
- url
- |> String.replace("%2F", replacement)
- |> URI.decode()
- |> URI.encode()
- |> String.replace(replacement, "%2F")
+ sig64 =
+ base64
+ |> signed_url
|> Base.url_encode64(@base64_opts)
- sig = :crypto.hmac(:sha, secret, base64)
- sig64 = sig |> Base.url_encode64(@base64_opts)
-
build_url(sig64, base64, filename(url))
end
def decode_url(sig, url) do
- secret = Pleroma.Config.get([Pleroma.Web.Endpoint, :secret_key_base])
- sig = Base.url_decode64!(sig, @base64_opts)
- local_sig = :crypto.hmac(:sha, secret, url)
-
- if local_sig == sig 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
-
- defp get_replacement(url, replacement) do
- if String.contains?(url, replacement) do
- get_replacement(url, replacement <> replacement)
- else
- replacement
- end
- end
end