85 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
# Pleroma: A lightweight social networking server
 | 
						|
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
 | 
						|
# SPDX-License-Identifier: AGPL-3.0-only
 | 
						|
 | 
						|
defmodule Pleroma.Web.MediaProxy do
 | 
						|
  alias Pleroma.Config
 | 
						|
  alias Pleroma.Upload
 | 
						|
  alias Pleroma.Web
 | 
						|
 | 
						|
  @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 disabled?() or local?(url) or whitelisted?(url) do
 | 
						|
      url
 | 
						|
    else
 | 
						|
      encode_url(url)
 | 
						|
    end
 | 
						|
  end
 | 
						|
 | 
						|
  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)
 | 
						|
 | 
						|
    mediaproxy_whitelist = Config.get([:media_proxy, :whitelist])
 | 
						|
 | 
						|
    upload_base_url_domain =
 | 
						|
      if !is_nil(Config.get([Upload, :base_url])) do
 | 
						|
        [URI.parse(Config.get([Upload, :base_url])).host]
 | 
						|
      else
 | 
						|
        []
 | 
						|
      end
 | 
						|
 | 
						|
    whitelist = mediaproxy_whitelist ++ upload_base_url_domain
 | 
						|
 | 
						|
    Enum.any?(whitelist, fn pattern ->
 | 
						|
      String.equivalent?(domain, pattern)
 | 
						|
    end)
 | 
						|
  end
 | 
						|
 | 
						|
  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
 | 
						|
 | 
						|
  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}
 | 
						|
    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], Web.base_url()),
 | 
						|
      "proxy",
 | 
						|
      sig_base64,
 | 
						|
      url_base64,
 | 
						|
      filename
 | 
						|
    ]
 | 
						|
    |> Enum.filter(& &1)
 | 
						|
    |> Path.join()
 | 
						|
  end
 | 
						|
end
 |