85 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
| # Pleroma: A lightweight social networking server
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| # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
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| # SPDX-License-Identifier: AGPL-3.0-only
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| 
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| defmodule Pleroma.Web.MediaProxy do
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|   alias Pleroma.Config
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|   alias Pleroma.Upload
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|   alias Pleroma.Web
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| 
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|   @base64_opts [padding: false]
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| 
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|   def url(url) when is_nil(url) or url == "", do: nil
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|   def url("/" <> _ = url), do: url
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| 
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|   def url(url) do
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|     if disabled?() or local?(url) or whitelisted?(url) do
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|       url
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|     else
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|       encode_url(url)
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|     end
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|   end
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| 
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|   defp disabled?, do: !Config.get([:media_proxy, :enabled], false)
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| 
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|   defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
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| 
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|   defp whitelisted?(url) do
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|     %{host: domain} = URI.parse(url)
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| 
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|     mediaproxy_whitelist = Config.get([:media_proxy, :whitelist])
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| 
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|     upload_base_url_domain =
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|       if !is_nil(Config.get([Upload, :base_url])) do
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|         [URI.parse(Config.get([Upload, :base_url])).host]
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|       else
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|         []
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|       end
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| 
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|     whitelist = mediaproxy_whitelist ++ upload_base_url_domain
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| 
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|     Enum.any?(whitelist, fn pattern ->
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|       String.equivalent?(domain, pattern)
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|     end)
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|   end
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| 
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|   def encode_url(url) do
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|     base64 = Base.url_encode64(url, @base64_opts)
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| 
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|     sig64 =
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|       base64
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|       |> signed_url
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|       |> Base.url_encode64(@base64_opts)
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| 
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|     build_url(sig64, base64, filename(url))
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|   end
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| 
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|   def decode_url(sig, url) do
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|     with {:ok, sig} <- Base.url_decode64(sig, @base64_opts),
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|          signature when signature == sig <- signed_url(url) do
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|       {:ok, Base.url_decode64!(url, @base64_opts)}
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|     else
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|       _ -> {:error, :invalid_signature}
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|     end
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|   end
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| 
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|   defp signed_url(url) do
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|     :crypto.hmac(:sha, Config.get([Web.Endpoint, :secret_key_base]), url)
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|   end
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| 
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|   def filename(url_or_path) do
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|     if path = URI.parse(url_or_path).path, do: Path.basename(path)
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|   end
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| 
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|   def build_url(sig_base64, url_base64, filename \\ nil) do
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|     [
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|       Pleroma.Config.get([:media_proxy, :base_url], Web.base_url()),
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|       "proxy",
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|       sig_base64,
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|       url_base64,
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|       filename
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|     ]
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|     |> Enum.filter(& &1)
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|     |> Path.join()
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|   end
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| end
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