Merge remote-tracking branch 'origin/develop' into global-status-expiration

[akkoma] / lib / pleroma / web / media_proxy / media_proxy.ex

diff --git a/lib/pleroma/web/media_proxy/media_proxy.ex b/lib/pleroma/web/media_proxy/media_proxy.ex
index 39a725a6941c86c61ae69d18657772ad7fb61c43..b2b524524570fa7a62fbbae9db9d850544e41885 100644 (file)
--- a/lib/pleroma/web/media_proxy/media_proxy.ex
+++ b/lib/pleroma/web/media_proxy/media_proxy.ex
@@ -1,76 +1,85 @@
 # Pleroma: A lightweight social networking server
-# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
 # 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.Upload
+  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
-    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
 
-      # Must preserve `%2F` for compatibility with S3 (https://git.pleroma.social/pleroma/pleroma/issues/580)
-      replacement = get_replacement(url, ":2F:")
+  defp disabled?, do: !Config.get([:media_proxy, :enabled], false)
 
-      # 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")
-        |> Base.url_encode64(@base64_opts)
+  defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
 
-      sig = :crypto.hmac(:sha, secret, base64)
-      sig64 = sig |> Base.url_encode64(@base64_opts)
+  defp whitelisted?(url) do
+    %{host: domain} = URI.parse(url)
 
-      build_url(sig64, base64, filename(url))
-    end
+    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 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)
 
-    if local_sig == sig do
+    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}
+      _ -> {: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