[#2497] Specified SHELL in .gitlab-ci.yml as required for `exexec`.

[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 dd8888a021635357b4fe88c1bb2748517c7c6062..4e01c14e4a765bf0047e2d649f89538413a7441e 100644 (file)
--- a/lib/pleroma/web/media_proxy/media_proxy.ex
+++ b/lib/pleroma/web/media_proxy/media_proxy.ex
@@ -1,70 +1,143 @@
 # 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
-    if !enabled?() or local?(url) or whitelisted?(url) do
+    if not enabled?() or local?(url) or whitelisted?(url) do
       url
     else
       encode_url(url)
     end
   end
 
-  defp enabled?, do: Pleroma.Config.get([:media_proxy, :enabled], false)
+  # Note: routing all URLs to preview handler (even local and whitelisted).
+  #   Preview handler will call url/1 on decoded URLs, and applicable ones will detour media proxy.
+  def preview_url(url) do
+    if preview_enabled?() do
+      encode_preview_url(url)
+    else
+      url
+    end
+  end
+
+  def enabled?, do: Config.get([:media_proxy, :enabled], false)
 
-  defp local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
+  # Note: media proxy must be enabled for media preview proxy in order to load all
+  #   non-local non-whitelisted URLs through it and be sure that body size constraint is preserved.
+  def preview_enabled?, do: enabled?() and Config.get([:media_preview_proxy, :enabled], false)
 
-  defp whitelisted?(url) do
+  def local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
+
+  def whitelisted?(url) do
     %{host: domain} = URI.parse(url)
 
-    Enum.any?(Pleroma.Config.get([:media_proxy, :whitelist]), fn pattern ->
+    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
-    secret = Pleroma.Config.get([Pleroma.Web.Endpoint, :secret_key_base])
+  defp base64_sig64(url) do
     base64 = Base.url_encode64(url, @base64_opts)
-    sig = :crypto.hmac(:sha, secret, base64)
-    sig64 = sig |> Base.url_encode64(@base64_opts)
+
+    sig64 =
+      base64
+      |> signed_url()
+      |> Base.url_encode64(@base64_opts)
+
+    {base64, sig64}
+  end
+
+  def encode_url(url) do
+    {base64, sig64} = base64_sig64(url)
 
     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)
+  def encode_preview_url(url) do
+    {base64, sig64} = base64_sig64(url)
+
+    build_preview_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
+  defp proxy_url(path, sig_base64, url_base64, filename) do
     [
-      Pleroma.Config.get([:media_proxy, :base_url], Pleroma.Web.base_url()),
-      "proxy",
+      Pleroma.Config.get([:media_proxy, :base_url], Web.base_url()),
+      path,
       sig_base64,
       url_base64,
       filename
     ]
-    |> Enum.filter(fn value -> value end)
+    |> Enum.filter(& &1)
     |> Path.join()
   end
+
+  def build_url(sig_base64, url_base64, filename \\ nil) do
+    proxy_url("proxy", sig_base64, url_base64, filename)
+  end
+
+  def build_preview_url(sig_base64, url_base64, filename \\ nil) do
+    proxy_url("proxy/preview", sig_base64, url_base64, filename)
+  end
+
+  def verify_request_path_and_url(
+        %Plug.Conn{params: %{"filename" => _}, request_path: request_path},
+        url
+      ) do
+    verify_request_path_and_url(request_path, url)
+  end
+
+  def verify_request_path_and_url(request_path, url) when is_binary(request_path) do
+    filename = filename(url)
+
+    if filename && not basename_matches?(request_path, filename) do
+      {:wrong_filename, filename}
+    else
+      :ok
+    end
+  end
+
+  def verify_request_path_and_url(_, _), do: :ok
+
+  defp basename_matches?(path, filename) do
+    basename = Path.basename(path)
+    basename == filename or URI.decode(basename) == filename or URI.encode(basename) == filename
+  end
 end