# 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 not enabled?() 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:")
+ # 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
- # 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)
+ def enabled?, do: Config.get([:media_proxy, :enabled], false)
- sig = :crypto.hmac(:sha, secret, base64)
- sig64 = sig |> Base.url_encode64(@base64_opts)
+ # 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)
- build_url(sig64, base64, filename(url))
- end
+ def local?(url), do: String.starts_with?(url, Pleroma.Web.base_url())
+
+ def 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 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)
+ defp base64_sig64(url) do
+ base64 = Base.url_encode64(url, @base64_opts)
+
+ sig64 =
+ base64
+ |> signed_url()
+ |> Base.url_encode64(@base64_opts)
+
+ {base64, sig64}
+ end
+
+ def encode_url(url) do
+ {base64, sig64} = base64_sig64(url)
- if local_sig == sig do
+ build_url(sig64, base64, filename(url))
+ end
+
+ def encode_preview_url(url) do
+ {base64, sig64} = base64_sig64(url)
+
+ build_preview_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
+ 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
- defp get_replacement(url, replacement) do
- if String.contains?(url, replacement) do
- get_replacement(url, replacement <> replacement)
+ 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
- replacement
+ :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
projects / akkoma / blobdiff