From af041db6dc443194b37217bc107f7c8f72a9b8e5 Mon Sep 17 00:00:00 2001 From: Norm Date: Tue, 20 Feb 2024 15:11:26 -0500 Subject: [PATCH] Limit emoji stealer to alphanum, dash, or underscore characters MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As suggested in b387f4a1c1ff02573f16de0b25403cf501afc3b4, only steal emoji with alphanumerc, dash, or underscore characters. Also consolidate all validation logic into a single function. === Taken from akkoma#703 with cosmetic tweaks This matches our existing validation logic from Pleroma.Emoji, and apart from excluding the dot also POSIX’s Portable Filename Character Set making it always safe for use in filenames. Mastodon is even stricter also disallowing U+002D HYPEN-MINUS and requiring at least two characters. Given both we and Mastodon reject shortcodes excluded by this anyway, this doesn’t seem like a loss. --- .../activity_pub/mrf/steal_emoji_policy.ex | 26 ++++++++++--------- 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex index 02a107c27..456fe88c5 100644 --- a/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex +++ b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex @@ -20,6 +20,19 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do String.match?(shortcode, pattern) end + defp reject_emoji?({shortcode, _url}, installed_emoji) do + valid_shortcode? = String.match?(shortcode, ~r/^[a-zA-Z0-9_-]+$/) + + rejected_shortcode? = + [:mrf_steal_emoji, :rejected_shortcodes] + |> Config.get([]) + |> Enum.any?(fn pattern -> shortcode_matches?(shortcode, pattern) end) + + emoji_installed? = Enum.member?(installed_emoji, shortcode) + + !valid_shortcode? or rejected_shortcode? or emoji_installed? + end + defp steal_emoji({shortcode, url}, emoji_dir_path) do url = Pleroma.Web.MediaProxy.url(url) @@ -76,18 +89,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do new_emojis = foreign_emojis - |> Enum.reject(fn {shortcode, _url} -> shortcode in installed_emoji end) - |> Enum.reject(fn {shortcode, _url} -> - String.contains?(shortcode, ["/", "\\", ".", ":"]) - end) - |> Enum.filter(fn {shortcode, _url} -> - reject_emoji? = - [:mrf_steal_emoji, :rejected_shortcodes] - |> Config.get([]) - |> Enum.find(false, fn pattern -> shortcode_matches?(shortcode, pattern) end) - - !reject_emoji? - end) + |> Enum.reject(&reject_emoji?(&1, installed_emoji)) |> Enum.map(&steal_emoji(&1, emoji_dir_path)) |> Enum.filter(& &1)