+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
defmodule Pleroma.HTML do
- alias HtmlSanitizeEx.Scrubber
+ defp get_scrubbers(scrubber) when is_atom(scrubber), do: [scrubber]
+ defp get_scrubbers(scrubbers) when is_list(scrubbers), do: scrubbers
+ defp get_scrubbers(_), do: [Pleroma.HTML.Scrubber.Default]
+
+ def get_scrubbers do
+ Pleroma.Config.get([:markup, :scrub_policy])
+ |> get_scrubbers
+ end
- @markup Application.get_env(:pleroma, :markup)
+ def filter_tags(html, nil) do
+ filter_tags(html, get_scrubbers())
+ end
- def filter_tags(html) do
- scrubber = Keyword.get(@markup, :scrub_policy)
- html |> Scrubber.scrub(scrubber)
+ def filter_tags(html, scrubbers) when is_list(scrubbers) do
+ Enum.reduce(scrubbers, html, fn scrubber, html ->
+ filter_tags(html, scrubber)
+ end)
end
- def strip_tags(html) do
- html |> Scrubber.scrub(Scrubber.StripTags)
+ def filter_tags(html, scrubber) do
+ {:ok, content} = FastSanitize.Sanitizer.scrub(html, scrubber)
+ content
end
+
+ def filter_tags(html), do: filter_tags(html, nil)
+ def strip_tags(html), do: filter_tags(html, FastSanitize.Sanitizer.StripTags)
+
+ def get_cached_scrubbed_html_for_activity(
+ content,
+ scrubbers,
+ activity,
+ key \\ "",
+ callback \\ fn x -> x end
+ ) do
+ key = "#{key}#{generate_scrubber_signature(scrubbers)}|#{activity.id}"
+
+ Cachex.fetch!(:scrubber_cache, key, fn _key ->
+ object = Pleroma.Object.normalize(activity)
+ ensure_scrubbed_html(content, scrubbers, object.data["fake"] || false, callback)
+ end)
+ end
+
+ def get_cached_stripped_html_for_activity(content, activity, key) do
+ get_cached_scrubbed_html_for_activity(
+ content,
+ FastSanitize.Sanitizer.StripTags,
+ activity,
+ key,
+ &HtmlEntities.decode/1
+ )
+ end
+
+ def ensure_scrubbed_html(
+ content,
+ scrubbers,
+ fake,
+ callback
+ ) do
+ content =
+ content
+ |> filter_tags(scrubbers)
+ |> callback.()
+
+ if fake do
+ {:ignore, content}
+ else
+ {:commit, content}
+ end
+ end
+
+ defp generate_scrubber_signature(scrubber) when is_atom(scrubber) do
+ generate_scrubber_signature([scrubber])
+ end
+
+ defp generate_scrubber_signature(scrubbers) do
+ Enum.reduce(scrubbers, "", fn scrubber, signature ->
+ "#{signature}#{to_string(scrubber)}"
+ end)
+ end
+
+ def extract_first_external_url(_, nil), do: {:error, "No content"}
+
+ def extract_first_external_url(object, content) do
+ key = "URL|#{object.id}"
+
+ Cachex.fetch!(:scrubber_cache, key, fn _key ->
+ result =
+ content
+ |> Floki.filter_out("a.mention,a.hashtag,a[rel~=\"tag\"]")
+ |> Floki.attribute("a", "href")
+ |> Enum.at(0)
+
+ {:commit, {:ok, result}}
+ end)
+ end
+end
+
+defmodule Pleroma.HTML.Scrubber.TwitterText do
+ @moduledoc """
+ An HTML scrubbing policy which limits to twitter-style text. Only
+ paragraphs, breaks and links are allowed through the filter.
+ """
+
+ @valid_schemes Pleroma.Config.get([:uri_schemes, :valid_schemes], [])
+
+ require FastSanitize.Sanitizer.Meta
+ alias FastSanitize.Sanitizer.Meta
+
+ Meta.strip_comments()
+
+ # links
+ Meta.allow_tag_with_uri_attributes(:a, ["href", "data-user", "data-tag"], @valid_schemes)
+
+ Meta.allow_tag_with_this_attribute_values(:a, "class", [
+ "hashtag",
+ "u-url",
+ "mention",
+ "u-url mention",
+ "mention u-url"
+ ])
+
+ Meta.allow_tag_with_this_attribute_values(:a, "rel", [
+ "tag",
+ "nofollow",
+ "noopener",
+ "noreferrer"
+ ])
+
+ Meta.allow_tag_with_these_attributes(:a, ["name", "title"])
+
+ # paragraphs and linebreaks
+ Meta.allow_tag_with_these_attributes(:br, [])
+ Meta.allow_tag_with_these_attributes(:p, [])
+
+ # microformats
+ Meta.allow_tag_with_this_attribute_values(:span, "class", ["h-card"])
+ Meta.allow_tag_with_these_attributes(:span, [])
+
+ # allow inline images for custom emoji
+ if Pleroma.Config.get([:markup, :allow_inline_images]) do
+ # restrict img tags to http/https only, because of MediaProxy.
+ Meta.allow_tag_with_uri_attributes(:img, ["src"], ["http", "https"])
+
+ Meta.allow_tag_with_these_attributes(:img, [
+ "width",
+ "height",
+ "class",
+ "title",
+ "alt"
+ ])
+ end
+
+ Meta.strip_everything_not_covered()
+end
+
+defmodule Pleroma.HTML.Scrubber.Default do
+ @doc "The default HTML scrubbing policy: no "
+
+ require FastSanitize.Sanitizer.Meta
+ alias FastSanitize.Sanitizer.Meta
+ # credo:disable-for-previous-line
+ # No idea how to fix this one…
+
+ @valid_schemes Pleroma.Config.get([:uri_schemes, :valid_schemes], [])
+
+ Meta.strip_comments()
+
+ Meta.allow_tag_with_uri_attributes(:a, ["href", "data-user", "data-tag"], @valid_schemes)
+
+ Meta.allow_tag_with_this_attribute_values(:a, "class", [
+ "hashtag",
+ "u-url",
+ "mention",
+ "u-url mention",
+ "mention u-url"
+ ])
+
+ Meta.allow_tag_with_this_attribute_values(:a, "rel", [
+ "tag",
+ "nofollow",
+ "noopener",
+ "noreferrer",
+ "ugc"
+ ])
+
+ Meta.allow_tag_with_these_attributes(:a, ["name", "title"])
+
+ Meta.allow_tag_with_these_attributes(:abbr, ["title"])
+
+ Meta.allow_tag_with_these_attributes(:b, [])
+ Meta.allow_tag_with_these_attributes(:blockquote, [])
+ Meta.allow_tag_with_these_attributes(:br, [])
+ Meta.allow_tag_with_these_attributes(:code, [])
+ Meta.allow_tag_with_these_attributes(:del, [])
+ Meta.allow_tag_with_these_attributes(:em, [])
+ Meta.allow_tag_with_these_attributes(:i, [])
+ Meta.allow_tag_with_these_attributes(:li, [])
+ Meta.allow_tag_with_these_attributes(:ol, [])
+ Meta.allow_tag_with_these_attributes(:p, [])
+ Meta.allow_tag_with_these_attributes(:pre, [])
+ Meta.allow_tag_with_these_attributes(:strong, [])
+ Meta.allow_tag_with_these_attributes(:sub, [])
+ Meta.allow_tag_with_these_attributes(:sup, [])
+ Meta.allow_tag_with_these_attributes(:u, [])
+ Meta.allow_tag_with_these_attributes(:ul, [])
+
+ Meta.allow_tag_with_this_attribute_values(:span, "class", ["h-card"])
+ Meta.allow_tag_with_these_attributes(:span, [])
+
+ @allow_inline_images Pleroma.Config.get([:markup, :allow_inline_images])
+
+ if @allow_inline_images do
+ # restrict img tags to http/https only, because of MediaProxy.
+ Meta.allow_tag_with_uri_attributes(:img, ["src"], ["http", "https"])
+
+ Meta.allow_tag_with_these_attributes(:img, [
+ "width",
+ "height",
+ "class",
+ "title",
+ "alt"
+ ])
+ end
+
+ if Pleroma.Config.get([:markup, :allow_tables]) do
+ Meta.allow_tag_with_these_attributes(:table, [])
+ Meta.allow_tag_with_these_attributes(:tbody, [])
+ Meta.allow_tag_with_these_attributes(:td, [])
+ Meta.allow_tag_with_these_attributes(:th, [])
+ Meta.allow_tag_with_these_attributes(:thead, [])
+ Meta.allow_tag_with_these_attributes(:tr, [])
+ end
+
+ if Pleroma.Config.get([:markup, :allow_headings]) do
+ Meta.allow_tag_with_these_attributes(:h1, [])
+ Meta.allow_tag_with_these_attributes(:h2, [])
+ Meta.allow_tag_with_these_attributes(:h3, [])
+ Meta.allow_tag_with_these_attributes(:h4, [])
+ Meta.allow_tag_with_these_attributes(:h5, [])
+ end
+
+ if Pleroma.Config.get([:markup, :allow_fonts]) do
+ Meta.allow_tag_with_these_attributes(:font, ["face"])
+ end
+
+ Meta.strip_everything_not_covered()
+end
+
+defmodule Pleroma.HTML.Transform.MediaProxy do
+ @moduledoc "Transforms inline image URIs to use MediaProxy."
+
+ alias Pleroma.Web.MediaProxy
+
+ def before_scrub(html), do: html
+
+ def scrub_attribute(:img, {"src", "http" <> target}) do
+ media_url =
+ ("http" <> target)
+ |> MediaProxy.url()
+
+ {"src", media_url}
+ end
+
+ def scrub_attribute(_tag, attribute), do: attribute
+
+ def scrub({:img, attributes, children}) do
+ attributes =
+ attributes
+ |> Enum.map(fn attr -> scrub_attribute(:img, attr) end)
+ |> Enum.reject(&is_nil(&1))
+
+ {:img, attributes, children}
+ end
+
+ def scrub({:comment, _text, _children}), do: ""
+
+ def scrub({tag, attributes, children}), do: {tag, attributes, children}
+ def scrub({_tag, children}), do: children
+ def scrub(text), do: text
+end
+
+defmodule Pleroma.HTML.Scrubber.LinksOnly do
+ @moduledoc """
+ An HTML scrubbing policy which limits to links only.
+ """
+
+ @valid_schemes Pleroma.Config.get([:uri_schemes, :valid_schemes], [])
+
+ require FastSanitize.Sanitizer.Meta
+ alias FastSanitize.Sanitizer.Meta
+
+ Meta.strip_comments()
+
+ # links
+ Meta.allow_tag_with_uri_attributes(:a, ["href"], @valid_schemes)
+
+ Meta.allow_tag_with_this_attribute_values(:a, "rel", [
+ "tag",
+ "nofollow",
+ "noopener",
+ "noreferrer",
+ "me",
+ "ugc"
+ ])
+
+ Meta.allow_tag_with_these_attributes(:a, ["name", "title"])
+ Meta.strip_everything_not_covered()
end
projects / akkoma / blobdiff