1 # Pleroma: A lightweight social networking server
2 # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
3 # SPDX-License-Identifier: AGPL-3.0-only
5 defmodule Pleroma.HTML do
6 alias HtmlSanitizeEx.Scrubber
8 defp get_scrubbers(scrubber) when is_atom(scrubber), do: [scrubber]
9 defp get_scrubbers(scrubbers) when is_list(scrubbers), do: scrubbers
10 defp get_scrubbers(_), do: [Pleroma.HTML.Scrubber.Default]
12 def get_scrubbers() do
13 Pleroma.Config.get([:markup, :scrub_policy])
17 def filter_tags(html, nil) do
18 filter_tags(html, get_scrubbers())
21 def filter_tags(html, scrubbers) when is_list(scrubbers) do
22 Enum.reduce(scrubbers, html, fn scrubber, html ->
23 filter_tags(html, scrubber)
27 def filter_tags(html, scrubber), do: Scrubber.scrub(html, scrubber)
28 def filter_tags(html), do: filter_tags(html, nil)
29 def strip_tags(html), do: Scrubber.scrub(html, Scrubber.StripTags)
31 def get_cached_scrubbed_html_for_object(content, scrubbers, object, module) do
32 key = "#{module}#{generate_scrubber_signature(scrubbers)}|#{object.id}"
33 Cachex.fetch!(:scrubber_cache, key, fn _key -> ensure_scrubbed_html(content, scrubbers) end)
36 def get_cached_stripped_html_for_object(content, object, module) do
37 get_cached_scrubbed_html_for_object(
39 HtmlSanitizeEx.Scrubber.StripTags,
45 def ensure_scrubbed_html(
49 {:commit, filter_tags(content, scrubbers)}
52 defp generate_scrubber_signature(scrubber) when is_atom(scrubber) do
53 generate_scrubber_signature([scrubber])
56 defp generate_scrubber_signature(scrubbers) do
57 Enum.reduce(scrubbers, "", fn scrubber, signature ->
58 "#{signature}#{to_string(scrubber)}"
63 defmodule Pleroma.HTML.Scrubber.TwitterText do
65 An HTML scrubbing policy which limits to twitter-style text. Only
66 paragraphs, breaks and links are allowed through the filter.
69 @markup Application.get_env(:pleroma, :markup)
70 @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
71 @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])
73 require HtmlSanitizeEx.Scrubber.Meta
74 alias HtmlSanitizeEx.Scrubber.Meta
76 Meta.remove_cdata_sections_before_scrub()
80 Meta.allow_tag_with_uri_attributes("a", ["href", "data-user", "data-tag"], @valid_schemes)
81 Meta.allow_tag_with_these_attributes("a", ["name", "title"])
83 # paragraphs and linebreaks
84 Meta.allow_tag_with_these_attributes("br", [])
85 Meta.allow_tag_with_these_attributes("p", [])
88 Meta.allow_tag_with_these_attributes("span", [])
90 # allow inline images for custom emoji
91 @allow_inline_images Keyword.get(@markup, :allow_inline_images)
93 if @allow_inline_images do
94 # restrict img tags to http/https only, because of MediaProxy.
95 Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
97 Meta.allow_tag_with_these_attributes("img", [
105 Meta.strip_everything_not_covered()
108 defmodule Pleroma.HTML.Scrubber.Default do
109 @doc "The default HTML scrubbing policy: no "
111 require HtmlSanitizeEx.Scrubber.Meta
112 alias HtmlSanitizeEx.Scrubber.Meta
114 @markup Application.get_env(:pleroma, :markup)
115 @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
116 @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])
118 Meta.remove_cdata_sections_before_scrub()
119 Meta.strip_comments()
121 Meta.allow_tag_with_uri_attributes("a", ["href", "data-user", "data-tag"], @valid_schemes)
122 Meta.allow_tag_with_these_attributes("a", ["name", "title"])
124 Meta.allow_tag_with_these_attributes("abbr", ["title"])
126 Meta.allow_tag_with_these_attributes("b", [])
127 Meta.allow_tag_with_these_attributes("blockquote", [])
128 Meta.allow_tag_with_these_attributes("br", [])
129 Meta.allow_tag_with_these_attributes("code", [])
130 Meta.allow_tag_with_these_attributes("del", [])
131 Meta.allow_tag_with_these_attributes("em", [])
132 Meta.allow_tag_with_these_attributes("i", [])
133 Meta.allow_tag_with_these_attributes("li", [])
134 Meta.allow_tag_with_these_attributes("ol", [])
135 Meta.allow_tag_with_these_attributes("p", [])
136 Meta.allow_tag_with_these_attributes("pre", [])
137 Meta.allow_tag_with_these_attributes("span", [])
138 Meta.allow_tag_with_these_attributes("strong", [])
139 Meta.allow_tag_with_these_attributes("u", [])
140 Meta.allow_tag_with_these_attributes("ul", [])
142 @allow_inline_images Keyword.get(@markup, :allow_inline_images)
144 if @allow_inline_images do
145 # restrict img tags to http/https only, because of MediaProxy.
146 Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
148 Meta.allow_tag_with_these_attributes("img", [
156 @allow_tables Keyword.get(@markup, :allow_tables)
159 Meta.allow_tag_with_these_attributes("table", [])
160 Meta.allow_tag_with_these_attributes("tbody", [])
161 Meta.allow_tag_with_these_attributes("td", [])
162 Meta.allow_tag_with_these_attributes("th", [])
163 Meta.allow_tag_with_these_attributes("thead", [])
164 Meta.allow_tag_with_these_attributes("tr", [])
167 @allow_headings Keyword.get(@markup, :allow_headings)
169 if @allow_headings do
170 Meta.allow_tag_with_these_attributes("h1", [])
171 Meta.allow_tag_with_these_attributes("h2", [])
172 Meta.allow_tag_with_these_attributes("h3", [])
173 Meta.allow_tag_with_these_attributes("h4", [])
174 Meta.allow_tag_with_these_attributes("h5", [])
177 @allow_fonts Keyword.get(@markup, :allow_fonts)
180 Meta.allow_tag_with_these_attributes("font", ["face"])
183 Meta.strip_everything_not_covered()
186 defmodule Pleroma.HTML.Transform.MediaProxy do
187 @moduledoc "Transforms inline image URIs to use MediaProxy."
189 alias Pleroma.Web.MediaProxy
191 def before_scrub(html), do: html
193 def scrub_attribute("img", {"src", "http" <> target}) do
201 def scrub_attribute(_tag, attribute), do: attribute
203 def scrub({"img", attributes, children}) do
206 |> Enum.map(fn attr -> scrub_attribute("img", attr) end)
207 |> Enum.reject(&is_nil(&1))
209 {"img", attributes, children}
212 def scrub({:comment, _children}), do: ""
214 def scrub({tag, attributes, children}), do: {tag, attributes, children}
215 def scrub({_tag, children}), do: children
216 def scrub(text), do: text