git.squeep.com Git - akkoma/blob - lib/pleroma/html.ex

   1 defmodule Pleroma.HTML do
   2   alias HtmlSanitizeEx.Scrubber
   3
   4   @markup Application.get_env(:pleroma, :markup)
   5
   6   defp get_scrubbers(scrubber) when is_atom(scrubber), do: [scrubber]
   7   defp get_scrubbers(scrubbers) when is_list(scrubbers), do: scrubbers
   8   defp get_scrubbers(_), do: [Pleroma.HTML.Scrubber.Default]
   9
  10   def get_scrubbers() do
  11     Keyword.get(@markup, :scrub_policy)
  12     |> get_scrubbers
  13   end
  14
  15   def filter_tags(html, nil) do
  16     get_scrubbers()
  17     |> Enum.reduce(html, fn scrubber, html ->
  18       filter_tags(html, scrubber)
  19     end)
  20   end
  21
  22   def filter_tags(html, scrubber) do
  23     html |> Scrubber.scrub(scrubber)
  24   end
  25
  26   def filter_tags(html), do: filter_tags(html, nil)
  27
  28   def strip_tags(html) do
  29     html |> Scrubber.scrub(Scrubber.StripTags)
  30   end
  31 end
  32
  33 defmodule Pleroma.HTML.Scrubber.TwitterText do
  34   @moduledoc """
  35   An HTML scrubbing policy which limits to twitter-style text.  Only
  36   paragraphs, breaks and links are allowed through the filter.
  37   """
  38
  39   @markup Application.get_env(:pleroma, :markup)
  40   @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
  41   @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])
  42
  43   require HtmlSanitizeEx.Scrubber.Meta
  44   alias HtmlSanitizeEx.Scrubber.Meta
  45
  46   alias Pleroma.HTML
  47
  48   Meta.remove_cdata_sections_before_scrub()
  49   Meta.strip_comments()
  50
  51   # links
  52   Meta.allow_tag_with_uri_attributes("a", ["href"], @valid_schemes)
  53   Meta.allow_tag_with_these_attributes("a", ["name", "title"])
  54
  55   # paragraphs and linebreaks
  56   Meta.allow_tag_with_these_attributes("br", [])
  57   Meta.allow_tag_with_these_attributes("p", [])
  58
  59   # microformats
  60   Meta.allow_tag_with_these_attributes("span", [])
  61
  62   # allow inline images for custom emoji
  63   @allow_inline_images Keyword.get(@markup, :allow_inline_images)
  64
  65   if @allow_inline_images do
  66     # restrict img tags to http/https only, because of MediaProxy.
  67     Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
  68
  69     Meta.allow_tag_with_these_attributes("img", [
  70       "width",
  71       "height",
  72       "title",
  73       "alt"
  74     ])
  75   end
  76
  77   Meta.strip_everything_not_covered()
  78 end
  79
  80 defmodule Pleroma.HTML.Scrubber.Default do
  81   @doc "The default HTML scrubbing policy: no "
  82
  83   require HtmlSanitizeEx.Scrubber.Meta
  84   alias HtmlSanitizeEx.Scrubber.Meta
  85
  86   alias Pleroma.HTML
  87
  88   @markup Application.get_env(:pleroma, :markup)
  89   @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
  90   @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])
  91
  92   Meta.remove_cdata_sections_before_scrub()
  93   Meta.strip_comments()
  94
  95   Meta.allow_tag_with_uri_attributes("a", ["href"], @valid_schemes)
  96   Meta.allow_tag_with_these_attributes("a", ["name", "title"])
  97
  98   Meta.allow_tag_with_these_attributes("b", [])
  99   Meta.allow_tag_with_these_attributes("blockquote", [])
 100   Meta.allow_tag_with_these_attributes("br", [])
 101   Meta.allow_tag_with_these_attributes("code", [])
 102   Meta.allow_tag_with_these_attributes("del", [])
 103   Meta.allow_tag_with_these_attributes("em", [])
 104   Meta.allow_tag_with_these_attributes("i", [])
 105   Meta.allow_tag_with_these_attributes("li", [])
 106   Meta.allow_tag_with_these_attributes("ol", [])
 107   Meta.allow_tag_with_these_attributes("p", [])
 108   Meta.allow_tag_with_these_attributes("pre", [])
 109   Meta.allow_tag_with_these_attributes("span", [])
 110   Meta.allow_tag_with_these_attributes("strong", [])
 111   Meta.allow_tag_with_these_attributes("u", [])
 112   Meta.allow_tag_with_these_attributes("ul", [])
 113
 114   @allow_inline_images Keyword.get(@markup, :allow_inline_images)
 115
 116   if @allow_inline_images do
 117     # restrict img tags to http/https only, because of MediaProxy.
 118     Meta.allow_tag_with_uri_attributes("img", ["src"], ["http", "https"])
 119
 120     Meta.allow_tag_with_these_attributes("img", [
 121       "width",
 122       "height",
 123       "title",
 124       "alt"
 125     ])
 126   end
 127
 128   @allow_tables Keyword.get(@markup, :allow_tables)
 129
 130   if @allow_tables do
 131     Meta.allow_tag_with_these_attributes("table", [])
 132     Meta.allow_tag_with_these_attributes("tbody", [])
 133     Meta.allow_tag_with_these_attributes("td", [])
 134     Meta.allow_tag_with_these_attributes("th", [])
 135     Meta.allow_tag_with_these_attributes("thead", [])
 136     Meta.allow_tag_with_these_attributes("tr", [])
 137   end
 138
 139   @allow_headings Keyword.get(@markup, :allow_headings)
 140
 141   if @allow_headings do
 142     Meta.allow_tag_with_these_attributes("h1", [])
 143     Meta.allow_tag_with_these_attributes("h2", [])
 144     Meta.allow_tag_with_these_attributes("h3", [])
 145     Meta.allow_tag_with_these_attributes("h4", [])
 146     Meta.allow_tag_with_these_attributes("h5", [])
 147   end
 148
 149   @allow_fonts Keyword.get(@markup, :allow_fonts)
 150
 151   if @allow_fonts do
 152     Meta.allow_tag_with_these_attributes("font", ["face"])
 153   end
 154
 155   Meta.strip_everything_not_covered()
 156 end
 157
 158 defmodule Pleroma.HTML.Transform.MediaProxy do
 159   @moduledoc "Transforms inline image URIs to use MediaProxy."
 160
 161   alias Pleroma.Web.MediaProxy
 162
 163   def before_scrub(html), do: html
 164
 165   def scrub_attribute("img", {"src", "http" <> target}) do
 166     media_url =
 167       ("http" <> target)
 168       |> MediaProxy.url()
 169
 170     {"src", media_url}
 171   end
 172
 173   def scrub_attribute(tag, attribute), do: attribute
 174
 175   def scrub({"img", attributes, children}) do
 176     attributes =
 177       attributes
 178       |> Enum.map(fn attr -> scrub_attribute("img", attr) end)
 179       |> Enum.reject(&is_nil(&1))
 180
 181     {"img", attributes, children}
 182   end
 183
 184   def scrub({tag, attributes, children}), do: {tag, attributes, children}
 185   def scrub({tag, children}), do: children
 186   def scrub(text), do: text
 187 end