Class: Banzai::Filter::BaseSanitizationFilter

Inherits:
HTML::Pipeline::SanitizationFilter
  • Object
show all
Extended by:
Gitlab::Utils::SanitizeNodeLink
Includes:
Concerns::TimeoutFilterHandler, Gitlab::Utils::StrongMemoize
Defined in:
lib/banzai/filter/base_sanitization_filter.rb

Overview

Sanitize HTML produced by markup languages (Markdown, AsciiDoc…). Specific rules are implemented in dedicated filters:

  • Banzai::Filter::SanitizationFilter (Markdown)

  • Banzai::Filter::AsciiDocSanitizationFilter (AsciiDoc/Asciidoctor)

  • Banzai::Filter::BroadcastMessageSanitizationFilter (Markdown with styled links and line breaks)

  • Banzai::Filter::MinimumMarkdownSanitizationFilter (only inline elements)

Extends HTML::Pipeline::SanitizationFilter with common rules.

Constant Summary collapse

UNSAFE_PROTOCOLS = 
%w[data javascript vbscript].freeze

Constants included from Gitlab::Utils::SanitizeNodeLink

Gitlab::Utils::SanitizeNodeLink::ATTRS_TO_SANITIZE

Constants included from Concerns::TimeoutFilterHandler

Concerns::TimeoutFilterHandler::COMPLEX_MARKDOWN_MESSAGE, Concerns::TimeoutFilterHandler::RENDER_TIMEOUT, Concerns::TimeoutFilterHandler::SANITIZATION_RENDER_TIMEOUT

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Gitlab::Utils::SanitizeNodeLink

permit_url?, remove_unsafe_links, safe_protocol?, sanitize_unsafe_links

Class Method Details

.remove_rel ⇒ Object 



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# File 'lib/banzai/filter/base_sanitization_filter.rb', line 88

def remove_rel
  ->(env) do
    if env[:node_name] == 'a'
      # we allow rel="license" to support the Rel-license microformat
      # http://microformats.org/wiki/rel-license
      unless env[:node].attribute('rel')&.value == 'license'
        env[:node].remove_attribute('rel')
      end
    end
  end
end

Instance Method Details

#allowlist ⇒ Object 



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# File 'lib/banzai/filter/base_sanitization_filter.rb', line 25

def allowlist
  strong_memoize(:allowlist) do
    allowlist = super.deep_dup

    # Allow span elements
    allowlist[:elements].push('span')

    # Allow data-math-style attribute in order to support LaTeX formatting
    allowlist[:attributes]['span'] = %w[data-math-style]
    allowlist[:attributes]['code'] = %w[data-math-style]
    allowlist[:attributes]['pre'] = %w[data-canonical-lang data-lang-params
      data-math-style data-mermaid-style data-kroki-style]

    # Allow data-placeholder from gitlab-glfm-markdown
    allowlist[:attributes]['span'].push('data-placeholder')

    # Allow html5 details/summary elements
    allowlist[:elements].push('details')
    allowlist[:elements].push('summary')

    # Allow abbr elements with title attribute
    allowlist[:elements].push('abbr')
    allowlist[:attributes]['abbr'] = %w[title]

    # Disallow `name` attribute globally, allow on `a`
    allowlist[:attributes][:all].delete('name')
    allowlist[:attributes]['a'].push('name')

    allowlist[:attributes]['a'].push('data-wikilink')
    allowlist[:attributes]['a'].push('data-placeholder')

    allowlist[:attributes]['img'].push('data-diagram')
    allowlist[:attributes]['img'].push('data-diagram-src')
    allowlist[:attributes]['img'].push('data-placeholder')

    # Allow any protocol in `a` elements
    # and then remove links with unsafe protocols in SanitizeLinkFilter
    allowlist[:protocols].delete('a')

    # Remove `rel` attribute from `a` elements
    allowlist[:transformers].push(self.class.remove_rel)

    customize_allowlist(allowlist)
  end
end

#call ⇒ Object 



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# File 'lib/banzai/filter/base_sanitization_filter.rb', line 21

def call
  Sanitize.clean_node!(doc, allowlist)
end

#customize_allowlist(allowlist) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/banzai/filter/base_sanitization_filter.rb', line 71

def customize_allowlist(allowlist)
  raise NotImplementedError
end