74 lines
2.5 KiB
Ruby
74 lines
2.5 KiB
Ruby
# frozen_string_literal: true
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module Banzai
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module Filter
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# Sanitize HTML produced by markup languages (Markdown, AsciiDoc...).
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# Specific rules are implemented in dedicated filters:
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#
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# - Banzai::Filter::SanitizationFilter (Markdown)
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# - Banzai::Filter::AsciiDocSanitizationFilter (AsciiDoc/Asciidoctor)
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# - Banzai::Filter::BroadcastMessageSanitizationFilter (Markdown with styled links and line breaks)
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#
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# Extends HTML::Pipeline::SanitizationFilter with common rules.
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class BaseSanitizationFilter < HTML::Pipeline::SanitizationFilter
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include Gitlab::Utils::StrongMemoize
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extend Gitlab::Utils::SanitizeNodeLink
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UNSAFE_PROTOCOLS = %w(data javascript vbscript).freeze
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def allowlist
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strong_memoize(:allowlist) do
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allowlist = super.deep_dup
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# Allow span elements
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allowlist[:elements].push('span')
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# Allow data-math-style attribute in order to support LaTeX formatting
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allowlist[:attributes]['code'] = %w(data-math-style)
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allowlist[:attributes]['pre'] = %w(data-math-style data-mermaid-style data-kroki-style)
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# Allow html5 details/summary elements
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allowlist[:elements].push('details')
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allowlist[:elements].push('summary')
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# Allow abbr elements with title attribute
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allowlist[:elements].push('abbr')
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allowlist[:attributes]['abbr'] = %w(title)
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# Disallow `name` attribute globally, allow on `a`
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allowlist[:attributes][:all].delete('name')
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allowlist[:attributes]['a'].push('name')
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# Allow any protocol in `a` elements
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# and then remove links with unsafe protocols
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allowlist[:protocols].delete('a')
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allowlist[:transformers].push(self.class.method(:remove_unsafe_links))
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# Remove `rel` attribute from `a` elements
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allowlist[:transformers].push(self.class.remove_rel)
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customize_allowlist(allowlist)
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end
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end
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def customize_allowlist(allowlist)
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raise NotImplementedError
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end
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class << self
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def remove_rel
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lambda do |env|
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if env[:node_name] == 'a'
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# we allow rel="license" to support the Rel-license microformat
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# http://microformats.org/wiki/rel-license
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unless env[:node].attribute('rel')&.value == 'license'
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env[:node].remove_attribute('rel')
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end
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end
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end
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end
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end
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end
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end
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end
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