89 lines
1.9 KiB
Ruby
89 lines
1.9 KiB
Ruby
# frozen_string_literal: true
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require 'content_security_policy/default'
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class ContentSecurityPolicy
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class Builder
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EXTENDABLE_DIRECTIVES = %i[
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base_uri
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frame_ancestors
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manifest_src
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object_src
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script_src
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worker_src
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].freeze
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# Make extending these directives no-op, until core includes them in default CSP
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TO_BE_EXTENDABLE = %i[
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connect_src
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default_src
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font_src
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form_action
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frame_src
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img_src
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media_src
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prefetch_src
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style_src
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].freeze
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def initialize(base_url:)
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@directives = Default.new(base_url: base_url).directives
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@base_url = base_url
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end
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def <<(extension)
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return unless valid_extension?(extension)
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extension.each { |directive, sources| extend_directive(normalize_directive(directive), sources) }
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end
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def build
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policy = ActionDispatch::ContentSecurityPolicy.new
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@directives.each do |directive, sources|
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if sources.is_a?(Array)
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policy.public_send(directive, *sources)
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else
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policy.public_send(directive, sources)
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end
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end
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policy.build
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end
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private
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def normalize_directive(directive)
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directive.to_s.gsub('-', '_').to_sym
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end
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def normalize_source(source)
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if source.starts_with?("/")
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"#{@base_url}#{source}"
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else
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source
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end
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rescue URI::ParseError
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source
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end
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def extend_directive(directive, sources)
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return unless extendable?(directive)
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@directives[directive] ||= []
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sources = Array(sources).map { |s| normalize_source(s) }
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@directives[directive].concat(sources)
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@directives[directive].delete(:none) if @directives[directive].count > 1
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end
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def extendable?(directive)
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EXTENDABLE_DIRECTIVES.include?(directive)
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end
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def valid_extension?(extension)
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extension.is_a?(Hash)
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end
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end
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end
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