mirror of
https://github.com/basecamp/once-campfire.git
synced 2026-08-28 17:42:50 +09:00
Jeremy Daer
262ac6be06
Web push delivery POSTed to the endpoint URL a user supplied when registering a subscription, with no scheme, host, or private-network check -- unlike the OpenGraph unfurl path, which already routes through the shared SSRF address policy (surfguard). Any authenticated user could register a subscription whose endpoint pointed at an internal address and have the server fetch it on every chat message: blind SSRF for internal recon and reachability probing, plus a thread-pool DoS on the delivery pool. Validate the endpoint when the subscription is saved: it must be HTTPS, its host must belong to a known browser push service (allowlist), and it must resolve to a public IP. On every delivery, re-resolve the host and pin the connection to that public IP so a later DNS rebind can't redirect the request to an internal address. If no public IP resolves at delivery time -- a rebind, or a subscription that predates this validation -- delivery is skipped rather than falling back to re-resolving the raw host. Adds model, controller, and delivery-pinning tests, plus a DNS stub helper for deterministic resolution in tests.
56 lines
1.9 KiB
Ruby
56 lines
1.9 KiB
Ruby
require "web-push"
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require "web_push/pool"
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require "web_push/notification"
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Rails.application.configure do
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config.x.web_push_pool = WebPush::Pool.new(
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invalid_subscription_handler: ->(subscription_id) do
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Rails.application.executor.wrap do
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Rails.logger.info "Destroying push subscription: #{subscription_id}"
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Push::Subscription.find_by(id: subscription_id)&.destroy
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end
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end
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)
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at_exit { config.x.web_push_pool.shutdown }
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end
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module WebPush::PersistentRequest
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def perform
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if endpoint_ip = @options[:endpoint_ip]
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# Pin the connection to the public IP resolved (and guarded) by
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# Push::Subscription so delivery can't be rebound to a private address
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# between resolution and connect. Bypasses the shared persistent pool,
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# which would re-resolve the host itself.
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http = Net::HTTP.new(uri.host, uri.port)
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http.ipaddr = endpoint_ip
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http.use_ssl = true
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http.ssl_timeout = @options[:ssl_timeout] unless @options[:ssl_timeout].nil?
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http.open_timeout = @options[:open_timeout] unless @options[:open_timeout].nil?
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http.read_timeout = @options[:read_timeout] unless @options[:read_timeout].nil?
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elsif @options[:connection]
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http = @options[:connection]
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else
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http = Net::HTTP.new(uri.host, uri.port, *proxy_options)
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http.use_ssl = true
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http.ssl_timeout = @options[:ssl_timeout] unless @options[:ssl_timeout].nil?
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http.open_timeout = @options[:open_timeout] unless @options[:open_timeout].nil?
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http.read_timeout = @options[:read_timeout] unless @options[:read_timeout].nil?
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end
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req = Net::HTTP::Post.new(uri.request_uri, headers)
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req.body = body
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if http.is_a?(Net::HTTP::Persistent)
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response = http.request uri, req
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else
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resp = http.request(req)
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verify_response(resp)
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end
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resp
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end
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end
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WebPush::Request.prepend WebPush::PersistentRequest
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