mirror of
https://github.com/basecamp/once-campfire.git
synced 2026-08-29 18:07:42 +09:00
Jeremy Daer
94a48aacb6
* Guard push-subscription endpoints against SSRF 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. * Route push endpoint guarding through RestrictedHTTP::PrivateNetworkGuard The endpoint SSRF check already delegated its private-network classification to surfguard, but called Surfguard.resolve_public_ips directly rather than through RestrictedHTTP::PrivateNetworkGuard -- the hostname-in, address-out shim #241 established as the app's single guarded-outbound entry point and that Opengraph::Fetch resolves through. Route push resolution through the same guard so once-campfire keeps one place that resolves and classifies outbound addresses. Behavior is unchanged: the guard raises Violation when a permitted host resolves only to blocked addresses (previously an empty list -> nil) and propagates Surfguard::Unresolvable for a host that resolves to nothing; both map to a nil endpoint IP, which fails validation and skips delivery. The allowlist, HTTPS/443 constraints, and per-delivery IP pinning are unchanged. * Address push-SSRF review: defer DNS off enqueue path, disable proxy on pinned path, revalidate on re-registration - Resolve the guarded endpoint IP lazily inside WebPush::Notification#deliver (on the bounded delivery worker) instead of eagerly when the notification is built on the serial enqueue path, so a slow resolver can't stall the push job before any delivery starts. resolved_endpoint_ip only reads the already-loaded endpoint attribute, so it is safe off the AR connection. - Pin the delivery socket with an explicit nil proxy address so http_proxy/ https_proxy can't route the request through a proxy that re-resolves the host and defeats the ipaddr pin. - Revalidate an existing subscription on re-registration so a row predating endpoint validation gets the same 422 as a fresh create instead of being kept alive by touch. - Regression tests: resolution deferred to delivery, pin survives proxy env, legacy invalid row rejected with 422. * Bound the web-push delivery queue (max_queue, not the ignored queue_size) Concurrent::ThreadPoolExecutor takes :max_queue; :queue_size was silently ignored, leaving the delivery backlog unbounded (max_queue: 0). A flood of valid push subscriptions could accumulate queued deliveries without limit -- more acute now that each delivery task also resolves DNS. Using max_queue: 10000 activates the intended cap; overflow raises RejectedExecutionError under the default :abort policy, which deliver_later already rescues (push is best-effort, retried on the next message). * Trim push-SSRF guard comments to match house style Apply the review suggestions on the push-subscription SSRF guard: replace the verbose rationale comments with terse one-liners (or drop them where the code speaks for itself). No behavior change -- the Surfguard-shim routing, per-delivery public-IP pin, and bounded delivery queue are untouched.
63 lines
2.3 KiB
Ruby
63 lines
2.3 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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#
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# The explicit nil proxy address disables proxy discovery from
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# http_proxy/https_proxy. An egress proxy would open the TCP connection
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# itself and re-resolve the endpoint host, so http.ipaddr would no longer
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# pin the destination and the DNS-rebinding guarantee would be lost. This
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# path is already committed to a direct connection (it bypasses the pool);
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# push delivery to public vendor endpoints goes direct.
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http = Net::HTTP.new(uri.host, uri.port, nil)
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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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