mirror of
https://github.com/basecamp/once-campfire.git
synced 2026-08-30 02:17:41 +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.
57 lines
1.9 KiB
Ruby
57 lines
1.9 KiB
Ruby
# This is in lib so we can use it in a thread pool without the Rails executor
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class WebPush::Pool
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attr_reader :delivery_pool, :invalidation_pool, :connection, :invalid_subscription_handler
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def initialize(invalid_subscription_handler:)
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@delivery_pool = Concurrent::ThreadPoolExecutor.new(max_threads: 50, max_queue: 10000)
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@invalidation_pool = Concurrent::FixedThreadPool.new(1)
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@connection = Net::HTTP::Persistent.new(name: "web_push", pool_size: 150)
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@invalid_subscription_handler = invalid_subscription_handler
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end
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def queue(payload, subscriptions)
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subscriptions.find_each do |subscription|
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deliver_later(payload, subscription)
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end
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end
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def shutdown
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connection.shutdown
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shutdown_pool(delivery_pool)
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shutdown_pool(invalidation_pool)
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end
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private
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def deliver_later(payload, subscription)
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# Ensure any AR operations happen before we post to the thread pool
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notification = subscription.notification(**payload)
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subscription_id = subscription.id
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delivery_pool.post do
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deliver(notification, subscription_id)
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rescue Exception => e
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Rails.logger.error "Error in WebPush::Pool.deliver: #{e.class} #{e.message}"
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end
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rescue Concurrent::RejectedExecutionError
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end
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def deliver(notification, id)
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notification.deliver(connection: connection)
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rescue WebPush::ExpiredSubscription, OpenSSL::OpenSSLError => ex
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invalidate_subscription_later(id) if invalid_subscription_handler
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end
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def invalidate_subscription_later(id)
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invalidation_pool.post do
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invalid_subscription_handler.call(id)
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rescue Exception => e
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Rails.logger.error "Error in WebPush::Pool.invalid_subscription_handler: #{e.class} #{e.message}"
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end
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end
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def shutdown_pool(pool)
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pool.shutdown
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pool.kill unless pool.wait_for_termination(1)
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end
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end
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