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.
32 lines
1.0 KiB
Ruby
32 lines
1.0 KiB
Ruby
class WebPush::Notification
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def initialize(title:, body:, path:, badge:, endpoint:, endpoint_ip_resolver:, p256dh_key:, auth_key:)
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@title, @body, @path, @badge = title, body, path, badge
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@endpoint, @endpoint_ip_resolver, @p256dh_key, @auth_key = endpoint, endpoint_ip_resolver, p256dh_key, auth_key
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end
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def deliver(connection: nil)
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if endpoint_ip = @endpoint_ip_resolver.call
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WebPush.payload_send \
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message: encoded_message,
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endpoint: @endpoint, endpoint_ip: endpoint_ip, p256dh: @p256dh_key, auth: @auth_key,
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vapid: vapid_identification,
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connection: connection,
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urgency: "high"
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end
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end
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private
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def vapid_identification
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{ subject: "mailto:support@37signals.com" }.merge \
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Rails.configuration.x.vapid.symbolize_keys
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end
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def encoded_message
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JSON.generate title: @title, options: { body: @body, icon: icon_path, data: { path: @path, badge: @badge } }
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end
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def icon_path
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Rails.application.routes.url_helpers.account_logo_path
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end
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end
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