mirror of
https://github.com/basecamp/once-campfire.git
synced 2026-08-29 10:02:37 +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.
54 lines
2.2 KiB
Ruby
54 lines
2.2 KiB
Ruby
require "test_helper"
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class WebPush::PersistentRequestTest < ActiveSupport::TestCase
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ENDPOINT = "https://fcm.googleapis.com/fcm/send/test123"
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# The delivery must connect to the public IP resolved and guarded by
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# Push::Subscription, never re-resolve the raw endpoint host at connect time --
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# otherwise a rebind between resolution and delivery reopens the SSRF. An empty
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# message keeps the request past encryption and onto the socket we assert on.
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test "pins delivery to endpoint_ip instead of re-resolving the host" do
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host = URI(ENDPOINT).host
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WebMock.disable_net_connect! allow: [ host ]
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TCPSocket.expects(:open).with { |*args, **| args.first == host }.never
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TCPSocket.expects(:open).with { |*args, **| args.first == DnsTestHelper::WEB_PUSH_PUBLIC_TEST_IP && args[1] == 443 }.throws(:pinned_to_ip)
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assert_throws :pinned_to_ip do
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WebPush.payload_send \
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message: "",
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endpoint: ENDPOINT,
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endpoint_ip: DnsTestHelper::WEB_PUSH_PUBLIC_TEST_IP,
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p256dh: "", auth: "", vapid: {},
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urgency: "high"
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end
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end
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# An egress proxy would open the TCP connection itself and re-resolve the
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# endpoint host, defeating the ipaddr pin. The pinned path must ignore
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# http_proxy/https_proxy and connect straight to the resolved public IP.
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test "ignores proxy env so the pin can't be routed through a re-resolving proxy" do
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host = URI(ENDPOINT).host
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saved = ENV.slice("http_proxy", "https_proxy", "HTTP_PROXY", "HTTPS_PROXY")
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%w[ http_proxy https_proxy HTTP_PROXY HTTPS_PROXY ].each { |k| ENV[k] = "http://proxy.internal:3128" }
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WebMock.disable_net_connect! allow: [ host ]
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TCPSocket.expects(:open).with { |*args, **| args.first == "proxy.internal" }.never
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TCPSocket.expects(:open).with { |*args, **| args.first == DnsTestHelper::WEB_PUSH_PUBLIC_TEST_IP && args[1] == 443 }.throws(:pinned_to_ip)
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assert_throws :pinned_to_ip do
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WebPush.payload_send \
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message: "",
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endpoint: ENDPOINT,
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endpoint_ip: DnsTestHelper::WEB_PUSH_PUBLIC_TEST_IP,
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p256dh: "", auth: "", vapid: {},
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urgency: "high"
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end
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ensure
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%w[ http_proxy https_proxy HTTP_PROXY HTTPS_PROXY ].each { |k| ENV.delete(k) }
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saved.each { |k, v| ENV[k] = v }
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end
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end
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