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.
78 lines
3.0 KiB
Ruby
78 lines
3.0 KiB
Ruby
require "test_helper"
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class Users::PushSubscriptionsControllerTest < ActionDispatch::IntegrationTest
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setup do
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sign_in :david
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stub_web_push_dns_resolution
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end
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test "create new push subscription" do
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subscription_params = { "endpoint" => "https://fcm.googleapis.com/fcm/send/abc123", "p256dh_key" => "123", "auth_key" => "456" }
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post user_push_subscriptions_url,
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params: { push_subscription: subscription_params }, headers: { "HTTP_USER_AGENT" => "Mozilla/5.0" }
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assert_response :ok
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assert_equal subscription_params, users(:david).push_subscriptions.last.attributes.slice("endpoint", "p256dh_key", "auth_key")
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assert_equal "Mozilla/5.0", users(:david).push_subscriptions.last.user_agent
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end
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test "touch existing subscription" do
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assert_no_difference -> { users(:david).push_subscriptions.count } do
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assert_changes -> { push_subscriptions(:david_chrome).reload.updated_at } do
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post user_push_subscriptions_url(params: {
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push_subscription: push_subscriptions(:david_chrome).attributes.slice("endpoint", "p256dh_key", "auth_key")
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})
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end
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end
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assert_response :ok
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end
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test "rejects subscription with non-permitted endpoint" do
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subscription_params = { "endpoint" => "https://attacker.example.com/steal", "p256dh_key" => "123", "auth_key" => "456" }
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assert_no_difference -> { Push::Subscription.count } do
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post user_push_subscriptions_url, params: { push_subscription: subscription_params }
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end
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assert_response :unprocessable_entity
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end
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test "rejects subscription with endpoint resolving to a private IP" do
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stub_dns_resolution("169.254.169.254")
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subscription_params = { "endpoint" => "https://fcm.googleapis.com/fcm/send/abc123", "p256dh_key" => "123", "auth_key" => "456" }
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assert_no_difference -> { Push::Subscription.count } do
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post user_push_subscriptions_url, params: { push_subscription: subscription_params }
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end
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assert_response :unprocessable_entity
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end
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test "re-registering a legacy invalid subscription is rejected with 422" do
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# A row that predates endpoint validation (saved without validation, as a
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# sink planted before this shipped could be). Re-POSTing its params must hit
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# the same 422 as a fresh create, not be kept alive by touch.
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legacy = users(:david).push_subscriptions.build \
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endpoint: "https://attacker.example.com/steal", p256dh_key: "123", auth_key: "456"
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legacy.save!(validate: false)
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assert_no_difference -> { Push::Subscription.count } do
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post user_push_subscriptions_url, params: {
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push_subscription: { endpoint: "https://attacker.example.com/steal", p256dh_key: "123", auth_key: "456" }
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}
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end
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assert_response :unprocessable_entity
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end
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test "destroy a push subscription via dev mode" do
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assert_difference -> { Push::Subscription.count }, -1 do
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delete user_push_subscription_url(push_subscriptions(:david_chrome))
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assert_redirected_to user_push_subscriptions_url
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end
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end
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end
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