Two gaps:
1. /api/v1/admin/apps/{id}/triggers/email accepted `inbound_secret: null`
and treated it as "this trigger is unsigned". The runtime then
skipped HMAC verification entirely. URL discovery (logs, ops
dashboards, bruteforce on the 122-bit TriggerId space) then fan-out-
amplified into the outbox for free — anonymous DoS via the
dispatcher.
2. Even signed triggers had no per-trigger rate limit on signature-
verify failures, so an attacker who knew the URL could pump unsigned
POSTs to force Argon2-equivalent work (HMAC verify + nonce-dedup +
stored-secret decrypt) at line rate.
Fix:
* triggers_api::create_email_trigger now requires a non-empty
inbound_secret. 400 on missing / empty / whitespace-only.
* email_inbound_api::receive_inbound_email returns 401 immediately when
the resolved target has no inbound_secret_encrypted column (pre-fix
rows). The previous `if let Some(ct), Some(nonce)` branch is gone.
* New `BadSignatureLimiter`: per-`(app_id, trigger_id)` sliding-window
bucket (10 fails / 60 s). On lockout the receiver returns 429 with
Retry-After instead of 401. record_failure runs on both the
"no-secret" 401 path and any verify_signature failure.
Test fallout:
* email_inbound integration tests that relied on None secret: removed
the now-impossible `unsigned_trigger_accepts_without_signature` test,
replaced with `create_without_inbound_secret_is_rejected` covering
null / "" / " "; updated `malformed_body_is_422` and
`cross_app_path_is_404` to pass + sign with a secret.
* Two new unit tests pin the limiter behavior (burst lockout + per-
trigger independence).
Audit refs: security_audit/08_dos_resource.md#h-3,
security_audit/09_external_integrations.md#f-ext-m-001.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Closes 4 High-severity audit findings:
- describe_event broken for HTTP-async payloads: was reading source/op
JSON fields that HttpDispatchPayload doesn't carry, producing empty
source on DL rows. from_wire("") then fell back to Kv on replay, the
dispatcher tried to resolve a non-existent trigger, and replay no-op'd
silently. Now branches on OutboxSourceKind: HTTP rows emit
"<method> <path>" + source="http"; Invoke rows emit "invoke_async" +
source="invoke"; TriggerEvent payloads keep top-level field extraction.
- HTTP outbound Authorization leaked across cross-origin redirects.
Manual redirect loop (Policy::none) reused header_map on every hop
and only scrubbed Content-Type for POST->GET. Now compares
url::Url::origin() across hops and strips Authorization,
Proxy-Authorization, Cookie when origin changes — matching reqwest's
default policy.
- F-S-010 inbound email HMAC had no replay protection. Signature was
computed over body only with no timestamp or nonce, so captured POSTs
were replayable indefinitely. Adds X-Picloud-Timestamp header bound
into the HMAC input (signed string is ts || "." || body), 300s
tolerance window, and a process-local LRU keyed on
(ts, sha256(body)) with 600s TTL to catch within-window replays.
Breaking change: webhook senders must include the timestamp header.
- expected_schema.txt re-blessed for migrations 0036-0039 (the previous
snapshot stopped at 0035 so CI would have gone red on first run).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Inbound email: a provider POSTs a normalized JSON message to
POST /api/v1/email-inbound/{app_id}/{trigger_id}; the public receiver
verifies the optional HMAC signature, builds a TriggerEvent::Email, and
enqueues an outbox row the dispatcher delivers like any async trigger.
Handlers see ctx.event.email = #{from,to,cc,subject,text,html,
received_at,message_id}.
- migration 0024: widen triggers.kind + outbox.source_kind CHECKs to
'email'; new email_trigger_details table.
- TriggerKind::Email, TriggerDetails::Email{has_inbound_secret},
OutboxSourceKind::Email, TriggerEvent::Email; dispatcher routes the
email row via the generic resolve_trigger path.
- Admin POST /apps/{id}/triggers/email (validate_trigger_target; module
+ cross-app rejection). inbound_secret is stored ENCRYPTED via the
master key (deviation from the brief's plaintext default; decrypted
per inbound request — see HANDBACK §7).
- Dashboard: email trigger form on the Triggers tab + webhook URL +
expected-payload help.
- 8 DB-gated e2e tests (202/401/404/422/cross-app/handler-fire) +
receiver unit tests (HMAC verify, secret round-trip, payload parse).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
