feat(secrets): AAD-bind email-trigger inbound secrets v0->v1 (Track A M3)

email_trigger_details.inbound_secret_encrypted was sealed v0 (no AAD, bound only
to the master key) because the table had no version column — a ciphertext could
in principle be relocated between rows (audit 2026-06-11 H-D1, Medium). Bring the
AAD versioning the `secrets` table gained in 0042 to email secrets.

- Migration 0069: `email_trigger_details.inbound_secret_version SMALLINT DEFAULT 0`.
- secrets_service: `seal_email`/`open_email` seal v1 with AAD bound to the
  SEALING OWNER (`email:{app}` / `email:group:{group}`) — deliberately NOT the
  per-row trigger_id, so a group template's sealed bytes stay valid when the
  materializer copies them verbatim to each descendant (all share the group AAD).
  v0 rows keep their exact legacy no-AAD read path.
- Both email-trigger create paths (declarative apply resolve_and_seal +
  triggers_api create_email_trigger) seal v1 under the trigger's owner; the
  version threads through CreateEmailTrigger + insert_email_trigger_tx.
- materialize copies inbound_secret_version verbatim with the bytes.
- email_inbound_target recovers the sealing owner (materialized_from ->
  template.group_id, else the app) so receive_inbound_email opens a v1 secret
  under the right AAD.

Cross-app/tenant relocation now fails the GCM tag; a same-owner swap is not
distinguished (accepted low-severity residual). Pinned by
email_secret_aad::materialized_email_copy_decrypts_under_the_group_aad (the
novel materialized-copy path) + the extended secret_round_trips_through_seal_open
lib test. Schema golden reblessed; materialization + email e2e regressions green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/manager-core/src/apply_service.rs

@@ -1342,12 +1342,20 @@ impl ApplyService {
                 // app trigger resolves the app's secret; a group EMAIL TEMPLATE
                 // resolves the group's own secret once here, and materialization
                 // copies the sealed bytes verbatim to each descendant.
-                let (ct, nonce) = self
+                let (ct, nonce, version) = self
                     .resolve_and_seal(owner.secret_owner(), inbound_secret_ref)
                     .await?;
-                insert_email_trigger_tx(&mut *tx, owner.as_script_owner(), sid, actor, &ct, &nonce)
-                    .await
-                    .map_err(map_trig)?;
+                insert_email_trigger_tx(
+                    &mut *tx,
+                    owner.as_script_owner(),
+                    sid,
+                    actor,
+                    &ct,
+                    &nonce,
+                    version,
+                )
+                .await
+                .map_err(map_trig)?;
             } else {
                 let (dispatch, retry_max, backoff, base) = self.trigger_settings(bt);
                 let details = bundle_trigger_details(
@@ -3009,7 +3017,7 @@ impl ApplyService {
         &self,
         owner: crate::secrets_service::SecretOwner,
         name: &str,
-    ) -> Result<(Vec<u8>, Vec<u8>), ApplyError> {
+    ) -> Result<(Vec<u8>, Vec<u8>, i16), ApplyError> {
         let stored = self
             .secrets
             .get(owner, "*", name)
@@ -3033,13 +3041,18 @@ impl ApplyService {
                 )))
             }
         }
-        let (ct, nonce) = crate::secrets_service::seal_legacy(
+        // §M5.5 / audit H-D1: seal v1 with AAD bound to the SEALING owner (the
+        // app for a standalone trigger, the group for a template — stable across
+        // materialized copies). The email inbound path recovers the same owner to
+        // open it.
+        let (ct, nonce, version) = crate::secrets_service::seal_email(
             &self.master_key,
+            owner,
             &plaintext,
             crate::secrets_service::DEFAULT_SECRET_MAX_VALUE_BYTES,
         )
         .map_err(|e| ApplyError::Invalid(format!("could not seal secret `{name}`: {e}")))?;
-        Ok((ct, nonce.to_vec()))
+        Ok((ct, nonce.to_vec(), version))
     }
 
     /// Validate each bundle route's host against the app's domain claims —

crates/manager-core/src/email_inbound_api.rs

@@ -36,7 +36,7 @@ use serde_json::json;
 use sha2::{Digest, Sha256};
 
 use crate::outbox_repo::{NewOutboxRow, OutboxRepo, OutboxSourceKind};
-use crate::secrets_service::open_legacy;
+use crate::secrets_service::{open_email, SecretOwner};
 use crate::trigger_repo::TriggerRepo;
 
 type HmacSha256 = Hmac<Sha256>;
@@ -244,7 +244,20 @@ async fn receive_inbound_email(
         s.bad_sig_limiter.record_failure(app_id, trigger_id);
         return Err(EmailInboundError::Unauthorized);
     };
-    let secret = decrypt_secret(&s.master_key, ct, nonce)?;
+    // §M5.5 / audit H-D1: recover the SEALING owner for a v1 (AAD-bound) secret —
+    // the source-template group for a materialized copy, else this app. v0 rows
+    // ignore the owner (legacy no-AAD path).
+    let sealing_owner = match target.sealing_group {
+        Some(group_id) => SecretOwner::Group(group_id),
+        None => SecretOwner::App(app_id),
+    };
+    let secret = decrypt_secret(
+        &s.master_key,
+        sealing_owner,
+        ct,
+        nonce,
+        target.inbound_secret_version,
+    )?;
     if let Err(err) = verify_signature(&headers, &body, secret.as_bytes(), &s.nonce_dedup) {
         s.bad_sig_limiter.record_failure(app_id, trigger_id);
         return Err(err);
@@ -286,16 +299,18 @@ async fn receive_inbound_email(
     Ok(StatusCode::ACCEPTED)
 }
 
-/// Decrypt the stored inbound secret back to its raw string. It was
-/// sealed as a JSON string by the admin layer (v0, no AAD — see
-/// secrets_service::seal_legacy), so `open_legacy` yields a
+/// Decrypt the stored inbound secret back to its raw string. Sealed as a JSON
+/// string by the admin/apply layer; `open_email` dispatches on `version` (v0 =
+/// legacy no-AAD, v1 = AAD bound to the sealing `owner`), yielding a
 /// `Value::String`.
 fn decrypt_secret(
     master_key: &MasterKey,
+    owner: SecretOwner,
     ciphertext: &[u8],
     nonce: &[u8],
+    version: i16,
 ) -> Result<String, EmailInboundError> {
-    let value = open_legacy(master_key, ciphertext, nonce).map_err(|_| {
+    let value = open_email(master_key, owner, ciphertext, nonce, version).map_err(|_| {
         // Corrupted secret means we can't verify — fail closed (401).
         EmailInboundError::Unauthorized
     })?;
@@ -421,8 +436,9 @@ mod tests {
     //! Postgres in `crates/picloud/tests/email_inbound.rs`.
 
     use super::*;
-    use crate::secrets_service::seal_legacy;
     use crate::secrets_service::DEFAULT_SECRET_MAX_VALUE_BYTES;
+    use crate::secrets_service::{seal_email, seal_legacy};
+    use picloud_shared::{AppId, GroupId};
 
     fn sign(secret: &[u8], ts: i64, body: &[u8]) -> String {
         let mut mac = HmacSha256::new_from_slice(secret).unwrap();
@@ -520,14 +536,36 @@ mod tests {
     #[test]
     fn secret_round_trips_through_seal_open() {
         let key = MasterKey::from_bytes([3u8; 32]);
-        let (ct, nonce) = seal_legacy(
+        // v0 (legacy no-AAD) still opens — backward compatibility for pre-M3 rows.
+        let (ct0, nonce0) = seal_legacy(
             &key,
             &serde_json::Value::String("provider-secret".into()),
             DEFAULT_SECRET_MAX_VALUE_BYTES,
         )
         .unwrap();
-        let recovered = decrypt_secret(&key, &ct, &nonce).unwrap();
+        let owner = SecretOwner::App(AppId::from(uuid::Uuid::from_u128(1)));
+        let recovered = decrypt_secret(&key, owner, &ct0, &nonce0, 0).unwrap();
         assert_eq!(recovered, "provider-secret");
+
+        // v1 (AAD bound to the sealing owner) round-trips under the SAME owner.
+        let (ct1, nonce1, ver) = seal_email(
+            &key,
+            owner,
+            &serde_json::Value::String("provider-secret".into()),
+            DEFAULT_SECRET_MAX_VALUE_BYTES,
+        )
+        .unwrap();
+        assert_eq!(ver, 1);
+        assert_eq!(
+            decrypt_secret(&key, owner, &ct1, &nonce1, ver).unwrap(),
+            "provider-secret"
+        );
+        // A DIFFERENT owner (cross-tenant relocation) fails the GCM tag → 401.
+        let other = SecretOwner::Group(GroupId::from(uuid::Uuid::from_u128(2)));
+        assert!(
+            decrypt_secret(&key, other, &ct1, &nonce1, ver).is_err(),
+            "a v1 secret must not open under a different sealing owner"
+        );
         let body = br#"{"from":"x@y.com"}"#;
         let ts = now_ts();
         let sig = sign(recovered.as_bytes(), ts, body);

crates/manager-core/src/materialize.rs

@@ -226,14 +226,17 @@ async fn materialize_one(
         "email" => {
             // §M5.5: the group template sealed its inbound HMAC secret against
             // the GROUP's own store once at apply (shared-group-secret model).
-            // The secret is v0 (no AAD) — bound only to the master key, not the
-            // owning row — so a verbatim byte-copy is a valid per-app secret; no
-            // master key is needed here. Each copy has its own trigger_id (its
-            // own inbound webhook URL).
+            // The secret's AAD (§M5.5 / audit H-D1) is bound to the GROUP owner,
+            // NOT this copy's row, so a verbatim byte-copy stays openable — the
+            // inbound path recovers the group via `materialized_from`. Copy the
+            // version verbatim too. Each copy has its own trigger_id (its own
+            // inbound webhook URL).
             sqlx::query(
                 "INSERT INTO email_trigger_details \
-                    (trigger_id, inbound_secret_encrypted, inbound_secret_nonce) \
-                 SELECT $1, inbound_secret_encrypted, inbound_secret_nonce \
+                    (trigger_id, inbound_secret_encrypted, inbound_secret_nonce, \
+                     inbound_secret_version) \
+                 SELECT $1, inbound_secret_encrypted, inbound_secret_nonce, \
+                        inbound_secret_version \
                  FROM email_trigger_details WHERE trigger_id = $2",
             )
             .bind(new_id.0)

crates/manager-core/src/secrets_service.rs

@@ -167,13 +167,11 @@ pub fn open(
     serde_json::from_slice(&plaintext).map_err(|_| SecretsError::Corrupted)
 }
 
-/// Legacy v0 seal (no AAD, no version) used by the email-trigger
-/// inbound-secret path. The `email_trigger_details` table has no
-/// `version` column yet, so the AAD-binding upgrade for that surface is
-/// **deferred to v1.2's key-versioning pass** (audit 2026-06-11 H-D1
-/// classifies the email-trigger AAD gap as Medium). Both this and
-/// [`open_legacy`] preserve the exact pre-audit wire format so existing
-/// email-trigger secrets keep decrypting.
+/// Legacy v0 seal (no AAD, no version). The email-trigger path now seals v1 via
+/// [`seal_email`] (Track A M3 / audit 2026-06-11 H-D1 closed — `email_trigger_details`
+/// gained an `inbound_secret_version` column in 0069). This and [`open_legacy`]
+/// remain to READ pre-M3 v0 rows that haven't been re-applied, preserving the
+/// exact pre-audit wire format so existing email-trigger secrets keep decrypting.
 ///
 /// # Errors
 ///
@@ -211,6 +209,75 @@ pub fn open_legacy(
     serde_json::from_slice(&plaintext).map_err(|_| SecretsError::Corrupted)
 }
 
+/// §M5.5 / audit 2026-06-11 H-D1 — AAD for an email-trigger inbound secret.
+/// Binds to the SEALING OWNER only (no per-row trigger id / name), so a group
+/// template's sealed bytes stay valid when the materializer copies them verbatim
+/// to each descendant (all share the group AAD). The `email:` prefix keeps this
+/// namespace disjoint from the per-app `secrets` table's `secret:` AAD, so an
+/// email ciphertext can't be swapped in for a same-owner secrets-table entry.
+/// A swap ACROSS owners (app↔app, group↔group) fails the GCM tag — the
+/// cross-tenant relocation the audit flags. (A swap between two email triggers
+/// of the SAME owner is not distinguished — an accepted, low-severity residual.)
+fn email_secret_aad(owner: SecretOwner) -> Vec<u8> {
+    match owner {
+        SecretOwner::App(app_id) => format!("email:{app_id}"),
+        SecretOwner::Group(group_id) => format!("email:group:{group_id}"),
+    }
+    .into_bytes()
+}
+
+/// Seal an email-trigger inbound secret at envelope v1 (AAD = the sealing
+/// owner). Returns `(ciphertext, nonce, version)`. The value is a JSON string
+/// (the HMAC key). Replaces the email path's former [`seal_legacy`] (v0).
+///
+/// # Errors
+///
+/// [`SecretsError::TooLarge`] / [`SecretsError::Backend`] as for [`seal`].
+pub fn seal_email(
+    master_key: &MasterKey,
+    owner: SecretOwner,
+    value: &serde_json::Value,
+    max_value_bytes: usize,
+) -> Result<(Vec<u8>, [u8; crypto::NONCE_LEN], i16), SecretsError> {
+    let plaintext = serde_json::to_vec(value)
+        .map_err(|e| SecretsError::Backend(format!("encode secret value: {e}")))?;
+    if plaintext.len() > max_value_bytes {
+        return Err(SecretsError::TooLarge {
+            limit: max_value_bytes,
+            actual: plaintext.len(),
+        });
+    }
+    let aad = email_secret_aad(owner);
+    let enc = crypto::encrypt_with_aad(&plaintext, &aad, master_key.as_bytes());
+    Ok((enc.ciphertext, enc.nonce, SECRET_ENVELOPE_V1))
+}
+
+/// Open an email-trigger inbound secret, dispatching on `version`: v0 is the
+/// legacy no-AAD layout ([`open_legacy`], owner ignored); v1 binds AAD to the
+/// sealing `owner`. The caller recovers the sealing owner (a materialized copy's
+/// source-template group, else the app) before calling.
+///
+/// # Errors
+///
+/// [`SecretsError::Corrupted`] when decryption or JSON decoding fails.
+pub fn open_email(
+    master_key: &MasterKey,
+    owner: SecretOwner,
+    ciphertext: &[u8],
+    nonce: &[u8],
+    version: i16,
+) -> Result<serde_json::Value, SecretsError> {
+    let plaintext = match version {
+        SECRET_ENVELOPE_V1 => {
+            let aad = email_secret_aad(owner);
+            crypto::decrypt_with_aad(ciphertext, nonce, &aad, master_key.as_bytes())
+        }
+        _ => crypto::decrypt(ciphertext, nonce, master_key.as_bytes()),
+    }
+    .map_err(|_| SecretsError::Corrupted)?;
+    serde_json::from_slice(&plaintext).map_err(|_| SecretsError::Corrupted)
+}
+
 pub struct SecretsServiceImpl {
     repo: Arc<dyn SecretsRepo>,
     authz: Arc<dyn AuthzRepo>,

crates/manager-core/src/trigger_repo.rs

@@ -306,6 +306,9 @@ pub struct CreateEmailTrigger {
     pub script_id: ScriptId,
     pub inbound_secret_encrypted: Option<Vec<u8>>,
     pub inbound_secret_nonce: Option<Vec<u8>>,
+    /// Envelope version of the sealed inbound secret (0 = legacy no-AAD, 1 =
+    /// AAD-bound to the sealing owner). `0` when there is no secret.
+    pub inbound_secret_version: i16,
     pub registered_by_principal: AdminUserId,
 }
 
@@ -358,6 +361,13 @@ pub struct EmailInboundTarget {
     /// trigger (accepts any POST).
     pub inbound_secret_encrypted: Option<Vec<u8>>,
     pub inbound_secret_nonce: Option<Vec<u8>>,
+    /// Envelope version of the sealed secret (0 = legacy no-AAD, 1 = AAD-bound).
+    pub inbound_secret_version: i16,
+    /// §M5.5 / audit H-D1: the group this secret was sealed under, when this row
+    /// is a materialized copy of a group EMAIL TEMPLATE (`materialized_from ->
+    /// template.group_id`). `None` for a standalone per-app trigger (sealed under
+    /// the app). Drives the AAD owner at open time for a v1 secret.
+    pub sealing_group: Option<GroupId>,
 }
 
 /// One match for the dispatcher's "which KV triggers fire on this
@@ -820,6 +830,7 @@ pub(crate) async fn insert_email_trigger_tx(
     registered_by: AdminUserId,
     inbound_secret_encrypted: &[u8],
     inbound_secret_nonce: &[u8],
+    inbound_secret_version: i16,
 ) -> Result<TriggerId, TriggerRepoError> {
     let (owner_app_id, owner_group_id) = match owner {
         ScriptOwner::App(a) => (Some(a.into_inner()), None),
@@ -840,12 +851,13 @@ pub(crate) async fn insert_email_trigger_tx(
     .await?;
     sqlx::query(
         "INSERT INTO email_trigger_details \
-            (trigger_id, inbound_secret_encrypted, inbound_secret_nonce) \
-         VALUES ($1, $2, $3)",
+            (trigger_id, inbound_secret_encrypted, inbound_secret_nonce, inbound_secret_version) \
+         VALUES ($1, $2, $3, $4)",
     )
     .bind(row.0)
     .bind(inbound_secret_encrypted)
     .bind(inbound_secret_nonce)
+    .bind(inbound_secret_version)
     .execute(&mut **tx)
     .await?;
     Ok(row.0.into())
@@ -1306,12 +1318,13 @@ impl TriggerRepo for PostgresTriggerRepo {
 
         sqlx::query(
             "INSERT INTO email_trigger_details \
-                (trigger_id, inbound_secret_encrypted, inbound_secret_nonce) \
-             VALUES ($1, $2, $3)",
+                (trigger_id, inbound_secret_encrypted, inbound_secret_nonce, inbound_secret_version) \
+             VALUES ($1, $2, $3, $4)",
         )
         .bind(parent.id)
         .bind(req.inbound_secret_encrypted.as_deref())
         .bind(req.inbound_secret_nonce.as_deref())
+        .bind(req.inbound_secret_version)
         .execute(&mut *tx)
         .await?;
 
@@ -1349,11 +1362,17 @@ impl TriggerRepo for PostgresTriggerRepo {
             // row — only its materialized per-app copies are directly invocable
             // (mirrors the cron-scheduler / queue-consumer guards). A template
             // has no app to run under, so hitting its webhook URL must 404.
+            // §M5.5 / audit H-D1: `tmpl.group_id` (via `materialized_from`) is the
+            // SEALING owner for a materialized copy of a group email template — the
+            // AAD owner needed to open a v1 secret. NULL for a standalone app
+            // trigger (sealed under the app).
             "SELECT t.app_id, t.script_id, t.enabled, t.dispatch_mode, \
                     t.registered_by_principal, \
-                    d.inbound_secret_encrypted, d.inbound_secret_nonce \
+                    d.inbound_secret_encrypted, d.inbound_secret_nonce, \
+                    d.inbound_secret_version, tmpl.group_id AS sealing_group \
              FROM triggers t \
              JOIN email_trigger_details d ON d.trigger_id = t.id \
+             LEFT JOIN triggers tmpl ON tmpl.id = t.materialized_from \
              WHERE t.id = $1 AND t.kind = 'email' AND t.app_id IS NOT NULL",
         )
         .bind(trigger_id.into_inner())
@@ -1367,6 +1386,8 @@ impl TriggerRepo for PostgresTriggerRepo {
             registered_by_principal: r.registered_by_principal.into(),
             inbound_secret_encrypted: r.inbound_secret_encrypted,
             inbound_secret_nonce: r.inbound_secret_nonce,
+            inbound_secret_version: r.inbound_secret_version,
+            sealing_group: r.sealing_group.map(Into::into),
         }))
     }
 
@@ -2122,6 +2143,8 @@ struct EmailInboundRow {
     registered_by_principal: Uuid,
     inbound_secret_encrypted: Option<Vec<u8>>,
     inbound_secret_nonce: Option<Vec<u8>>,
+    inbound_secret_version: i16,
+    sealing_group: Option<Uuid>,
 }
 
 #[derive(sqlx::FromRow)]

crates/manager-core/src/triggers_api.rs

@@ -26,7 +26,7 @@ use serde_json::json;
 use crate::app_repo::AppRepository;
 use crate::authz::{require, AuthzDenied, AuthzError, AuthzRepo, Capability};
 use crate::repo::{ScriptRepository, ScriptRepositoryError};
-use crate::secrets_service::seal_legacy;
+use crate::secrets_service::{seal_email, SecretOwner};
 use crate::trigger_config::{BackoffShape, TriggerConfig};
 use crate::trigger_repo::{
     CreateCronTrigger, CreateDeadLetterTrigger, CreateDocsTrigger, CreateEmailTrigger,
@@ -610,13 +610,12 @@ async fn create_email_trigger(
             ))
         }
     };
-    // 64 KB cap is irrelevant for a signing secret, but `seal_legacy`
-    // takes one; reuse the secrets default. Audit 2026-06-11 H-D1: the
-    // email-trigger secret is still sealed v0 (no AAD) — the AAD upgrade
-    // for this surface is deferred to v1.2 since email_trigger_details
-    // has no version column yet. See secrets_service::seal_legacy.
-    let (ct, nonce) = seal_legacy(
+    // 64 KB cap is irrelevant for a signing secret, but `seal_email` takes one;
+    // reuse the secrets default. §M5.5 / audit H-D1: sealed v1 with AAD bound to
+    // the app owner (this is a standalone per-app trigger — never materialized).
+    let (ct, nonce, version) = seal_email(
         &s.master_key,
+        SecretOwner::App(app_id),
         &serde_json::Value::String(secret),
         crate::secrets_service::DEFAULT_SECRET_MAX_VALUE_BYTES,
     )
@@ -628,6 +627,7 @@ async fn create_email_trigger(
         script_id: input.script_id,
         inbound_secret_encrypted,
         inbound_secret_nonce,
+        inbound_secret_version: version,
         registered_by_principal: principal.user_id,
     };
     let created = s.triggers.create_email_trigger(app_id, req).await?;
@@ -1043,6 +1043,8 @@ mod tests {
                     registered_by_principal: t.registered_by_principal,
                     inbound_secret_encrypted: None,
                     inbound_secret_nonce: None,
+                    inbound_secret_version: 0,
+                    sealing_group: None,
                 }))
         }
         async fn create_cron_trigger(