feat(core): FK for user_id columns; MCP search requires user

- Add fk_entries_user_id, fk_entries_history_user_id, fk_audit_log_user_id (ON DELETE SET NULL)
- Add scripts/cleanup-orphan-user-ids.sql for pre-deploy orphan user_id cleanup
- Remove deprecated SERVER_MASTER_KEY / per-user key wrap helpers from secrets-core
- secrets-mcp: require authenticated user for secrets_search; improve body-read failure response
- Bump secrets-mcp to 0.2.1

Made-with: Cursor

crates/secrets-core/src/crypto.rs

@@ -55,35 +55,6 @@ pub fn decrypt_json(master_key: &[u8; 32], data: &[u8]) -> Result<Value> {
     serde_json::from_slice(&bytes).context("deserialize decrypted JSON")
 }
 
-// ─── Per-user key management (DEPRECATED — kept only for migration) ───────────
-
-/// Generate a new random 32-byte per-user encryption key.
-#[allow(dead_code)]
-pub fn generate_user_key() -> [u8; 32] {
-    use aes_gcm::aead::rand_core::RngCore;
-    let mut key = [0u8; 32];
-    OsRng.fill_bytes(&mut key);
-    key
-}
-
-/// Wrap a per-user key with the server master key using AES-256-GCM.
-#[allow(dead_code)]
-pub fn wrap_user_key(server_master_key: &[u8; 32], user_key: &[u8; 32]) -> Result<Vec<u8>> {
-    encrypt(server_master_key, user_key.as_ref())
-}
-
-/// Unwrap a per-user key using the server master key.
-#[allow(dead_code)]
-pub fn unwrap_user_key(server_master_key: &[u8; 32], wrapped: &[u8]) -> Result<[u8; 32]> {
-    let bytes = decrypt(server_master_key, wrapped)?;
-    if bytes.len() != 32 {
-        bail!("unwrapped user key has unexpected length {}", bytes.len());
-    }
-    let mut key = [0u8; 32];
-    key.copy_from_slice(&bytes);
-    Ok(key)
-}
-
 // ─── Client-supplied key extraction ──────────────────────────────────────────
 
 /// Parse a 64-char hex string (from X-Encryption-Key header) into a 32-byte key.
@@ -100,33 +71,6 @@ pub fn extract_key_from_hex(hex_str: &str) -> Result<[u8; 32]> {
     Ok(key)
 }
 
-// ─── Server master key ────────────────────────────────────────────────────────
-
-/// Load the server master key from `SERVER_MASTER_KEY` environment variable (64 hex chars).
-pub fn load_master_key_auto() -> Result<[u8; 32]> {
-    let hex_str = std::env::var("SERVER_MASTER_KEY").map_err(|_| {
-        anyhow::anyhow!(
-            "SERVER_MASTER_KEY is not set. \
-             Generate one with: openssl rand -hex 32"
-        )
-    })?;
-
-    if hex_str.is_empty() {
-        bail!("SERVER_MASTER_KEY is set but empty");
-    }
-
-    let bytes = hex::decode_hex(hex_str.trim())?;
-    if bytes.len() != 32 {
-        bail!(
-            "SERVER_MASTER_KEY must be 64 hex chars (32 bytes), got {} bytes",
-            bytes.len()
-        );
-    }
-    let mut key = [0u8; 32];
-    key.copy_from_slice(&bytes);
-    Ok(key)
-}
-
 // ─── Public hex helpers ───────────────────────────────────────────────────────
 
 pub mod hex {
@@ -186,22 +130,4 @@ mod tests {
         let dec = decrypt_json(&key, &enc).unwrap();
         assert_eq!(dec, value);
     }
-
-    #[test]
-    fn user_key_wrap_unwrap_roundtrip() {
-        let server_key = [0xABu8; 32];
-        let user_key = [0xCDu8; 32];
-        let wrapped = wrap_user_key(&server_key, &user_key).unwrap();
-        let unwrapped = unwrap_user_key(&server_key, &wrapped).unwrap();
-        assert_eq!(unwrapped, user_key);
-    }
-
-    #[test]
-    fn user_key_wrap_wrong_server_key_fails() {
-        let server_key1 = [0xABu8; 32];
-        let server_key2 = [0xEFu8; 32];
-        let user_key = [0xCDu8; 32];
-        let wrapped = wrap_user_key(&server_key1, &user_key).unwrap();
-        assert!(unwrap_user_key(&server_key2, &wrapped).is_err());
-    }
 }

crates/secrets-core/src/db.rs

@@ -156,6 +156,37 @@ pub async fn migrate(pool: &PgPool) -> Result<()> {
         CREATE INDEX IF NOT EXISTS idx_oauth_accounts_user ON oauth_accounts(user_id);
         CREATE UNIQUE INDEX IF NOT EXISTS idx_oauth_accounts_user_provider
             ON oauth_accounts(user_id, provider);
+
+        -- FK: user_id columns -> users(id) (nullable = legacy rows; ON DELETE SET NULL)
+        DO $$ BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM pg_constraint WHERE conname = 'fk_entries_user_id'
+            ) THEN
+                ALTER TABLE entries
+                    ADD CONSTRAINT fk_entries_user_id
+                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE SET NULL;
+            END IF;
+        END $$;
+
+        DO $$ BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM pg_constraint WHERE conname = 'fk_entries_history_user_id'
+            ) THEN
+                ALTER TABLE entries_history
+                    ADD CONSTRAINT fk_entries_history_user_id
+                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE SET NULL;
+            END IF;
+        END $$;
+
+        DO $$ BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM pg_constraint WHERE conname = 'fk_audit_log_user_id'
+            ) THEN
+                ALTER TABLE audit_log
+                    ADD CONSTRAINT fk_audit_log_user_id
+                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE SET NULL;
+            END IF;
+        END $$;
         "#,
     )
     .execute(pool)