/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

/**
 * Scriptable wrapper over the Lockstore keystore. A single instance per
 * process is opened against the current profile's keystore file
 * (lockstore.keys.sqlite).
 *
 * KEK references are opaque strings of the form
 * `lockstore::kek::<type>:<base64url(random_id)>`, minted by
 * `createKek`. A collection is an arbitrary namespace under which a
 * single DEK (data encryption key) is wrapped by one or more KEKs;
 * see `createDek`.
 *
 * Methods that touch SQLite or run PBKDF2 return a `Promise` and
 * execute on a private background queue so they do not block the main
 * thread. The cheap in-memory state check (`isKekUnlocked`) remains
 * synchronous; `lockKek` and `lock` are also cheap but return a Promise
 * so the API shape is uniform.
 */
[scriptable, uuid(a83f5d62-7b1c-4d2e-9f0a-3c5e8b6a1d4e)]
interface nsILockstore : nsISupports
{
  /* --- Unified KEK lock / unlock --------------------------------------- */
  //
  // These work for any KEK type that might require user interaction:
  //
  //   Password    → `secret` is the user's password, fed into PBKDF2
  //                 to derive the wrapping key that AES-GCM-unwraps the
  //                 stored KEK; the unwrapped KEK is cached in memory
  //                 for `timeoutMs`. Required — must not be empty.
  //   Pkcs11Token → `secret` is the PIN. When supplied, Lockstore
  //                 authenticates the slot via
  //                 `PK11_CheckUserPassword` (direct `C_Login`),
  //                 bypassing the NSS password callback. When empty,
  //                 Lockstore falls back to `slot.authenticate()`,
  //                 which delegates to whatever password callback
  //                 the embedding application registered (e.g. PSM
  //                 in Firefox).
  //   LocalKey    → no-op; `isKekUnlocked` always returns true,
  //                 `lockKek`/`unlockKek` succeed without side effects.
  //
  // The copy of `secret` handed to the FFI is zeroised once the FFI has
  // consumed it; callers should still follow their own hygiene rules for
  // the string they passed in.

  /**
   * Unlock `kekRef` so subsequent DEK accesses under it succeed for at
   * most `timeoutMs` milliseconds.
   *
   * The returned Promise resolves with `undefined` on success and rejects
   * with:
   *   - NS_ERROR_ABORT on wrong secret / PIN.
   *   - NS_ERROR_NOT_INITIALIZED if the KEK requires initialisation that
   *     hasn't been performed yet (e.g. no Password kek_ref minted).
   *   - NS_ERROR_INVALID_ARG on an unrecognised `kekRef`.
   */
  [implicit_jscontext]
  Promise unlockKek(in AUTF8String kekRef,
                    in ACString secret,
                    in uint32_t timeoutMs);

  /// Drop any cached authentication for `kekRef`. Subsequent DEK accesses
  /// will throw NS_ERROR_NOT_AVAILABLE until the caller re-unlocks. For
  /// PKCS#11 this also calls `PK11_Logout` so NSS's own
  /// authenticated-slot state is cleared alongside the Lockstore cache.
  /// The operation is cheap (in-memory cache eviction + best-effort
  /// `PK11_Logout`), but the Promise shape matches the rest of the API
  /// so JS callers don't have to special-case it.
  [implicit_jscontext]
  Promise lockKek(in AUTF8String kekRef);

  /// True iff `kekRef` is currently unlocked. A valid-but-unrecognised
  /// `kekRef` (one that doesn't correspond to any KEK type Lockstore
  /// knows about) returns `false` rather than throwing. An empty
  /// `kekRef` throws `NS_ERROR_INVALID_ARG`.
  boolean isKekUnlocked(in AUTF8String kekRef);

  /// Lock every KEK that holds cached authentication: zeroises every
  /// cached Password KEK in memory, clears every PKCS#11 unlock entry,
  /// and calls `PK11_Logout` on each previously-unlocked slot. Intended
  /// for shutdown / logout paths. The operation is cheap; the Promise
  /// shape matches the rest of the API.
  [implicit_jscontext]
  Promise lock();

  /* --- DEK / collection management ------------------------------------- */

  /**
   * Create a new DEK for `collection`, wrapped under `kekRef`. The
   * returned Promise rejects with NS_ERROR_FAILURE if the collection
   * already has a DEK.
   *
   * `extractable` controls whether the raw DEK bytes can later be
   * exported via `getDek`. Use the default (`false`) unless an
   * external cipher demands raw key material (e.g. mozStorage's
   * ObfuscatingVFS, which needs a 32-byte key for SQLite page
   * encryption); `encrypt`/`decrypt` work regardless of `extractable`.
   */
  [implicit_jscontext]
  Promise createDek(in AUTF8String collection,
                    in AUTF8String kekRef,
                    in boolean extractable);

  /**
   * Install caller-supplied `dekBytes` as the DEK for `collection`,
   * wrapped under the existing `kekRef`. Used for migrating data
   * already encrypted under a known external DEK into the keystore-
   * managed model without re-encrypting at rest.
   *
   * `dekBytes` must be 32 bytes (AES-256-GCM default cipher suite).
   * The Promise rejects with:
   *   - NS_ERROR_INVALID_ARG on wrong length, or empty `collection`
   *     / `kekRef`
   *   - NS_ERROR_NOT_AVAILABLE if `kekRef` doesn't exist or is locked
   *   - NS_ERROR_FAILURE if `collection` already has a DEK
   *
   * Note: imported DEKs are inherently extractable by the caller (the
   * bytes are already in their hands). The `extractable` flag controls
   * only whether future `getDek` calls succeed on this DEK.
   */
  [implicit_jscontext]
  Promise importDek(in AUTF8String collection,
                    in AUTF8String kekRef,
                    in Array<octet> dekBytes,
                    in boolean extractable);

  /**
   * Resolves with `true` iff the DEK for `collection` was created
   * with `extractable = true`. Touches SQLite (loads the DEK metadata
   * row), hence async — distinct from `isKekUnlocked`, which is an
   * in-memory cache check.
   *
   * Rejects with NS_ERROR_NOT_AVAILABLE if `collection` doesn't exist.
   */
  [implicit_jscontext]
  Promise isDekExtractable(in AUTF8String collection);

  /**
   * Delete the DEK for `collection`. Rejects with
   * NS_ERROR_NOT_AVAILABLE if no DEK exists. The keystore does not
   * track any associated datastore; callers are responsible for
   * disposing of ciphertext under this collection by other means.
   */
  [implicit_jscontext]
  Promise deleteDek(in AUTF8String collection);

  /// Resolves with an Array<ACString> of every collection currently
  /// managed by this keystore.
  [implicit_jscontext]
  Promise listDeks();

  /// Resolves with an Array<AUTF8String> of every kekRef that
  /// currently wraps the DEK named `dekName`. The array is non-empty
  /// for any DEK that exists (the keystore enforces at least one KEK
  /// wrapping); the Promise rejects with NS_ERROR_NOT_AVAILABLE if no
  /// DEK by that name exists (including the empty string). Returns
  /// only the kekRef strings, never the wrapped key bytes themselves
  /// — useful for callers that need to discover the wrapping state
  /// (e.g. login crypto deciding whether to encrypt under LocalKey or
  /// Password for a given DEK).
  [implicit_jscontext]
  Promise listKeks(in AUTF8String dekName);

  /// Wrap an existing collection's DEK under an additional `kekRef`.
  [implicit_jscontext]
  Promise addKek(in AUTF8String collection,
                 in AUTF8String fromKekRef,
                 in AUTF8String toKekRef);

  /// Remove a `kekRef` wrapping from a collection. The last remaining
  /// wrapping cannot be removed.
  [implicit_jscontext]
  Promise removeKek(in AUTF8String collection,
                    in AUTF8String kekRef);

  /**
   * Atomically rewrap the DEK for `collection` from `oldKekRef` to
   * `newKekRef`. The DEK bytes are unchanged, so ciphertexts at rest
   * under this collection remain valid. Equivalent in effect to
   * `addKek(collection, oldKekRef, newKekRef)` followed by
   * `removeKek(collection, oldKekRef)` but atomic at the kvstore-row
   * level — a crash mid-operation leaves the keystore in the old
   * state or the new state, never a transient half-state.
   *
   * `oldKekRef` must currently wrap the collection and be unlocked.
   * The Promise rejects with:
   *   - NS_ERROR_INVALID_ARG if `oldKekRef` == `newKekRef`, or either
   *     is empty
   *   - NS_ERROR_NOT_AVAILABLE if `collection` or its `oldKekRef`
   *     wrapping doesn't exist
   *   - NS_ERROR_FAILURE if `newKekRef` already wraps this collection
   *   - NS_ERROR_NOT_AVAILABLE (`Locked`) if `oldKekRef` is locked
   */
  [implicit_jscontext]
  Promise switchKek(in AUTF8String collection,
                    in AUTF8String oldKekRef,
                    in AUTF8String newKekRef);

  /* --- Crypto (async, byte-oriented) ----------------------------------- */

  /**
   * Encrypt `plaintext` with the DEK for `(collection, kekRef)`. The work
   * runs off the main thread. The returned Promise resolves with a byte
   * array (Array<octet>) containing a self-describing blob:
   *   [cipher_suite_id(1)] || [nonce] || [ciphertext+tag]
   * and rejects with an nsresult on failure. The DEK need not be
   * extractable.
   */
  [implicit_jscontext]
  Promise encrypt(in AUTF8String collection,
                  in AUTF8String kekRef,
                  in Array<octet> plaintext);

  /**
   * Decrypt a blob produced by `encrypt`. Cipher suite is inferred from
   * the blob's leading byte. Runs off the main thread; the Promise
   * resolves with the plaintext bytes.
   */
  [implicit_jscontext]
  Promise decrypt(in AUTF8String collection,
                  in AUTF8String kekRef,
                  in Array<octet> ciphertext);

  /**
   * Return the raw DEK bytes for `(collection, kekRef)` as an
   * `Array<octet>` (32 bytes for the default AES-256-GCM /
   * ChaCha20-Poly1305 suites). The DEK must have been created with
   * `extractable = true`; otherwise the Promise rejects with
   * `NS_ERROR_NOT_AVAILABLE`.
   *
   * The returned bytes are sensitive: any caller is now in possession
   * of the symmetric key that can decrypt every ciphertext stored
   * under this DEK. Prefer `encrypt`/`decrypt` unless an external
   * cipher (e.g. mozStorage's ObfuscatingVFS, which needs a 32-byte
   * key for SQLite page encryption) requires raw key material.
   *
   * The Promise also rejects with `NS_ERROR_NOT_AVAILABLE` if no DEK
   * exists for `(collection, kekRef)`, and with `NS_ERROR_INVALID_ARG`
   * if either argument is empty.
   */
  [implicit_jscontext]
  Promise getDek(in AUTF8String collection, in AUTF8String kekRef);

  /* --- KEK creation --------------------------------------------------- */

  /**
   * Generic KEK-creation entry point. Always mints a fresh kek_ref of
   * the form `lockstore::kek::<type>:<base64url(random_id)>`; a profile
   * can host any number of KEKs per `KekType`. Dispatches on `kekType`:
   *
   *   "local"
   *       Generates a fresh AES-256 KEK and persists it (verbatim) in
   *       a `LocalKekRecord`. LocalKey has no unlock ceremony — its
   *       confidentiality at rest is provided by the underlying SQLite
   *       encryption layer. `secret` and `cacheTimeoutMs` are ignored.
   *
   *   "password"
   *       Wraps a fresh AES-256 KEK under PBKDF2-HMAC-SHA256 of
   *       `secret` (must be non-empty). Each kek_ref carries an
   *       independent salt + iteration count + ciphertext, so multiple
   *       password KEKs coexist without shared state. Rotation is
   *       `createKek("password", new)` + `switchKek(oldKekRef, newKekRef)`
   *       + `removeKek(oldKekRef)`. If `cacheTimeoutMs` is non-zero the
   *       just-derived KEK is also inserted into the auth cache with
   *       that expiry, so callers can use the returned kek_ref without
   *       an immediate `unlockKek`.
   *
   *   "pkcs11"
   *       Provisions a fresh PKCS#11-backed KEK against the slot
   *       named by the PKCS#11 URI in `secret`. The slot is
   *       authenticated via NSS's registered password callback (PSM
   *       in Firefox); Lockstore then finds-or-creates a long-lived
   *       AES wrapping key on the slot, generates a fresh software
   *       KEK, wraps it under the wrapping key, and persists a
   *       record. `cacheTimeoutMs` is ignored — PKCS#11 unlock is
   *       mediated by NSS, not by the Lockstore cache.
   *
   * `identifier` selects the kek_ref `<id>` suffix: empty (the usual
   * case) mints a fresh random id; a non-empty base64url
   * (`[A-Za-z0-9_-]`) identifier is used verbatim, making the call a
   * deterministic get-or-create -- a later `createKek` with the same
   * `kekType` + `identifier` returns the existing KEK untouched.
   *
   * `cacheTimeoutMs` is the duration (in milliseconds) that the
   * just-derived KEK is kept in the in-memory auth cache. Only
   * meaningful for the `"password"` tier; ignored elsewhere.
   *
   * Lockstore copies the secret bytes into its own buffer, consumes
   * them, and zeroises the buffer before resolving the Promise; the
   * caller's `ACString` is never mutated.
   *
   * The returned Promise resolves with the freshly-minted `kek_ref`
   * the caller should hand to subsequent `createDek` / `encrypt`
   * calls, and rejects with:
   *   - NS_ERROR_INVALID_ARG on an unknown `kekType`, a non-base64url
   *     `identifier`, an empty Password `secret`, or a malformed
   *     PKCS#11 URI.
   *   - NS_ERROR_ABORT if a PKCS#11 token unlock prompt is cancelled.
   *   - NS_ERROR_FAILURE on any other failure (SQLite write error,
   *     crypto-layer error).
   */
  [implicit_jscontext]
  Promise createKek(in ACString kekType,
                    in ACString identifier,
                    in ACString secret,
                    in uint32_t cacheTimeoutMs);

  /**
   * Destroy the KEK referenced by `kekRef`. The persisted row is
   * dropped along with the per-`kekRef` unlock-cache entry — the
   * authenticated KEK bytes derived from a password / PIN that
   * `unlockKek` cached and that `lockKek` would otherwise clear. No
   * DEK material is touched: every DEK wrapping under `kekRef` must
   * already be gone (via `removeKek` / `switchKek`) before this call
   * succeeds. For a PKCS#11 KEK the slot is logged out via the same
   * `PK11_Logout` path used by `lockKek`.
   *
   * Deletion is always explicit. `removeKek` and `deleteDek` drop
   * wrappings only; the per-`kekRef` KEK record stays on disk until
   * `deleteKek` is called for it.
   *
   * The returned Promise resolves with `undefined` on success and
   * rejects with:
   *   - NS_ERROR_INVALID_ARG on an empty `kekRef`.
   *   - NS_ERROR_NOT_AVAILABLE if no record exists at `kekRef`.
   *   - NS_ERROR_FAILURE if any DEK still wraps under `kekRef`, or
   *     on SQLite / crypto-layer errors.
   */
  [implicit_jscontext]
  Promise deleteKek(in AUTF8String kekRef);
};