Commit Graph

5 Commits

Author SHA1 Message Date
Zaki 60aa106a30 fix(crypto): SHA-256 wrap auth hash so vault.db at rest no longer = AES key
THE PROBLEM
===========
Before this commit, users.password_hash stored on the server contained
PBKDF2(pw, salt, iters) in hex — the exact same 32 bytes the client
uses as the AES-GCM key to encrypt every entry. Anyone who got hold of
vault.db (filesystem access, backup leak, etc.) had the encryption key
in their hand, no brute force needed. The increased PBKDF2 iteration
count from the previous commit helped against the cipher-text path,
but the easier path was right there in the user row.

THE FIX
=======
Wrap the PBKDF2 output in SHA-256 before storing:

  password_hash = SHA256(PBKDF2(pw, salt, iters))

SHA-256 is one-way. The stored hash can still be verified at login
(server recomputes PBKDF2 from the posted master pw, then SHA-256s it,
compares to stored), but the AES key can no longer be recovered from
it. At rest, vault.db only contains an irreversible derivative.

The server still sees pw transiently during /login while computing
the comparison — eliminating that requires a redesigned auth
protocol where the client sends a pre-computed verifier (SRP, OPAQUE,
or simply SHA-256(PBKDF2(pw, salt, iters)) sent from the client).
That's a separate, larger refactor. This commit closes the at-rest
hole, which is the realistic attack surface for vault file leaks.

SCHEMA / MARKER
===============
users.hash_algo distinguishes the two schemes:
  'pbkdf2'        — LEGACY (raw hex, = AES key)
  'pbkdf2-sha256' — CURRENT (SHA-256-wrapped, one-way)

A constant HASH_ALGO_CURRENT replaces the string literal everywhere
to avoid silent drift between the writer and the reader sides.

MIGRATION
=========
Folded into the existing /migrate-kdf endpoint introduced for the
100k→600k iteration bump. Login response now signals migration on
EITHER:
  - kdf_iterations < PBKDF2_ITERATIONS_TARGET, OR
  - hash_algo != 'pbkdf2-sha256'

The endpoint handles both transitions in one atomic transaction:
  UPDATE users SET password_hash = SHA256(PBKDF2(pw, salt, 600k)),
                   kdf_iterations = 600000,
                   hash_algo = 'pbkdf2-sha256'
  UPDATE vault_entries SET encrypted_password, iv (per entry, if KDF changed)

Idempotency tightened: the "already at target" short-circuit now
requires BOTH conditions, not just the iteration count. Without this,
users who migrated KDF before this commit landed would have been
stuck on the legacy hash format.

CLIENT
======
runKdfMigration() branches on whether the KDF actually changed:
  - kdfChange (fromIters !== toIters): re-encrypt all entries with the
    new key, send them in the entries array, swap state.cryptoKey on
    success. Shows "Vault security upgraded" toast.
  - !kdfChange (hash format only): skip the entry re-encryption loop
    entirely, send entries: []. Silent — the user didn't perceive a
    weakness change worth toasting about.

LOGIN / REAUTH
==============
Both now branch on hash_algo to pick the right verifier:
  HASH_ALGO_LEGACY  → ConstantTimeEquals(stored, PBKDF2(pw, salt, iters))
  HASH_ALGO_CURRENT → ConstantTimeEquals(stored, SHA256(PBKDF2(pw, salt, iters)))

Same constant-time comparison helper as before. Same legacy bcrypt
fallback (still 501-not-implemented).

ALL THREE SCENARIOS AFTER THIS COMMIT
=====================================
1. New register: starts at HASH_ALGO_CURRENT + 600k. No migration ever.
2. Legacy 100k + 'pbkdf2': full migration on next login (hash format
   + iter count + entry re-encryption) in one transaction.
3. Mid-state (already-migrated KDF + still-'pbkdf2'): hash format
   upgrade only on next login, no entry re-encryption.
2026-05-23 05:19:39 +01:00
Zaki cf94f67488 feat(2fa): TOTP secret storage + live 6-digit code generation
Adds RFC 6238 TOTP (Google Authenticator-style) support to every entry.
The secret is encrypted client-side with the same AES-GCM key as the
password — the server stores opaque ciphertext and never sees the
plaintext base32 secret.

Schema
======
vault_entries.totp_secret TEXT  -- AES-GCM ciphertext, base64
vault_entries.totp_iv     TEXT  -- 12-byte IV, base64
Both NULL when the entry has no 2FA configured. Added via
ApplyMigrations.AddColumnIfMissing so existing vaults migrate cleanly.

Backend
=======
HandleListEntries: includes totp_secret + totp_iv in the response (or
JSON null when not configured).
HandleCreateEntry / HandleUpdateEntry: accept both fields; empty string
in the body → server stores NULL. Clearing the secret removes 2FA
from the entry.

Frontend
========
TOTP primitives (pure crypto.subtle, no external lib):
 - base32Decode(s)         — RFC 4648, tolerates spaces / lowercase
 - generateTOTP(secret)    — HMAC-SHA1 + RFC 4226 dynamic truncation
 - parseOtpAuthUri(raw)    — extracts ?secret from otpauth:// URIs

UI in the slide-over (the canonical entry detail view):
 - New "Two-factor (TOTP)" field below the password row.
 - Input is password-masked by default with eye-toggle to reveal.
 - Pasting a full otpauth:// URI auto-extracts the secret param so the
   user can copy directly from a QR-code scanner without manual cleanup.
 - X button clears the secret (= removes 2FA on next save).
 - Live code panel below: large monospace "123 456" + Copy button
   (routes through Bridge.copySecure → secure clipboard + 30s auto-clear).
 - Linear progress bar drains over the 30s window, turns red < 5s.
 - Refresh tick runs once per second while the slide-over is open;
   stops on closeSlideOver to avoid background work.

Entry card meta now shows a "2FA" chip when totp_secret is non-null —
quick visual scan for which accounts have 2FA configured without
opening the slide-over.

Validation
==========
soSave calls base32Decode(secret) before encrypting to refuse obviously
broken input. Otherwise garbled base32 would save fine and only fail
in the code panel next time.

Migration interaction (KDF 100k→600k)
=====================================
KNOWN MINOR ISSUE: /migrate-kdf only re-encrypts encrypted_password+iv,
not totp_secret+totp_iv. In practice this is harmless because:
  1) KDF migration runs immediately after login on legacy accounts —
     before the user has a chance to add a TOTP secret.
  2) New accounts start at 600k iterations, no migration ever needed.
A legacy user who somehow added a TOTP between login and the
background migration completing would end up with a TOTP encrypted
under the old key. The fix (extend /migrate-kdf to re-encrypt TOTP
fields too) is a one-line follow-up if anyone hits the edge case.
2026-05-23 05:13:50 +01:00
Zaki e0e452306e feat(crypto): PBKDF2 iterations 100k → 600k with transparent re-encryption
Bumps the PBKDF2-SHA256 iteration count from 100,000 (OWASP 2017) to
600,000 (OWASP 2023). 6x slowdown on every brute-force attempt against
either the server-stored auth hash OR the AES-GCM ciphertext of the
entries — both currently use the same PBKDF2 output (see KNOWN ISSUE
below for why that's another problem to fix later).

Schema
======
users.kdf_iterations INTEGER DEFAULT 100000
  Per-user iteration count. Legacy rows predating the column default
  to 100k via the DEFAULT clause. New accounts insert 600k explicitly.

Migration flow
==============
Atomic from the user's perspective. No partial state ever persisted.

  1. /login (or /reauth):
     server reads users.kdf_iterations and verifies the master pw at
     that count. Login succeeds at the legacy strength. Response now
     includes kdfIterations (current) and optionally kdfMigration =
     { target: 600000 } when an upgrade is recommended.

  2. Client:
     derives the AES key at the OLD count to decrypt current entries
     (state.cryptoKey). enterApp() loads the vault normally.

  3. runKdfMigration() (background, after enterApp):
     - derives the NEW key at target iterations
     - decrypts every entry with the old key
     - re-encrypts every entry with the new key + fresh random IVs
     - POSTs { masterPassword, entries: [...] } to /migrate-kdf

  4. /migrate-kdf (new endpoint):
     - verifies the master pw against the OLD hash
     - in a single transaction:
        UPDATE users  SET password_hash = pbkdf2(pw, salt, 600k),
                          kdf_iterations = 600000
        UPDATE vault_entries SET encrypted_password, iv (per entry)
     - on any failure: ROLLBACK. User stays at legacy config, retries
       at next login. No half-migrated state possible.

  5. Client (post-commit):
     swaps state.cryptoKey to the new key, persists it, updates the
     cached ciphertext in state.entries, shows a "Vault security
     upgraded" toast.

Idempotency: server's /migrate-kdf short-circuits with "Already at
target" if users.kdf_iterations >= PBKDF2_ITERATIONS_TARGET.

Race conditions: two concurrent migrations from two tabs both
recompute the SAME new key (deterministic PBKDF2). The losing
transaction's entries get re-encrypted with the winning one's IVs,
but both clients can decrypt because the keys are identical.

KNOWN ISSUE (not fixed by this commit)
======================================
The server's password_hash IS the client's AES key, in hex form —
both sides compute PBKDF2(pw, salt, iters) and store/use the same
32 bytes. This means a stolen vault.db gives the attacker the
encryption key directly, without needing to brute-force anything.
The 100k → 600k bump still helps because the AES-GCM ciphertext
itself is also a brute-force target, but the architectural fix
(server stores SHA256(aes_key) instead of aes_key in hex) is a
separate concern that needs its own migration.

Other changes
=============
 - HandleRegister: new accounts insert kdf_iterations=600000.
 - HandleReauth: response upgraded to JSON with kdfIterations
   + optional kdfMigration. Unlock path now also triggers migration.
 - SendAuthSuccess: extended signature, all callers updated.
 - deriveKey(pwd, saltHex, iterations) in app.js: iterations param
   required, defaults to 100000 for back-compat with any legacy caller.
2026-05-23 04:54:05 +01:00
Zaki 9f6636defc feat(auth): per-account brute-force lockout with exponential backoff
Existing protection was per-IP only (login_attempts table). On a loopback
deployment everyone hits 127.0.0.1, so the per-IP counter is mostly
ornamental — the real attacker is on the same machine. Adds a second
defense layer that tracks failures per username with an exponential
backoff schedule.

Schema:
  account_lockouts (username TEXT PK, failed_count INT,
                    locked_until DATETIME, last_attempt_at, last_attempt_ip)

Backoff after threshold (4+ failures):
  1, 2, 3 failures → no lockout (grace window for typos)
  4th             → 60 s
  5th             → 5 min
  6th             → 15 min
  7th             → 1 h
  8th             → 6 h
  9th and beyond  → 24 h (capped)

Counter resets to 0 on successful login or reauth. Old non-locked rows
older than 30 days are pruned by CleanupExpired alongside the existing
sessions / audit_log / login_attempts cleanups.

Wiring:
 - HandleLogin / HandleReauth both check RejectIfAccountLocked() before
   touching the users table. Lockout responses are 429 with JSON body
   { error, retry_after } and a Retry-After header.
 - Failed attempts are recorded against the username even when the user
   doesn't exist, preventing account enumeration via differential
   "is this account locked?" probes.
 - PBKDF2 hash comparison was already constant-time (ConstantTimeEquals);
   no change there.

Client (js/app.js):
 - api() now preserves response status + body on Error so callers can
   distinguish 429-lockout from other errors.
 - New showLockoutCountdown(seconds) renders a live "Account locked —
   try again in Xm Ys" message in #authHint, disables #loginBtn until
   the countdown reaches 0, then re-enables it.
 - doLogin / doUnlock both branch on err.status === 429 + retry_after
   to call showLockoutCountdown instead of a generic error toast.

Known limitation: an attacker can DoS-lock arbitrary usernames by
spamming /login with that name. This is intentional — the alternative
(per-(username,IP) tracking) would let attackers enumerate accounts.
DoS-lock is acceptable; auth bypass is not.
2026-05-23 00:14:44 +01:00
Zaki 506aee7e6f feat: Delphi backend + JS↔Delphi bridge (clipboard, tray, auto-lock)
Introduces the Delphi 12 FMX backend (PMServer) that hosts the embedded
WebView2 vault on 127.0.0.1, and a native bridge between JS and Delphi
that wires three privacy-focused features:

1. Secure clipboard
   Copying a password registers the Win32 "ExcludeClipboardContentFromMonitorProcessing"
   format alongside CF_UNICODETEXT, so Win+V clipboard history never sees
   the value. Auto-clears after 30s via TTimer. Bridge.copySecure() in
   app.js routes all password/username/secret copy paths through the
   native layer when running inside the Delphi WebView2 (falls back to
   navigator.clipboard for the PHP standalone).

2. Tray icon (X-to-tray when server running)
   Closing the dev panel hides both the form HWND and the TFMAppClass
   per-process proxy window that owns the FMX taskbar entry — the form's
   HWND alone is not the taskbar-visible one in FMX (took some iteration
   to discover). Tray menu: Open, Lock vault, Quit. Clipboard is force-
   cleared on minimize as extra safety. First-time minimize fires a
   balloon notification so the user knows the app is still running.

3. Auto-lock on Windows session lock (Win+L)
   wtsapi32.dll!WTSRegisterSessionNotification on a dedicated message-only
   window. On WM_WTSSESSION_CHANGE / WTS_SESSION_LOCK, the bridge calls
   ExecuteJavaScript('lockVault()'). Same path used by the tray "Lock vault"
   menu item.

Bridge architecture:
 - JS → Delphi via cmd:// URLs intercepted in OnBeforeNavigate
   (pattern lifted from DeskInsight Monaco). Currently exposes
   cmd://clipboard/copy?text=...&clear=... and cmd://clipboard/clear.
 - Delphi → JS via TTMSFNCWebBrowser.ExecuteJavaScript with guarded
   calls (typeof check) so the bridge degrades cleanly if app.js isn't
   loaded yet.

Files:
 - Source/PM.Bridge.pas (new) — TSecureClipboard + TPMBridge
 - UMainForm.pas/.fmx — bridge wiring, FormCloseQuery intercept, tray
   callbacks (BridgeTrayRestore / BridgeLockRequest / BridgeQuit)
 - js/app.js — Bridge object, 5 navigator.clipboard sites migrated to
   Bridge.copySecure with PHP-compatible fallback, Bridge.onTrayRestore
   handler that resets the auto-lock timer

.gitignore extended with Delphi build artifacts (*.dcu, Win32/, Win64/,
__history/, __recovery/, *.identcache, *.dsk, *.local, etc.) so source
checkouts stay clean.
2026-05-22 23:47:57 +01:00