diff --git a/Cargo.lock b/Cargo.lock index 402c2d9295..ca8c6f0e42 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -5229,6 +5229,7 @@ dependencies = [ "refinery", "region", "rusqlite", + "schemars 1.2.1", "serde", "serde_json", "serial_test", diff --git a/packages/rs-platform-wallet-storage/Cargo.toml b/packages/rs-platform-wallet-storage/Cargo.toml index 88d1a2b397..3678307816 100644 --- a/packages/rs-platform-wallet-storage/Cargo.toml +++ b/packages/rs-platform-wallet-storage/Cargo.toml @@ -61,6 +61,11 @@ chrono = { version = "0.4", default-features = false, features = [ "clock", ], optional = true } sha2 = { version = "0.10", optional = true } +# Opt-in `JsonSchema` for `SecretString` (gated by `secret-schemars`). +# Reuses the workspace-locked 1.2.1. `default-features = false` drops the +# `derive` feature (we hand-write the impl), matching the crate's existing +# derive-free schemars usage so the lock gains no `schemars_derive` entry. +schemars = { version = "1", optional = true, default-features = false } # Secret-storage deps (gated by the `secrets` feature). RustSec-clean # pins (Smythe §7); `aes-gcm` is deliberately omitted. `keyring`'s @@ -194,6 +199,10 @@ secrets = [ # the feature list (not a `default-features = false` rewrite) so # argon2's own default features stay intact. "argon2/zeroize", + # bincode is the producer for the Tier-2 envelope wire format and the + # three AAD encodings (`Tier2Aad`/`EntryAad`/`VerifyAad`) — see + # `secrets/wire/`. `=2.0.1` is the workspace-wide pin. + "dep:bincode", "dep:chacha20poly1305", # secrets uses serde directly (vault format + crypto envelope derive # `Serialize`/`Deserialize`); declare the dep here so @@ -213,6 +222,15 @@ secrets = [ "dep:apple-native-keyring-store", "dep:windows-native-keyring-store", ] +# Opt-in `SecretString` serde/schemars impls. Deliberately DEFAULT-OFF +# even though `secrets` (and, via it, the `serde` dep) are default-on: +# these gate the IMPLS, not the dep, so the impls are absent unless a +# consumer explicitly opts in. `secret-serde` requires `secrets` (the type +# only exists under it). NO `Serialize` is ever provided. `secret-schemars` +# implies `secret-serde`. (design §5.4 / GAP-001 names / GAP-002 satisfiable +# default-off.) +secret-serde = ["secrets", "dep:serde"] +secret-schemars = ["secret-serde", "dep:schemars"] # Per-object-type key/value metadata API # (`platform_wallet_storage::{KvStore, KvError, ObjectId}`) plus the # SQLite-backed impl. Requires `sqlite` because the only shipped backend diff --git a/packages/rs-platform-wallet-storage/SECRETS.md b/packages/rs-platform-wallet-storage/SECRETS.md index 8a1c7fcc39..9f1361702b 100644 --- a/packages/rs-platform-wallet-storage/SECRETS.md +++ b/packages/rs-platform-wallet-storage/SECRETS.md @@ -62,8 +62,22 @@ use platform_wallet_storage::secrets::{SecretBytes, SecretStore, SecretString, W let store = SecretStore::file("/var/lib/wallet/secrets.pwsvault", SecretString::new("pw"))?; let wallet = WalletId::from(wallet_id); + +// Tier-1 only (unprotected by an object password). `set`/`get` are +// `..,None` wrappers over `set_secret`/`get_secret`. store.set(&wallet, "mnemonic", &SecretBytes::from_slice(b"abandon ability ..."))?; let plaintext: Option = store.get(&wallet, "mnemonic")?; // never a bare Vec + +// Tier-2: protect a critical object under an extra OBJECT PASSWORD that +// the backend never sees. Reading it back REQUIRES the password. +let pw = SecretString::new("a strong object password"); +store.set_secret(&wallet, "seed", &SecretBytes::from_slice(b""), Some(&pw))?; +let seed = store.get_secret(&wallet, "seed", Some(&pw))?; // Some(secret) +// Reading a protected object WITHOUT the password fails closed: +assert!(store.get_secret(&wallet, "seed", None).is_err()); // NeedsPassword + +// Add / change / remove an object password in one atomic same-slot flow: +store.reprotect(&wallet, "seed", Some(&pw), None)?; // remove → now unprotected store.delete(&wallet, "mnemonic")?; // idempotent ``` @@ -72,6 +86,202 @@ filename); the parent directory is materialized on the first write. Use `SecretStore::os()` for the platform OS keyring arm instead of `SecretStore::file(..)`. +See **Two-tier secret protection** below for the model, the envelope +format, which tier defeats which adversary, and the strict fail-closed +read that is the heart of the opt-in scheme. + +### Two-tier secret protection + +Secret protection comes in two layers. Tier-1 is always on (it is just +"which backend you opened"); Tier-2 is opt-in, per critical object, and +backend-independent. + +| Tier | Provided by | Defeats | Mechanism | +|---|---|---|---| +| **1 — backend baseline** | the *backend* | another local user, a lost laptop, the vault at rest | OS keychain ACLs **or** Argon2id + XChaCha20-Poly1305 vault under a **real** passphrase | +| **2 — per-object password** | the *library*, above `SecretStore`, over **both** arms | **backend compromise** — the keychain scraped, or the vault stolen *and* its passphrase cracked | the object's bytes are Argon2id + XChaCha20-Poly1305 **enveloped under a per-object password BEFORE they reach the backend** | + +**Why Tier-2 is more than key granularity.** Its value is not a sub-key — +it is (a) an **independent human password the backend never sees** and (b) +**envelope-before-backend ordering**, so for a protected object the backend +only ever stores ciphertext. That is the first and only control that keeps +a chosen critical object confidential across a *full* backend compromise +(the A2/A3/A6 gap Tier-1 leaves open). + +Tier-2 has two guarantees of different strength: + +- **Confidentiality** (an attacker cannot *read* a protected secret) is + **unconditional** — the object password never enters any backend, so a + full backend dump yields only ciphertext + a per-object salt to + offline-Argon2id-crack against the password's entropy. +- **Integrity / anti-downgrade** is delivered by the **strict fail-closed + read** below and is **conditional on the caller's trusted model staying + intact** (see the documented residual). + +#### The envelope (wire format) + +Every value written through `set_secret`/`set` is wrapped in a +self-describing, authenticated envelope before it reaches the backend. The +backend (file vault or OS keychain) stores only these opaque bytes. + +The canonical wire format is **bincode-encoded** under a single +`WIRE_CONFIG = standard().with_big_endian().with_no_limit()` against +two `pub(crate)` types whose shapes are the source of truth — see +[`src/secrets/wire/envelope.rs`](src/secrets/wire/envelope.rs) and +[`src/secrets/wire/mod.rs`](src/secrets/wire/mod.rs): + +```rust +struct Envelope { version: u32, payload: Payload } +enum Payload { + Unprotected(Vec), // scheme 0 + Password { // scheme 1 + kdf: KdfParamsEncoded, // id u8 ‖ m_kib u32 ‖ t u32 ‖ p u32 + salt: [u8; 32], nonce: [u8; 24], + ciphertext: Vec, // includes the 16-byte Poly1305 tag + }, +} +``` + +`ENVELOPE_VERSION = 1` is bumped only on a breaking layout change, +independent of the vault `FORMAT_VERSION`. Decoding goes through a +budget-limited `DECODE_CONFIG = WIRE_CONFIG.with_limit::()` so a +hostile blob declaring a multi-GiB length prefix is rejected before +allocation (security-positive deviation from the no-limit encoder +config). Trailing bytes after a valid decode are also refused — +`consumed == blob.len()` is a fail-closed invariant. + +- **AAD (scheme 1)** is bincode-encoded from `Tier2Aad` + ([`src/secrets/wire/aad.rs`](src/secrets/wire/aad.rs)), which binds + `domain (PWSEV-TIER2-AAD-v2) ‖ envelope_version ‖ scheme_discriminant + ‖ kdf ‖ salt ‖ wallet_id ‖ label`. The vault's own per-entry AAD goes + through `EntryAad` (`domain (PWSV-ENTRY-AAD-v2) ‖ format_version ‖ + wallet_id ‖ label`) and the vault verify-token AAD through `VerifyAad` + (`domain (PWSV-VERIFY-AAD-v2) ‖ format_version ‖ salt ‖ kdf`). All + three domain tags are pair-wise byte-disjoint by construction. A + protected blob relocated to another slot — or any in-place header + edit — fails the tag (relocation/header-tamper resistance). On the + file arm this AAD is *in addition* to the vault's own per-entry AAD + + tag; on the OS arm it is the only authentication layer. +- **KDF ceiling before derivation (anti-DoS).** The KDF params live in + the (attacker-controllable) header, so on a read the Argon2 ceiling + is enforced **before** any derivation/allocation — both the wider + `enforce_bounds` (algorithm id + floors/ceilings) AND a tighter + per-read gate that refuses any `m_kib > default_target().m_kib` OR + `t > default_target().t`. A forged header cannot inflate memory by + more than the shipped default or CPU by more than the shipped + iteration count. +- **No vault format bump.** The envelope lives *inside* the entry + bytes, identical over File and Os, so there is no vault-parser or + migration change. +- **Size cap.** The plaintext is capped at `MAX_PLAINTEXT_LEN` + (`MAX_SECRET_LEN − MAX_ENVELOPE_OVERHEAD`), uniformly for both + schemes, so the enveloped bytes always fit the backend's own + `MAX_SECRET_LEN` cap and the user-visible limit is stable regardless + of scheme. Oversize → `SecretTooLarge { found, max }` with + `max = MAX_PLAINTEXT_LEN` (re-exported as `secrets::MAX_PLAINTEXT_LEN`). +- **Unknown envelope version** → `UnsupportedEnvelopeVersion` — fail + closed **regardless of the password**: an envelope tagged for a + future layout can be neither safely unwrapped nor treated as + unprotected. +- **Unparseable bytes / unknown scheme tag / trailing garbage** → + `Corruption`. There is no magic-byte peek — every blob runs through + the bincode decoder, and anything that does not round-trip cleanly + with `consumed == blob.len()` fails closed. + +#### The strict, fail-closed read + +The defining risk of any opt-in "some objects are extra-protected" scheme +is **strip / downgrade**: an attacker who can WRITE the backend replaces a +protected blob with a fresh, internally-valid *unprotected* (scheme-0) blob +carrying a chosen seed/xpriv. There is nothing in that blob alone to prove +an envelope was *expected*, so inferring protection from the stored bytes +would silently return the attacker's secret — funds redirection, password +prompt bypassed. + +The fix: **the "expected-protected" bit lives in the CALLER's trusted +model, surfaced solely by whether a password is supplied to `get_secret` — +NEVER inferred from the blob.** The library does not guess and does not +persist the expectation. A supplied password *is* the assertion "this +object must be protected": + +| `password` arg | stored blob | result | +|---|---|---| +| `Some(pw)` | valid scheme-1 | the secret, or `WrongPassword` on tag fail | +| **`Some(pw)`** | **valid scheme-0 envelope** | **`ExpectedProtectedButUnsealed` — FAIL CLOSED** | +| `Some(pw)` | scheme-1 but truncated/corrupt | `Corruption` | +| `Some/None` | unknown envelope version | `UnsupportedEnvelopeVersion` | +| `Some/None` | unparseable / non-envelope bytes / trailing garbage | `Corruption` | +| `None` | valid scheme-1 | `NeedsPassword` (never ciphertext) | +| `None` | valid scheme-0 envelope | the secret | +| any | absent entry | `Ok(None)` (deletion = DoS, never injection) | + +The load-bearing row is **`Some(pw)` + scheme-0 envelope ⇒ +`ExpectedProtectedButUnsealed`**: with a password in hand, an +unprotected envelope can only mean a strip, so it is refused and **no +bytes are returned**. A consumer bug alone — over- or under-supplying +a password — fails closed in *every* direction. + +**Arm asymmetry.** On the file arm the stored bytes are themselves sealed +under the vault key, so producing a *readable* stripped blob at a slot +requires the vault key; a cold/backup-swap actor can only corrupt +(→ DoS), not inject-to-readable. On the OS-keychain arm the stored item is +the bare envelope with no second seal, so the strip defence there leans +entirely on the `Some(pw)` strict rule plus the consumer's metadata +integrity — this is where the residual bites hardest. + +**Documented residual (out of the library's reach).** If an attacker ALSO +rewrites the consumer's trusted DB so the consumer calls `get_secret(X, +None)` for a stripped object, the `(scheme-0, None)` quadrant returns the +attacker's bytes. The library only ever sees the blob and the caller's +`Some/None`; the "should be protected" fact lives entirely in the +consumer's metadata store. **Anti-downgrade strength therefore equals the +tamper-resistance of the consumer's protection-status record** — store it +as integrity-protected, security-critical state (it is one more field +alongside the addresses/policy the wallet DB must already protect). + +**Value rollback is NOT defended.** Restoring an *older valid* scheme-1 +envelope under the *current* password decrypts cleanly. The strict read +closes the strip/downgrade injection, not value rollback; if +backup-swap/restore-old is in scope, anchor a monotonic version in +integrity-protected consumer metadata. Do not mistake the strict read for +rollback protection. + +#### Add / change / remove an object password + +`reprotect(service, label, current, new)` does it in one same-slot +unwrap→rewrap→overwrite: read under the `current` expectation (so a strip +is caught before any rewrite), then write under `new` — `None`→`Some` adds, +`Some`→`Some` changes, `Some`→`None` removes. An absent object returns +`Err(SecretStoreError::NoEntry)` — `reprotect` is operational, so absence +means the caller's protection-status record disagrees with the backend and +must not be silently dropped. The rewrite is a same-slot overwrite — atomic on the file arm, +and on the OS arm inheriting the backend's single-item-replace contract — +so a crash between the read and the commit leaves the prior value intact +and readable under `current`. **After a successful call the consumer MUST +update its own protection-status record** (the protection expectation lives +there). There is **no password recovery** — losing an object password +bricks that object (an availability trade-off the UX must state plainly). + +#### Entropy policy is the consumer's + +The library enforces only **non-blank** at enrol (and a coarse +`MIN_PASSPHRASE_LEN` floor, `1` today = merely non-blank) for both the +vault passphrase and the Tier-2 object password. It ships **no** +password-strength estimator: real entropy policy (zxcvbn-style strength, +dictionary checks, UX feedback) is locale- and threat-specific and is the +**consumer's responsibility**. For a protected object the password's +entropy is the *whole* guarantee against an offline Argon2id attacker who +already holds the backend — choose it accordingly. + +#### Greenfield only — no legacy tolerance + +The envelope is the only on-disk Tier-2 format this build understands. +A decrypted entry that does not bincode-decode to a valid `Envelope` +under `WIRE_CONFIG` (including trailing-byte extension probes) surfaces +as `Corruption` on every read — there is no magic-byte peek and no +magic-less raw legacy path. The shipped wire layer is the source of +truth; older non-enveloped stored values are out of scope. + ### Internal SPI Below `SecretStore`, `EncryptedFileStore` and `default_credential_store` @@ -138,7 +348,20 @@ unwrapped copy is allocated. Each secret is capped at `MAX_SECRET_LEN` (64 KiB) at the write boundary — generously above any mnemonic/seed/xpriv — so a single oversized entry cannot inflate the shared document past the read-side - 128 MiB ceiling and brick every wallet on the next open. + 128 MiB ceiling and brick every wallet on the next open. (Through + `SecretStore::set_secret`/`set` the user-facing plaintext cap is the + slightly lower `MAX_PLAINTEXT_LEN`, leaving room for the envelope + overhead; see **Two-tier secret protection**.) + **Blank passphrase is rejected.** `open` (and `rekey`) refuse a blank + (empty / all-whitespace) passphrase with `SecretStoreError::BlankPassphrase` + — a blank passphrase derives a key from a public salt only, i.e. + obfuscation, not confidentiality. This is an **intended behavioural + break** for any caller that relied on `SecretString::empty()`. A + deliberate keyless vault uses the explicit + `EncryptedFileStore::open_unprotected(path)` / + `SecretStore::file_unprotected(path)` door instead (use it only where the + stored secrets carry their own Tier-2 object password, or as a staging + step before `rekey` to a real passphrase — the empty→real migration). - **OS keyring (`SecretStore::os` / `default_credential_store`)** — returns an `Arc` over the platform's default credential store. The backend on Linux/FreeBSD is @@ -184,7 +407,16 @@ automatic fallback between backends. is **lossless**: `WrongPassphrase`, `Corruption`, `AlreadyLocked`, `KdfFailure`, `VersionUnsupported`, `MalformedVault`, `InsecurePermissions`, `InsecureParentDir`, `SecretTooLarge`, `VaultTooLarge`, `Encrypt`, and -`InvalidLabel` are distinct typed variants. `VaultTooLarge` surfaces when +`InvalidLabel` are distinct typed variants. The Tier-2 layer adds five more: +`ExpectedProtectedButUnsealed` (the fail-closed strip refusal), +`NeedsPassword` (a protected object read with no password), `WrongPassword` +(object-password tag fail — distinct from the Tier-1 `WrongPassphrase`), +`BlankPassphrase` (a blank vault passphrase or object password), and +`UnsupportedEnvelopeVersion { found }` (a future envelope format, fail +closed regardless of the password). The four Tier-2 credential/protection +*state* variants project to a recoverable `NoStorageAccess` (boxed, +downcast-recoverable, like `WrongPassphrase`); `UnsupportedEnvelopeVersion` +joins the secret-free `BadStoreFormat` group. `VaultTooLarge` surfaces when the on-disk vault exceeds the read-side ceiling; `SecretTooLarge` rejects an oversized secret at the write boundary before it can inflate the shared vault; `InsecureParentDir` refuses a vault whose parent directory is @@ -198,15 +430,25 @@ discriminant — keyring variants carrying raw bytes (`BadEncoding`, `BadDataFormat`) are collapsed so their bytes never enter the error (CWE-209/CWE-532). +**`WrongPassword` on the OS arm is ambiguous.** A Tier-2 envelope AEAD tag +failure surfaces as `WrongPassword`, but on the OS-keyring arm the stored +item is the bare envelope with no second authentication layer, so a tag +failure can mean EITHER a wrong object password OR a corrupted keychain +item — one AEAD tag cannot disambiguate the two. Treat `WrongPassword` on +the OS arm as "wrong password or corrupted item." On the file arm it is +unambiguous: the vault's own per-entry tag has already authenticated the +stored bytes before the envelope is parsed. + The internal SPI projection `From for keyring_core::Error` keeps the `WrongPassphrase` / `AlreadyLocked` variants recoverable: they ride in `NoStorageAccess` with the typed `SecretStoreError` boxed as the source, so an SPI-only consumer can recover them via `err.source().and_then(|s| s.downcast_ref::())`. The `BadStoreFormat` group (`Corruption`, `KdfFailure`, -`VersionUnsupported`, `MalformedVault`, `InsecurePermissions`, -`InsecureParentDir`, `SecretTooLarge`, `VaultTooLarge`, `Decrypt`, -`Encrypt`, `OsKeyring`) has no box slot and carries only a secret-free +`VersionUnsupported`, `UnsupportedEnvelopeVersion`, `MalformedVault`, +`InsecurePermissions`, `InsecureParentDir`, `SecretTooLarge`, +`VaultTooLarge`, `Decrypt`, `Encrypt`, `OsKeyring`) has no box slot and +carries only a secret-free string; those remain fully typed on the `SecretStore` path (so e.g. `VaultTooLarge` / `SecretTooLarge` are not losslessly recoverable through the SPI downcast). diff --git a/packages/rs-platform-wallet-storage/src/secrets/error.rs b/packages/rs-platform-wallet-storage/src/secrets/error.rs index 94e7375e1b..f735183c7a 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/error.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/error.rs @@ -20,6 +20,41 @@ pub enum SecretStoreError { #[error("wrong passphrase")] WrongPassphrase, + /// Tier-2 strip/downgrade guard: the caller asserted — by supplying + /// an object password — that this object MUST be password-protected, + /// but the stored value is a well-formed UNPROTECTED envelope + /// (scheme-0), i.e. a strip/downgrade. **Fails closed:** the stored + /// bytes are NEVER returned (CWE-757/CWE-345). + #[error("expected a password-protected secret but the stored value is unprotected")] + ExpectedProtectedButUnsealed, + + /// Tier-2: a valid password-protected (scheme-1) envelope was read + /// with NO object password supplied. Never returns ciphertext. + #[error("secret is password-protected; a password is required")] + NeedsPassword, + + /// Tier-2: the object password failed the envelope's AEAD tag. Carries + /// **no** plaintext and no source (CWE-347). Distinct from + /// [`WrongPassphrase`] (the Tier-1 vault passphrase). On the + /// [`SecretStore::Os`] arm a tag failure may also indicate keychain + /// corruption rather than a wrong password — documented in + /// `SECRETS.md`; one AEAD tag cannot disambiguate the two. + /// + /// [`WrongPassphrase`]: SecretStoreError::WrongPassphrase + /// [`SecretStore::Os`]: crate::secrets::SecretStore::Os + #[error("wrong object password")] + WrongPassword, + + /// A vault passphrase (Tier-1 `open`/`rekey`) or an object password + /// (Tier-2 enrol) was blank — empty or all-whitespace — rejected via + /// [`SecretString::is_blank`]. CWE-521. + /// + /// [`SecretString::is_blank`]: crate::secrets::SecretString::is_blank + #[error( + "passphrase must not be blank; for a deliberately keyless file vault use open_unprotected" + )] + BlankPassphrase, + /// AEAD tag failure on a stored entry (or rekey re-encrypt) *after* /// the header verify-token passed: the entry ciphertext is corrupt or /// tampered, **not** a wrong passphrase. No plaintext (CWE-347). @@ -39,6 +74,20 @@ pub enum SecretStoreError { found: u32, }, + /// A Tier-2 secret envelope decoded with a `version` this build does + /// not understand. Fails closed REGARDLESS of the password argument + /// — an unparseable future format can be neither safely unwrapped + /// nor safely treated as unprotected, so it is refused both ways. + /// Mirrors [`VersionUnsupported`] for the vault format. + /// + /// [`VersionUnsupported`]: SecretStoreError::VersionUnsupported + #[error("unsupported secret envelope version {found}")] + UnsupportedEnvelopeVersion { + /// The envelope `version` byte read from the (unauthenticated) + /// header. + found: u8, + }, + /// The vault file was malformed (bad magic, truncated header, bad /// record framing) — no plaintext was produced. #[error("malformed vault file")] @@ -49,6 +98,17 @@ pub enum SecretStoreError { #[error("invalid label")] InvalidLabel, + /// No credential exists under `(service, label)` on either arm. Returned + /// by mutators that need an entry to operate on (e.g. [`reprotect`]) so + /// absence is a signal, not a silent no-op — caller's protection-status + /// record disagreeing with the backend must not be swallowed. Surfaced + /// by the file arm when `delete_bytes` reports `Ok(false)` and by the + /// OS arm when [`keyring_core::Error::NoEntry`] bubbles out. + /// + /// [`reprotect`]: crate::secrets::SecretStore::reprotect + #[error("no entry under (service, label)")] + NoEntry, + /// A pre-existing vault file had permissions looser than `0600`. /// Refuse rather than tighten-and-trust. #[error("vault file has insecure permissions")] @@ -186,8 +246,6 @@ impl From for IoError { /// [`SecretStore::Os`]: crate::secrets::SecretStore::Os #[derive(Debug, Clone, Copy, PartialEq, Eq)] pub enum OsKeyringErrorKind { - /// `keyring_core::Error::NoEntry`. - NoEntry, /// `keyring_core::Error::NoStorageAccess` (store locked / inaccessible). NoStorageAccess, /// `keyring_core::Error::NoDefaultStore` (no reachable backend). @@ -203,7 +261,6 @@ pub enum OsKeyringErrorKind { impl std::fmt::Display for OsKeyringErrorKind { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { let s = match self { - Self::NoEntry => "no entry", Self::NoStorageAccess => "storage inaccessible", Self::NoDefaultStore => "no default store", Self::BadStoreFormat => "bad store format", @@ -231,11 +288,18 @@ impl From for SecretStoreError { /// seam. Lossy by design — the lossless typed path is the /// [`SecretStore`](crate::secrets::SecretStore) API. /// -/// - [`WrongPassphrase`] / [`AlreadyLocked`] ride in +/// - [`WrongPassphrase`] / [`AlreadyLocked`] and the Tier-2 credential / +/// protection states ([`NeedsPassword`], [`WrongPassword`], +/// [`ExpectedProtectedButUnsealed`], [`BlankPassphrase`]) ride in /// [`KeyringError::NoStorageAccess`] with the typed error boxed as the /// source, recoverable via /// `err.source().and_then(|s| s.downcast_ref::())`. -/// - The format/crypto group collapses into +/// These are all "the caller must act on a credential/expectation to +/// proceed" states, so lossless recovery lets an SPI consumer react +/// precisely. +/// - The format/crypto group — including [`UnsupportedEnvelopeVersion`] +/// (a fail-closed forward-format incompatibility, mirroring +/// [`VersionUnsupported`]) — collapses into /// [`KeyringError::BadStoreFormat`] (a static secret-free string — that /// variant has no box slot). /// - [`InvalidLabel`] → `KeyringError::Invalid("user", _)`; @@ -243,16 +307,28 @@ impl From for SecretStoreError { /// /// [`WrongPassphrase`]: SecretStoreError::WrongPassphrase /// [`AlreadyLocked`]: SecretStoreError::AlreadyLocked +/// [`NeedsPassword`]: SecretStoreError::NeedsPassword +/// [`WrongPassword`]: SecretStoreError::WrongPassword +/// [`ExpectedProtectedButUnsealed`]: SecretStoreError::ExpectedProtectedButUnsealed +/// [`BlankPassphrase`]: SecretStoreError::BlankPassphrase +/// [`UnsupportedEnvelopeVersion`]: SecretStoreError::UnsupportedEnvelopeVersion +/// [`VersionUnsupported`]: SecretStoreError::VersionUnsupported /// [`InvalidLabel`]: SecretStoreError::InvalidLabel /// [`Io`]: SecretStoreError::Io impl From for KeyringError { fn from(e: SecretStoreError) -> Self { use SecretStoreError as E; match e { - E::WrongPassphrase | E::AlreadyLocked => KeyringError::NoStorageAccess(Box::new(e)), + E::WrongPassphrase + | E::AlreadyLocked + | E::NeedsPassword + | E::WrongPassword + | E::ExpectedProtectedButUnsealed + | E::BlankPassphrase => KeyringError::NoStorageAccess(Box::new(e)), E::Corruption | E::KdfFailure | E::VersionUnsupported { .. } + | E::UnsupportedEnvelopeVersion { .. } | E::MalformedVault | E::InsecurePermissions { .. } | E::InsecureParentDir { .. } @@ -264,6 +340,7 @@ impl From for KeyringError { E::InvalidLabel => { KeyringError::Invalid("user".to_string(), "label allowlist violation".to_string()) } + E::NoEntry => KeyringError::NoEntry, E::Io(io) => KeyringError::PlatformFailure(Box::new(io.source)), } } @@ -386,6 +463,102 @@ mod tests { assert!(!format!("{k}").contains("plaintext")); } + /// The five new variants exist, are constructable, render + /// distinct non-empty messages, and the Tier-2 `WrongPassword` is NOT + /// the Tier-1 `WrongPassphrase` (nor is the unseal error `Corruption`). + #[test] + fn new_variants_exist_and_are_distinct() { + use SecretStoreError as E; + assert_ne!(E::WrongPassword.to_string(), E::WrongPassphrase.to_string()); + assert_ne!( + E::ExpectedProtectedButUnsealed.to_string(), + E::Corruption.to_string() + ); + let msgs: std::collections::HashSet = [ + E::NeedsPassword.to_string(), + E::WrongPassword.to_string(), + E::BlankPassphrase.to_string(), + E::ExpectedProtectedButUnsealed.to_string(), + E::UnsupportedEnvelopeVersion { found: 2 }.to_string(), + ] + .into_iter() + .collect(); + assert_eq!(msgs.len(), 5, "all five messages must be distinct"); + } + + /// Display + Debug render static, secret-free text. The + /// version variant surfaces the (non-secret) version byte and nothing + /// more. + #[test] + fn new_variants_carry_no_secret_in_display() { + use SecretStoreError as E; + assert_eq!( + E::NeedsPassword.to_string(), + "secret is password-protected; a password is required" + ); + assert_eq!(E::WrongPassword.to_string(), "wrong object password"); + assert_eq!( + E::BlankPassphrase.to_string(), + "passphrase must not be blank; for a deliberately keyless file vault use open_unprotected" + ); + assert_eq!( + E::ExpectedProtectedButUnsealed.to_string(), + "expected a password-protected secret but the stored value is unprotected" + ); + assert_eq!( + E::UnsupportedEnvelopeVersion { found: 7 }.to_string(), + "unsupported secret envelope version 7" + ); + // Debug is non-empty and free of plaintext-ish tokens for all. + for e in [ + E::NeedsPassword, + E::WrongPassword, + E::BlankPassphrase, + E::ExpectedProtectedButUnsealed, + E::UnsupportedEnvelopeVersion { found: 7 }, + ] { + let rendered = format!("{e} {e:?}"); + assert!(!rendered.contains("plaintext")); + } + } + + /// The four Tier-2 credential / + /// protection states project to a recoverable `NoStorageAccess` with + /// the typed error losslessly downcast-able, leaking no secret. + #[test] + fn tier2_state_errors_project_to_recoverable_no_storage_access() { + for original in [ + SecretStoreError::NeedsPassword, + SecretStoreError::WrongPassword, + SecretStoreError::ExpectedProtectedButUnsealed, + SecretStoreError::BlankPassphrase, + ] { + let want = original.to_string(); + let k: KeyringError = original.into(); + assert!(!format!("{k}").contains("plaintext")); + match &k { + KeyringError::NoStorageAccess(src) => { + let recovered = src.downcast_ref::(); + assert!( + matches!(recovered, Some(e) if e.to_string() == want), + "expected recoverable {want}, got {recovered:?}" + ); + } + other => panic!("expected NoStorageAccess for {want}, got {other:?}"), + } + } + } + + /// `UnsupportedEnvelopeVersion` projects to the + /// secret-free `BadStoreFormat` group (forward-format incompat, + /// mirroring `VersionUnsupported`). + #[test] + fn unsupported_envelope_version_projects_to_bad_store_format() { + let k: KeyringError = SecretStoreError::UnsupportedEnvelopeVersion { found: 9 }.into(); + assert!(matches!(k, KeyringError::BadStoreFormat(_))); + assert!(!format!("{k}").contains("plaintext")); + } + #[test] fn os_keyring_projects_to_bad_store_format() { let k: KeyringError = SecretStoreError::OsKeyring { diff --git a/packages/rs-platform-wallet-storage/src/secrets/file/crypto.rs b/packages/rs-platform-wallet-storage/src/secrets/file/crypto.rs index 4bb0a350b6..bbfb6b2642 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/file/crypto.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/file/crypto.rs @@ -140,6 +140,33 @@ pub(crate) fn seal( Ok((nonce_bytes, ct)) } +/// Like [`seal`] but takes a caller-supplied `nonce` instead of pulling +/// from the CSPRNG. **Test-only** — golden-vector / size-budget tests +/// need byte-deterministic ciphertext output. Production code MUST use +/// [`seal`] so nonces stay unique (XChaCha20-Poly1305 nonce reuse leaks +/// the keystream). +#[cfg(test)] +pub(crate) fn seal_with_nonce( + key: &SecretBytes, + nonce_bytes: [u8; NONCE_LEN], + aad: &[u8], + plaintext: &[u8], +) -> Result<([u8; NONCE_LEN], Vec), SecretStoreError> { + let cipher = XChaCha20Poly1305::new_from_slice(key.expose_secret()) + .map_err(|_| SecretStoreError::Encrypt)?; + let nonce = XNonce::from_slice(&nonce_bytes); + let ct = cipher + .encrypt( + nonce, + chacha20poly1305::aead::Payload { + msg: plaintext, + aad, + }, + ) + .map_err(|_| SecretStoreError::Encrypt)?; + Ok((nonce_bytes, ct)) +} + /// Decrypt `ciphertext` under `key`/`nonce`/`aad`. On tag failure /// returns [`SecretStoreError::Decrypt`] and **no** plaintext — the /// combined (non-detached) API never materializes unverified bytes at diff --git a/packages/rs-platform-wallet-storage/src/secrets/file/format.rs b/packages/rs-platform-wallet-storage/src/secrets/file/format.rs index bb6d90769e..c137afb243 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/file/format.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/file/format.rs @@ -37,6 +37,9 @@ use serde::{Deserialize, Serialize}; use super::crypto::{KdfParams, NONCE_LEN, SALT_LEN}; use crate::secrets::error::SecretStoreError; +use crate::secrets::wire::aad::{EntryAad, VerifyAad}; +use crate::secrets::wire::config::{ENTRY_DOMAIN_V2, VERIFY_DOMAIN_V2, WIRE_CONFIG}; +use crate::secrets::wire::kdf::KdfParamsEncoded; pub(crate) const FORMAT_VERSION: u32 = 1; pub(crate) const KDF_ID_ARGON2ID: u8 = 1; @@ -46,17 +49,6 @@ pub(crate) const KDF_ID_ARGON2ID: u8 = 1; /// value itself is not secret. pub(crate) const VERIFY_CONSTANT: &[u8] = b"PWSVAULT-VERIFY-v1"; -/// AAD slot label for the verification token. The leading NUL keeps it -/// disjoint from every allowlisted entry label, so the token can never -/// alias a real entry's AAD. -pub(crate) const VERIFY_LABEL: &str = "\0verify"; - -/// Sentinel wallet id for the verify-token AAD slot. Keeps the AAD shape -/// identical to entry AAD without aliasing a real wallet: even a real -/// `[0u8; 32]` id yields a different AAD because [`VERIFY_LABEL`] differs -/// from any allowlisted label. -const VERIFY_WALLET_ID: [u8; 32] = [0u8; 32]; - /// Minimum AEAD ciphertext length: the Poly1305 tag is always present /// even for an empty plaintext, so any `verify_ct`/`ciphertext` shorter /// than this is structurally impossible and rejected. @@ -96,43 +88,43 @@ pub(crate) struct EntryBody { pub ciphertext: Vec, } -/// Canonical length-prefixed AAD binding ciphertext to its slot: -/// `format_version ‖ wallet_id ‖ label`. A blob moved to another slot, or -/// a rolled-back `format_version`, fails the tag. +/// Canonical AAD binding a vault entry's ciphertext to its slot: +/// `domain ‖ format_version ‖ wallet_id ‖ label`, bincode-encoded +/// against [`WIRE_CONFIG`]. A blob moved to another slot, or one +/// version-rolled-back, fails the tag. /// /// Determinism invariant: AAD is built solely from this typed triple, /// never from serialized JSON bytes or key order. `format_version` is -/// always the compiled-in [`FORMAT_VERSION`]; the JSON `version` field is -/// a dispatch gate only and is never routed into AAD. +/// always the compiled-in [`FORMAT_VERSION`]; the JSON `version` field +/// is a dispatch gate only and is never routed into AAD. pub(crate) fn aad(format_version: u32, wallet_id: &[u8; 32], label: &str) -> Vec { - let lb = label.as_bytes(); - let mut v = Vec::with_capacity(4 + 4 + 32 + 4 + lb.len()); - v.extend_from_slice(&format_version.to_le_bytes()); - v.extend_from_slice(&(wallet_id.len() as u32).to_le_bytes()); - v.extend_from_slice(wallet_id); - v.extend_from_slice(&(lb.len() as u32).to_le_bytes()); - v.extend_from_slice(lb); - v + bincode::encode_to_vec( + EntryAad { + domain: ENTRY_DOMAIN_V2, + format_version, + wallet_id: *wallet_id, + label, + }, + WIRE_CONFIG, + ) + .expect("EntryAad encode is infallible") } -/// AAD for the verify-token. Reuses the entry-AAD construction (sentinel -/// wallet id + NUL-prefixed [`VERIFY_LABEL`], disjoint from any real -/// slot), then binds the KDF header: `salt` plus a length-prefixed LE -/// encoding of (`id`, `m_kib`, `t`, `p`). -/// -/// Folding the header in makes the token authenticate the salt + KDF -/// params it was derived under, so header tamper / KDF downgrade is -/// detected fail-closed (it surfaces as `WrongPassphrase` because a -/// tampered header also yields a different derived key). +/// AAD for the verify-token: bincode-encoded `VerifyAad` binding the +/// vault-wide salt + KDF header against the verify domain tag. A +/// tampered header yields a different AAD AND a different derived key, +/// so the token surfaces `WrongPassphrase`. pub(crate) fn verify_aad(format_version: u32, salt: &[u8; SALT_LEN], kdf: &KdfParams) -> Vec { - let mut v = aad(format_version, &VERIFY_WALLET_ID, VERIFY_LABEL); - v.extend_from_slice(&(salt.len() as u32).to_le_bytes()); - v.extend_from_slice(salt); - v.extend_from_slice(&[kdf.id]); - v.extend_from_slice(&kdf.m_kib.to_le_bytes()); - v.extend_from_slice(&kdf.t.to_le_bytes()); - v.extend_from_slice(&kdf.p.to_le_bytes()); - v + bincode::encode_to_vec( + VerifyAad { + domain: VERIFY_DOMAIN_V2, + format_version, + salt: *salt, + kdf: KdfParamsEncoded::from(*kdf), + }, + WIRE_CONFIG, + ) + .expect("VerifyAad encode is infallible") } /// Serde helpers encoding `Vec` as lowercase hex. Hex is already a @@ -249,70 +241,6 @@ pub(crate) fn deserialize(buf: &[u8]) -> Result { mod tests { use super::*; - #[test] - fn aad_binds_slot() { - let w = [1u8; 32]; - assert_ne!(aad(1, &w, "a"), aad(1, &w, "b")); - assert_ne!(aad(1, &w, "a"), aad(2, &w, "a")); - assert_ne!(aad(1, &w, "a"), aad(1, &[2u8; 32], "a")); - // Length-prefix defeats `"a"+"bc"` vs `"ab"+"c"` ambiguity. - assert_ne!(aad(1, &w, "ab"), { - let mut v = aad(1, &w, "a"); - v.extend_from_slice(b"b"); - v - }); - } - - #[test] - fn verify_aad_disjoint_from_every_entry_aad() { - // VERIFY_LABEL starts with NUL (allowlist-forbidden), so no real - // entry's AAD can collide — even on the all-zero wallet id. - let salt = [7u8; SALT_LEN]; - let kdf = KdfParams::default_target(); - let v = verify_aad(FORMAT_VERSION, &salt, &kdf); - assert_ne!(v, aad(FORMAT_VERSION, &VERIFY_WALLET_ID, "seed")); - assert_ne!(v, aad(FORMAT_VERSION, &[1u8; 32], "seed")); - } - - #[test] - fn verify_aad_binds_salt_and_kdf_params() { - // The verify-token AAD authenticates the salt + KDF header, so a - // flipped salt or an in-bounds KDF-param shift yields a different - // AAD (and hence a token-tag failure at verify). - let salt = [7u8; SALT_LEN]; - let kdf = KdfParams::default_target(); - let base = verify_aad(FORMAT_VERSION, &salt, &kdf); - - let mut salt2 = salt; - salt2[0] ^= 0x01; - assert_ne!(base, verify_aad(FORMAT_VERSION, &salt2, &kdf)); - - assert_ne!( - base, - verify_aad( - FORMAT_VERSION, - &salt, - &KdfParams { - m_kib: kdf.m_kib / 2, - ..kdf - } - ) - ); - assert_ne!( - base, - verify_aad( - FORMAT_VERSION, - &salt, - &KdfParams { - t: kdf.t - 1, - ..kdf - } - ) - ); - // Identical inputs are deterministic. - assert_eq!(base, verify_aad(FORMAT_VERSION, &salt, &kdf)); - } - fn test_vault(wallets: BTreeMap>) -> Vault { Vault { version: FORMAT_VERSION, diff --git a/packages/rs-platform-wallet-storage/src/secrets/file/mod.rs b/packages/rs-platform-wallet-storage/src/secrets/file/mod.rs index 628b249f8e..8131f2643b 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/file/mod.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/file/mod.rs @@ -34,8 +34,13 @@ //! by zeroize + mlock. The derived AEAD key stays resident in a //! [`SecretBytes`] (to avoid per-op Argon2) and is zeroized on Drop. -mod crypto; -mod format; +// `pub(super)` (= visible within `crate::secrets`) so the Tier-2 +// `envelope` module — a sibling of `file` under `secrets` — can reuse the +// shared Argon2id/XChaCha primitives and `KDF_ID_ARGON2ID` without +// duplicating crypto. Items inside stay `pub(crate)`/`pub(in …file)`, so +// nothing escapes the secrets tree (see the crypto.rs module doc). +pub(super) mod crypto; +pub(super) mod format; use std::any::Any; use std::collections::HashMap; @@ -52,7 +57,7 @@ use format::{EntryBody, Vault}; use super::error::SecretStoreError; -use super::secret::{SecretBytes, SecretString}; +use super::secret::{SecretBytes, SecretString, MIN_PASSPHRASE_LEN}; use super::validate::{validated_label, WalletId}; /// Service-prefix for vault entries: the full `service` string is @@ -134,7 +139,34 @@ impl EncryptedFileStore { path: impl AsRef, passphrase: SecretString, ) -> Result { - let path = path.as_ref().to_path_buf(); + // Tier-1 baseline: reject a blank passphrase (empty / all-whitespace) + // BEFORE touching the filesystem. A blank passphrase derives a key + // from a public salt only — obfuscation, not confidentiality + // (obfuscation, not confidentiality). This is an INTENDED behavioural break for any caller + // that relied on `SecretString::empty()`; a deliberate keyless vault + // must use [`open_unprotected`](Self::open_unprotected). No vault + // file is created or altered for a blank passphrase. + reject_weak_passphrase(&passphrase)?; + Self::open_inner(path.as_ref(), passphrase) + } + + /// Open (or create) a **deliberately keyless** vault — the only door + /// that accepts no passphrase. The vault key is derived from an empty + /// passphrase under the public salt, so this is **obfuscation, not + /// confidentiality**: use it only where the stored secrets carry their + /// own Tier-2 object password, or as a staging step before + /// [`rekey`](Self::rekey) to a real passphrase. This is the explicit + /// keyless door, distinct from [`open`](Self::open) (which now rejects a + /// blank passphrase). + pub fn open_unprotected(path: impl AsRef) -> Result { + Self::open_inner(path.as_ref(), SecretString::empty()) + } + + /// Shared open/create core for [`open`](Self::open) and + /// [`open_unprotected`](Self::open_unprotected). Does NOT apply the + /// blank-passphrase guard — the public doors decide that. + fn open_inner(path: &Path, passphrase: SecretString) -> Result { + let path = path.to_path_buf(); // Materialize the parent so the lock-sidecar open and vault // create do not fail on a not-yet-existing dir. @@ -199,6 +231,11 @@ impl EncryptedFileStore { /// new passphrase + fresh salt, so paying ~hundreds of ms inside the /// critical section would needlessly stall unrelated put/get ops. pub fn rekey(&self, new_passphrase: SecretString) -> Result<(), SecretStoreError> { + // Reject a blank target passphrase: `rekey` always advances to a + // REAL passphrase (the empty→real migration uses this). The resident + // vault, key, and on-disk file are untouched on rejection. To make a + // vault keyless, use `open_unprotected` on a fresh path instead. + reject_weak_passphrase(&new_passphrase)?; let (new_vault, new_key) = build_fresh_vault(&new_passphrase)?; lock_inner(&self.inner).rekey(new_vault, new_key, new_passphrase) } @@ -466,6 +503,18 @@ fn lock_path_for(path: &Path) -> PathBuf { PathBuf::from(s) } +/// Reject a blank (empty / all-whitespace) or sub-floor passphrase → +/// [`SecretStoreError::BlankPassphrase`]. The floor is the coarse +/// [`MIN_PASSPHRASE_LEN`] (1 today = merely non-blank); the real entropy +/// policy is the consumer's (see `SECRETS.md`). A blank check alone closes +/// the length term keeps the floor wired for a future bump. +fn reject_weak_passphrase(passphrase: &SecretString) -> Result<(), SecretStoreError> { + if passphrase.is_blank() || passphrase.trimmed().len() < MIN_PASSPHRASE_LEN { + return Err(SecretStoreError::BlankPassphrase); + } + Ok(()) +} + /// Build a fresh entry-less vault (random salt, default Argon2 params, /// verify-token sealed under the derived key) plus that derived key, so /// the caller can seal entries without re-deriving. @@ -1426,6 +1475,174 @@ mod tests { ); } + /// The no-plaintext-at-rest guarantee also holds through the public + /// `SecretStore::set` path (which writes an unprotected envelope sealed + /// under the vault key), not just the raw SPI entry path. + #[test] + fn no_plaintext_in_vault_file_via_secret_store_set() { + use crate::secrets::SecretStore; + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + let store = SecretStore::file(&path, SecretString::new("pw-correct")).unwrap(); + store + .set( + &wid(1), + "seed", + &SecretBytes::from_slice(b"PLAINTEXTNEEDLE"), + ) + .unwrap(); + let raw = fs::read(&path).unwrap(); + assert!( + raw.windows(b"PLAINTEXTNEEDLE".len()) + .all(|w| w != b"PLAINTEXTNEEDLE"), + "plaintext leaked into vault file via SecretStore::set" + ); + } + + /// A blank passphrase is rejected at `open` → + /// `BlankPassphrase`; no vault file (or lock sidecar) is created. + #[test] + fn open_rejects_blank_passphrase() { + for blank in [ + SecretString::empty(), + SecretString::new(""), + SecretString::new(" "), + SecretString::new("\t\n"), + ] { + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + let err = EncryptedFileStore::open(&path, blank).unwrap_err(); + assert!( + matches!(err, SecretStoreError::BlankPassphrase), + "blank passphrase must be rejected, got {err:?}" + ); + assert!(!path.exists(), "no vault file for a blank passphrase"); + assert!( + !lock_path_for(&path).exists(), + "no lock sidecar for a blank passphrase" + ); + } + } + + /// A blank passphrase is rejected at `rekey`; the resident + /// vault, key, and on-disk file are UNCHANGED — the original passphrase + /// still reads every entry, live and after reopen. + #[test] + fn rekey_rejects_blank_passphrase_vault_unchanged() { + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + let s = store_at(&path); // real "pw-correct" + entry(&s, wid(1), "seed").set_secret(b"v1").unwrap(); + for blank in [SecretString::empty(), SecretString::new(" ")] { + let err = s.rekey(blank).unwrap_err(); + assert!( + matches!(err, SecretStoreError::BlankPassphrase), + "blank rekey must be rejected, got {err:?}" + ); + } + // Old passphrase still reads the entry, live… + assert_eq!(entry(&s, wid(1), "seed").get_secret().unwrap(), b"v1"); + // …and after a clean reopen under the original passphrase. + drop(s); + let s2 = store_at(&path); + assert_eq!(entry(&s2, wid(1), "seed").get_secret().unwrap(), b"v1"); + } + + /// `open_unprotected` permits a deliberate keyless vault that + /// round-trips; a real-passphrase `open` of that keyless vault then + /// fails with `WrongPassphrase` (it is keyless, not real-pass). + #[test] + fn open_unprotected_permits_keyless_vault() { + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + { + let s = EncryptedFileStore::open_unprotected(&path).unwrap(); + entry(&s, wid(1), "seed") + .set_secret(b"keyless-seed") + .unwrap(); + } + { + let s = EncryptedFileStore::open_unprotected(&path).unwrap(); + assert_eq!( + entry(&s, wid(1), "seed").get_secret().unwrap(), + b"keyless-seed" + ); + } + let err = EncryptedFileStore::open(&path, SecretString::new("real")).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassphrase), + "real-pass open of a keyless vault must fail, got {err:?}" + ); + } + + /// Empty→real passphrase migration via `rekey`. After rekey, + /// `open(real)` reads every entry; the keyless door no longer opens it; + /// no `.bak`/`.tmp` residue beside the vault. + #[test] + fn empty_to_real_rekey_migration() { + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + { + let s = EncryptedFileStore::open_unprotected(&path).unwrap(); + entry(&s, wid(1), "seed").set_secret(b"migrate-me").unwrap(); + s.rekey(SecretString::new("real-pass")).unwrap(); + // The live handle keeps working post-rekey. + assert_eq!( + entry(&s, wid(1), "seed").get_secret().unwrap(), + b"migrate-me" + ); + } + // Reopen under the real passphrase reads the entry. + { + let s = EncryptedFileStore::open(&path, SecretString::new("real-pass")).unwrap(); + assert_eq!( + entry(&s, wid(1), "seed").get_secret().unwrap(), + b"migrate-me" + ); + } + // The keyless door no longer opens it. + let err = EncryptedFileStore::open_unprotected(&path).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassphrase), + "keyless open after migration must fail, got {err:?}" + ); + // No .bak / .tmp residue (mirrors rekey_reencrypts_and_old_passphrase_fails). + for sibling in fs::read_dir(dir.path()).unwrap().flatten() { + let name = sibling.file_name(); + let name = name.to_string_lossy(); + assert!( + !name.ends_with(".bak") && !name.ends_with(".tmp"), + "unexpected residue: {name}" + ); + } + } + + /// Crash-safety: a disk-write failure mid-rekey leaves the + /// pre-rekey keyless vault intact and readable via `open_unprotected` + /// (mirrors rekey_does_not_corrupt_on_disk_temp_failure). + #[cfg(unix)] + #[test] + fn empty_to_real_rekey_crash_safe_stays_keyless() { + use std::os::unix::fs::PermissionsExt; + let dir = tempfile::tempdir().unwrap(); + let path = vault_path(dir.path()); + let s = EncryptedFileStore::open_unprotected(&path).unwrap(); + entry(&s, wid(1), "seed").set_secret(b"keyless").unwrap(); + + // Read-only parent → the rekey atomic temp-write fails. + fs::set_permissions(dir.path(), fs::Permissions::from_mode(0o500)).unwrap(); + let err = s.rekey(SecretString::new("real-pass")).unwrap_err(); + assert!(matches!(err, SecretStoreError::Io(_)), "got {err:?}"); + fs::set_permissions(dir.path(), fs::Permissions::from_mode(0o700)).unwrap(); + + // The live handle still serves the pre-rekey keyless vault… + assert_eq!(entry(&s, wid(1), "seed").get_secret().unwrap(), b"keyless"); + // …and on disk it is still the keyless vault. + drop(s); + let s2 = EncryptedFileStore::open_unprotected(&path).unwrap(); + assert_eq!(entry(&s2, wid(1), "seed").get_secret().unwrap(), b"keyless"); + } + #[test] fn build_rejects_malformed_service() { let dir = tempfile::tempdir().unwrap(); diff --git a/packages/rs-platform-wallet-storage/src/secrets/mod.rs b/packages/rs-platform-wallet-storage/src/secrets/mod.rs index d69754429f..6989a6e69e 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/mod.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/mod.rs @@ -21,6 +21,13 @@ //! This `src/secrets/` tree is the sole secret-bearing module: //! `tests/secrets_scan.rs` exempts it, so it owns its own review //! discipline via `tests/secrets_guard.rs`. +//! +//! Cryptographic wire format lives in [`mod@wire`]: the Tier-2 +//! envelope (`wire::envelope`) and the three AAD constructions +//! (`wire::aad`) are bincode-encoded against a single `WIRE_CONFIG`, so +//! a future bincode-config drift is caught by the golden-vector tests +//! in `wire::envelope::tests` rather than silently corrupting every +//! stored blob. mod error; mod file; @@ -28,6 +35,7 @@ mod keyring; mod secret; mod store; mod validate; +mod wire; pub use error::{IoError, OsKeyringErrorKind, SecretStoreError}; pub use file::{ @@ -35,6 +43,7 @@ pub use file::{ SERVICE_PREFIX, }; pub use keyring::default_credential_store; -pub use secret::{SecretBytes, SecretString}; +pub use secret::{SecretBytes, SecretString, MIN_PASSPHRASE_LEN}; pub use store::SecretStore; pub use validate::WalletId; +pub use wire::envelope::MAX_PLAINTEXT_LEN; diff --git a/packages/rs-platform-wallet-storage/src/secrets/secret.rs b/packages/rs-platform-wallet-storage/src/secrets/secret.rs index 3dd5c53746..87faf066ef 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/secret.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/secret.rs @@ -15,6 +15,18 @@ use zeroize::{Zeroize, Zeroizing}; /// buffer behind — virtually impossible for any human-entered secret. const DEFAULT_CAPACITY: usize = 4096; +/// Minimal post-trim length floor for a vault passphrase or a Tier-2 +/// object password, in bytes. A **coarse** guard only: `1` means "merely +/// non-blank" (the same outcome [`SecretString::is_blank`] enforces). +/// +/// The library deliberately ships **no** password-strength estimator. The +/// real entropy policy — zxcvbn-style strength, dictionary checks, UX +/// feedback — is locale- and threat-specific and therefore the +/// **consumer's** responsibility (documented in `SECRETS.md`). Baking a +/// fixed estimator into a storage crate would be both too weak for some +/// callers and too rigid for others. +pub const MIN_PASSPHRASE_LEN: usize = 1; + /// Zeroize-on-drop wrapper for secret UTF-8 strings (BIP-39 mnemonic, /// `EncryptedFileStore` passphrase). /// @@ -47,6 +59,10 @@ impl SecretString { let cap = source.len().max(DEFAULT_CAPACITY); let mut buf = String::with_capacity(cap); buf.push_str(&source); + // Do not remove: wipes the moved-in plaintext source before it drops. + // A direct freed-buffer scan would require `unsafe`, which this crate + // forbids; the test `secret_string_new_zeroizes_string_source` instead + // pins the `String::zeroize` primitive and this call site. source.zeroize(); let lock = region::lock(buf.as_ptr(), buf.capacity()) .map_err(|e| { @@ -87,6 +103,18 @@ impl SecretString { pub fn trimmed(&self) -> Self { Self::new(self.inner.trim().to_string()) } + + /// Whether the secret is empty or all Unicode-whitespace. + /// + /// Returns only blank-ness — never a borrowed view of the plaintext — + /// and uses [`str::trim`] (the Unicode `White_Space` property), so a + /// NBSP (`U+00A0`) trims to blank but a ZWSP (`U+200B`, not + /// `White_Space`) does not. This is the enforcement primitive behind + /// the Tier-1 blank-passphrase guard and the Tier-2 blank-object- + /// password reject. Always available — **not** feature-gated. + pub fn is_blank(&self) -> bool { + self.inner.trim().is_empty() + } } impl Default for SecretString { @@ -143,6 +171,86 @@ impl From<&str> for SecretString { } } +/// Deserialize a UTF-8 secret (a vault passphrase or a Tier-2 object +/// password arriving via config), routing the owned `String` through +/// [`SecretString::new`] — which zeroizes its source — so no +/// intermediate plaintext buffer **we own** lingers (CWE-316). +/// +/// Gated behind the dedicated, default-off `secret-serde` feature, NOT the +/// crate's internal `serde` dep (which `secrets` already pulls): the gate +/// is on the IMPL, so the impl is absent unless explicitly opted in, even +/// though `serde` itself is compiled. There is deliberately **no** +/// `Serialize` companion (a secret is read-from-config, never written +/// back / round-tripped / logged), so this type cannot leak out through +/// serde under any feature combination. +/// +/// **Residual (documented, not closeable here):** the deserializer's own +/// input buffer holds the cleartext before this visitor runs and is +/// outside `SecretString`'s ownership, so it cannot be wiped here — feed +/// secrets from a zeroizing source. Mirrors the Argon2 `Block` residual +/// noted at `crypto::derive_key`. +#[cfg(feature = "secret-serde")] +impl<'de> serde::Deserialize<'de> for SecretString { + fn deserialize(deserializer: D) -> Result + where + D: serde::Deserializer<'de>, + { + struct SecretStringVisitor; + + impl<'v> serde::de::Visitor<'v> for SecretStringVisitor { + type Value = SecretString; + + fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("a secret string") + } + + fn visit_str(self, v: &str) -> Result + where + E: serde::de::Error, + { + // Take ownership of the borrowed bytes, then hand the owned + // `String` to the zeroizing constructor below. + self.visit_string(v.to_owned()) + } + + fn visit_string(self, v: String) -> Result + where + E: serde::de::Error, + { + // `SecretString::new` zeroizes the moved-in `String`. + Ok(SecretString::new(v)) + } + } + + deserializer.deserialize_string(SecretStringVisitor) + } +} + +/// Render the JSON schema as a plain `string` carrying **no** length or +/// value policy: no `minLength`/`maxLength`/`pattern`/`format` (would leak +/// a length policy) and no `example`/`default` (would embed a value) +/// A short, value-free `description` marks sensitivity. +/// +/// Gated behind the default-off `secret-schemars` feature (which implies +/// `secret-serde`). Pulls in no `Serialize`/`Display` path. +#[cfg(feature = "secret-schemars")] +impl schemars::JsonSchema for SecretString { + fn schema_name() -> std::borrow::Cow<'static, str> { + std::borrow::Cow::Borrowed("SecretString") + } + + fn schema_id() -> std::borrow::Cow<'static, str> { + std::borrow::Cow::Borrowed("platform_wallet_storage::secrets::SecretString") + } + + fn json_schema(_generator: &mut schemars::SchemaGenerator) -> schemars::Schema { + schemars::json_schema!({ + "type": "string", + "description": "A secret string. Write-only: never serialized, never echoed." + }) + } +} + /// Zeroize-on-drop wrapper for secret **bytes**: BIP-32 seed /// (`[u8; 64]`), xpriv, Argon2 output, AEAD key, decrypted plaintext. /// @@ -265,6 +373,21 @@ mod tests { assert_eq!(s.trimmed().expose_secret(), "abandon ability"); } + /// Two sound checks (a direct freed-buffer scan would be use-after-free, + /// and this crate forbids `unsafe`): (1) `String::zeroize` empties a + /// buffer — the primitive `new` relies on; (2) `new` copies the content + /// into the wrapper faithfully. That `new` actually calls + /// `source.zeroize()` on its moved-in source is pinned by the + /// do-not-remove comment at that call site, not asserted here. + #[test] + fn secret_string_new_zeroizes_string_source() { + let mut source = String::from("super secret seed material"); + source.zeroize(); + assert!(source.is_empty(), "String::zeroize must empty the source"); + let s = SecretString::new(String::from("super secret seed material")); + assert_eq!(s.expose_secret(), "super secret seed material"); + } + #[test] fn secret_string_ct_eq_is_value_based() { // Equality goes through `ConstantTimeEq` only. @@ -282,6 +405,112 @@ mod tests { assert_eq!(SecretString::default().len(), 0); } + /// `is_blank()` truth table. The boundary deliberately + /// exercises Unicode whitespace — `str::trim` uses the `White_Space` + /// property, so NBSP (`U+00A0`) trims to blank but ZWSP (`U+200B`, + /// not `White_Space`) does not. + #[test] + fn is_blank_truth_table() { + // Blank inputs. + assert!(SecretString::empty().is_blank()); + assert!(SecretString::new("").is_blank()); + assert!(SecretString::new(" ").is_blank()); + assert!(SecretString::new("\t\r\n ").is_blank()); + assert!( + SecretString::new("\u{00A0}").is_blank(), + "NBSP is White_Space" + ); + // Non-blank inputs. + assert!(!SecretString::new("pw").is_blank()); + assert!(!SecretString::new(" pw ").is_blank()); + assert!( + !SecretString::new("\u{200B}").is_blank(), + "ZWSP is NOT White_Space" + ); + } + + /// `is_blank` returns a `bool` and exposes no borrowed + /// plaintext, callable with only `secrets` (no serde/schemars). + #[test] + fn is_blank_signature_returns_bool_no_borrow() { + let f: fn(&SecretString) -> bool = SecretString::is_blank; + assert!(f(&SecretString::new(""))); + assert!(!f(&SecretString::new("x"))); + } + + /// `SecretString` must never implement + /// `Serialize` or `Display`, even with serde compiled in. This is a + /// compile-time `!impl` assertion — adding either impl breaks the + /// build. `serde::Serialize` is nameable here because `secrets` always + /// pulls the `serde` dep. + #[test] + fn secret_string_has_no_serialize_no_display() { + static_assertions::assert_not_impl_any!(SecretString: serde::Serialize, std::fmt::Display); + } + + /// Regression: the `serde` DEP is on under + /// `secrets`, yet the `Deserialize` IMPL stays ABSENT because it is + /// gated on the dedicated `secret-serde` feature — proving the + /// default-off gate is satisfiable even while serde is compiled. + #[cfg(not(feature = "secret-serde"))] + #[test] + fn deserialize_absent_without_secret_serde_even_though_serde_dep_on() { + static_assertions::assert_not_impl_any!( + SecretString: serde::de::DeserializeOwned + ); + } + + /// With `secret-serde` on, the `Deserialize` impl is + /// present (and `Serialize` is still absent — see the always-on test). + #[cfg(feature = "secret-serde")] + #[test] + fn deserialize_present_with_secret_serde() { + static_assertions::assert_impl_all!(SecretString: serde::de::DeserializeOwned); + static_assertions::assert_not_impl_any!(SecretString: serde::Serialize); + } + + /// `Deserialize` round-trips the value through the + /// zeroizing constructor; the result `ct_eq`s a directly-built secret + /// and has the right length. + #[cfg(feature = "secret-serde")] + #[test] + fn deserialize_routes_value_through_zeroizing_constructor() { + let s: SecretString = serde_json::from_str("\"correct horse battery staple\"").unwrap(); + assert!(bool::from( + s.ct_eq(&SecretString::new("correct horse battery staple")) + )); + assert_eq!(s.len(), 28); + } + + /// `JsonSchema` renders a plain `string` and leaks no + /// length/value policy — no `minLength`/`maxLength`/`pattern`/`format`, + /// no `example`/`default`/`enum`. + #[cfg(feature = "secret-schemars")] + #[test] + fn json_schema_is_plain_string_no_policy_leak() { + let schema = schemars::schema_for!(SecretString); + let v = serde_json::to_value(&schema).unwrap(); + assert_eq!(v["type"], serde_json::json!("string")); + for forbidden in [ + "minLength", + "maxLength", + "pattern", + "format", + "example", + "default", + "enum", + ] { + assert!( + v.get(forbidden).is_none(), + "schema leaked `{forbidden}`: {v}" + ); + } + // Any description present must carry no example/secret value. + if let Some(desc) = v.get("description").and_then(|d| d.as_str()) { + assert!(!desc.contains("horse")); + } + } + #[test] fn secret_bytes_debug_redacted() { let b = SecretBytes::from_slice(&[1, 2, 3, 4, 5]); diff --git a/packages/rs-platform-wallet-storage/src/secrets/store.rs b/packages/rs-platform-wallet-storage/src/secrets/store.rs index 82157f4338..7f0147f165 100644 --- a/packages/rs-platform-wallet-storage/src/secrets/store.rs +++ b/packages/rs-platform-wallet-storage/src/secrets/store.rs @@ -13,16 +13,19 @@ use keyring_core::api::CredentialStoreApi; use keyring_core::{Entry, Error as KeyringError}; use super::error::{OsKeyringErrorKind, SecretStoreError}; -use super::secret::SecretBytes; +use super::secret::{SecretBytes, SecretString}; use super::validate::WalletId; -use super::{default_credential_store, EncryptedFileStore, SERVICE_PREFIX}; +use super::wire::envelope; +use super::{default_credential_store, EncryptedFileStore, MAX_SECRET_LEN, SERVICE_PREFIX}; /// A passphrase-or-OS-keyring backed store for wallet secret material. /// -/// The only public read path is [`get`](SecretStore::get), which yields a -/// zeroizing [`SecretBytes`] — a raw `Vec` never crosses this -/// boundary. Backend selection is an explicit operator decision; there is -/// no silent fallback between the two arms. +/// Every read path ([`get`](SecretStore::get), +/// [`get_secret`](SecretStore::get_secret), and the read inside +/// [`reprotect`](SecretStore::reprotect)) yields a zeroizing +/// [`SecretBytes`] — a raw `Vec` never crosses this boundary. Backend +/// selection is an explicit operator decision; there is no silent fallback +/// between the two arms. pub enum SecretStore { /// Self-contained Argon2id + XChaCha20-Poly1305 vault file. /// Recommended on headless / server hosts. @@ -43,40 +46,118 @@ impl SecretStore { Ok(Self::File(EncryptedFileStore::open(path, passphrase)?)) } + /// Open (or create) a **deliberately keyless** file-backed vault — the + /// only door that takes no passphrase. Obfuscation, not confidentiality + /// (the key derives from an empty passphrase under the public salt): use + /// it where the stored secrets carry their own Tier-2 object password, + /// or as a staging step before [`EncryptedFileStore::rekey`] to a real + /// passphrase. [`file`](SecretStore::file) rejects a blank passphrase; + /// this is the explicit keyless alternative. + pub fn file_unprotected(path: impl AsRef) -> Result { + Ok(Self::File(EncryptedFileStore::open_unprotected(path)?)) + } + /// Open the platform's default OS keyring, failing closed when none /// is reachable (headless / no Secret Service). pub fn os() -> Result { Ok(Self::Os(default_credential_store().map_err(map_spi)?)) } - /// Store `secret` under `(service, label)`, overwriting any prior - /// value. Takes `&SecretBytes` so the caller cannot pass an unwrapped - /// buffer; the wrapped bytes are exposed to the SPI only at the last - /// moment. + /// Store `secret` under `(service, label)` UNPROTECTED (Tier-2 + /// scheme-0), overwriting any prior value — a `set_secret(.., None)` + /// wrapper kept for non-breaking back-compat. Takes `&SecretBytes` so + /// the caller cannot pass an unwrapped buffer. pub fn set( &self, service: &WalletId, label: &str, secret: &SecretBytes, + ) -> Result<(), SecretStoreError> { + self.set_secret(service, label, secret, None) + } + + /// Store `secret` under `(service, label)`, overwriting any prior value. + /// + /// `password` selects the protection: `None` writes an unprotected + /// envelope; `Some(pw)` seals the bytes under the object password `pw` + /// (Argon2id + XChaCha20-Poly1305) **before** they reach the backend, so + /// a protected object stays confidential even under a full backend + /// compromise. A blank `pw` is rejected + /// ([`BlankPassphrase`](SecretStoreError::BlankPassphrase)). + /// + /// **No recovery (availability):** if a protected object's password is + /// lost, the object is permanently unrecoverable — there is no reset + /// path. The UX must state this plainly. + /// + /// **Entropy is the caller's:** a protected object's confidentiality + /// rests entirely on the password's entropy against an offline Argon2id + /// attacker who already holds the backend. This crate enforces only + /// non-blank; strength estimation / policy is the caller's job. + /// + /// The write is a same-slot overwrite that leaves the prior value intact + /// on a crash: on the `File` arm via the vault's atomic replace; on the + /// `Os` arm via the backend's single-item-replace contract. + /// Add/change/remove flows go through [`reprotect`](SecretStore::reprotect). + pub fn set_secret( + &self, + service: &WalletId, + label: &str, + secret: &SecretBytes, + password: Option<&SecretString>, + ) -> Result<(), SecretStoreError> { + // Wrap above the backend: the backend only ever stores the opaque + // envelope (ciphertext for a protected object). + let blob = envelope::wrap(service, label, password, secret.expose_secret())?; + self.put_raw(service, label, &blob) + } + + /// Store the already-enveloped opaque `blob` under `(service, label)`. + /// The shared write seam under [`set`] and [`set_secret`]. + /// + /// [`set`]: SecretStore::set + fn put_raw( + &self, + service: &WalletId, + label: &str, + blob: &SecretBytes, ) -> Result<(), SecretStoreError> { match self { // Inherent typed path — no lossy SPI seam, no bare buffer. - Self::File(s) => s.put_bytes(service, label, secret), + Self::File(s) => s.put_bytes(service, label, blob), Self::Os(store) => { let entry = build_os(store, service, label)?; - entry.set_secret(secret.expose_secret()).map_err(map_spi) + entry.set_secret(blob.expose_secret()).map_err(map_spi) } } } - /// Retrieve the secret stored under `(service, label)`, or `Ok(None)` - /// if absent. The plaintext is wrapped into [`SecretBytes`] at the - /// seam with no named `Vec` intermediate, so the bare-buffer window is - /// zero statements. + /// Retrieve the UNPROTECTED secret stored under `(service, label)`, or + /// `Ok(None)` if absent — a `get_secret(.., None)` wrapper kept for + /// non-breaking back-compat. A scheme-1 (password-protected) object read + /// through this path returns + /// [`NeedsPassword`](SecretStoreError::NeedsPassword); use + /// [`get_secret`](SecretStore::get_secret) with the object password. pub fn get( &self, service: &WalletId, label: &str, + ) -> Result, SecretStoreError> { + self.get_secret(service, label, None) + } + + /// Read the opaque bytes stored under `(service, label)`, or + /// `Ok(None)` if absent — the raw backend value, always a Tier-2 + /// envelope (writes go through + /// [`set_secret`](SecretStore::set_secret)). The typed-vs-SPI + /// distinction is preserved exactly as the pre-Tier-2 path did. This + /// is the shared seam under [`get`] and [`get_secret`]; it does NOT + /// interpret the envelope. + /// + /// [`get`]: SecretStore::get + fn get_raw( + &self, + service: &WalletId, + label: &str, ) -> Result, SecretStoreError> { match self { // Inherent typed path: keeps WrongPassphrase vs Corruption @@ -85,7 +166,23 @@ impl SecretStore { Self::Os(store) => { let entry = build_os(store, service, label)?; match entry.get_secret() { - Ok(v) => Ok(Some(SecretBytes::new(v))), + Ok(v) => { + // Defense-in-depth: reject an oversized backend blob + // before it reaches the envelope parse/derive path. + // The File arm's stored bytes are already capped at + // MAX_SECRET_LEN by `put_bytes`; the Os backend has no + // such ceiling, so cap here. A legitimate envelope + // never exceeds MAX_SECRET_LEN; the overhead is + // headroom. + let cap = MAX_SECRET_LEN + envelope::MAX_ENVELOPE_OVERHEAD; + if v.len() > cap { + return Err(SecretStoreError::SecretTooLarge { + found: v.len(), + max: cap, + }); + } + Ok(Some(SecretBytes::new(v))) + } Err(KeyringError::NoEntry) => Ok(None), Err(e) => Err(map_spi(e)), } @@ -93,18 +190,95 @@ impl SecretStore { } } - /// Delete the secret stored under `(service, label)`. Absent entries - /// are a no-op (`Ok(())`), so deletion is idempotent. - pub fn delete(&self, service: &WalletId, label: &str) -> Result<(), SecretStoreError> { + /// Retrieve the secret under `(service, label)` applying the strict, + /// fail-closed read, or `Ok(None)` if absent. + /// + /// `password` IS the caller's protection assertion — supply `Some(pw)` + /// for an object the caller's trusted model says is protected, `None` + /// otherwise. The expectation lives ONLY here, never in the stored + /// blob (see [`envelope::unwrap`]): + /// + /// - `Some(pw)` + a protected blob → the secret (or + /// [`WrongPassword`](SecretStoreError::WrongPassword) on tag fail); + /// - `Some(pw)` + an unprotected blob → + /// [`ExpectedProtectedButUnsealed`](SecretStoreError::ExpectedProtectedButUnsealed) + /// — a strip/downgrade, refused, no bytes returned; + /// - `None` + a protected blob → + /// [`NeedsPassword`](SecretStoreError::NeedsPassword) (never ciphertext); + /// - `None` + an unprotected blob → the secret. + /// + /// **Documented residual:** an attacker who ALSO rewrites the + /// consumer's trusted DB so the caller passes `None` for a stripped + /// object can still downgrade — out of this library's reach by + /// construction (the protection expectation is the caller's; see + /// `SECRETS.md`). The expectation is NEVER persisted by the library. + pub fn get_secret( + &self, + service: &WalletId, + label: &str, + password: Option<&SecretString>, + ) -> Result, SecretStoreError> { + // Absence is availability-only (deletion = DoS, never injection): + // a missing entry is Ok(None) under either password argument. + let Some(stored) = self.get_raw(service, label)? else { + return Ok(None); + }; + envelope::unwrap(service, label, password, stored.expose_secret()).map(Some) + } + + /// Add / change / remove an object password in one same-slot + /// unwrap→rewrap→overwrite — the canonical re-protection flow. + /// + /// Reads the object under the `current` expectation (so a strip is + /// caught fail-closed before any rewrap), then re-writes it under + /// `new`: + /// - **add:** `current = None`, `new = Some(pw)`; + /// - **change:** `current = Some(old)`, `new = Some(pw_new)`; + /// - **remove:** `current = Some(old)`, `new = None`. + /// + /// An absent object returns [`Err(NoEntry)`][SecretStoreError::NoEntry] — + /// `reprotect` is operational; absence means the caller's protection-status + /// record disagrees with the backend, which is a signal not to be silently + /// dropped. The rewrite is the same-slot overwrite of [`set_secret`], so a + /// crash between the read and the commit leaves the prior value intact + /// and readable under `current`. After a successful call the consumer MUST + /// update its own trusted protection-status record (the protection + /// expectation lives there). + /// + /// **No recovery:** changing or removing requires the `current` + /// password; if it is lost the object cannot be re-protected or read, + /// and is permanently unrecoverable (availability trade-off). + /// + /// **Entropy is the caller's:** the `new` password's entropy is the + /// whole confidentiality guarantee for the re-protected object; this + /// crate enforces only non-blank, not strength. + pub fn reprotect( + &self, + service: &WalletId, + label: &str, + current: Option<&SecretString>, + new: Option<&SecretString>, + ) -> Result<(), SecretStoreError> { + let Some(secret) = self.get_secret(service, label, current)? else { + return Err(SecretStoreError::NoEntry); + }; + self.set_secret(service, label, &secret, new) + } + + /// Delete the secret stored under `(service, label)`. + /// + /// Returns `Ok(true)` if a credential was removed, `Ok(false)` if no + /// credential existed under `(service, label)`. Idempotent for callers + /// that don't care — `.delete(...)?;` still discards the bool; + /// race-detecting callers can `match delete()?`. + pub fn delete(&self, service: &WalletId, label: &str) -> Result { match self { - Self::File(s) => { - s.delete_bytes(service, label)?; - Ok(()) - } + Self::File(s) => s.delete_bytes(service, label), Self::Os(store) => { let entry = build_os(store, service, label)?; match entry.delete_credential() { - Ok(()) | Err(KeyringError::NoEntry) => Ok(()), + Ok(()) => Ok(true), + Err(KeyringError::NoEntry) => Ok(false), Err(e) => Err(map_spi(e)), } } @@ -152,9 +326,7 @@ impl std::fmt::Debug for SecretStore { /// The [`File`](SecretStore::File) arm never reaches this projection. fn map_spi(e: KeyringError) -> SecretStoreError { match e { - KeyringError::NoEntry => SecretStoreError::OsKeyring { - kind: OsKeyringErrorKind::NoEntry, - }, + KeyringError::NoEntry => SecretStoreError::NoEntry, KeyringError::NoStorageAccess(_) => SecretStoreError::OsKeyring { kind: OsKeyringErrorKind::NoStorageAccess, }, @@ -219,17 +391,31 @@ mod tests { } #[test] - fn delete_is_idempotent() { + fn delete_returns_false_on_absent_true_on_present() { let dir = tempfile::tempdir().unwrap(); let s = file_store(dir.path()); - // Absent → Ok, no error. - s.delete(&wid(1), "seed").unwrap(); + // Absent → Ok(false), no error. + assert!(!s.delete(&wid(1), "seed").unwrap()); s.set(&wid(1), "seed", &SecretBytes::from_slice(b"x")) .unwrap(); - s.delete(&wid(1), "seed").unwrap(); + // Present → Ok(true). + assert!(s.delete(&wid(1), "seed").unwrap()); assert!(s.get(&wid(1), "seed").unwrap().is_none()); - // Second delete on the now-absent entry is still Ok. - s.delete(&wid(1), "seed").unwrap(); + // Second delete on the now-absent entry is Ok(false). + assert!(!s.delete(&wid(1), "seed").unwrap()); + } + + #[test] + fn reprotect_absent_returns_no_entry() { + let dir = tempfile::tempdir().unwrap(); + let s = file_store(dir.path()); + let err = s + .reprotect(&wid(1), "seed", None, Some(&SecretString::new("pw"))) + .unwrap_err(); + assert!( + matches!(err, SecretStoreError::NoEntry), + "expected NoEntry on absent reprotect, got {err:?}" + ); } #[test] @@ -357,4 +543,675 @@ mod tests { ); } } + + // ===== Tier-2 strict fail-closed read ===== + // + // Parameterised over BOTH arms. The "attacker who can write the + // backend" is modelled per arm by `Backend::place_raw`: on File it + // re-seals the chosen blob under the resident vault key via `put_bytes` + // (a cold/backup-swap actor could only corrupt → DoS, so the strip + // requires the vault key — the File-arm asymmetry); on Os it overwrites + // the keychain item directly (the bare envelope, no second AEAD — where + // the strip residual bites hardest). The writable Os fixture is the + // upstream `keyring_core::mock::Store` (a raw SPI `set_secret` bypasses + // the envelope), so no bespoke mock is needed. + + use keyring_core::mock; + + use crate::secrets::file::crypto::{KdfParams, ARGON2_MIN_M_KIB, ARGON2_MIN_T, ARGON2_P}; + use crate::secrets::file::format::KDF_ID_ARGON2ID; + + /// Argon2id floor params — fast enough for these tests. + fn floor() -> KdfParams { + KdfParams { + id: KDF_ID_ARGON2ID, + m_kib: ARGON2_MIN_M_KIB, + t: ARGON2_MIN_T, + p: ARGON2_P, + } + } + + fn protected(w: &WalletId, label: &str, pw: &str, secret: &[u8]) -> Vec { + envelope::wrap_with_params(w, label, Some(&SecretString::new(pw)), secret, floor()) + .unwrap() + .expose_secret() + .to_vec() + } + + fn unprotected(w: &WalletId, label: &str, secret: &[u8]) -> Vec { + envelope::wrap(w, label, None, secret) + .unwrap() + .expose_secret() + .to_vec() + } + + /// A backend under test plus the raw-write hook that plays the + /// backend-write attacker. + struct Backend { + store: SecretStore, + _dir: Option, + mock: Option>, + name: &'static str, + } + + impl Backend { + /// Write `blob` to `(w, label)` as opaque backend bytes (the + /// attacker's primitive / the protected-enrol setup). On Os this is + /// a raw SPI `set_secret` on the shared mock store, bypassing the + /// `SecretStore` envelope layer exactly as a breached keychain write + /// would. + fn place_raw(&self, w: &WalletId, label: &str, blob: &[u8]) { + match (&self.store, &self.mock) { + (SecretStore::File(fs), _) => fs + .put_bytes(w, label, &SecretBytes::from_slice(blob)) + .unwrap(), + (SecretStore::Os(_), Some(mock)) => { + let service = format!("{SERVICE_PREFIX}{}", w.to_hex()); + mock.build(&service, label, None) + .unwrap() + .set_secret(blob) + .unwrap(); + } + _ => unreachable!("os backend must carry its mock"), + } + } + } + + fn file_backend() -> Backend { + let dir = tempfile::tempdir().unwrap(); + let store = file_store(dir.path()); + Backend { + store, + _dir: Some(dir), + mock: None, + name: "File", + } + } + + fn os_backend() -> Backend { + // The upstream in-memory mock store. The clone handed to + // `SecretStore::Os` and the handle kept for raw attacker writes + // share the same backing credentials by `Arc`. + let mock = mock::Store::new().unwrap(); + let store = SecretStore::Os(mock.clone()); + Backend { + store, + _dir: None, + mock: Some(mock), + name: "Os", + } + } + + /// The strict-read quadrant. + fn run_quadrant(b: &Backend) { + let w = wid(1); + let pw = SecretString::new("object-pw"); + + // scheme-0 + None → bytes (the ONLY byte-returning quadrant). + b.place_raw(&w, "u0", &unprotected(&w, "u0", b"plain-seed")); + assert_eq!( + b.store + .get_secret(&w, "u0", None) + .unwrap() + .unwrap() + .expose_secret(), + b"plain-seed", + "[{}] scheme-0 + None", + b.name + ); + + // scheme-1 + None → NeedsPassword (never ciphertext). + b.place_raw(&w, "p1", &protected(&w, "p1", "object-pw", b"real-seed")); + assert!( + matches!( + b.store.get_secret(&w, "p1", None).unwrap_err(), + SecretStoreError::NeedsPassword + ), + "[{}] scheme-1 + None", + b.name + ); + + // scheme-1 + Some(correct) → secret. + assert_eq!( + b.store + .get_secret(&w, "p1", Some(&pw)) + .unwrap() + .unwrap() + .expose_secret(), + b"real-seed", + "[{}] scheme-1 + Some(correct)", + b.name + ); + + // scheme-1 + Some(wrong) → WrongPassword. + assert!( + matches!( + b.store + .get_secret(&w, "p1", Some(&SecretString::new("nope"))) + .unwrap_err(), + SecretStoreError::WrongPassword + ), + "[{}] scheme-1 + Some(wrong)", + b.name + ); + + // scheme-0 + Some(pw) → ExpectedProtectedButUnsealed (fail closed). + assert!( + matches!( + b.store.get_secret(&w, "u0", Some(&pw)).unwrap_err(), + SecretStoreError::ExpectedProtectedButUnsealed + ), + "[{}] scheme-0 + Some", + b.name + ); + + // Truncated envelope (below the bincode minimum) → Corruption, + // both with and without a password — no magic byte to peek at. + b.place_raw(&w, "broken", &[0x01]); + for arg in [None, Some(&pw)] { + assert!( + matches!( + b.store.get_secret(&w, "broken", arg).unwrap_err(), + SecretStoreError::Corruption + ), + "[{}] truncated envelope ({:?})", + b.name, + arg.map(|_| "Some") + ); + } + + // Raw, non-envelope bytes → Corruption under either password + // arg: every read goes through the bincode decoder. + b.place_raw(&w, "raw", b"raw-bytes-not-a-valid-envelope"); + for arg in [None, Some(&pw)] { + assert!( + matches!( + b.store.get_secret(&w, "raw", arg).unwrap_err(), + SecretStoreError::Corruption + ), + "[{}] raw non-envelope bytes ({:?})", + b.name, + arg.map(|_| "Some") + ); + } + + // absent entry → Ok(None) under either arg (deletion = DoS). + assert!(b.store.get_secret(&w, "absent", None).unwrap().is_none()); + assert!(b + .store + .get_secret(&w, "absent", Some(&pw)) + .unwrap() + .is_none()); + } + + #[test] + fn l1_quadrant_file() { + run_quadrant(&file_backend()); + } + + #[test] + fn l1_quadrant_os() { + run_quadrant(&os_backend()); + } + + /// The non-vacuous strip-injection regression. The single + /// test the whole feature exists to make pass. + fn run_strip_injection(b: &Backend) { + let w = wid(2); + let pw = SecretString::new("object-pw"); + + // Enrol protected: stored = a valid scheme-1 envelope of S_real. + b.place_raw( + &w, + "seed", + &protected(&w, "seed", "object-pw", b"REAL-SEED-S_real"), + ); + assert_eq!( + b.store + .get_secret(&w, "seed", Some(&pw)) + .unwrap() + .unwrap() + .expose_secret(), + b"REAL-SEED-S_real", + "[{}] legit protected read", + b.name + ); + + // Attacker overwrites the slot with a fresh, internally-valid + // scheme-0 envelope carrying a DIFFERENT seed S_evil. + let attacker_blob = unprotected(&w, "seed", b"EVIL-SEED-S_evil"); + b.place_raw(&w, "seed", &attacker_blob); + + // A password-supplied read of the stripped slot fails closed; + // S_evil is NEVER returned. + let err = b.store.get_secret(&w, "seed", Some(&pw)).unwrap_err(); + assert!( + matches!(err, SecretStoreError::ExpectedProtectedButUnsealed), + "[{}] strip must fail closed, got {err:?}", + b.name + ); + + // Non-vacuity: the attacker blob IS a valid unprotected envelope + // that WOULD decode to S_evil under `None` — so the refusal above is + // caused SOLELY by the Some(pw)+scheme-0 strict rule, not by any + // malformation (without the strict rule, S_evil would be returned). + let would_be = envelope::unwrap(&w, "seed", None, &attacker_blob).unwrap(); + assert_eq!( + would_be.expose_secret(), + b"EVIL-SEED-S_evil", + "[{}] non-vacuity: blob decodes to S_evil under None", + b.name + ); + } + + #[test] + fn l1_strip_injection_file() { + run_strip_injection(&file_backend()); + } + + #[test] + fn l1_strip_injection_os() { + run_strip_injection(&os_backend()); + } + + /// A consumer bug alone fails closed in BOTH directions. + fn run_both_det_bug_directions(b: &Backend) { + let w = wid(3); + let pw = SecretString::new("pw"); + // (a) over-supply a password on a genuinely unprotected object. + b.place_raw(&w, "u", &unprotected(&w, "u", b"x")); + assert!(matches!( + b.store.get_secret(&w, "u", Some(&pw)).unwrap_err(), + SecretStoreError::ExpectedProtectedButUnsealed + )); + // (b) under-supply on a genuinely protected object. + b.place_raw(&w, "p", &protected(&w, "p", "pw", b"y")); + assert!(matches!( + b.store.get_secret(&w, "p", None).unwrap_err(), + SecretStoreError::NeedsPassword + )); + } + + #[test] + fn l1_both_det_bug_directions_file() { + run_both_det_bug_directions(&file_backend()); + } + + #[test] + fn l1_both_det_bug_directions_os() { + run_both_det_bug_directions(&os_backend()); + } + + /// The expectation is NEVER inferred from the blob's scheme + /// byte — identical scheme-1 blobs diverge solely on the password arg. + fn run_expectation_not_inferred(b: &Backend) { + let w = wid(4); + let pw = SecretString::new("pw"); + let blob = protected(&w, "a", "pw", b"seed"); + b.place_raw(&w, "a", &blob); + b.place_raw(&w, "b", &blob); + assert_eq!( + b.store + .get_secret(&w, "a", Some(&pw)) + .unwrap() + .unwrap() + .expose_secret(), + b"seed" + ); + assert!(matches!( + b.store.get_secret(&w, "b", None).unwrap_err(), + SecretStoreError::NeedsPassword + )); + } + + #[test] + fn l1_expectation_not_inferred_file() { + run_expectation_not_inferred(&file_backend()); + } + + #[test] + fn l1_expectation_not_inferred_os() { + run_expectation_not_inferred(&os_backend()); + } + + /// Unprotected→protected upgrade confusion is availability- + /// only, fail-closed (NeedsPassword), no leak / no injection. + fn run_upgrade_confusion(b: &Backend) { + let w = wid(5); + b.place_raw(&w, "x", &protected(&w, "x", "attacker-pw", b"whatever")); + assert!(matches!( + b.store.get_secret(&w, "x", None).unwrap_err(), + SecretStoreError::NeedsPassword + )); + } + + #[test] + fn l1_upgrade_confusion_file() { + run_upgrade_confusion(&file_backend()); + } + + #[test] + fn l1_upgrade_confusion_os() { + run_upgrade_confusion(&os_backend()); + } + + /// A scheme-flip from `Password` → `Unprotected`: `Some(pw)` is + /// caught by the strict rule regardless; `None` reads the body as + /// scheme-0 opaque bytes (never the real seed) — a known residual, + /// dominated by the consumer-DB residual; pinned, not "fixed". + fn run_scheme_flip(b: &Backend) { + use crate::secrets::wire::config::WIRE_CONFIG; + use crate::secrets::wire::envelope::{Envelope, Payload}; + + let w = wid(6); + let pw = SecretString::new("pw"); + let blob = protected(&w, "x", "pw", b"real-seed"); + let (env, _): (Envelope, usize) = bincode::decode_from_slice(&blob, WIRE_CONFIG).unwrap(); + let flipped = match env.payload { + Payload::Password { ciphertext, .. } => Envelope { + version: env.version, + payload: Payload::Unprotected(ciphertext), + }, + Payload::Unprotected(_) => panic!("protected() must yield a Password payload"), + }; + let flipped_blob = bincode::encode_to_vec(&flipped, WIRE_CONFIG).unwrap(); + b.place_raw(&w, "x", &flipped_blob); + + assert!(matches!( + b.store.get_secret(&w, "x", Some(&pw)).unwrap_err(), + SecretStoreError::ExpectedProtectedButUnsealed + )); + let got = b.store.get_secret(&w, "x", None).unwrap().unwrap(); + assert_ne!( + got.expose_secret(), + b"real-seed", + "the real seed must never surface from a flipped scheme byte" + ); + } + + #[test] + fn l1_scheme_flip_file() { + run_scheme_flip(&file_backend()); + } + + #[test] + fn l1_scheme_flip_os() { + run_scheme_flip(&os_backend()); + } + + // ===== Add / change / remove password + arm matrix ===== + // + // These exercise the PUBLIC set_secret/get_secret/reprotect API, so the + // protected writes/reads run the real (default 64 MiB) Argon2 — kept to + // a small number of derivations per test. + + /// The full enrol → change → remove lifecycle, each + /// step verified through the strict read. + fn run_pw_lifecycle(b: &Backend) { + let w = wid(10); + let pw1 = SecretString::new("pw-one"); + let pw2 = SecretString::new("pw-two"); + + // ADD: start unprotected, enrol a password. + b.store + .set(&w, "seed", &SecretBytes::from_slice(b"SEED")) + .unwrap(); + assert_eq!( + b.store.get(&w, "seed").unwrap().unwrap().expose_secret(), + b"SEED" + ); + b.store.reprotect(&w, "seed", None, Some(&pw1)).unwrap(); + assert!( + matches!( + b.store.get(&w, "seed").unwrap_err(), + SecretStoreError::NeedsPassword + ), + "[{}] after add, None read needs a password", + b.name + ); + assert_eq!( + b.store + .get_secret(&w, "seed", Some(&pw1)) + .unwrap() + .unwrap() + .expose_secret(), + b"SEED" + ); + + // CHANGE: rotate to a new password (unwrap-old → rewrap-new). + b.store + .reprotect(&w, "seed", Some(&pw1), Some(&pw2)) + .unwrap(); + assert_eq!( + b.store + .get_secret(&w, "seed", Some(&pw2)) + .unwrap() + .unwrap() + .expose_secret(), + b"SEED" + ); + assert!( + matches!( + b.store.get_secret(&w, "seed", Some(&pw1)).unwrap_err(), + SecretStoreError::WrongPassword + ), + "[{}] old password no longer unlocks after change", + b.name + ); + + // REMOVE: back to unprotected. + b.store.reprotect(&w, "seed", Some(&pw2), None).unwrap(); + assert_eq!( + b.store.get(&w, "seed").unwrap().unwrap().expose_secret(), + b"SEED" + ); + assert!( + matches!( + b.store.get_secret(&w, "seed", Some(&pw2)).unwrap_err(), + SecretStoreError::ExpectedProtectedButUnsealed + ), + "[{}] after remove, a password read fails closed until the consumer updates its DB", + b.name + ); + } + + #[test] + fn pw_lifecycle_file() { + run_pw_lifecycle(&file_backend()); + } + + #[test] + fn pw_lifecycle_os() { + run_pw_lifecycle(&os_backend()); + } + + /// Losing the object password bricks the object — no recovery + /// path exists, every read fails closed. + fn run_pw_no_recovery(b: &Backend) { + let w = wid(11); + let pw = SecretString::new("the-only-pw"); + b.store + .set_secret(&w, "seed", &SecretBytes::from_slice(b"SEED"), Some(&pw)) + .unwrap(); + assert!(matches!( + b.store + .get_secret(&w, "seed", Some(&SecretString::new("guess"))) + .unwrap_err(), + SecretStoreError::WrongPassword + )); + assert!(matches!( + b.store.get(&w, "seed").unwrap_err(), + SecretStoreError::NeedsPassword + )); + } + + #[test] + fn pw_no_recovery_file() { + run_pw_no_recovery(&file_backend()); + } + + #[test] + fn pw_no_recovery_os() { + run_pw_no_recovery(&os_backend()); + } + + /// `set`/`get` are additive `..,None` wrappers — `set` + /// writes a scheme-0 envelope, `get` reads it byte-exact, and a + /// password-supplied read of that unprotected object fails closed. + fn run_set_get_wrappers(b: &Backend) { + let w = wid(12); + b.store + .set(&w, "seed", &SecretBytes::from_slice(b"plain")) + .unwrap(); + assert_eq!( + b.store.get(&w, "seed").unwrap().unwrap().expose_secret(), + b"plain" + ); + assert!(matches!( + b.store + .get_secret(&w, "seed", Some(&SecretString::new("pw"))) + .unwrap_err(), + SecretStoreError::ExpectedProtectedButUnsealed + )); + } + + #[test] + fn set_get_wrappers_file() { + run_set_get_wrappers(&file_backend()); + } + + #[test] + fn set_get_wrappers_os() { + run_set_get_wrappers(&os_backend()); + } + + /// The Os arm has no passphrase concept; the Tier-1 blank + /// guard never fires and the round-trip is byte-exact. + #[test] + fn os_arm_roundtrip_no_blank_guard() { + let b = os_backend(); + let w = wid(13); + b.store + .set(&w, "seed", &SecretBytes::from_slice(b"abc")) + .unwrap(); + assert_eq!( + b.store.get(&w, "seed").unwrap().unwrap().expose_secret(), + b"abc" + ); + b.store.delete(&w, "seed").unwrap(); + assert!(b.store.get(&w, "seed").unwrap().is_none()); + } + + /// [File]: a crash (disk-write failure) between the unwrap + /// and the overwrite-commit leaves the OLD protected value intact and + /// readable — no half-rotated / unprotected state. + #[cfg(unix)] + #[test] + fn pw_change_crash_safety_leaves_old_intact_file() { + use std::os::unix::fs::PermissionsExt; + + let dir = tempfile::tempdir().unwrap(); + let s = file_store(dir.path()); + let w = wid(14); + let old = SecretString::new("old-pw"); + let new = SecretString::new("new-pw"); + + s.set_secret(&w, "seed", &SecretBytes::from_slice(b"REAL"), Some(&old)) + .unwrap(); + + // Make the vault's parent read-only so the atomic temp-write fails + // mid-change (mirrors rekey_does_not_corrupt_on_disk_temp_failure). + std::fs::set_permissions(dir.path(), std::fs::Permissions::from_mode(0o500)).unwrap(); + let err = s.reprotect(&w, "seed", Some(&old), Some(&new)).unwrap_err(); + assert!(matches!(err, SecretStoreError::Io(_)), "got {err:?}"); + + // Restore write so the resident store can sync/clean up at drop. + std::fs::set_permissions(dir.path(), std::fs::Permissions::from_mode(0o700)).unwrap(); + + // The OLD value is still readable under the OLD password; the new + // password does not unlock it (no half-rotation). + assert_eq!( + s.get_secret(&w, "seed", Some(&old)) + .unwrap() + .unwrap() + .expose_secret(), + b"REAL" + ); + assert!(matches!( + s.get_secret(&w, "seed", Some(&new)).unwrap_err(), + SecretStoreError::WrongPassword + )); + } + + /// [Os]: a backend failure during the rewrite's write (after the read + /// succeeds) leaves the OLD value intact — no half-rotation. The mock's + /// one-shot error injection fails the next write, simulating a crash + /// mid-rewrite. `reprotect` is read-then-`set_secret`, split here so the + /// error lands on the write. + #[test] + fn os_rewrite_mid_write_failure_leaves_old_intact() { + let mock = mock::Store::new().unwrap(); + let store = SecretStore::Os(mock.clone()); + let w = wid(15); + let old = SecretString::new("old-pw"); + let new = SecretString::new("new-pw"); + store + .set_secret(&w, "seed", &SecretBytes::from_slice(b"REAL"), Some(&old)) + .unwrap(); + + // Read succeeds (the rewrite's first step) … + let secret = store.get_secret(&w, "seed", Some(&old)).unwrap().unwrap(); + // … then inject a one-shot backend error so the write fails. + let service = format!("{SERVICE_PREFIX}{}", w.to_hex()); + let entry = mock.build(&service, "seed", None).unwrap(); + let cred: &mock::Cred = entry.as_any().downcast_ref().unwrap(); + cred.set_error(KeyringError::PlatformFailure(Box::new( + std::io::Error::other("simulated backend write failure"), + ))); + let err = store + .set_secret(&w, "seed", &secret, Some(&new)) + .unwrap_err(); + assert!( + matches!(err, SecretStoreError::OsKeyring { .. }), + "got {err:?}" + ); + + // The OLD value is still readable; nothing rotated to `new`. + assert_eq!( + store + .get_secret(&w, "seed", Some(&old)) + .unwrap() + .unwrap() + .expose_secret(), + b"REAL" + ); + assert!(matches!( + store.get_secret(&w, "seed", Some(&new)).unwrap_err(), + SecretStoreError::WrongPassword + )); + } + + /// [Os]: the read-size guard rejects an oversized backend blob (a + /// malicious keychain returning more than a legitimate envelope ever + /// could) BEFORE it reaches the envelope parse/derive path. The bound is + /// `MAX_SECRET_LEN + MAX_ENVELOPE_OVERHEAD`; both the `get_secret` and + /// legacy `get` read paths enforce it. + #[test] + fn os_read_rejects_oversized_blob() { + let b = os_backend(); + let w = wid(16); + let cap = MAX_SECRET_LEN + envelope::MAX_ENVELOPE_OVERHEAD; + // Attacker writes a blob one byte over the cap straight to the slot. + b.place_raw(&w, "seed", &vec![0u8; cap + 1]); + let err = b.store.get_secret(&w, "seed", None).unwrap_err(); + assert!( + matches!(err, SecretStoreError::SecretTooLarge { found, max } if found == cap + 1 && max == cap), + "get_secret got {err:?}" + ); + // The legacy `get` path is bounded too. + assert!(matches!( + b.store.get(&w, "seed").unwrap_err(), + SecretStoreError::SecretTooLarge { found, max } if found == cap + 1 && max == cap + )); + } } diff --git a/packages/rs-platform-wallet-storage/src/secrets/wire/aad.rs b/packages/rs-platform-wallet-storage/src/secrets/wire/aad.rs new file mode 100644 index 0000000000..f6b750eef7 --- /dev/null +++ b/packages/rs-platform-wallet-storage/src/secrets/wire/aad.rs @@ -0,0 +1,252 @@ +//! Bincode-encoded AAD structs for the three contexts that authenticate +//! ciphertexts under `secrets/`: Tier-2 scheme-1 envelopes, vault entry +//! bodies, and the vault passphrase-verify token. +//! +//! Each struct is `Encode`-only — AAD is producer-side; the decoder +//! re-builds it from the surrounding context and bincode-encodes again +//! against [`WIRE_CONFIG`]. Pair-wise byte disjointness is guaranteed by +//! the three domain constants declared in [`super::config`] and pinned +//! empirically by the tests `tier2_and_entry_aad_byte_disjoint`, +//! `tier2_and_verify_aad_byte_disjoint`, and +//! `entry_and_verify_aad_byte_disjoint`. + +use crate::secrets::file::crypto::SALT_LEN; +use crate::secrets::wire::kdf::KdfParamsEncoded; + +/// AAD bound into every scheme-1 (password-protected) Tier-2 envelope. +/// Binds object identity (`wallet_id` + `label`) + header +/// (`envelope_version`, `scheme_discriminant`, `kdf`, `salt`) so any +/// in-place edit of those fields fails the AEAD tag. +/// +/// `scheme_discriminant` is explicit (not inferred from a Rust enum +/// variant tag) so the AAD shape is stable under a future `Payload` +/// re-ordering. +#[derive(bincode::Encode)] +pub(crate) struct Tier2Aad<'a> { + /// Domain tag — `TIER2_DOMAIN_V2`. Length-prefixed by bincode and + /// byte-disjoint from `ENTRY_DOMAIN_V2` / `VERIFY_DOMAIN_V2` by + /// content past the common prefix; pinned by the disjointness tests + /// in [`super::aad::tests`]. + pub domain: &'static [u8], + /// Envelope wire version (`ENVELOPE_VERSION`). + pub envelope_version: u32, + /// `0 = Unprotected`, `1 = Password`. Authenticates the scheme byte + /// independently of the enum's bincode-derived tag. + pub scheme_discriminant: u8, + /// The exact bytes encoded into the envelope's `Payload::Password` + /// body — AAD == body, so a wire-edited KDF header fails the tag. + pub kdf: KdfParamsEncoded, + /// Per-wrap CSPRNG salt. + pub salt: [u8; SALT_LEN], + /// 32-byte wallet correlation id (public, not secret). + pub wallet_id: [u8; 32], + /// Caller-allowlisted slot label. + pub label: &'a str, +} + +/// AAD bound into every vault entry's AEAD seal. Replaces the +/// hand-rolled `format::aad()` byte concatenation; binds slot identity +/// (`wallet_id` + `label`) at a stable `format_version`. A relocated +/// or version-rolled-back blob fails the tag. +#[derive(bincode::Encode)] +pub(crate) struct EntryAad<'a> { + /// Domain tag — `ENTRY_DOMAIN_V2`. + pub domain: &'static [u8], + /// Vault `FORMAT_VERSION` (the compiled-in dispatch version, + /// never the parsed JSON version). + pub format_version: u32, + /// 32-byte wallet correlation id. + pub wallet_id: [u8; 32], + /// Caller-allowlisted slot label. + pub label: &'a str, +} + +/// AAD bound into the vault passphrase-verify token's AEAD seal. +/// Binds salt + KDF header so a flipped salt or KDF-param shift fails +/// the token tag (surfaces as `WrongPassphrase` — a tampered header +/// also yields a different derived key). +#[derive(bincode::Encode)] +pub(crate) struct VerifyAad { + /// Domain tag — `VERIFY_DOMAIN_V2`. + pub domain: &'static [u8], + /// Vault `FORMAT_VERSION`. + pub format_version: u32, + /// Vault-wide CSPRNG salt. + pub salt: [u8; SALT_LEN], + /// Vault-wide KDF parameters (the same wire image used by every + /// scheme-1 Tier-2 envelope). + pub kdf: KdfParamsEncoded, +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::secrets::file::crypto::KdfParams; + use crate::secrets::wire::config::{ + ENTRY_DOMAIN_V2, TIER2_DOMAIN_V2, VERIFY_DOMAIN_V2, WIRE_CONFIG, + }; + + fn floor_kdf() -> KdfParamsEncoded { + KdfParamsEncoded::from(KdfParams::default_target()) + } + + fn tier2_with_domain(domain: &'static [u8]) -> Vec { + let aad = Tier2Aad { + domain, + envelope_version: 1, + scheme_discriminant: 1, + kdf: floor_kdf(), + salt: [0x77u8; SALT_LEN], + wallet_id: [0x11u8; 32], + label: "seed", + }; + bincode::encode_to_vec(aad, WIRE_CONFIG).unwrap() + } + + fn tier2_with_version(envelope_version: u32) -> Vec { + let aad = Tier2Aad { + domain: TIER2_DOMAIN_V2, + envelope_version, + scheme_discriminant: 1, + kdf: floor_kdf(), + salt: [0x77u8; SALT_LEN], + wallet_id: [0x11u8; 32], + label: "seed", + }; + bincode::encode_to_vec(aad, WIRE_CONFIG).unwrap() + } + + fn tier2_with_scheme(scheme_discriminant: u8) -> Vec { + let aad = Tier2Aad { + domain: TIER2_DOMAIN_V2, + envelope_version: 1, + scheme_discriminant, + kdf: floor_kdf(), + salt: [0x77u8; SALT_LEN], + wallet_id: [0x11u8; 32], + label: "seed", + }; + bincode::encode_to_vec(aad, WIRE_CONFIG).unwrap() + } + + fn entry(format_version: u32, wallet_id: [u8; 32], label: &str) -> Vec { + let aad = EntryAad { + domain: ENTRY_DOMAIN_V2, + format_version, + wallet_id, + label, + }; + bincode::encode_to_vec(aad, WIRE_CONFIG).unwrap() + } + + fn verify(salt: [u8; SALT_LEN], kdf: KdfParamsEncoded) -> Vec { + let aad = VerifyAad { + domain: VERIFY_DOMAIN_V2, + format_version: 1, + salt, + kdf, + }; + bincode::encode_to_vec(aad, WIRE_CONFIG).unwrap() + } + + /// Two byte strings where neither is a prefix of the other. + fn assert_prefix_disjoint(a: &[u8], b: &[u8]) { + assert!( + !a.starts_with(b) && !b.starts_with(a), + "prefix containment: a.len={} b.len={}", + a.len(), + b.len() + ); + } + + /// TC-014 — Tier2Aad.domain is bincode-encoded. + #[test] + fn tier2_aad_domain_field_binds_bytes() { + let a = tier2_with_domain(TIER2_DOMAIN_V2); + let b = tier2_with_domain(b"PWSEV-TIER2-AAD-vX"); + assert_ne!(a, b); + assert_prefix_disjoint(&a, &b); + } + + /// TC-015 — Tier2Aad.envelope_version is bincode-encoded. + #[test] + fn tier2_aad_envelope_version_field_binds_bytes() { + assert_ne!(tier2_with_version(1), tier2_with_version(2)); + } + + /// TC-016 — Tier2Aad.scheme_discriminant is bincode-encoded and + /// explicit (not inferred from a Rust enum tag). + #[test] + fn tier2_aad_scheme_discriminant_field_binds_bytes() { + assert_ne!(tier2_with_scheme(0), tier2_with_scheme(1)); + } + + /// TC-025 — Tier2Aad and EntryAad are byte-disjoint at the prefix. + #[test] + fn tier2_and_entry_aad_byte_disjoint() { + let t = tier2_with_domain(TIER2_DOMAIN_V2); + let e = entry(1, [0x11u8; 32], "seed"); + assert_prefix_disjoint(&t, &e); + } + + /// TC-026 — Tier2Aad and VerifyAad are byte-disjoint at the prefix. + #[test] + fn tier2_and_verify_aad_byte_disjoint() { + let t = tier2_with_domain(TIER2_DOMAIN_V2); + let v = verify([0x77u8; SALT_LEN], floor_kdf()); + assert_prefix_disjoint(&t, &v); + } + + /// TC-027 — EntryAad and VerifyAad are byte-disjoint at the prefix. + /// Now backed by an explicit domain constant on top of the existing + /// VERIFY_LABEL leading-NUL trick at the `format.rs` call site. + #[test] + fn entry_and_verify_aad_byte_disjoint() { + let e = entry(1, [0u8; 32], "\0verify"); + let v = verify([0x77u8; SALT_LEN], floor_kdf()); + assert_prefix_disjoint(&e, &v); + } + + /// TC-037 — EntryAad binds (format_version, wallet_id, label) and + /// the label encoding carries its length prefix (`"a"+"b"` vs + /// `"ab"` are distinct). + #[test] + fn entry_aad_binds_format_version_wallet_id_and_label() { + let base = entry(1, [1u8; 32], "a"); + assert_ne!(base, entry(2, [1u8; 32], "a")); + assert_ne!(base, entry(1, [2u8; 32], "a")); + assert_ne!(base, entry(1, [1u8; 32], "b")); + // Length-prefix sanity: "ab" must not equal the concatenation of + // the encoding of "a" with the literal byte `b`. + let ab = entry(1, [1u8; 32], "ab"); + let mut a_plus_b = base.clone(); + a_plus_b.extend_from_slice(b"b"); + assert_ne!(ab, a_plus_b); + } + + /// TC-038 — VerifyAad binds salt + KDF; identical inputs produce + /// identical bytes (determinism). + #[test] + fn verify_aad_binds_salt_and_kdf_params() { + let salt = [7u8; SALT_LEN]; + let kdf = floor_kdf(); + let base = verify(salt, kdf); + let mut salt2 = salt; + salt2[0] ^= 0x01; + assert_ne!(base, verify(salt2, kdf)); + + let kdf_mkib = KdfParamsEncoded { + m_kib: kdf.m_kib / 2, + ..kdf + }; + assert_ne!(base, verify(salt, kdf_mkib)); + let kdf_t = KdfParamsEncoded { + t: kdf.t - 1, + ..kdf + }; + assert_ne!(base, verify(salt, kdf_t)); + + // Determinism: identical inputs ⇒ identical bytes. + assert_eq!(base, verify(salt, kdf)); + } +} diff --git a/packages/rs-platform-wallet-storage/src/secrets/wire/config.rs b/packages/rs-platform-wallet-storage/src/secrets/wire/config.rs new file mode 100644 index 0000000000..b6c6031a63 --- /dev/null +++ b/packages/rs-platform-wallet-storage/src/secrets/wire/config.rs @@ -0,0 +1,43 @@ +//! Single bincode configuration + domain / version constants every +//! encoder in `secrets/wire/` uses. +//! +//! `WIRE_CONFIG` matches the platform-wide +//! `bincode::config::standard().with_big_endian().with_no_limit()` +//! (`rs-platform-serialization`) — big-endian for human-readable hex +//! dumps, varint integer encoding, no decode limit. +//! +//! Changing this constant invalidates every stored Tier-2 blob; the +//! golden-vector tests in [`super::envelope::tests`] catch any drift. + +use bincode::config::{BigEndian, Configuration, NoLimit, Varint}; + +/// The one bincode config used to encode every wire byte under +/// `secrets/wire/` (envelope payload + the three AAD structs). +pub(crate) const WIRE_CONFIG: Configuration = + bincode::config::standard() + .with_big_endian() + .with_no_limit(); + +/// Tier-2 envelope wire version — bumped only on a breaking layout +/// change, independent of the vault `FORMAT_VERSION`. Bound into every +/// scheme-1 envelope's AAD so a forged version byte fails the tag. +pub(crate) const ENVELOPE_VERSION: u32 = 1; + +/// Domain-separation tag leading the Tier-2 scheme-1 AAD. `-v2` marks the +/// wire-format break from the pre-bincode hand-rolled `PWSEV-TIER2-AAD-v1`. +pub(crate) const TIER2_DOMAIN_V2: &[u8] = b"PWSEV-TIER2-AAD-v2"; + +/// Domain-separation tag leading every vault `EntryAad`. Pre-bincode +/// `aad()` had no domain tag; bound here for symmetry + cross-context +/// disjointness with [`TIER2_DOMAIN_V2`] and [`VERIFY_DOMAIN_V2`]. +pub(crate) const ENTRY_DOMAIN_V2: &[u8] = b"PWSV-ENTRY-AAD-v2"; + +/// Domain-separation tag leading every vault `VerifyAad`. Disjoint +/// from [`TIER2_DOMAIN_V2`] and [`ENTRY_DOMAIN_V2`] by **content past +/// the common prefix** (the three tags are NOT length-distinct — +/// TIER2 and VERIFY are both 18 bytes; ENTRY is 17). Pair-wise +/// byte-disjointness is pinned by the tests +/// `tier2_and_verify_aad_byte_disjoint`, +/// `tier2_and_entry_aad_byte_disjoint`, and +/// `entry_and_verify_aad_byte_disjoint`. +pub(crate) const VERIFY_DOMAIN_V2: &[u8] = b"PWSV-VERIFY-AAD-v2"; diff --git a/packages/rs-platform-wallet-storage/src/secrets/wire/envelope.rs b/packages/rs-platform-wallet-storage/src/secrets/wire/envelope.rs new file mode 100644 index 0000000000..d9ee13db5b --- /dev/null +++ b/packages/rs-platform-wallet-storage/src/secrets/wire/envelope.rs @@ -0,0 +1,1029 @@ +//! Tier-2 envelope wire format — bincode-encoded `Envelope` / `Payload` +//! plus the [`wrap`] / [`wrap_with_params`] / [`unwrap`] API. +//! +//! Every byte that crosses the AEAD seam is produced by +//! `bincode::encode_to_vec` against [`WIRE_CONFIG`], so a future config +//! drift surfaces in the golden-vector tests, not in silently corrupted +//! blobs. Decoding goes through [`DECODE_CONFIG`] — the same +//! configuration with a byte limit, so a hostile blob declaring a +//! multi-GiB length prefix is rejected before any allocation. + +use bincode::config::{BigEndian, Configuration, Limit, Varint}; + +use crate::secrets::error::SecretStoreError; +use crate::secrets::file::crypto::{self, KdfParams, NONCE_LEN, SALT_LEN}; +use crate::secrets::secret::{SecretBytes, SecretString}; +use crate::secrets::validate::WalletId; +use crate::secrets::wire::aad::Tier2Aad; +use crate::secrets::wire::config::{ENVELOPE_VERSION, TIER2_DOMAIN_V2, WIRE_CONFIG}; +use crate::secrets::wire::kdf::KdfParamsEncoded; +use crate::secrets::MAX_SECRET_LEN; + +/// On-disk Tier-2 wire envelope. The whole struct is bincode-encoded +/// in one call; a wire-edited `version` is gated to +/// `SecretStoreError::UnsupportedEnvelopeVersion` before dispatch. +#[derive(bincode::Encode, bincode::Decode, Debug, PartialEq, Eq)] +pub(crate) struct Envelope { + /// Envelope wire version (`ENVELOPE_VERSION`). + pub version: u32, + /// Tagged payload selecting unprotected vs password-protected. + pub payload: Payload, +} + +/// Tagged payload: scheme-0 ships the plaintext as-is (the backend's +/// own at-rest crypto is the only defence); scheme-1 ships the AEAD +/// triple under an object-password-derived key. +#[derive(bincode::Encode, bincode::Decode, Debug, PartialEq, Eq)] +pub(crate) enum Payload { + /// Scheme 0 — unprotected passthrough; the bytes are the secret. + Unprotected(Vec), + /// Scheme 1 — sealed under an Argon2id-derived key with + /// XChaCha20-Poly1305. The AAD bound at seal time is + /// [`crate::secrets::wire::aad::Tier2Aad`]. + Password { + /// Argon2 parameters used to derive the key. + kdf: KdfParamsEncoded, + /// Per-wrap CSPRNG salt fed into Argon2. + salt: [u8; SALT_LEN], + /// Per-wrap CSPRNG nonce fed into XChaCha20-Poly1305. + nonce: [u8; NONCE_LEN], + /// Ciphertext + 16-byte Poly1305 tag. + ciphertext: Vec, + }, +} + +/// Upper bound on the bincode-encoded envelope overhead over its +/// plaintext (header + KDF + salt + nonce + AEAD tag + bincode framing). +/// Pinned by a runtime cross-check in `tests::max_envelope_overhead_matches_runtime` +/// so any bincode-config drift surfaces immediately. The smallest +/// scheme-1 envelope (empty plaintext sealed → 16-byte tag) measures +/// 81 bytes; rounded up to the next 16-byte boundary that satisfies a +/// 16-byte safety margin (81 + 16 = 97 → 112) for headroom against a +/// future header field. +pub(crate) const MAX_ENVELOPE_OVERHEAD: usize = 112; + +/// Plaintext cap at the envelope boundary: `MAX_SECRET_LEN − +/// MAX_ENVELOPE_OVERHEAD`. Capping the plaintext (uniformly for both +/// schemes) keeps the user-visible limit stable AND guarantees the +/// enveloped bytes always fit the backend vault's own `MAX_SECRET_LEN` +/// `put_bytes` cap. +pub const MAX_PLAINTEXT_LEN: usize = MAX_SECRET_LEN - MAX_ENVELOPE_OVERHEAD; + +/// Decode-side budget: caps the bytes the bincode decoder will consume +/// from a single envelope. Equal to the on-disk cap. +const DECODE_BUDGET: usize = MAX_SECRET_LEN + MAX_ENVELOPE_OVERHEAD; + +/// Bincode decode config — derived from [`WIRE_CONFIG`] but with a +/// [`DECODE_BUDGET`] byte limit applied. +/// +/// **Asymmetric on purpose, security-positive deviation from +/// design-brief NF2** (which locks the wire config to +/// `with_no_limit()`). The deviation exists for hostile-decode +/// hardening: an attacker-controlled length prefix in the blob would +/// otherwise drive `Vec::with_capacity` to a multi-GiB allocation +/// before any tag check. With `Limit`, bincode refuses the +/// allocation up front and the unwrap fails closed as `Corruption`. +/// +/// The encoder retains [`WIRE_CONFIG`] (no limit) because AAD and +/// envelope encoding are producer-only — every input is library-owned +/// and bounded by `MAX_PLAINTEXT_LEN`, so a limit there has no +/// security benefit and would be a foot-gun against legitimate +/// at-cap secrets. +const DECODE_CONFIG: Configuration> = + WIRE_CONFIG.with_limit::(); + +/// Wrap `plaintext` for `(wallet_id, label)` using the shipped default +/// Argon2 target when a password is supplied. +/// +/// `None` → an unprotected (scheme-0) envelope; `Some(pw)` → a scheme-1 +/// envelope sealed under `pw`. A blank password is rejected at enrol +/// (`SecretStoreError::BlankPassphrase`). +/// +/// Returns the envelope inside a zeroizing [`SecretBytes`]. +pub(crate) fn wrap( + wallet_id: &WalletId, + label: &str, + password: Option<&SecretString>, + plaintext: &[u8], +) -> Result { + wrap_with_params( + wallet_id, + label, + password, + plaintext, + KdfParams::default_target(), + ) +} + +/// [`wrap`] with explicit Argon2 `params` (tests use floor params for +/// speed). `params` is ignored when `password` is `None`. +pub(crate) fn wrap_with_params( + wallet_id: &WalletId, + label: &str, + password: Option<&SecretString>, + plaintext: &[u8], + params: KdfParams, +) -> Result { + // Cap the PLAINTEXT (before overhead) uniformly for both schemes so + // the enveloped bytes always fit the backend cap. + if plaintext.len() > MAX_PLAINTEXT_LEN { + return Err(SecretStoreError::SecretTooLarge { + found: plaintext.len(), + max: MAX_PLAINTEXT_LEN, + }); + } + + let Some(pw) = password else { + let envelope = Envelope { + version: ENVELOPE_VERSION, + payload: Payload::Unprotected(plaintext.to_vec()), + }; + return Ok(SecretBytes::new(encode_envelope(&envelope))); + }; + + // Reject a blank object password BEFORE any salt / derive. + if pw.is_blank() { + return Err(SecretStoreError::BlankPassphrase); + } + + let mut salt = [0u8; SALT_LEN]; + crypto::random_bytes(&mut salt)?; + let key = crypto::derive_key(pw, &salt, params)?; + let kdf = KdfParamsEncoded::from(params); + let aad = encode_tier2_aad(wallet_id, label, kdf, &salt); + let (nonce, ciphertext) = crypto::seal(&key, &aad, plaintext)?; + + let envelope = Envelope { + version: ENVELOPE_VERSION, + payload: Payload::Password { + kdf, + salt, + nonce, + ciphertext, + }, + }; + Ok(SecretBytes::new(encode_envelope(&envelope))) +} + +/// Bincode-encode the scheme-1 AAD against [`WIRE_CONFIG`]. Shared by +/// [`wrap_with_params`] and [`unwrap_password_payload`] so the encode +/// and decode AADs cannot drift apart. +pub(crate) fn encode_tier2_aad( + wallet_id: &WalletId, + label: &str, + kdf: KdfParamsEncoded, + salt: &[u8; SALT_LEN], +) -> Vec { + let aad = Tier2Aad { + domain: TIER2_DOMAIN_V2, + envelope_version: ENVELOPE_VERSION, + scheme_discriminant: 1, + kdf, + salt: *salt, + wallet_id: *wallet_id.as_bytes(), + label, + }; + // AAD encode is infallible — every field is owned/borrowed bincode- + // Encode-able. A failure would be a logic bug. + bincode::encode_to_vec(aad, WIRE_CONFIG).expect("Tier2Aad encode is infallible") +} + +/// Bincode-encode the whole envelope. Wrapping in `SecretBytes::new` +/// keeps the (possibly plaintext-bearing) scheme-0 buffer zeroizing. +fn encode_envelope(envelope: &Envelope) -> Vec { + bincode::encode_to_vec(envelope, WIRE_CONFIG).expect("Envelope encode is infallible") +} + +/// Unwrap `blob` for `(wallet_id, label)`, applying the strict +/// fail-closed read. +/// +/// `password` carries the caller's protection assertion — never the +/// blob's scheme byte. Decode errors (truncated, garbage bytes, unknown +/// enum tag) collapse to `Corruption`; an envelope version this build +/// does not recognise yields `UnsupportedEnvelopeVersion` ahead of +/// dispatch. +/// +/// | `password` | `payload` | result | +/// |---|---|---| +/// | `Some(pw)` | `Password { .. }` | the secret, or `WrongPassword` on tag fail | +/// | `Some(pw)` | `Unprotected(_)` | `ExpectedProtectedButUnsealed` (strip/downgrade) | +/// | `None` | `Password { .. }` | `NeedsPassword` (never ciphertext) | +/// | `None` | `Unprotected(pt)` | the secret | +pub(crate) fn unwrap( + wallet_id: &WalletId, + label: &str, + password: Option<&SecretString>, + blob: &[u8], +) -> Result { + let (envelope, consumed) = bincode::decode_from_slice::(blob, DECODE_CONFIG) + .map_err(|_| SecretStoreError::Corruption)?; + // Trailing bytes after a valid decode are a truncation/extension + // probe — fail closed. + if consumed != blob.len() { + return Err(SecretStoreError::Corruption); + } + + if envelope.version != ENVELOPE_VERSION { + // `found` keeps the historical u8 — the error API stayed u8 for + // back-compat; an out-of-range u32 wraps but the decoder above + // already accepts every u32 so this only narrows the diagnostic. + return Err(SecretStoreError::UnsupportedEnvelopeVersion { + found: envelope.version as u8, + }); + } + + match (envelope.payload, password) { + (Payload::Unprotected(plaintext), None) => Ok(SecretBytes::new(plaintext)), + // Caller asserted protection but blob is unprotected: strip / + // downgrade — fail closed, never return the bytes. + (Payload::Unprotected(_), Some(_)) => Err(SecretStoreError::ExpectedProtectedButUnsealed), + (Payload::Password { .. }, None) => Err(SecretStoreError::NeedsPassword), + ( + Payload::Password { + kdf, + salt, + nonce, + ciphertext, + }, + Some(pw), + ) => unwrap_password_payload(wallet_id, label, pw, kdf, salt, nonce, &ciphertext), + } +} + +/// Decrypt a `Payload::Password` body. The KDF params, salt and nonce +/// come from the (attacker-controllable) envelope; `enforce_bounds` +/// AND a stricter per-read `default_target` ceiling gate the params +/// BEFORE `derive_key` allocates. +fn unwrap_password_payload( + wallet_id: &WalletId, + label: &str, + password: &SecretString, + kdf_encoded: KdfParamsEncoded, + salt: [u8; SALT_LEN], + nonce: [u8; NONCE_LEN], + ciphertext: &[u8], +) -> Result { + // (a0) Mirror wrap's invariant: a blank object password is rejected on + // read as well as enrol, so a backend-write attacker who plants a + // scheme-1 envelope sealed under the blank password cannot inject + // plaintext into a caller that accidentally forwards Some(empty). + if password.is_blank() { + return Err(SecretStoreError::BlankPassphrase); + } + // (a) Wider Argon2 floors/ceilings — refuses an inflated header + // before any allocation. + let kdf = KdfParams::try_from(kdf_encoded)?; + // (b) Per-read ceiling tighter than `enforce_bounds`: a header + // declaring more memory OR more time than this build's shipped + // target is refused before `derive_key` allocates. Closes the gaps + // between `ARGON2_MAX_M_KIB` (1 GiB) / `ARGON2_MAX_T` (16) and the + // shipped 64 MiB / t=3 default — bounds the worst-case forged read + // at the shipped target on both axes (no headroom for an attacker + // to inflate memory by 16× or CPU by 5.3×). + let target = KdfParams::default_target(); + if kdf.m_kib > target.m_kib || kdf.t > target.t { + return Err(SecretStoreError::KdfFailure); + } + // (c) AAD binds identity + header — the same bytes the encoder + // produced, by construction. + let aad = encode_tier2_aad(wallet_id, label, kdf_encoded, &salt); + let key = crypto::derive_key(password, &salt, kdf)?; + match crypto::open(&key, &nonce, &aad, ciphertext) { + Ok(plaintext) => Ok(plaintext), + // Tag failure (wrong password, relocated blob, header tamper): + // no plaintext ever materialises (CWE-347). + Err(SecretStoreError::Decrypt) => Err(SecretStoreError::WrongPassword), + Err(e) => Err(e), + } +} + +/// Test-only deterministic encoder: takes pre-supplied `salt` and +/// `nonce` instead of pulling from the CSPRNG, so golden-vector tests +/// produce reproducible bytes. Production callers MUST use +/// [`wrap_with_params`]. +#[cfg(test)] +pub(crate) fn wrap_with_params_for_test( + wallet_id: &WalletId, + label: &str, + pw: &SecretString, + plaintext: &[u8], + params: KdfParams, + salt: [u8; SALT_LEN], + nonce: [u8; NONCE_LEN], +) -> Result { + if plaintext.len() > MAX_PLAINTEXT_LEN { + return Err(SecretStoreError::SecretTooLarge { + found: plaintext.len(), + max: MAX_PLAINTEXT_LEN, + }); + } + if pw.is_blank() { + return Err(SecretStoreError::BlankPassphrase); + } + let key = crypto::derive_key(pw, &salt, params)?; + let kdf = KdfParamsEncoded::from(params); + let aad = encode_tier2_aad(wallet_id, label, kdf, &salt); + let (nonce, ciphertext) = crypto::seal_with_nonce(&key, nonce, &aad, plaintext)?; + let envelope = Envelope { + version: ENVELOPE_VERSION, + payload: Payload::Password { + kdf, + salt, + nonce, + ciphertext, + }, + }; + Ok(SecretBytes::new(encode_envelope(&envelope))) +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::secrets::file::crypto::{ARGON2_MIN_M_KIB, ARGON2_MIN_T, ARGON2_P}; + use crate::secrets::file::format::KDF_ID_ARGON2ID; + + /// Captured once from the runtime encoder; a subsequent CI failure + /// here means a wire-format drift to investigate, NOT to "fix" by + /// re-generating the constant. + /// + /// Decoding: 0x01 envelope.version=1, 0x00 Payload::Unprotected, + /// 0x05 Vec length=5, "hello". + const SCHEME0_GOLDEN_HEX: &str = "01000568656c6c6f"; + + /// scheme-1 deterministic golden: wid=[0;32], label="seed", + /// pw="pw", plaintext="hello", floor params, salt=[0x11;32], + /// nonce=[0x22;24]. Bytes: version + Payload::Password tag + + /// kdf(id,m_kib,t,p as varints) + salt[32] + nonce[24] + + /// ciphertext-with-tag length + ciphertext+tag(21B). + const SCHEME1_GOLDEN_HEX: &str = "010101fb4c000201111111111111111111111111111111111111111111111111111111111111111122222222222222222222222222222222222222222222222215e2ffdf3f0476b6bfb99b4f71b3039ff965132b92f0"; + + fn wid(b: u8) -> WalletId { + WalletId::from([b; 32]) + } + + fn pw(s: &str) -> SecretString { + SecretString::new(s) + } + + fn floor() -> KdfParams { + KdfParams { + id: KDF_ID_ARGON2ID, + m_kib: ARGON2_MIN_M_KIB, + t: ARGON2_MIN_T, + p: ARGON2_P, + } + } + + /// TC-033 — blank object password rejected at enrol (wrap-side). + #[test] + fn blank_object_password_rejected_at_wrap() { + for blank in [SecretString::empty(), pw(""), pw(" "), pw("\t\n")] { + let err = + wrap_with_params(&wid(1), "seed", Some(&blank), b"seed", floor()).unwrap_err(); + assert!( + matches!(err, SecretStoreError::BlankPassphrase), + "got {err:?}" + ); + } + } + + /// Symmetric guard on the read side: a `Some(blank)` password reaching + /// `unwrap_password_payload` is refused with `BlankPassphrase` BEFORE + /// any KDF or AEAD work — never `WrongPassword`, never `Decrypt`, + /// never plaintext. Pins the contract that closes the asymmetry where + /// a backend-write attacker could plant a scheme-1 envelope sealed + /// under the blank password and have a caller that accidentally + /// forwards `Some(SecretString::empty())` accept attacker-controlled + /// plaintext. + #[test] + fn unwrap_password_payload_rejects_some_blank_password() { + let blob = scheme1_blob(&pw("good")); + let err = unwrap(&wid(1), "seed", Some(&SecretString::empty()), &blob).unwrap_err(); + assert!( + matches!(err, SecretStoreError::BlankPassphrase), + "blank object password must be refused before KDF/AEAD, got {err:?}" + ); + } + + /// TC-034 — plaintext cap accept at MAX_PLAINTEXT_LEN, reject at + /// +1, for both schemes. + #[test] + fn plaintext_cap_accept_then_reject() { + let at_cap = vec![0x5Au8; MAX_PLAINTEXT_LEN]; + let over = vec![0x5Au8; MAX_PLAINTEXT_LEN + 1]; + + // Scheme 0 + assert!(wrap(&wid(1), "seed", None, &at_cap).is_ok()); + assert!(matches!( + wrap(&wid(1), "seed", None, &over).unwrap_err(), + SecretStoreError::SecretTooLarge { found, max } + if found == MAX_PLAINTEXT_LEN + 1 && max == MAX_PLAINTEXT_LEN + )); + + // Scheme 1 — cap check fires before any derivation. + let p = pw("pw"); + assert!(matches!( + wrap_with_params(&wid(1), "seed", Some(&p), &over, floor()).unwrap_err(), + SecretStoreError::SecretTooLarge { found, max } + if found == MAX_PLAINTEXT_LEN + 1 && max == MAX_PLAINTEXT_LEN + )); + + // Scheme-0 enveloped bytes for an at-cap plaintext fit the backend cap. + let enveloped = wrap(&wid(1), "seed", None, &at_cap).unwrap(); + assert!(enveloped.len() <= MAX_SECRET_LEN); + } + + /// TC-035 (size-budget half) — scheme-1 accepts plaintext at the + /// exact MAX_PLAINTEXT_LEN boundary; the enveloped bytes fit the + /// backend cap. The round-trip half is `scheme1_at_cap_round_trips_within_backend_cap`. + #[test] + fn scheme1_at_cap_envelope_fits_backend_cap() { + let p = pw("pw"); + let pt = vec![0x5Au8; MAX_PLAINTEXT_LEN]; + let blob = wrap_with_params(&wid(1), "seed", Some(&p), &pt, floor()).unwrap(); + assert!( + blob.len() <= MAX_SECRET_LEN, + "enveloped bytes ({} B) exceed backend cap ({} B)", + blob.len(), + MAX_SECRET_LEN + ); + } + + /// TC-028 — golden hex vector for the scheme-0 wire bytes. Any + /// bincode-config drift (endianness, varint mode, limit) trips this. + #[test] + fn scheme0_golden_vector_matches_const() { + let blob = wrap(&WalletId::from([0u8; 32]), "seed", None, b"hello").unwrap(); + let actual = hex::encode(blob.expose_secret()); + assert_eq!(actual, SCHEME0_GOLDEN_HEX); + } + + /// TC-029 — golden hex vector for the scheme-1 wire bytes, produced + /// via the deterministic encoder seam. + #[test] + fn scheme1_golden_vector_matches_const() { + let blob = wrap_with_params_for_test( + &WalletId::from([0u8; 32]), + "seed", + &pw("pw"), + b"hello", + floor(), + [0x11u8; SALT_LEN], + [0x22u8; NONCE_LEN], + ) + .unwrap(); + let actual = hex::encode(blob.expose_secret()); + assert_eq!(actual, SCHEME1_GOLDEN_HEX); + } + + /// Minimum overhead within budget AND the budget not absurdly above + /// the actual encoding — bound on both sides so the constant stays + /// honest as the wire shape evolves. + const SAFETY_MARGIN: usize = 16; + + /// TC-030 — `MAX_ENVELOPE_OVERHEAD` cross-checks the runtime + /// bincode encoding of the smallest possible scheme-1 envelope + /// (empty plaintext sealed → ciphertext == 16-byte AEAD tag). + #[test] + fn max_envelope_overhead_matches_runtime() { + let blob = wrap_with_params_for_test( + &WalletId::from([0u8; 32]), + "seed", + &pw("pw"), + b"", + floor(), + [0x11u8; SALT_LEN], + [0x22u8; NONCE_LEN], + ) + .unwrap(); + let actual = blob.len(); + assert!( + actual + SAFETY_MARGIN <= MAX_ENVELOPE_OVERHEAD, + "overhead {} + margin {} exceeds const {}", + actual, + SAFETY_MARGIN, + MAX_ENVELOPE_OVERHEAD + ); + assert!( + MAX_ENVELOPE_OVERHEAD - actual < 64, + "MAX_ENVELOPE_OVERHEAD {} is more than 64 B above the runtime measurement {} — tighten it", + MAX_ENVELOPE_OVERHEAD, + actual + ); + } + + // ===== Decoder: dispatch / wire-flip / fuzz / property ===== + + use crate::secrets::file::crypto::{ARGON2_MAX_M_KIB, ARGON2_MAX_T}; + use crate::secrets::wire::config::WIRE_CONFIG; + use subtle::ConstantTimeEq; + + /// Decode a real envelope so wire-flip tests can mutate one field + /// and re-encode. + fn decode(blob: &[u8]) -> Envelope { + bincode::decode_from_slice::(blob, WIRE_CONFIG) + .unwrap() + .0 + } + + fn encode(envelope: &Envelope) -> Vec { + bincode::encode_to_vec(envelope, WIRE_CONFIG).unwrap() + } + + /// Build a fresh scheme-1 envelope (under wid(1)/"seed"/pw=`p`) and + /// hand back the bytes for mutation tests. + fn scheme1_blob(p: &SecretString) -> Vec { + wrap_with_params(&wid(1), "seed", Some(p), b"seed", floor()) + .unwrap() + .expose_secret() + .to_vec() + } + + /// TC-001 — scheme-0 round-trip preserves plaintext. + #[test] + fn scheme0_round_trip_preserves_plaintext() { + let blob = wrap(&wid(1), "seed", None, b"top secret seed bytes").unwrap(); + let got = unwrap(&wid(1), "seed", None, blob.expose_secret()).unwrap(); + assert_eq!(got.expose_secret(), b"top secret seed bytes"); + } + + /// TC-002 — scheme-1 round-trip preserves plaintext. + #[test] + fn scheme1_round_trip_preserves_plaintext() { + let p = pw("hunter2"); + let blob = wrap_with_params( + &wid(7), + "seed", + Some(&p), + b"correct horse battery staple", + floor(), + ) + .unwrap(); + assert_ne!(blob.expose_secret(), b"correct horse battery staple"); + let got = unwrap(&wid(7), "seed", Some(&p), blob.expose_secret()).unwrap(); + assert_eq!(got.expose_secret(), b"correct horse battery staple"); + } + + /// TC-003 — scheme-1 produces a fresh salt + nonce per wrap. + #[test] + fn scheme1_uses_fresh_salt_and_nonce_per_wrap() { + let p = pw("pw"); + let a = scheme1_blob(&p); + let b = scheme1_blob(&p); + let (sa, na) = match decode(&a).payload { + Payload::Password { salt, nonce, .. } => (salt, nonce), + _ => panic!("scheme-1 wrap must yield Password"), + }; + let (sb, nb) = match decode(&b).payload { + Payload::Password { salt, nonce, .. } => (salt, nonce), + _ => panic!("scheme-1 wrap must yield Password"), + }; + assert_ne!(sa, sb, "salt must be fresh per wrap"); + assert_ne!(na, nb, "nonce must be fresh per wrap"); + } + + /// TC-004 — wrong object password yields WrongPassword. + #[test] + fn wrong_password_fails_closed() { + let blob = scheme1_blob(&pw("right")); + let err = unwrap(&wid(1), "seed", Some(&pw("wrong")), &blob).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// Mutate the `Payload::Password` body in-place via decode → patch + /// → encode. Returns the new blob. + fn mutate_scheme1( + blob: &[u8], + patch: impl FnOnce(&mut KdfParamsEncoded, &mut [u8; SALT_LEN], &mut [u8; NONCE_LEN]), + ) -> Vec { + let mut env = decode(blob); + match env.payload { + Payload::Password { + ref mut kdf, + ref mut salt, + ref mut nonce, + .. + } => patch(kdf, salt, nonce), + _ => panic!("mutate_scheme1 expects a Password payload"), + } + encode(&env) + } + + /// TC-005 — wire-flip of kdf.m_kib (in-bounds shift) yields WrongPassword. + #[test] + fn wire_flip_kdf_m_kib_fails_closed() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.m_kib = ARGON2_MIN_M_KIB + 1024; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-006 — wire-flip of kdf.t (in-bounds shift) yields WrongPassword. + #[test] + fn wire_flip_kdf_t_fails_closed() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.t = ARGON2_MIN_T + 1; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-007 — wire-flip of kdf.id to an unknown value is rejected by + /// `enforce_bounds` BEFORE `derive_key` allocates. + #[test] + fn wire_flip_kdf_id_unknown_rejected_pre_derive() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.id = 7; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!(matches!(err, SecretStoreError::KdfFailure), "got {err:?}"); + } + + /// TC-008 — wire-flip of salt[0] yields WrongPassword. + #[test] + fn wire_flip_salt_fails_closed() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |_, salt, _| { + salt[0] ^= 0x01; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-009 — wire-flip of nonce[0] yields WrongPassword. + #[test] + fn wire_flip_nonce_fails_closed() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |_, _, nonce| { + nonce[0] ^= 0x01; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-010 — re-binding the unwrap to a different wallet_id rejects. + #[test] + fn relocation_across_wallet_id_rejected() { + let p = pw("pw"); + let blob = wrap_with_params(&wid(0xA), "seed", Some(&p), b"seed", floor()).unwrap(); + let err = unwrap(&wid(0xB), "seed", Some(&p), blob.expose_secret()).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-011 — re-binding the unwrap to a different label rejects. + #[test] + fn relocation_across_label_rejected() { + let p = pw("pw"); + let blob = wrap_with_params(&wid(1), "labelA", Some(&p), b"seed", floor()).unwrap(); + let err = unwrap(&wid(1), "labelB", Some(&p), blob.expose_secret()).unwrap_err(); + assert!( + matches!(err, SecretStoreError::WrongPassword), + "got {err:?}" + ); + } + + /// TC-012 — wire-flip of envelope.version (via re-encode) is gated + /// to UnsupportedEnvelopeVersion before AAD bind. + #[test] + fn wire_flip_version_rejected_pre_aad() { + let blob = scheme1_blob(&pw("pw")); + let mut env = decode(&blob); + env.version = 2; + let tampered = encode(&env); + let err = unwrap(&wid(1), "seed", Some(&pw("pw")), &tampered).unwrap_err(); + assert!( + matches!( + err, + SecretStoreError::UnsupportedEnvelopeVersion { found: 2 } + ), + "got {err:?}" + ); + } + + /// TC-013 — forged `Payload::Unprotected` with ciphertext bytes + + /// `Some(pw)` redirects to ExpectedProtectedButUnsealed. + #[test] + fn wire_flip_scheme_dispatch_redirects_safely() { + let env = Envelope { + version: ENVELOPE_VERSION, + payload: Payload::Unprotected(vec![0xDEu8; 32]), + }; + let blob = encode(&env); + let err = unwrap(&wid(1), "seed", Some(&pw("pw")), &blob).unwrap_err(); + assert!( + matches!(err, SecretStoreError::ExpectedProtectedButUnsealed), + "got {err:?}" + ); + } + + /// TC-017 — truncated blob (< minimum envelope length) yields + /// Corruption. + #[test] + fn truncated_blob_yields_corruption() { + let blob = scheme1_blob(&pw("pw")); + let cut = blob.len() / 2; + let err = unwrap(&wid(1), "seed", Some(&pw("pw")), &blob[..cut]).unwrap_err(); + assert!(matches!(err, SecretStoreError::Corruption), "got {err:?}"); + } + + /// TC-018 — random-byte blob yields Corruption (both arms). + #[test] + fn random_garbage_yields_corruption() { + let garbage = b"NOTANEVELOPE........................."; + let err = unwrap(&wid(1), "seed", None, garbage).unwrap_err(); + assert!(matches!(err, SecretStoreError::Corruption), "got {err:?}"); + let err = unwrap(&wid(1), "seed", Some(&pw("pw")), garbage).unwrap_err(); + assert!(matches!(err, SecretStoreError::Corruption), "got {err:?}"); + } + + /// TC-019 — a manually-built envelope at version=2 fails closed + /// regardless of password. + #[test] + fn unsupported_version_rejected_for_any_password() { + let env = Envelope { + version: 2, + payload: Payload::Unprotected(b"x".to_vec()), + }; + let blob = encode(&env); + for arg in [None, Some(&pw("pw"))] { + let err = unwrap(&wid(1), "seed", arg, &blob).unwrap_err(); + assert!( + matches!( + err, + SecretStoreError::UnsupportedEnvelopeVersion { found: 2 } + ), + "got {err:?}" + ); + } + } + + /// TC-020 — a hand-crafted byte stream with an unknown payload + /// enum tag yields Corruption (bincode's natural fail-closed). + #[test] + fn unknown_scheme_discriminant_yields_corruption() { + // envelope.version = 1 (varint = 0x01) then a Payload enum tag + // of 7 (varint = 0x07) — the two-variant enum decode rejects. + let blob = [0x01u8, 0x07]; + let err = unwrap(&wid(1), "seed", None, &blob).unwrap_err(); + assert!(matches!(err, SecretStoreError::Corruption), "got {err:?}"); + } + + /// TC-021 — Some(pw) + scheme-0 yields ExpectedProtectedButUnsealed. + #[test] + fn some_pw_on_scheme0_fails_closed() { + let blob = wrap(&wid(1), "seed", None, b"attacker-seed").unwrap(); + let err = unwrap(&wid(1), "seed", Some(&pw("pw")), blob.expose_secret()).unwrap_err(); + assert!( + matches!(err, SecretStoreError::ExpectedProtectedButUnsealed), + "got {err:?}" + ); + } + + /// TC-022 — None + scheme-1 yields NeedsPassword. + #[test] + fn none_pw_on_scheme1_yields_needs_password() { + let blob = scheme1_blob(&pw("pw")); + let err = unwrap(&wid(1), "seed", None, &blob).unwrap_err(); + assert!( + matches!(err, SecretStoreError::NeedsPassword), + "got {err:?}" + ); + } + + /// TC-023 — inflated KDF param rejected by `enforce_bounds` before + /// `derive_key` allocates (a ~4 TiB allocation would OOM the test). + #[test] + fn kdf_enforce_bounds_rejects_before_derive() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.m_kib = u32::MAX; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!(matches!(err, SecretStoreError::KdfFailure), "got {err:?}"); + + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.t = ARGON2_MAX_T + 1; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!(matches!(err, SecretStoreError::KdfFailure), "got {err:?}"); + } + + /// TC-024 — per-read `default_target` ceiling rejects an envelope + /// whose `m_kib` exceeds the shipped target even when still inside + /// `enforce_bounds`. Catches inflated headers BEFORE `derive_key`. + #[test] + fn per_read_default_target_ceiling_rejects_inflated_header() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let bumped = KdfParams::default_target().m_kib * 2; + // Sanity: the bumped value stays inside the wider enforce_bounds + // ceiling, so only the per-read gate can refuse it. + assert!(bumped <= ARGON2_MAX_M_KIB); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + kdf.m_kib = bumped; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!(matches!(err, SecretStoreError::KdfFailure), "got {err:?}"); + } + + /// Sibling to TC-024 on the `t` axis — per-read `default_target` + /// ceiling rejects an envelope whose `t` exceeds the shipped target + /// even when still inside `enforce_bounds` (`ARGON2_MAX_T = 16`). + /// Closes the CPU-axis gap that would otherwise let a forged header + /// run Argon2 at 5.3× the shipped iteration count. + #[test] + fn kdf_t_ceiling_fires_before_derive() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let target = KdfParams::default_target(); + let bumped_t = target.t + 1; + // Sanity: the bumped t stays inside the wider enforce_bounds + // ceiling, so only the per-read gate can refuse it. + assert!(bumped_t <= ARGON2_MAX_T); + let tampered = mutate_scheme1(&blob, |kdf, _, _| { + // Keep m_kib at the shipped default so the m_kib gate + // cannot fire — t must be the sole reason this rejects. + kdf.m_kib = target.m_kib; + kdf.t = bumped_t; + }); + let err = unwrap(&wid(1), "seed", Some(&p), &tampered).unwrap_err(); + assert!(matches!(err, SecretStoreError::KdfFailure), "got {err:?}"); + } + + /// Trailing bytes appended after a valid envelope are rejected as + /// `Corruption` — defends against a truncation/extension probe. + #[test] + fn decode_rejects_trailing_garbage() { + let p = pw("pw"); + let blob = scheme1_blob(&p); + let mut extended = blob.clone(); + extended.extend_from_slice(&[0xFFu8; 16]); + let err = unwrap(&wid(1), "seed", Some(&p), &extended).unwrap_err(); + assert!(matches!(err, SecretStoreError::Corruption), "got {err:?}"); + + // The same blob without the suffix still unwraps cleanly — + // proves the rejection is on the trailing bytes, not the + // envelope itself. + let ok = unwrap(&wid(1), "seed", Some(&p), &blob).unwrap(); + assert_eq!(ok.expose_secret(), b"seed"); + } + + /// TC-031 — round-tripped secret matches the original under a + /// constant-time compare. + #[test] + fn round_trip_is_constant_time_equal() { + let p = pw("pw"); + let original = SecretBytes::from_slice(b"seed material"); + let blob = + wrap_with_params(&wid(1), "seed", Some(&p), original.expose_secret(), floor()).unwrap(); + let got = unwrap(&wid(1), "seed", Some(&p), blob.expose_secret()).unwrap(); + assert!(bool::from(got.ct_eq(&original))); + } + + /// TC-035 (round-trip half) — scheme-1 at exact MAX_PLAINTEXT_LEN + /// round-trips and the enveloped bytes fit the backend cap. + #[test] + fn scheme1_at_cap_round_trips_within_backend_cap() { + let p = pw("pw"); + let pt = vec![0x5Au8; MAX_PLAINTEXT_LEN]; + let blob = wrap_with_params(&wid(1), "seed", Some(&p), &pt, floor()).unwrap(); + assert!(blob.len() <= MAX_SECRET_LEN); + let got = unwrap(&wid(1), "seed", Some(&p), blob.expose_secret()).unwrap(); + assert_eq!(got.expose_secret(), &pt[..]); + } + + /// TC-036 — value rollback is intentionally NOT defended. + #[test] + fn value_rollback_is_not_defended() { + let p = pw("pw"); + let old = wrap_with_params(&wid(1), "seed", Some(&p), b"OLD-VALUE", floor()).unwrap(); + let _new = wrap_with_params(&wid(1), "seed", Some(&p), b"NEW-VALUE", floor()).unwrap(); + let got = unwrap(&wid(1), "seed", Some(&p), old.expose_secret()).unwrap(); + assert_eq!(got.expose_secret(), b"OLD-VALUE"); + } + + /// TC-032 — random byte mutations and truncations never panic; + /// every outcome is a permitted typed variant. + #[test] + fn fuzz_byte_mutation_and_truncation_never_panics() { + let p = pw("fuzz-pw"); + let valid = scheme1_blob(&p); + // Pristine envelope unwraps cleanly. + assert_eq!( + unwrap(&wid(1), "seed", Some(&p), &valid) + .unwrap() + .expose_secret(), + b"seed" + ); + + let mut state: u32 = 0x9E37_79B9; + let mut next = || { + state ^= state << 13; + state ^= state >> 17; + state ^= state << 5; + state + }; + + let assert_typed = |arg: Option<&SecretString>, buf: &[u8]| { + let res = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| { + unwrap(&wid(1), "seed", arg, buf) + })) + .expect("unwrap must never panic on hostile input"); + match res { + Ok(_) + | Err(SecretStoreError::Corruption) + | Err(SecretStoreError::WrongPassword) + | Err(SecretStoreError::NeedsPassword) + | Err(SecretStoreError::ExpectedProtectedButUnsealed) + | Err(SecretStoreError::UnsupportedEnvelopeVersion { .. }) + | Err(SecretStoreError::KdfFailure) => {} + Err(other) => panic!("unexpected error variant: {other:?}"), + } + }; + + for i in 0..2_000 { + let mut buf = valid.clone(); + let flips = 1 + (next() % 4) as usize; + for _ in 0..flips { + let idx = (next() as usize) % buf.len(); + buf[idx] ^= (next() & 0xFF) as u8; + } + // None path every iteration (cheap, no derive). + assert_typed(None, &buf); + // Some path on a representative subset (each may derive). + if i % 16 == 0 { + assert_typed(Some(&p), &buf); + } + } + + // Truncation at every offset — a short read must never panic. + for cut in 0..valid.len() { + assert_typed(None, &valid[..cut]); + assert_typed(Some(&p), &valid[..cut]); + } + } + + // TC-040 — proptest: no single-byte flip surfaces the plaintext. + // Minimises to the offset that breaks coverage if one exists. + proptest::proptest! { + #[test] + fn prop_single_byte_flip_never_yields_plaintext( + (offset, mask) in (0usize..200usize, 1u8..=255u8), + ) { + // Re-built per case so the proptest harness can shrink + // independently of the host RNG. + let plaintext: &[u8] = b"goldfinch"; + let p = pw("pw"); + let valid = wrap_with_params(&wid(1), "seed", Some(&p), plaintext, floor()) + .unwrap() + .expose_secret() + .to_vec(); + if offset >= valid.len() { + // Out-of-bounds offset → skip via prop_assume so proptest + // shrinks toward in-bounds offsets. + proptest::prop_assume!(offset < valid.len()); + } + let mut buf = valid.clone(); + buf[offset] ^= mask; + match unwrap(&wid(1), "seed", Some(&p), &buf) { + Ok(secret) => { + proptest::prop_assert_ne!( + secret.expose_secret(), + plaintext, + "single-byte flip at offset {} surfaced the plaintext", + offset + ); + } + Err(_) => { /* any typed error is fine */ } + } + } + } +} diff --git a/packages/rs-platform-wallet-storage/src/secrets/wire/kdf.rs b/packages/rs-platform-wallet-storage/src/secrets/wire/kdf.rs new file mode 100644 index 0000000000..e869b29159 --- /dev/null +++ b/packages/rs-platform-wallet-storage/src/secrets/wire/kdf.rs @@ -0,0 +1,56 @@ +//! Bincode-encoded wire image of [`KdfParams`] — the Argon2 parameter +//! header read out of every scheme-1 envelope. +//! +//! Kept as a separate type from [`KdfParams`] (the in-memory + JSON- +//! vault type) so the wire layer owns its own bincode derives and the +//! in-memory type keeps its serde derives for the human-debuggable JSON +//! vault format. + +use crate::secrets::error::SecretStoreError; +use crate::secrets::file::crypto::KdfParams; + +/// Wire image of [`KdfParams`]: `id ‖ m_kib ‖ t ‖ p`, each a fixed- +/// width integer under the bincode varint config. Encoded once into +/// every scheme-1 envelope's `Payload::Password` body AND into the +/// scheme-1 AAD, so the two cannot disagree without failing the tag. +#[derive(bincode::Encode, bincode::Decode, Debug, PartialEq, Eq, Clone, Copy)] +pub(crate) struct KdfParamsEncoded { + /// Argon2 algorithm discriminator (only `KDF_ID_ARGON2ID = 1` + /// today; enforced by [`KdfParams::enforce_bounds`]). + pub id: u8, + /// Argon2 memory cost (KiB). Bounded. + pub m_kib: u32, + /// Argon2 time cost (iterations). Bounded. + pub t: u32, + /// Argon2 parallelism. Pinned to 1. + pub p: u32, +} + +impl From for KdfParamsEncoded { + fn from(k: KdfParams) -> Self { + Self { + id: k.id, + m_kib: k.m_kib, + t: k.t, + p: k.p, + } + } +} + +impl TryFrom for KdfParams { + type Error = SecretStoreError; + + /// Convert the wire image into the in-memory [`KdfParams`], gated on + /// [`KdfParams::enforce_bounds`] so an inflated header never + /// reaches `derive_key`. + fn try_from(k: KdfParamsEncoded) -> Result { + let out = KdfParams { + id: k.id, + m_kib: k.m_kib, + t: k.t, + p: k.p, + }; + out.enforce_bounds()?; + Ok(out) + } +} diff --git a/packages/rs-platform-wallet-storage/src/secrets/wire/mod.rs b/packages/rs-platform-wallet-storage/src/secrets/wire/mod.rs new file mode 100644 index 0000000000..d53ff9bbb9 --- /dev/null +++ b/packages/rs-platform-wallet-storage/src/secrets/wire/mod.rs @@ -0,0 +1,36 @@ +//! Bincode wire format for the Tier-2 envelope and the three AAD +//! constructions used inside `secrets/`. +//! +//! Every byte that crosses the AEAD seam — the on-disk Tier-2 blob and the +//! AAD bound into each ciphertext — is produced by a `#[derive(bincode:: +//! Encode)]` (or `Encode + Decode`) struct in this module, against the +//! single [`config::WIRE_CONFIG`] constant. A future bincode-config drift +//! is then caught by the golden vector tests in [`envelope::tests`] +//! instead of silently corrupting every stored blob. +//! +//! Module is `pub(crate)` only — the Tier-2 wire format is an +//! implementation detail of [`SecretStore`](super::store::SecretStore); +//! external callers see the unchanged `set_secret` / `get_secret` API. +//! +//! Audit-readable layout: +//! +//! - [`config`] — the single bincode config + domain-tag / version +//! constants every encoder uses. +//! - [`kdf`] — `KdfParamsEncoded`, the wire image of [`KdfParams`]. +//! - [`aad`] — the three AAD structs (`Tier2Aad` / `EntryAad` / +//! `VerifyAad`). +//! - [`envelope`] — the `Envelope` + `Payload` structs plus the +//! `wrap` / `unwrap` API. +//! +//! [`KdfParams`]: super::file::crypto::KdfParams +//! +//! Domain tags include an explicit `-v2` suffix to mark the +//! wire-format break from the pre-bincode hand-rolled layout +//! (`PWSEV-TIER2-AAD-v1` and the implicitly-untagged +//! `secrets/file/format.rs::aad` / `verify_aad` outputs). +#![deny(missing_docs)] + +pub(crate) mod aad; +pub(crate) mod config; +pub(crate) mod envelope; +pub(crate) mod kdf; diff --git a/packages/rs-platform-wallet-storage/tests/secrets_default_on_compiles.rs b/packages/rs-platform-wallet-storage/tests/secrets_default_on_compiles.rs index 23cc10d582..1f45e2ceae 100644 --- a/packages/rs-platform-wallet-storage/tests/secrets_default_on_compiles.rs +++ b/packages/rs-platform-wallet-storage/tests/secrets_default_on_compiles.rs @@ -9,7 +9,7 @@ use platform_wallet_storage::secrets::{ default_credential_store, EncryptedFileStore, SecretBytes, SecretStoreError, SecretString, - WalletId, SERVICE_PREFIX, + WalletId, MAX_PLAINTEXT_LEN, MIN_PASSPHRASE_LEN, SERVICE_PREFIX, }; #[test] @@ -23,6 +23,9 @@ fn default_build_exposes_secrets_surface() { } let _ = _accepts_path as fn(_, _) -> _; let _ = SERVICE_PREFIX.len(); + // The Tier-2 public consts are re-exported on the default build. + let _ = MAX_PLAINTEXT_LEN; + let _ = MIN_PASSPHRASE_LEN; let _ = std::mem::size_of::(); let _ = std::mem::size_of::(); let _ = std::mem::size_of::();