alkssh/tests/common/mod.rs

//! alkssh's wave-1 test doubles — the in-memory seams every later
//! wave's contract tests run against (the alkgit `tests/common/`
//! convention, adapted): an in-memory `IdentityProvider`
//! ([`MemIdentityProvider`]), the in-memory vault seam ([`TestVault`]),
//! an in-memory `HostKeyPolicy` ([`MemHostKeyPolicy`]), and the
//! ed25519 test-key fixtures ([`FIXTURE_KEYS`]).
//!
//! **Location decision (recorded, the OQ-03 freeze-inventory
//! discipline):** the doubles live *only* here — a shared module under
//! `tests/` reached with `mod common;` — and never in the public API:
//! no re-export from `lib.rs`, no feature gate, nothing doubles-related
//! reachable from the crate root. The doubles' shapes are test
//! surface, test-versioned freely; the only `src/`-side consumers are
//! `#[cfg(test)]` modules reading the fixture *files* through
//! `include_str!`, never a public export.
//!
//! **Vault double decision (recorded, flagged for the wave-1 gate):**
//! alkvault 0.1 ships an in-memory construction —
//! `VaultServiceHandle::new()` is an in-process vault that
//! `unlock_new` arms in-memory. The double is therefore a *wrapper*
//! ([`TestVault`]) around that construction, not a local re-impl
//! behind the source trait: the same decrypt error taxonomy, GCM
//! integrity behavior, and rotation semantics the production source
//! seam sees are exercised verbatim, and the POC-2 §3 failure postures
//! (locked / absent / tampered / wrong seed) ride the real seams.
//!
//! **Fixture decision (recorded):** committed static OpenSSH-PEM test
//! keys, minted by `ssh-keygen` at vector-generation time (the
//! independent issuer), never generated at test time — determinism and
//! no tooling dependency. The committed private halves are throwaway
//! fixtures, not secrets: minted for this suite only, never registered
//! anywhere real, never deployed. Each key's fingerprint is recorded
//! byte-verbatim from `ssh-keygen -lf` in
//! `tests/vectors/fingerprints.txt`; [`FIXTURE_KEYS`] carries the
//! recorded values and every fingerprint comparison in the suite
//! asserts parity against them.
//!
//! Each test binary's `mod common;` compiles the whole shared module
//! and no single binary exercises every double — dead_code is allowed
//! module-wide so one binary's suite never fails the next's.
//!
//! The row/stamp discipline (adapted from the sibling crates): test
//! functions are *rows* — the name states the property, not the
//! caller — and each carries a doc-comment list item beginning
//! **`Contract stamp:`** citing the pinning spec §/ADR § (never a bare
//! wave or date). The marker is greppable:
//! `grep -rn "Contract stamp:" tests/` is the inventory.

#![allow(dead_code)]

/// The loopback harness — *the* contract-test vehicle (its own
/// location/transport decisions live in its module docs:
/// `tests/common/harness.rs`).
pub mod harness;

use std::collections::HashMap;

use alkcall::core::auth::{AuthToken, Identity, IdentityProvider};
use alkvault::{EncryptedData, VaultServiceHandle};
use async_trait::async_trait;
use russh::keys::{PrivateKey, PublicKey, decode_secret_key, parse_public_key_base64};

use alkssh::{HostKeyPolicy, HostKeySource, KeySourceError, PresentedHostKey};

/// One committed ed25519 test-key fixture: the private OpenSSH-PEM
/// (`tests/vectors/<name>.key`), the public one-line blob
/// (`tests/vectors/<name>.pub`), and the fingerprint recorded
/// byte-verbatim from `ssh-keygen -lf` (`tests/vectors/fingerprints.txt`).
///
/// The `pem`/`blob`/`fingerprint` values are committed constants — throwaway
/// fixture material, never registered or deployed anywhere real.
#[derive(Debug)]
pub struct FixtureKey {
    /// The fixture's name (`alpha` … `delta`).
    pub name: &'static str,
    /// The OpenSSH private-key PEM, included verbatim from the
    /// committed fixture file.
    pub pem: &'static str,
    /// The public key's base64 blob — the OpenSSH one-line encoding,
    /// `ssh-ed25519 <blob>` stripped of the key-type prefix and comment.
    pub blob: &'static str,
    /// The fingerprint recorded from `ssh-keygen -lf` — the
    /// independent-issuer value every comparison in the suite asserts
    /// parity against (ADR-004 decision 1's contract invariant).
    pub fingerprint: &'static str,
}

impl FixtureKey {
    /// The decoded public key (parity input; ADR-004 decision 1).
    pub fn public_key(&self) -> PublicKey {
        parse_public_key_base64(self.blob).expect("committed fixture blob parses")
    }

    /// The decoded private key — `decode_secret_key(pem, None)`, the
    /// ADR-005 decision 2 conversion (the fixtures' inner format is
    /// exactly the at-rest contract: unencrypted OpenSSH PEM).
    pub fn private_key(&self) -> PrivateKey {
        decode_secret_key(self.pem, None).expect("committed fixture PEM decodes")
    }
}

/// The wave-1 fixture set: four minted ed25519 keys. `alpha` is the
/// canonical client-dial fixture; `bravo`/`charlie` are the host-key
/// pair (rotation/multi-key rows); `delta` is the independent extra
/// (unregistered-peer, mismatch, and wrong-key rows).
pub const FIXTURE_KEYS: &[FixtureKey] = &[
    FixtureKey {
        name: "alpha",
        pem: include_str!("../vectors/alpha.key"),
        blob: "AAAAC3NzaC1lZDI1NTE5AAAAIM28sP5UAl3npJJ8trZgPt2kE+Af6477/Rx6J2VbM14z",
        fingerprint: "SHA256:YyaiL42Xl8tcRRUhNCiqQBsiiRWVHHDR9hpXC45EQ6A",
    },
    FixtureKey {
        name: "bravo",
        pem: include_str!("../vectors/bravo.key"),
        blob: "AAAAC3NzaC1lZDI1NTE5AAAAIMvu9S+hH9Dug7fdiHLeW+B9kee+i495jPAdBH8YaOvQ",
        fingerprint: "SHA256:yQf/w2wYBoZ9adDlRGbcNh7AHE3mbqWRCqoGHra1ib0",
    },
    FixtureKey {
        name: "charlie",
        pem: include_str!("../vectors/charlie.key"),
        blob: "AAAAC3NzaC1lZDI1NTE5AAAAIKL8zAzLkR0jKFY2l+QrBjC3Cv4Q3OBUUCX7rQV1jXQe",
        fingerprint: "SHA256:b5jdwosbZUx5nsY5zfr/ZCt+4sJYehVBq7Xl/wstJ9U",
    },
    FixtureKey {
        name: "delta",
        pem: include_str!("../vectors/delta.key"),
        blob: "AAAAC3NzaC1lZDI1NTE5AAAAIIcMK+njeiGqh8THEBPU9MTYrSJ3WHvxv3ZH11JTS/SU",
        fingerprint: "SHA256:4MiQ0KGoTEaklHBTlxPDuQkeu0FTyqEbne10K6Z8CKs",
    },
];

/// Looks a fixture up by name — `fixture("alpha")` is the canonical
/// client-dial key.
pub fn fixture(name: &str) -> &'static FixtureKey {
    FIXTURE_KEYS
        .iter()
        .find(|k| k.name == name)
        .unwrap_or_else(|| panic!("no fixture named {name}"))
}

/// Builds an [`Identity`] for registration (`id` + scopes; the
/// `resources` map is empty — the wire layer only needs the resolved
/// identity, richer ACL shapes are the assembly's).
pub fn identity(id: &str, scopes: &[&str]) -> Identity {
    Identity {
        id: id.into(),
        scopes: scopes.iter().map(|s| s.to_string()).collect(),
        resources: HashMap::new(),
    }
}

/// The in-memory [`IdentityProvider`] — registered fingerprints →
/// [`Identity`] resolutions over alkcall's trait verbatim.
///
/// The double the wave-2 auth bridge and dispatch tests resolve
/// against, and the analog of serving `Arc<dyn IdentityProvider>` in
/// [`alkssh::ServeConfig`]: the fingerprint → identity path is ADR-004
/// decision 1's only resolution shape.
pub struct MemIdentityProvider {
    identities: parking_lot::RwLock<HashMap<String, Identity>>,
}

impl MemIdentityProvider {
    /// An empty registry — nothing resolves until registered
    /// (fail-closed: unregistered fingerprints decline).
    pub fn new() -> Self {
        Self {
            identities: parking_lot::RwLock::new(HashMap::new()),
        }
    }

    /// Registers (or replaces) one fingerprint → identity mapping.
    pub fn register(&self, fingerprint: &str, identity: Identity) {
        self.identities
            .write()
            .insert(fingerprint.to_string(), identity);
    }

    /// Removes a registration — the post-resolution-revoke shape.
    pub fn revoke(&self, fingerprint: &str) {
        self.identities.write().remove(fingerprint);
    }

    /// The registered fingerprints — inspection for test assertions.
    pub fn registered_fingerprints(&self) -> Vec<String> {
        let mut keys = self
            .identities
            .read()
            .keys()
            .cloned()
            .collect::<Vec<String>>();
        keys.sort();
        keys
    }
}

impl Default for MemIdentityProvider {
    fn default() -> Self {
        Self::new()
    }
}

impl IdentityProvider for MemIdentityProvider {
    /// The fingerprint path — ADR-004 decision 1's single resolution
    /// shape: exact string equality against registered values.
    fn resolve_from_fingerprint(&self, fingerprint: &str) -> Option<Identity> {
        self.identities.read().get(fingerprint).cloned()
    }

    /// The token path resolves nothing in the SSH direction —
    /// ADR-004's dispositions are fingerprint-only on this surface
    /// (`auth-bridge.md`); the double never invents a token shape.
    fn resolve_from_token(&self, _: &AuthToken) -> Option<Identity> {
        None
    }
}

/// The in-memory vault seam — a wrapper over alkvault 0.1's own
/// in-memory construction ([`VaultServiceHandle`], unlocked at
/// construction via `unlock_new`).
///
/// The locked/absent/tampered/mismatch failure postures (POC-2 §3) are
/// exercised *through the real production seams* the source traits
/// call, against this handle — the double exists so tests never touch
/// vault lifecycle decisions themselves: [`TestVault::unlocked`] arms
/// it, `lock` closes it, and the sources keep refusing, never
/// retrying (the crate never unlocks — ADR-005's separation).
#[derive(Clone)]
pub struct TestVault {
    handle: VaultServiceHandle,
}

impl TestVault {
    /// A freshly armed in-memory vault — unlocked, ready to encrypt.
    pub fn unlocked() -> Self {
        let handle = VaultServiceHandle::new();
        handle
            .unlock_new(24)
            .expect("in-memory vault arms unlocked");
        Self { handle }
    }

    /// The vault handle the production sources consume — clones share
    /// the same vault state (locking through one is visible to all).
    pub fn handle(&self) -> VaultServiceHandle {
        self.handle.clone()
    }

    /// Seals one fixture key's PEM into an at-rest record — the
    /// ADR-005 inner-format contract (unencrypted OpenSSH PEM in an
    /// `EncryptedData` record).
    pub fn seal(&self, key: &FixtureKey) -> EncryptedData {
        self.encrypt(key.pem)
    }

    /// Encrypts an arbitrary plaintext (the non-key and tamper rows
    /// need it; ADR-005 decision 4's decode-refusal shape).
    pub fn encrypt(&self, plaintext: &str) -> EncryptedData {
        self.handle
            .encrypt(plaintext, alkvault::CURRENT_KEY_VERSION)
            .expect("in-memory vault encrypts the plaintext")
    }

    /// Locks the vault — the locked-vault posture (POC-2 §3, the
    /// `KeySourceError::Locked` refusal class).
    pub fn lock(&self) {
        self.handle.lock();
    }

    /// The vault's lifecycle state, for posture assertions.
    pub fn is_unlocked(&self) -> bool {
        self.handle.is_unlocked()
    }
}

/// The in-memory [`HostKeySource`] double — a static decrypted key set
/// (wave-2 addition): the wire-shaped rows construct a real
/// `SshAdapter`, whose construction wants a non-empty host-key set, and
/// the direct-hook rows want a source that is never loaded (the handler
/// construction loads nothing — host keys are the russh `Config`'s
/// business, built in [`alkssh::SshAdapter::new`]).
///
/// `absent()` is the empty-set shape — its load refuses with
/// [`KeySourceError::Absent`] (the fail-closed contract), so any row
/// that accidentally loads an absent double fails loudly.
pub struct MemHostKeySource {
    keys: Vec<PrivateKey>,
}

impl MemHostKeySource {
    /// The never-loaded / absent shape.
    pub fn absent() -> Self {
        Self { keys: Vec::new() }
    }

    /// A static decrypted set from the fixture keys — the wire rows'
    /// host-key set (e.g. `["bravo"]`, the rotation-pair member).
    pub fn from_fixtures(keys: &[&'static FixtureKey]) -> Self {
        Self {
            keys: keys.iter().map(|k| k.private_key()).collect(),
        }
    }
}

#[async_trait]
impl HostKeySource for MemHostKeySource {
    async fn load(&self) -> Result<Vec<PrivateKey>, KeySourceError> {
        if self.keys.is_empty() {
            Err(KeySourceError::Absent)
        } else {
            Ok(self.keys.clone())
        }
    }
}

/// The in-memory [`HostKeyPolicy`] — a configurable verdict double with
/// an inspectable decision log, for the wave-4 dial tests (and the
/// case-1/case-2 rows of every host-key contract test).
///
/// Verdicts: a rules list of exact `(host, fingerprint)` matches —
/// last matching rule wins — falling back to a configurable
/// default verdict for unlisted pairs. The default of the
/// **default-constructed double is reject** (the crate's fail-closed
/// posture, `OQ-05`); permissive verdicts are the test's explicit
/// choice, mirroring "permissive policy is the assembly's to write".
/// Every decision is recorded with the full [`PresentedHostKey`]
/// context; the log is the inspectable record.
pub struct MemHostKeyPolicy {
    default_verdict: bool,
    rules: parking_lot::RwLock<Vec<Rule>>,
    log: parking_lot::Mutex<Vec<Decision>>,
}

struct Rule {
    host: String,
    fingerprint: String,
    accept: bool,
}

/// One recorded host-key decision — the presented key and the verdict
/// the policy returned.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Decision {
    /// The presented key that was decided.
    pub presented: PresentedHostKey,
    /// The verdict: `true` = accept, `false` = decline.
    pub accepted: bool,
}

impl MemHostKeyPolicy {
    /// A decision double with the fail-closed default (reject
    /// everything without a matching accept rule).
    pub fn new() -> Self {
        Self::with_default(false)
    }

    /// A decision double with an explicit default verdict — the
    /// case-2 permissive posture (`accepting` doubles) is the test's
    /// explicit choice, never a default.
    pub fn with_default(default_verdict: bool) -> Self {
        Self {
            default_verdict,
            rules: parking_lot::RwLock::new(Vec::new()),
            log: parking_lot::Mutex::new(Vec::new()),
        }
    }

    /// Adds a rule: exact `(host, fingerprint)` → verdict. Last match
    /// wins, so later rules override earlier ones.
    pub fn rule(&self, host: &str, fingerprint: &str, accept: bool) {
        self.rules.write().push(Rule {
            host: host.into(),
            fingerprint: fingerprint.into(),
            accept,
        });
    }

    /// Pins an accept rule for one `(host, fingerprint)` — the case-1
    /// trust-anchor shape (hard accept on exact match).
    pub fn pin(&self, host: &str, fingerprint: &str) {
        self.rule(host, fingerprint, true);
    }

    /// The decision log — every [`Decision`] in call order.
    pub fn decisions(&self) -> Vec<Decision> {
        self.log.lock().clone()
    }
}

impl Default for MemHostKeyPolicy {
    fn default() -> Self {
        Self::new()
    }
}

#[async_trait]
impl HostKeyPolicy for MemHostKeyPolicy {
    async fn decide(&self, presented: &PresentedHostKey) -> bool {
        let rules = self.rules.read();
        let verdict = rules
            .iter()
            .rev()
            .find(|r| r.host == presented.host && r.fingerprint == presented.fingerprint)
            .map(|r| r.accept)
            .unwrap_or(self.default_verdict);
        drop(rules);
        self.log.lock().push(Decision {
            presented: presented.clone(),
            accepted: verdict,
        });
        verdict
    }
}