sozu-lib 2.0.2

//! Crypto provider selection.
//!
//! - `crypto-ring` (default): pure Rust via [ring](https://github.com/briansmith/ring).
//! - `crypto-aws-lc-rs`: post-quantum-capable [aws-lc-rs](https://github.com/aws/aws-lc-rs).
//!   Requires `cmake`.
//! - `crypto-openssl`: system OpenSSL via [rustls-openssl](https://github.com/rustls/rustls-openssl).
//!   Requires `cmake` + OpenSSL headers.
//! - `fips`: implies `crypto-aws-lc-rs` plus `rustls/fips` (FIPS 140-3 build).
//!
//! At least one provider feature must be enabled. When several are enabled
//! together (e.g. `cargo build --all-features` in CI, or `--features fips`
//! on top of the default `crypto-ring`), a deterministic precedence chain
//! selects one: `fips > ring > aws-lc-rs > openssl`. `fips` always wins, so
//! a binary built with `--features fips` runs aws-lc-rs in FIPS mode even
//! when `crypto-ring` is also enabled. Downstream packaging (Dockerfile,
//! RPM, PKGBUILD) selects exactly one provider explicitly.

use std::sync::LazyLock;

use rustls::crypto::CryptoProvider;

static DEFAULT_PROVIDER: LazyLock<CryptoProvider> = LazyLock::new(default_provider);

#[cfg(not(any(
    feature = "crypto-ring",
    feature = "crypto-aws-lc-rs",
    feature = "crypto-openssl"
)))]
compile_error!(
    "No crypto provider selected. Enable one of: `crypto-ring`, `crypto-aws-lc-rs`, or `crypto-openssl`."
);

// `fips` wins. It implies `crypto-aws-lc-rs` plus `rustls/fips`, so the
// resulting binary uses aws-lc-rs in FIPS mode regardless of which other
// provider features are enabled by `default` or `--all-features`. This
// lets `cargo build --features fips` produce a genuine FIPS binary even
// while the default `crypto-ring` is still active, instead of silently
// linking ring and emitting a non-FIPS provider in a `+fips`-tagged
// build. Below `fips`, the precedence chain falls back to `ring >
// aws-lc-rs > openssl`, matching the binary default. Downstream
// packaging surfaces (`Dockerfile`, `os-build/...`) still select exactly
// one feature in production builds.

#[cfg(feature = "fips")]
pub use rustls::crypto::aws_lc_rs::{
    cipher_suite::{
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
        TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
        TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
        TLS13_AES_128_GCM_SHA256, TLS13_AES_256_GCM_SHA384, TLS13_CHACHA20_POLY1305_SHA256,
    },
    default_provider,
    sign::any_supported_type,
};

#[cfg(all(feature = "crypto-ring", not(feature = "fips")))]
pub use rustls::crypto::ring::{
    cipher_suite::{
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
        TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
        TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
        TLS13_AES_128_GCM_SHA256, TLS13_AES_256_GCM_SHA384, TLS13_CHACHA20_POLY1305_SHA256,
    },
    default_provider,
    sign::any_supported_type,
};

#[cfg(all(
    feature = "crypto-aws-lc-rs",
    not(feature = "fips"),
    not(feature = "crypto-ring")
))]
pub use rustls::crypto::aws_lc_rs::{
    cipher_suite::{
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
        TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
        TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
        TLS13_AES_128_GCM_SHA256, TLS13_AES_256_GCM_SHA384, TLS13_CHACHA20_POLY1305_SHA256,
    },
    default_provider,
    sign::any_supported_type,
};

#[cfg(all(
    feature = "crypto-openssl",
    not(feature = "fips"),
    not(feature = "crypto-ring"),
    not(feature = "crypto-aws-lc-rs")
))]
pub use rustls_openssl::{
    cipher_suite::{
        TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
        TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
        TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
        TLS13_AES_128_GCM_SHA256, TLS13_AES_256_GCM_SHA384, TLS13_CHACHA20_POLY1305_SHA256,
    },
    default_provider,
};

/// Load a private key into a signing key.
///
/// For `ring` and `aws-lc-rs`, this delegates to `sign::any_supported_type`.
/// For `rustls-openssl`, this delegates to `KeyProvider::load_private_key`.
#[cfg(all(
    feature = "crypto-openssl",
    not(feature = "fips"),
    not(feature = "crypto-ring"),
    not(feature = "crypto-aws-lc-rs")
))]
pub fn any_supported_type(
    der: &rustls::pki_types::PrivateKeyDer<'_>,
) -> Result<std::sync::Arc<dyn rustls::sign::SigningKey>, rustls::Error> {
    use rustls::crypto::KeyProvider;
    rustls_openssl::KeyProvider.load_private_key(der.clone_key())
}

/// Look up a key exchange group by its string name.
///
/// Accepts the standard TLS named group identifiers used in sozu configuration:
/// - `"x25519"` / `"X25519"` — Curve25519 ECDHE
/// - `"secp256r1"` / `"P-256"` — NIST P-256 ECDHE
/// - `"secp384r1"` / `"P-384"` — NIST P-384 ECDHE
/// - `"X25519MLKEM768"` — Post-quantum hybrid (aws-lc-rs and openssl only)
///
/// Returns `None` if the group name is unknown or not supported by the compiled provider.
pub fn kx_group_by_name(name: &str) -> Option<&'static dyn rustls::crypto::SupportedKxGroup> {
    let provider = &*DEFAULT_PROVIDER;
    let named_group = match name {
        "x25519" | "X25519" => rustls::NamedGroup::X25519,
        "secp256r1" | "P-256" => rustls::NamedGroup::secp256r1,
        "secp384r1" | "P-384" => rustls::NamedGroup::secp384r1,
        "X25519MLKEM768" => rustls::NamedGroup::X25519MLKEM768,
        _ => return None,
    };
    provider
        .kx_groups
        .iter()
        .find(|g| g.name() == named_group)
        .copied()
}

/// Look up a cipher suite by its string name, filtered through the active
/// crypto provider's supported set.
///
/// Accepts the rustls cipher suite names used in sozu configuration.
/// Returns `None` if the name is unknown OR if the suite is not present
/// in `default_provider().cipher_suites` for the active provider build.
///
/// The filter step is what keeps a FIPS build (aws-lc-rs with the
/// upstream `fips` feature) from silently advertising non-FIPS suites
/// such as ChaCha20-Poly1305 when `DEFAULT_CIPHER_LIST` includes them:
/// rustls 0.23 only reports `ServerConfig::fips() == true` if every
/// configured cipher and KX group is FIPS-approved (see
/// `rustls/src/crypto/mod.rs` and `aws_lc_rs/mod.rs` ChaCha gating
/// under `feature = "fips"`).
pub fn cipher_suite_by_name(name: &str) -> Option<rustls::SupportedCipherSuite> {
    let candidate = match name {
        "TLS13_AES_256_GCM_SHA384" => Some(TLS13_AES_256_GCM_SHA384),
        "TLS13_AES_128_GCM_SHA256" => Some(TLS13_AES_128_GCM_SHA256),
        "TLS13_CHACHA20_POLY1305_SHA256" => Some(TLS13_CHACHA20_POLY1305_SHA256),
        "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384" => Some(TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384),
        "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256" => Some(TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256),
        "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256" => {
            Some(TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256)
        }
        "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384" => Some(TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384),
        "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256" => Some(TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256),
        "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256" => {
            Some(TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256)
        }
        _ => None,
    }?;

    // Only return the suite if the active provider actually advertises
    // it. Compare by `CipherSuite` enum (newtype around the IANA value)
    // since `SupportedCipherSuite` does not implement `Eq`.
    let wanted = candidate.suite();
    DEFAULT_PROVIDER
        .cipher_suites
        .iter()
        .find(|s| s.suite() == wanted)
        .copied()
}

#[cfg(test)]
mod tests {
    use super::*;
    use rustls::NamedGroup;

    #[test]
    fn default_provider_has_tls13_cipher_suites() {
        let provider = default_provider();
        let names: Vec<_> = provider.cipher_suites.iter().map(|cs| cs.suite()).collect();
        assert!(
            names.contains(&rustls::CipherSuite::TLS13_AES_256_GCM_SHA384),
            "provider must support TLS13_AES_256_GCM_SHA384"
        );
        assert!(
            names.contains(&rustls::CipherSuite::TLS13_AES_128_GCM_SHA256),
            "provider must support TLS13_AES_128_GCM_SHA256"
        );
        // CHACHA20_POLY1305 is not FIPS-approved
        #[cfg(not(feature = "fips"))]
        assert!(
            names.contains(&rustls::CipherSuite::TLS13_CHACHA20_POLY1305_SHA256),
            "provider must support TLS13_CHACHA20_POLY1305_SHA256"
        );
    }

    #[test]
    fn default_provider_has_tls12_cipher_suites() {
        let provider = default_provider();
        let names: Vec<_> = provider.cipher_suites.iter().map(|cs| cs.suite()).collect();
        assert!(
            names.contains(&rustls::CipherSuite::TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384),
            "provider must support TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384"
        );
        assert!(
            names.contains(&rustls::CipherSuite::TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384),
            "provider must support TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384"
        );
    }

    #[test]
    fn default_provider_has_classical_kx_groups() {
        let provider = default_provider();
        let groups: Vec<_> = provider.kx_groups.iter().map(|g| g.name()).collect();
        // X25519 is not FIPS-approved (only NIST curves are)
        #[cfg(not(feature = "fips"))]
        assert!(
            groups.contains(&NamedGroup::X25519),
            "provider must support X25519 key exchange"
        );
        assert!(
            groups.contains(&NamedGroup::secp256r1),
            "provider must support secp256r1 key exchange"
        );
        assert!(
            groups.contains(&NamedGroup::secp384r1),
            "provider must support secp384r1 key exchange"
        );
    }

    #[cfg(all(feature = "crypto-aws-lc-rs", not(feature = "fips")))]
    #[test]
    fn aws_lc_rs_supports_post_quantum_kx() {
        let provider = default_provider();
        let groups: Vec<_> = provider.kx_groups.iter().map(|g| g.name()).collect();
        assert!(
            groups.contains(&NamedGroup::X25519MLKEM768),
            "aws-lc-rs provider must support X25519MLKEM768 post-quantum key exchange"
        );
    }

    #[cfg(all(feature = "crypto-aws-lc-rs", not(feature = "fips")))]
    #[test]
    fn aws_lc_rs_has_more_kx_groups_than_classical() {
        let provider = default_provider();
        // aws-lc-rs should have more kx groups than just the 3 classical ones
        // (X25519, secp256r1, secp384r1) because it also includes PQ groups
        assert!(
            provider.kx_groups.len() > 3,
            "aws-lc-rs should have more than 3 kx groups (has {}), including post-quantum",
            provider.kx_groups.len()
        );
    }

    #[cfg(feature = "fips")]
    #[test]
    fn fips_provider_has_nist_kx_groups() {
        let provider = default_provider();
        let groups: Vec<_> = provider.kx_groups.iter().map(|g| g.name()).collect();
        assert!(
            groups.contains(&NamedGroup::secp256r1),
            "FIPS provider must support secp256r1"
        );
        assert!(
            groups.contains(&NamedGroup::secp384r1),
            "FIPS provider must support secp384r1"
        );
    }

    #[cfg(feature = "fips")]
    #[test]
    fn fips_provider_has_aes_gcm_cipher_suites() {
        let provider = default_provider();
        let suites: Vec<_> = provider.cipher_suites.iter().map(|cs| cs.suite()).collect();
        assert!(
            suites.contains(&rustls::CipherSuite::TLS13_AES_256_GCM_SHA384),
            "FIPS provider must support TLS13_AES_256_GCM_SHA384"
        );
        assert!(
            suites.contains(&rustls::CipherSuite::TLS13_AES_128_GCM_SHA256),
            "FIPS provider must support TLS13_AES_128_GCM_SHA256"
        );
    }

    #[cfg(all(feature = "crypto-ring", not(feature = "fips")))]
    #[test]
    fn ring_has_no_mlkem() {
        let provider = default_provider();
        let groups: Vec<_> = provider.kx_groups.iter().map(|g| g.name()).collect();
        assert!(
            !groups.contains(&NamedGroup::X25519MLKEM768),
            "ring provider should not advertise X25519MLKEM768"
        );
    }

    #[cfg(all(
        feature = "crypto-openssl",
        not(feature = "fips"),
        not(feature = "crypto-ring"),
        not(feature = "crypto-aws-lc-rs")
    ))]
    #[test]
    fn openssl_pq_kx_depends_on_openssl_version() {
        let provider = default_provider();
        let groups: Vec<_> = provider.kx_groups.iter().map(|g| g.name()).collect();
        let has_pq = groups.contains(&NamedGroup::X25519MLKEM768);
        // X25519MLKEM768 is only available with OpenSSL 3.5+.
        // On older versions, the provider should still work with classical groups.
        if has_pq {
            println!("OpenSSL 3.5+ detected: X25519MLKEM768 is available");
        } else {
            println!("OpenSSL < 3.5: X25519MLKEM768 not available, classical groups only");
        }
        // In all cases, classical groups must be present
        assert!(groups.contains(&NamedGroup::X25519));
        assert!(groups.contains(&NamedGroup::secp256r1));
    }

    #[cfg(not(feature = "fips"))]
    #[test]
    fn kx_group_by_name_resolves_x25519() {
        let group = kx_group_by_name("x25519").expect("x25519 should be supported");
        assert_eq!(group.name(), NamedGroup::X25519);
    }

    #[cfg(not(feature = "fips"))]
    #[test]
    fn kx_group_by_name_resolves_x25519_uppercase() {
        let group = kx_group_by_name("X25519").expect("X25519 should be supported");
        assert_eq!(group.name(), NamedGroup::X25519);
    }

    #[cfg(feature = "fips")]
    #[test]
    fn kx_group_by_name_returns_none_for_x25519_in_fips() {
        assert!(
            kx_group_by_name("x25519").is_none(),
            "X25519 is not FIPS-approved"
        );
        assert!(
            kx_group_by_name("X25519").is_none(),
            "X25519 is not FIPS-approved"
        );
    }

    #[test]
    fn kx_group_by_name_resolves_p256() {
        let group = kx_group_by_name("P-256").expect("P-256 should be supported");
        assert_eq!(group.name(), NamedGroup::secp256r1);
    }

    #[test]
    fn kx_group_by_name_resolves_secp256r1() {
        let group = kx_group_by_name("secp256r1").expect("secp256r1 should be supported");
        assert_eq!(group.name(), NamedGroup::secp256r1);
    }

    #[test]
    fn kx_group_by_name_resolves_p384() {
        let group = kx_group_by_name("P-384").expect("P-384 should be supported");
        assert_eq!(group.name(), NamedGroup::secp384r1);
    }

    #[test]
    fn kx_group_by_name_returns_none_for_unknown() {
        assert!(kx_group_by_name("P-521").is_none());
        assert!(kx_group_by_name("unknown").is_none());
        assert!(kx_group_by_name("").is_none());
    }

    #[cfg(all(feature = "crypto-aws-lc-rs", not(feature = "fips")))]
    #[test]
    fn kx_group_by_name_resolves_x25519mlkem768() {
        let group = kx_group_by_name("X25519MLKEM768").expect("X25519MLKEM768 should be supported");
        assert_eq!(group.name(), NamedGroup::X25519MLKEM768);
    }

    #[cfg(all(feature = "crypto-ring", not(feature = "fips")))]
    #[test]
    fn kx_group_by_name_returns_none_for_mlkem_on_ring() {
        assert!(
            kx_group_by_name("X25519MLKEM768").is_none(),
            "ring does not support X25519MLKEM768"
        );
    }

    #[test]
    fn can_load_rsa_private_key() {
        use rustls::pki_types::PrivateKeyDer;
        use rustls::pki_types::pem::PemObject;

        let key_pem = include_str!("../assets/key.pem");
        let private_key =
            PrivateKeyDer::from_pem_slice(key_pem.as_bytes()).expect("failed to parse PEM key");
        any_supported_type(&private_key).expect("provider must be able to load RSA private key");
    }

    #[test]
    fn can_build_server_config_with_tls13() {
        use std::sync::Arc;

        let provider = default_provider();
        let config = rustls::ServerConfig::builder_with_provider(Arc::new(provider))
            .with_protocol_versions(&[&rustls::version::TLS13])
            .expect("failed to build TLS 1.3 config")
            .with_no_client_auth()
            .with_cert_resolver(Arc::new(crate::tls::MutexCertificateResolver::default()));
        assert!(
            !config.alpn_protocols.contains(&b"h2".to_vec()),
            "default config should not have ALPN set"
        );
    }

    #[test]
    fn can_build_server_config_with_tls12_and_tls13() {
        use std::sync::Arc;

        let provider = default_provider();
        rustls::ServerConfig::builder_with_provider(Arc::new(provider))
            .with_protocol_versions(&[&rustls::version::TLS12, &rustls::version::TLS13])
            .expect("failed to build TLS 1.2+1.3 config")
            .with_no_client_auth()
            .with_cert_resolver(Arc::new(crate::tls::MutexCertificateResolver::default()));
    }

    #[cfg(all(feature = "crypto-aws-lc-rs", not(feature = "fips")))]
    #[test]
    fn pq_kx_compatible_with_server_config() {
        use std::sync::Arc;

        let provider = default_provider();
        // Verify the PQ kx group is present
        let has_pq = provider
            .kx_groups
            .iter()
            .any(|g| g.name() == NamedGroup::X25519MLKEM768);
        assert!(has_pq, "X25519MLKEM768 must be in the provider");

        // Build a TLS 1.3 config (PQ kx is only for TLS 1.3)
        let config = rustls::ServerConfig::builder_with_provider(Arc::new(provider))
            .with_protocol_versions(&[&rustls::version::TLS13])
            .expect("TLS 1.3 config with PQ kx should build successfully")
            .with_no_client_auth()
            .with_cert_resolver(Arc::new(crate::tls::MutexCertificateResolver::default()));

        // The config should be valid
        assert!(
            !config.alpn_protocols.contains(&b"h2".to_vec()),
            "default config should not have ALPN set"
        );
    }

    #[test]
    fn default_cipher_list_names_resolve_to_valid_suites() {
        use sozu_command::config::DEFAULT_CIPHER_LIST;

        let all_suites = [
            ("TLS13_AES_256_GCM_SHA384", TLS13_AES_256_GCM_SHA384.suite()),
            ("TLS13_AES_128_GCM_SHA256", TLS13_AES_128_GCM_SHA256.suite()),
            (
                "TLS13_CHACHA20_POLY1305_SHA256",
                TLS13_CHACHA20_POLY1305_SHA256.suite(),
            ),
            (
                "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
                TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384.suite(),
            ),
            (
                "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
                TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.suite(),
            ),
            (
                "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
                TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256.suite(),
            ),
            (
                "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
                TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384.suite(),
            ),
            (
                "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
                TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256.suite(),
            ),
            (
                "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256",
                TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256.suite(),
            ),
        ];

        // Verify every name in DEFAULT_CIPHER_LIST matches a known suite
        for name in DEFAULT_CIPHER_LIST {
            let found = all_suites.iter().any(|(n, _)| *n == name);
            assert!(
                found,
                "DEFAULT_CIPHER_LIST entry {name:?} does not match any known cipher suite"
            );
        }

        // Verify the count matches (no duplicates, no missing)
        assert_eq!(
            DEFAULT_CIPHER_LIST.len(),
            all_suites.len(),
            "DEFAULT_CIPHER_LIST length should match number of known suites"
        );
    }

    #[test]
    fn cipher_suite_by_name_resolves_tls13() {
        assert!(cipher_suite_by_name("TLS13_AES_256_GCM_SHA384").is_some());
        assert!(cipher_suite_by_name("TLS13_AES_128_GCM_SHA256").is_some());
        #[cfg(not(feature = "fips"))]
        assert!(cipher_suite_by_name("TLS13_CHACHA20_POLY1305_SHA256").is_some());
    }

    #[test]
    fn cipher_suite_by_name_resolves_tls12() {
        assert!(cipher_suite_by_name("TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384").is_some());
        assert!(cipher_suite_by_name("TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384").is_some());
    }

    #[test]
    fn cipher_suite_by_name_returns_none_for_unknown() {
        assert!(cipher_suite_by_name("UNKNOWN_CIPHER").is_none());
        assert!(cipher_suite_by_name("").is_none());
        // OpenSSL-style names should NOT match (this was the old bug)
        assert!(cipher_suite_by_name("TLS_AES_256_GCM_SHA384").is_none());
    }
}