neon/proxy/src/config.rs

use crate::auth;
use anyhow::{bail, ensure, Context, Ok};
use rustls::{sign, Certificate, PrivateKey};
use sha2::{Digest, Sha256};
use std::{
    collections::{HashMap, HashSet},
    str::FromStr,
    sync::Arc,
    time::Duration,
};
use tracing::{error, info};
use x509_parser::oid_registry;

pub struct ProxyConfig {
    pub tls_config: Option<TlsConfig>,
    pub auth_backend: auth::BackendType<'static, ()>,
    pub metric_collection: Option<MetricCollectionConfig>,
    pub allow_self_signed_compute: bool,
    pub http_config: HttpConfig,
    pub authentication_config: AuthenticationConfig,
    pub require_client_ip: bool,
    pub disable_ip_check_for_http: bool,
}

#[derive(Debug)]
pub struct MetricCollectionConfig {
    pub endpoint: reqwest::Url,
    pub interval: Duration,
}

pub struct TlsConfig {
    pub config: Arc<rustls::ServerConfig>,
    pub common_names: Option<HashSet<String>>,
    pub cert_resolver: Arc<CertResolver>,
}

pub struct HttpConfig {
    pub timeout: tokio::time::Duration,
    pub pool_opt_in: bool,
}

pub struct AuthenticationConfig {
    pub scram_protocol_timeout: tokio::time::Duration,
}

impl TlsConfig {
    pub fn to_server_config(&self) -> Arc<rustls::ServerConfig> {
        self.config.clone()
    }
}

/// Configure TLS for the main endpoint.
pub fn configure_tls(
    key_path: &str,
    cert_path: &str,
    certs_dir: Option<&String>,
) -> anyhow::Result<TlsConfig> {
    let mut cert_resolver = CertResolver::new();

    // add default certificate
    cert_resolver.add_cert_path(key_path, cert_path, true)?;

    // add extra certificates
    if let Some(certs_dir) = certs_dir {
        for entry in std::fs::read_dir(certs_dir)? {
            let entry = entry?;
            let path = entry.path();
            if path.is_dir() {
                // file names aligned with default cert-manager names
                let key_path = path.join("tls.key");
                let cert_path = path.join("tls.crt");
                if key_path.exists() && cert_path.exists() {
                    cert_resolver.add_cert_path(
                        &key_path.to_string_lossy(),
                        &cert_path.to_string_lossy(),
                        false,
                    )?;
                }
            }
        }
    }

    let common_names = cert_resolver.get_common_names();

    let cert_resolver = Arc::new(cert_resolver);

    let config = rustls::ServerConfig::builder()
        .with_safe_default_cipher_suites()
        .with_safe_default_kx_groups()
        // allow TLS 1.2 to be compatible with older client libraries
        .with_protocol_versions(&[&rustls::version::TLS13, &rustls::version::TLS12])?
        .with_no_client_auth()
        .with_cert_resolver(cert_resolver.clone())
        .into();

    Ok(TlsConfig {
        config,
        common_names: Some(common_names),
        cert_resolver,
    })
}

/// Channel binding parameter
///
/// <https://www.rfc-editor.org/rfc/rfc5929#section-4>
/// Description: The hash of the TLS server's certificate as it
/// appears, octet for octet, in the server's Certificate message.  Note
/// that the Certificate message contains a certificate_list, in which
/// the first element is the server's certificate.
///
/// The hash function is to be selected as follows:
///
/// * if the certificate's signatureAlgorithm uses a single hash
///   function, and that hash function is either MD5 or SHA-1, then use SHA-256;
///
/// * if the certificate's signatureAlgorithm uses a single hash
///   function and that hash function neither MD5 nor SHA-1, then use
///   the hash function associated with the certificate's
///   signatureAlgorithm;
///
/// * if the certificate's signatureAlgorithm uses no hash functions or
///   uses multiple hash functions, then this channel binding type's
///   channel bindings are undefined at this time (updates to is channel
///   binding type may occur to address this issue if it ever arises).
#[derive(Debug, Clone, Copy)]
pub enum TlsServerEndPoint {
    Sha256([u8; 32]),
    Undefined,
}

impl TlsServerEndPoint {
    pub fn new(cert: &Certificate) -> anyhow::Result<Self> {
        let sha256_oids = [
            // I'm explicitly not adding MD5 or SHA1 here... They're bad.
            oid_registry::OID_SIG_ECDSA_WITH_SHA256,
            oid_registry::OID_PKCS1_SHA256WITHRSA,
        ];

        let pem = x509_parser::parse_x509_certificate(&cert.0)
            .context("Failed to parse PEM object from cerficiate")?
            .1;

        info!(subject = %pem.subject, "parsing TLS certificate");

        let reg = oid_registry::OidRegistry::default().with_all_crypto();
        let oid = pem.signature_algorithm.oid();
        let alg = reg.get(oid);
        if sha256_oids.contains(oid) {
            let tls_server_end_point: [u8; 32] =
                Sha256::new().chain_update(&cert.0).finalize().into();
            info!(subject = %pem.subject, signature_algorithm = alg.map(|a| a.description()), tls_server_end_point = %base64::encode(tls_server_end_point), "determined channel binding");
            Ok(Self::Sha256(tls_server_end_point))
        } else {
            error!(subject = %pem.subject, signature_algorithm = alg.map(|a| a.description()), "unknown channel binding");
            Ok(Self::Undefined)
        }
    }

    pub fn supported(&self) -> bool {
        !matches!(self, TlsServerEndPoint::Undefined)
    }
}

#[derive(Default)]
pub struct CertResolver {
    certs: HashMap<String, (Arc<rustls::sign::CertifiedKey>, TlsServerEndPoint)>,
    default: Option<(Arc<rustls::sign::CertifiedKey>, TlsServerEndPoint)>,
}

impl CertResolver {
    pub fn new() -> Self {
        Self::default()
    }

    fn add_cert_path(
        &mut self,
        key_path: &str,
        cert_path: &str,
        is_default: bool,
    ) -> anyhow::Result<()> {
        let priv_key = {
            let key_bytes = std::fs::read(key_path)
                .context(format!("Failed to read TLS keys at '{key_path}'"))?;
            let mut keys = rustls_pemfile::pkcs8_private_keys(&mut &key_bytes[..])
                .context(format!("Failed to parse TLS keys at '{key_path}'"))?;

            ensure!(keys.len() == 1, "keys.len() = {} (should be 1)", keys.len());
            keys.pop().map(rustls::PrivateKey).unwrap()
        };

        let cert_chain_bytes = std::fs::read(cert_path)
            .context(format!("Failed to read TLS cert file at '{cert_path}.'"))?;

        let cert_chain = {
            rustls_pemfile::certs(&mut &cert_chain_bytes[..])
                .with_context(|| {
                    format!(
                    "Failed to read TLS certificate chain from bytes from file at '{cert_path}'."
                )
                })?
                .into_iter()
                .map(rustls::Certificate)
                .collect()
        };

        self.add_cert(priv_key, cert_chain, is_default)
    }

    pub fn add_cert(
        &mut self,
        priv_key: PrivateKey,
        cert_chain: Vec<Certificate>,
        is_default: bool,
    ) -> anyhow::Result<()> {
        let key = sign::any_supported_type(&priv_key).context("invalid private key")?;

        let first_cert = &cert_chain[0];
        let tls_server_end_point = TlsServerEndPoint::new(first_cert)?;
        let pem = x509_parser::parse_x509_certificate(&first_cert.0)
            .context("Failed to parse PEM object from cerficiate")?
            .1;

        let common_name = pem.subject().to_string();

        // We only use non-wildcard certificates in link proxy so it seems okay to treat them the same as
        // wildcard ones as we don't use SNI there. That treatment only affects certificate selection, so
        // verify-full will still check wildcard match. Old coding here just ignored non-wildcard common names
        // and passed None instead, which blows up number of cases downstream code should handle. Proper coding
        // here should better avoid Option for common_names, and do wildcard-based certificate selection instead
        // of cutting off '*.' parts.
        let common_name = if common_name.starts_with("CN=*.") {
            common_name.strip_prefix("CN=*.").map(|s| s.to_string())
        } else {
            common_name.strip_prefix("CN=").map(|s| s.to_string())
        }
        .context("Failed to parse common name from certificate")?;

        let cert = Arc::new(rustls::sign::CertifiedKey::new(cert_chain, key));

        if is_default {
            self.default = Some((cert.clone(), tls_server_end_point));
        }

        self.certs.insert(common_name, (cert, tls_server_end_point));

        Ok(())
    }

    pub fn get_common_names(&self) -> HashSet<String> {
        self.certs.keys().map(|s| s.to_string()).collect()
    }
}

impl rustls::server::ResolvesServerCert for CertResolver {
    fn resolve(
        &self,
        client_hello: rustls::server::ClientHello,
    ) -> Option<Arc<rustls::sign::CertifiedKey>> {
        self.resolve(client_hello.server_name()).map(|x| x.0)
    }
}

impl CertResolver {
    pub fn resolve(
        &self,
        server_name: Option<&str>,
    ) -> Option<(Arc<rustls::sign::CertifiedKey>, TlsServerEndPoint)> {
        // loop here and cut off more and more subdomains until we find
        // a match to get a proper wildcard support. OTOH, we now do not
        // use nested domains, so keep this simple for now.
        //
        // With the current coding foo.com will match *.foo.com and that
        // repeats behavior of the old code.
        if let Some(mut sni_name) = server_name {
            loop {
                if let Some(cert) = self.certs.get(sni_name) {
                    return Some(cert.clone());
                }
                if let Some((_, rest)) = sni_name.split_once('.') {
                    sni_name = rest;
                } else {
                    return None;
                }
            }
        } else {
            // No SNI, use the default certificate, otherwise we can't get to
            // options parameter which can be used to set endpoint name too.
            // That means that non-SNI flow will not work for CNAME domains in
            // verify-full mode.
            //
            // If that will be a problem we can:
            //
            // a) Instead of multi-cert approach use single cert with extra
            //    domains listed in Subject Alternative Name (SAN).
            // b) Deploy separate proxy instances for extra domains.
            self.default.as_ref().cloned()
        }
    }
}

/// Helper for cmdline cache options parsing.
#[derive(Debug)]
pub struct CacheOptions {
    /// Max number of entries.
    pub size: usize,
    /// Entry's time-to-live.
    pub ttl: Duration,
}

impl CacheOptions {
    /// Default options for [`crate::console::provider::NodeInfoCache`].
    pub const DEFAULT_OPTIONS_NODE_INFO: &'static str = "size=4000,ttl=4m";

    /// Parse cache options passed via cmdline.
    /// Example: [`Self::DEFAULT_OPTIONS_NODE_INFO`].
    fn parse(options: &str) -> anyhow::Result<Self> {
        let mut size = None;
        let mut ttl = None;

        for option in options.split(',') {
            let (key, value) = option
                .split_once('=')
                .with_context(|| format!("bad key-value pair: {option}"))?;

            match key {
                "size" => size = Some(value.parse()?),
                "ttl" => ttl = Some(humantime::parse_duration(value)?),
                unknown => bail!("unknown key: {unknown}"),
            }
        }

        // TTL doesn't matter if cache is always empty.
        if let Some(0) = size {
            ttl.get_or_insert(Duration::default());
        }

        Ok(Self {
            size: size.context("missing `size`")?,
            ttl: ttl.context("missing `ttl`")?,
        })
    }
}

impl FromStr for CacheOptions {
    type Err = anyhow::Error;

    fn from_str(options: &str) -> Result<Self, Self::Err> {
        let error = || format!("failed to parse cache options '{options}'");
        Self::parse(options).with_context(error)
    }
}

/// Helper for cmdline cache options parsing.
pub struct WakeComputeLockOptions {
    /// The number of shards the lock map should have
    pub shards: usize,
    /// The number of allowed concurrent requests for each endpoitn
    pub permits: usize,
    /// Garbage collection epoch
    pub epoch: Duration,
    /// Lock timeout
    pub timeout: Duration,
}

impl WakeComputeLockOptions {
    /// Default options for [`crate::console::provider::ApiLocks`].
    pub const DEFAULT_OPTIONS_WAKE_COMPUTE_LOCK: &'static str = "permits=0";

    // pub const DEFAULT_OPTIONS_WAKE_COMPUTE_LOCK: &'static str = "shards=32,permits=4,epoch=10m,timeout=1s";

    /// Parse lock options passed via cmdline.
    /// Example: [`Self::DEFAULT_OPTIONS_WAKE_COMPUTE_LOCK`].
    fn parse(options: &str) -> anyhow::Result<Self> {
        let mut shards = None;
        let mut permits = None;
        let mut epoch = None;
        let mut timeout = None;

        for option in options.split(',') {
            let (key, value) = option
                .split_once('=')
                .with_context(|| format!("bad key-value pair: {option}"))?;

            match key {
                "shards" => shards = Some(value.parse()?),
                "permits" => permits = Some(value.parse()?),
                "epoch" => epoch = Some(humantime::parse_duration(value)?),
                "timeout" => timeout = Some(humantime::parse_duration(value)?),
                unknown => bail!("unknown key: {unknown}"),
            }
        }

        // these dont matter if lock is disabled
        if let Some(0) = permits {
            timeout = Some(Duration::default());
            epoch = Some(Duration::default());
            shards = Some(2);
        }

        let out = Self {
            shards: shards.context("missing `shards`")?,
            permits: permits.context("missing `permits`")?,
            epoch: epoch.context("missing `epoch`")?,
            timeout: timeout.context("missing `timeout`")?,
        };

        ensure!(out.shards > 1, "shard count must be > 1");
        ensure!(
            out.shards.is_power_of_two(),
            "shard count must be a power of two"
        );

        Ok(out)
    }
}

impl FromStr for WakeComputeLockOptions {
    type Err = anyhow::Error;

    fn from_str(options: &str) -> Result<Self, Self::Err> {
        let error = || format!("failed to parse cache lock options '{options}'");
        Self::parse(options).with_context(error)
    }
}

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

    #[test]
    fn test_parse_cache_options() -> anyhow::Result<()> {
        let CacheOptions { size, ttl } = "size=4096,ttl=5min".parse()?;
        assert_eq!(size, 4096);
        assert_eq!(ttl, Duration::from_secs(5 * 60));

        let CacheOptions { size, ttl } = "ttl=4m,size=2".parse()?;
        assert_eq!(size, 2);
        assert_eq!(ttl, Duration::from_secs(4 * 60));

        let CacheOptions { size, ttl } = "size=0,ttl=1s".parse()?;
        assert_eq!(size, 0);
        assert_eq!(ttl, Duration::from_secs(1));

        let CacheOptions { size, ttl } = "size=0".parse()?;
        assert_eq!(size, 0);
        assert_eq!(ttl, Duration::default());

        Ok(())
    }

    #[test]
    fn test_parse_lock_options() -> anyhow::Result<()> {
        let WakeComputeLockOptions {
            epoch,
            permits,
            shards,
            timeout,
        } = "shards=32,permits=4,epoch=10m,timeout=1s".parse()?;
        assert_eq!(epoch, Duration::from_secs(10 * 60));
        assert_eq!(timeout, Duration::from_secs(1));
        assert_eq!(shards, 32);
        assert_eq!(permits, 4);

        let WakeComputeLockOptions {
            epoch,
            permits,
            shards,
            timeout,
        } = "epoch=60s,shards=16,timeout=100ms,permits=8".parse()?;
        assert_eq!(epoch, Duration::from_secs(60));
        assert_eq!(timeout, Duration::from_millis(100));
        assert_eq!(shards, 16);
        assert_eq!(permits, 8);

        let WakeComputeLockOptions {
            epoch,
            permits,
            shards,
            timeout,
        } = "permits=0".parse()?;
        assert_eq!(epoch, Duration::ZERO);
        assert_eq!(timeout, Duration::ZERO);
        assert_eq!(shards, 2);
        assert_eq!(permits, 0);

        Ok(())
    }
}