praxis-proxy-core 0.5.5

// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2024 Praxis Contributors

//! Consolidated security override flags.
//!
//! All options default to `false` (secure by default). Each flag
//! demotes one specific security check from an error to a warning.

use serde::Deserialize;

// -----------------------------------------------------------------------------
// SkipPipelineChecks
// -----------------------------------------------------------------------------

/// Per-check flags for pipeline validation bypass.
///
/// Each flag skips one specific ordering check in the filter pipeline.
/// Prefer these granular flags over the blanket
/// [`InsecureOptions::skip_pipeline_validation`] flag.
///
/// ```
/// use praxis_core::config::SkipPipelineChecks;
///
/// let checks = SkipPipelineChecks::default();
/// assert!(!checks.any());
///
/// let all = SkipPipelineChecks::all();
/// assert!(all.conditional_security);
/// assert!(all.misaligned_clusters);
/// ```
#[expect(clippy::struct_excessive_bools, reason = "per-check skip flags")]
#[derive(Clone, Debug, Default, Deserialize, serde::Serialize)]
#[serde(default, deny_unknown_fields)]
pub struct SkipPipelineChecks {
    /// Skip check: security filters with request conditions (bypass risk).
    pub conditional_security: bool,

    /// Skip check: multiple cluster-selecting filters before load balancer.
    pub conflicting_cluster_selectors: bool,

    /// Skip check: duplicate `load_balancer` filters.
    pub duplicate_load_balancers: bool,

    /// Skip check: multiple path rewriting filters.
    pub duplicate_rewrite_filters: bool,

    /// Skip check: duplicate `router` filters.
    pub duplicate_routers: bool,

    /// Skip check: `load_balancer` without a preceding router.
    pub lb_without_router: bool,

    /// Skip check: cluster references not matching load balancer config.
    pub misaligned_clusters: bool,

    /// Skip check: unconditional `static_response` blocking subsequent
    /// filters.
    pub unreachable_filters: bool,
}

impl SkipPipelineChecks {
    /// Returns a [`SkipPipelineChecks`] with all flags set to `true`.
    ///
    /// ```
    /// use praxis_core::config::SkipPipelineChecks;
    ///
    /// let all = SkipPipelineChecks::all();
    /// assert!(all.any());
    /// assert!(all.lb_without_router);
    /// assert!(all.duplicate_routers);
    /// ```
    pub fn all() -> Self {
        Self {
            conditional_security: true,
            conflicting_cluster_selectors: true,
            duplicate_load_balancers: true,
            duplicate_rewrite_filters: true,
            duplicate_routers: true,
            lb_without_router: true,
            misaligned_clusters: true,
            unreachable_filters: true,
        }
    }

    /// Returns `true` if any check is skipped.
    ///
    /// ```
    /// use praxis_core::config::SkipPipelineChecks;
    ///
    /// assert!(!SkipPipelineChecks::default().any());
    ///
    /// let mut checks = SkipPipelineChecks::default();
    /// checks.duplicate_routers = true;
    /// assert!(checks.any());
    /// ```
    pub fn any(&self) -> bool {
        self.conditional_security
            || self.conflicting_cluster_selectors
            || self.duplicate_load_balancers
            || self.duplicate_rewrite_filters
            || self.duplicate_routers
            || self.lb_without_router
            || self.misaligned_clusters
            || self.unreachable_filters
    }
}

// -----------------------------------------------------------------------------
// InsecureOptions
// -----------------------------------------------------------------------------

/// Consolidated security overrides for Praxis.
///
/// Every field defaults to `false`. Setting a flag to `true`
/// demotes the corresponding security check from an error to a warning.
///
/// Only intended for use in development and testing.
///
/// ```
/// use praxis_core::config::InsecureOptions;
///
/// let opts = InsecureOptions::default();
/// assert!(!opts.allow_open_security_filters);
/// assert!(!opts.allow_private_endpoints);
/// assert!(!opts.allow_private_health_checks);
/// assert!(!opts.allow_private_upstreams);
/// assert!(!opts.allow_public_admin);
/// assert!(!opts.allow_root);
/// assert!(!opts.allow_tls_no_verify);
/// assert!(!opts.allow_tls_without_sni);
/// assert!(!opts.allow_unbounded_body);
/// assert!(!opts.csrf_log_only);
/// assert!(!opts.skip_pipeline_validation);
/// assert!(!opts.skip_pipeline_checks.any());
/// ```
///
/// ```
/// use praxis_core::config::InsecureOptions;
///
/// let opts: InsecureOptions =
///     serde_yaml::from_str("allow_root: true\nallow_public_admin: true\n").unwrap();
/// assert!(opts.allow_root);
/// assert!(opts.allow_public_admin);
/// assert!(!opts.allow_unbounded_body);
/// ```
#[expect(clippy::struct_excessive_bools, reason = "security override flags")]
#[derive(Clone, Debug, Default, Deserialize, serde::Serialize)]
#[serde(default, deny_unknown_fields)]
pub struct InsecureOptions {
    /// Allow security-critical filters to use `failure_mode: open`,
    /// demoting the validation error to a warning.
    pub allow_open_security_filters: bool,

    /// Allow cluster endpoints to resolve to loopback, link-local,
    /// or cloud metadata addresses.
    pub allow_private_endpoints: bool,

    /// Allow health checks to loopback/metadata addresses.
    pub allow_private_health_checks: bool,

    /// Allow upstream connections to resolve to private or reserved IP
    /// addresses at runtime. Without this flag, DNS-resolved upstream
    /// addresses in RFC 1918, loopback, link-local, CGNAT, and IPv6
    /// unique-local ranges are rejected to prevent DNS rebinding and
    /// SSRF attacks, on the TCP and HTTP data planes alike.
    ///
    /// Literal `host:port` upstreams are not affected: they cannot be
    /// substituted by a resolver, and are gated at config time by
    /// [`allow_private_endpoints`].
    ///
    /// [`allow_private_endpoints`]: InsecureOptions::allow_private_endpoints
    pub allow_private_upstreams: bool,

    /// Allow admin endpoint on non-loopback addresses (`0.0.0.0`, LAN IPs, etc.).
    pub allow_public_admin: bool,

    /// Allow running as root (UID 0).
    pub allow_root: bool,

    /// Allow disabling upstream TLS certificate verification (`tls.verify: false`).
    ///
    /// Without this flag, setting `verify: false` on a cluster is a hard
    /// validation error. Enabling it demotes the error to a warning.
    pub allow_tls_no_verify: bool,

    /// Allow TLS without SNI hostname verification.
    pub allow_tls_without_sni: bool,

    /// Allow startup without `body_limits.max_request_bytes` or
    /// `body_limits.max_response_bytes` configured. Without this
    /// flag, missing body limits are a hard validation error.
    pub allow_unbounded_body: bool,

    /// Run the CSRF filter in log-only mode: evaluate all rules
    /// but log violations as warnings instead of rejecting requests.
    pub csrf_log_only: bool,

    /// Granular pipeline validation bypass flags.
    ///
    /// Prefer these over the blanket [`skip_pipeline_validation`]
    /// flag for targeted overrides.
    ///
    /// [`skip_pipeline_validation`]: InsecureOptions::skip_pipeline_validation
    pub skip_pipeline_checks: SkipPipelineChecks,

    /// **Deprecated.** Skip ALL pipeline ordering validation checks.
    ///
    /// Prefer [`skip_pipeline_checks`] for granular control. When this
    /// flag is `true`, [`effective_pipeline_checks`] returns
    /// [`SkipPipelineChecks::all`], overriding individual flags.
    ///
    /// [`skip_pipeline_checks`]: InsecureOptions::skip_pipeline_checks
    /// [`effective_pipeline_checks`]: InsecureOptions::effective_pipeline_checks
    pub skip_pipeline_validation: bool,
}

impl InsecureOptions {
    /// Returns the effective pipeline check skip flags.
    ///
    /// When [`skip_pipeline_validation`] is `true`, all checks are
    /// skipped (backward compatibility). Otherwise, returns the
    /// granular [`skip_pipeline_checks`] flags.
    ///
    /// ```
    /// use praxis_core::config::InsecureOptions;
    ///
    /// let blanket: InsecureOptions = serde_yaml::from_str("skip_pipeline_validation: true").unwrap();
    /// let checks = blanket.effective_pipeline_checks();
    /// assert!(checks.lb_without_router);
    /// assert!(checks.conditional_security);
    ///
    /// let granular: InsecureOptions =
    ///     serde_yaml::from_str("skip_pipeline_checks:\n  duplicate_routers: true").unwrap();
    /// let checks = granular.effective_pipeline_checks();
    /// assert!(checks.duplicate_routers);
    /// assert!(!checks.lb_without_router);
    /// ```
    ///
    /// [`skip_pipeline_validation`]: InsecureOptions::skip_pipeline_validation
    /// [`skip_pipeline_checks`]: InsecureOptions::skip_pipeline_checks
    pub fn effective_pipeline_checks(&self) -> SkipPipelineChecks {
        if self.skip_pipeline_validation {
            SkipPipelineChecks::all()
        } else {
            self.skip_pipeline_checks.clone()
        }
    }
}

// -----------------------------------------------------------------------------
// Tests
// -----------------------------------------------------------------------------

#[cfg(test)]
#[expect(clippy::allow_attributes, reason = "blanket test suppressions")]
#[allow(
    clippy::unwrap_used,
    clippy::expect_used,
    clippy::indexing_slicing,
    clippy::needless_raw_strings,
    clippy::needless_raw_string_hashes,
    clippy::too_many_lines,
    reason = "tests use unwrap/expect/indexing/raw strings for brevity"
)]
mod tests {
    use super::*;

    #[test]
    fn all_flags_default_to_false() {
        let opts = InsecureOptions::default();
        assert!(
            !opts.allow_open_security_filters,
            "allow_open_security_filters should default to false"
        );
        assert!(
            !opts.allow_private_endpoints,
            "allow_private_endpoints should default to false"
        );
        assert!(
            !opts.allow_private_health_checks,
            "allow_private_health_checks should default to false"
        );
        assert!(
            !opts.allow_private_upstreams,
            "allow_private_upstreams should default to false"
        );
        assert!(!opts.allow_public_admin, "allow_public_admin should default to false");
        assert!(!opts.allow_root, "allow_root should default to false");
        assert!(!opts.allow_tls_no_verify, "allow_tls_no_verify should default to false");
        assert!(
            !opts.allow_tls_without_sni,
            "allow_tls_without_sni should default to false"
        );
        assert!(
            !opts.allow_unbounded_body,
            "allow_unbounded_body should default to false"
        );
        assert!(!opts.csrf_log_only, "csrf_log_only should default to false");
        assert!(
            !opts.skip_pipeline_validation,
            "skip_pipeline_validation should default to false"
        );
        assert!(
            !opts.skip_pipeline_checks.any(),
            "skip_pipeline_checks should all default to false"
        );
    }

    #[test]
    fn deserializes_partial_overrides() {
        let yaml = "allow_root: true\nskip_pipeline_validation: true\n";
        let opts: InsecureOptions = serde_yaml::from_str(yaml).unwrap();
        assert!(opts.allow_root, "allow_root should be true");
        assert!(opts.skip_pipeline_validation, "skip_pipeline_validation should be true");
        assert!(!opts.allow_public_admin, "allow_public_admin should still be false");
    }

    #[test]
    fn deserializes_empty_to_defaults() {
        let opts: InsecureOptions = serde_yaml::from_str("{}").unwrap();
        assert!(!opts.allow_root, "empty YAML should produce defaults");
    }

    #[test]
    fn skip_pipeline_checks_all_sets_every_flag() {
        let checks = SkipPipelineChecks::all();
        assert!(checks.conditional_security, "conditional_security should be true");
        assert!(
            checks.conflicting_cluster_selectors,
            "conflicting_cluster_selectors should be true"
        );
        assert!(
            checks.duplicate_load_balancers,
            "duplicate_load_balancers should be true"
        );
        assert!(
            checks.duplicate_rewrite_filters,
            "duplicate_rewrite_filters should be true"
        );
        assert!(checks.duplicate_routers, "duplicate_routers should be true");
        assert!(checks.lb_without_router, "lb_without_router should be true");
        assert!(checks.misaligned_clusters, "misaligned_clusters should be true");
        assert!(checks.unreachable_filters, "unreachable_filters should be true");
    }

    #[test]
    fn skip_pipeline_checks_any_detects_single_flag() {
        let mut checks = SkipPipelineChecks::default();
        assert!(!checks.any(), "default checks should have no flags set");
        checks.duplicate_routers = true;
        assert!(checks.any(), "any() should detect single flag");
    }

    #[test]
    fn effective_pipeline_checks_blanket_overrides_granular() {
        let opts = InsecureOptions {
            skip_pipeline_validation: true,
            ..Default::default()
        };
        let checks = opts.effective_pipeline_checks();
        assert!(checks.lb_without_router, "blanket flag should set all checks");
        assert!(checks.conditional_security, "blanket flag should set all checks");
        assert!(checks.misaligned_clusters, "blanket flag should set all checks");
    }

    #[test]
    fn effective_pipeline_checks_uses_granular_when_blanket_off() {
        let opts = InsecureOptions {
            skip_pipeline_checks: SkipPipelineChecks {
                duplicate_routers: true,
                ..Default::default()
            },
            ..Default::default()
        };
        let checks = opts.effective_pipeline_checks();
        assert!(checks.duplicate_routers, "granular flag should be preserved");
        assert!(!checks.lb_without_router, "other flags should remain false");
    }

    #[test]
    fn deserializes_granular_pipeline_checks() {
        let yaml = "skip_pipeline_checks:\n  duplicate_routers: true\n  misaligned_clusters: true\n";
        let opts: InsecureOptions = serde_yaml::from_str(yaml).unwrap();
        assert!(
            opts.skip_pipeline_checks.duplicate_routers,
            "duplicate_routers should be true"
        );
        assert!(
            opts.skip_pipeline_checks.misaligned_clusters,
            "misaligned_clusters should be true"
        );
        assert!(
            !opts.skip_pipeline_checks.lb_without_router,
            "lb_without_router should remain false"
        );
        assert!(!opts.skip_pipeline_validation, "blanket flag should remain false");
    }

    #[test]
    fn rejects_unknown_skip_pipeline_checks_field() {
        let yaml = "skip_pipeline_checks:\n  nonexistent_check: true\n";
        let err = serde_yaml::from_str::<InsecureOptions>(yaml).unwrap_err();
        assert!(
            err.to_string().contains("nonexistent_check"),
            "unknown skip_pipeline_checks field should be rejected: {err}"
        );
    }
}