feat: add CRL health aggregation logic and audit events (PR 5 of 6)

* feat: add CRL health aggregation logic and audit events (PR 5 of 6)

* style: fix cargo fmt in health_poller.rs

---------

Co-authored-by: Draco Lunaris <331325+Draco-Lunaris@users.noreply.github.com>

crates/pm-core/src/audit.rs

@@ -57,6 +57,10 @@ pub enum AuditAction {
     IpWhitelistUpdated,
     OidcTestPerformed,
     OidcDiscoverPerformed,
+    // CRL health aggregation events (system-initiated)
+    CrlStatusChanged,
+    CrlStaleDetected,
+    CrlInvalid,
 }
 
 impl AuditAction {
@@ -100,6 +104,10 @@ impl AuditAction {
             Self::IpWhitelistUpdated => "ip_whitelist_updated",
             Self::OidcTestPerformed => "oidc_test_performed",
             Self::OidcDiscoverPerformed => "oidc_discover_performed",
+            // CRL health aggregation events
+            Self::CrlStatusChanged => "crl_status_changed",
+            Self::CrlStaleDetected => "crl_stale_detected",
+            Self::CrlInvalid => "crl_invalid",
         }
     }
 }

crates/pm-worker/src/health_poller.rs

@@ -4,11 +4,24 @@
 //! `health_poll_interval_secs`, with bounded concurrency controlled by a
 //! [`tokio::sync::Semaphore`]. Also calls `/system/info` to refresh
 //! `os_family`, `os_name`, `arch`, and `agent_version` in the hosts table.
+//!
+//! CRL health aggregation rules (PR 5):
+//! - `crl_status = "invalid"` → host health_status overridden to `unreachable`
+//! - `crl_status = "expired"` → host health_status overridden to `degraded` (if currently healthy)
+//! - `crl_status = "missing"` AND registered > 24h ago → host health_status overridden to `degraded` (if currently healthy)
+//! - `crl_status = "valid"` or NULL → no override
+//!
+//! Audit events are logged for CRL state transitions.
 
 use std::sync::Arc;
 
+use chrono::{DateTime, Duration, Utc};
 use pm_agent_client::{AgentClient, AgentClientError};
-use pm_core::{config::AppConfig, models::HostHealthStatus};
+use pm_core::{
+    audit::{log_event, AuditAction},
+    config::AppConfig,
+    models::HostHealthStatus,
+};
 use sqlx::{FromRow, PgPool};
 use tokio::{sync::Semaphore, time};
 use uuid::Uuid;
@@ -21,6 +34,10 @@ struct HostRow {
     id: Uuid,
     ip_address: String,
     agent_port: i32,
+    /// Current CRL status from the hosts table (for transition detection).
+    crl_status: Option<String>,
+    /// When the host was first registered (for enrollment age checks).
+    registered_at: DateTime<Utc>,
 }
 
 /// Run the health poller loop indefinitely.
@@ -50,9 +67,9 @@ pub async fn run_health_poller(pool: PgPool, config: Arc<AppConfig>) {
         let client_key = Arc::new(certs.client_key);
         let ca_cert = Arc::new(certs.ca_cert);
 
-        // Fetch all hosts.
+        // Fetch all hosts with CRL status and registration time.
         let hosts: Vec<HostRow> = match sqlx::query_as(
-            "SELECT id, host(ip_address)::text AS ip_address, agent_port FROM hosts ORDER BY id",
+            "SELECT id, host(ip_address)::text AS ip_address, agent_port, crl_status, registered_at FROM hosts ORDER BY id",
         )
         .fetch_all(&pool)
         .await
@@ -118,7 +135,8 @@ pub async fn run_health_poller(pool: PgPool, config: Arc<AppConfig>) {
 ///
 /// Also updates `agent_version` from the health response,
 /// `os_family`/`os_name`/`arch` from the `/system/info` endpoint when available,
-/// and CRL status fields from the health response when reported by the agent.
+/// CRL status fields from the health response when reported by the agent,
+/// and applies CRL health aggregation rules.
 async fn poll_host_health(
     pool: PgPool,
     host: HostRow,
@@ -127,8 +145,15 @@ async fn poll_host_health(
     ca_cert: &[u8],
 ) -> HostHealthStatus {
     // Determine status, payload, agent version, optional system info, and CRL fields.
-    let (status, payload, agent_version, sys_info, crl_status, crl_age_seconds, crl_next_update) =
-        match AgentClient::new(
+    let (
+        natural_status,
+        payload,
+        agent_version,
+        sys_info,
+        crl_status,
+        crl_age_seconds,
+        crl_next_update,
+    ) = match AgentClient::new(
         &host.ip_address,
         host.agent_port as u16,
         client_cert,
@@ -228,7 +253,11 @@ async fn poll_host_health(
         },
     };
 
-    // Insert into host_health_data.
+    // Apply CRL health aggregation rules to determine the effective status.
+    // Only apply when the agent reported a CRL status (non-NULL).
+    let effective_status = apply_crl_health_rules(&natural_status, &crl_status, host.registered_at);
+
+    // Insert into host_health_data with the natural (pre-aggregation) status.
     if let Err(e) = sqlx::query(
         r#"
         INSERT INTO host_health_data (host_id, status, payload)
@@ -236,7 +265,7 @@ async fn poll_host_health(
         "#,
     )
     .bind(host.id)
-    .bind(&status)
+    .bind(&natural_status)
     .bind(&payload)
     .execute(&pool)
     .await
@@ -255,7 +284,8 @@ async fn poll_host_health(
         .and_then(|s| chrono::DateTime::parse_from_rfc3339(s).ok())
         .map(|dt| dt.to_utc());
 
-    // Update hosts table with health status, agent version, OS details, and CRL fields.
+    // Update hosts table with the effective (post-aggregation) health status,
+    // agent version, OS details, and CRL fields.
     // COALESCE preserves existing values when new data is unavailable.
     if let Err(e) = sqlx::query(
         r#"
@@ -272,7 +302,7 @@ async fn poll_host_health(
         "#,
     )
     .bind(host.id)
-    .bind(&status)
+    .bind(&effective_status)
     .bind(&agent_version)
     .bind(sys_info.as_ref().map(|i| i.os.as_str()))
     .bind(os_name_from_sysinfo)
@@ -284,7 +314,145 @@ async fn poll_host_health(
     .await
     {
         tracing::error!(host_id = %host.id, error = %e, "Health poller: failed to update host status");
+        // Don't log audit events if the DB update failed.
+        return effective_status;
     }
 
-    status
+    // Log CRL audit events after successful database update.
+    if let Some(ref new_crl) = crl_status {
+        log_crl_audit_events(
+            &pool,
+            host.id,
+            host.crl_status.as_deref(),
+            new_crl,
+            crl_age_seconds,
+        )
+        .await;
+    }
+
+    effective_status
+}
+
+/// Apply CRL health aggregation rules to determine the effective health status.
+///
+/// Rules:
+/// - `crl_status = "invalid"` → `Unreachable` (security event, always overrides)
+/// - `crl_status = "expired"` → `Degraded` (only if natural status is `Healthy`)
+/// - `crl_status = "missing"` AND registered > 24h ago → `Degraded` (only if natural status is `Healthy`)
+/// - `crl_status = "valid"` or NULL → no override
+fn apply_crl_health_rules(
+    natural_status: &HostHealthStatus,
+    crl_status: &Option<String>,
+    registered_at: DateTime<Utc>,
+) -> HostHealthStatus {
+    let Some(crl) = crl_status else {
+        // Older agent not reporting CRL — don't modify health status.
+        return natural_status.clone();
+    };
+
+    match crl.as_str() {
+        "invalid" => HostHealthStatus::Unreachable,
+        "expired" => {
+            if *natural_status == HostHealthStatus::Healthy {
+                HostHealthStatus::Degraded
+            } else {
+                natural_status.clone()
+            }
+        },
+        "missing" => {
+            let age = Utc::now() - registered_at;
+            if age > Duration::hours(24) && *natural_status == HostHealthStatus::Healthy {
+                HostHealthStatus::Degraded
+            } else {
+                natural_status.clone()
+            }
+        },
+        // "valid" or any other value — no override
+        _ => natural_status.clone(),
+    }
+}
+
+/// Log audit events for CRL state transitions.
+///
+/// Called after the hosts table has been successfully updated.
+/// Logs:
+/// - `CrlStatusChanged` when the CRL status transitions to a different value
+/// - `CrlStaleDetected` when CRL status becomes "expired"
+/// - `CrlInvalid` when CRL status becomes "invalid"
+async fn log_crl_audit_events(
+    pool: &PgPool,
+    host_id: Uuid,
+    old_crl_status: Option<&str>,
+    new_crl_status: &str,
+    crl_age_seconds: Option<i64>,
+) {
+    let host_id_str = host_id.to_string();
+    let old_str = old_crl_status.unwrap_or("null");
+
+    // Log a transition event if the status changed.
+    if old_crl_status != Some(new_crl_status) {
+        let details = serde_json::json!({
+            "host_id": host_id_str,
+            "old_crl_status": old_str,
+            "new_crl_status": new_crl_status,
+            "crl_age_seconds": crl_age_seconds,
+        });
+        log_event(
+            pool,
+            AuditAction::CrlStatusChanged,
+            None,               // actor_user_id — system-initiated
+            None,               // actor_username
+            Some("host"),       // target_type
+            Some(&host_id_str), // target_id
+            details,
+            None, // ip_address
+            None, // request_id
+        )
+        .await;
+    }
+
+    // Log specific events for problematic CRL states.
+    match new_crl_status {
+        "expired" => {
+            let details = serde_json::json!({
+                "host_id": host_id_str,
+                "old_crl_status": old_str,
+                "new_crl_status": new_crl_status,
+                "crl_age_seconds": crl_age_seconds,
+            });
+            log_event(
+                pool,
+                AuditAction::CrlStaleDetected,
+                None,
+                None,
+                Some("host"),
+                Some(&host_id_str),
+                details,
+                None,
+                None,
+            )
+            .await;
+        },
+        "invalid" => {
+            let details = serde_json::json!({
+                "host_id": host_id_str,
+                "old_crl_status": old_str,
+                "new_crl_status": new_crl_status,
+                "crl_age_seconds": crl_age_seconds,
+            });
+            log_event(
+                pool,
+                AuditAction::CrlInvalid,
+                None,
+                None,
+                Some("host"),
+                Some(&host_id_str),
+                details,
+                None,
+                None,
+            )
+            .await;
+        },
+        _ => {},
+    }
 }

docs/REST_API.md

@@ -161,6 +161,33 @@ Fleet status response includes CRL counts:
 | `crl_invalid` | `integer` | Hosts with CRL status `invalid` (security event) |
 | `crl_not_reporting` | `integer` | Hosts not reporting CRL status (older agents) |
 
+### CRL Audit Events
+
+The health poller logs the following system-initiated audit events when a host's CRL status changes:
+
+| Audit Action | Trigger | Details Fields |
+|---|---|---|
+| `crl_status_changed` | Any CRL status transition | `host_id`, `old_crl_status`, `new_crl_status`, `crl_age_seconds` |
+| `crl_stale_detected` | CRL status becomes `expired` | `host_id`, `old_crl_status`, `new_crl_status`, `crl_age_seconds` |
+| `crl_invalid` | CRL status becomes `invalid` | `host_id`, `old_crl_status`, `new_crl_status`, `crl_age_seconds` |
+
+All CRL audit events use `target_type = "host"` and `target_id = <host_id>`. Actor fields (`actor_user_id`, `actor_username`) are `null` because these are system-initiated events.
+
+### CRL Health Aggregation Rules
+
+The health poller applies the following rules to determine a host's effective health status based on CRL state:
+
+| CRL Status | Condition | Effective Health Status |
+|---|---|---|
+| `invalid` | Always | `unreachable` (security event) |
+| `expired` | If natural status is `healthy` | `degraded` |
+| `missing` | Registered > 24h ago AND natural status is `healthy` | `degraded` |
+| `missing` | Registered ≤ 24h ago | Natural status (new agent enrollment) |
+| `valid` | Any | Natural status (no override) |
+| `null` | Any | Natural status (older agent, not reporting CRL) |
+
+When CRL status transitions from `invalid`/`expired`/`missing` back to `valid`, the next health poll cycle restores the host to its natural health status based on the agent's health response.
+
 ## 14. Real-Time Updates (WebSocket)
 | Method | Endpoint | Description |
 |--------|----------|-------------|

migrations/022_crl_audit_actions.sql

@@ -0,0 +1,8 @@
+-- Migration: 022_crl_audit_actions
+-- Description: Add audit_action enum values for CRL health aggregation events.
+--              These are system-initiated events logged by the health poller
+--              when a host's CRL status transitions or indicates a problem.
+
+ALTER TYPE audit_action ADD VALUE IF NOT EXISTS 'crl_status_changed';
+ALTER TYPE audit_action ADD VALUE IF NOT EXISTS 'crl_stale_detected';
+ALTER TYPE audit_action ADD VALUE IF NOT EXISTS 'crl_invalid';