Files
siem-backend/internal/api/server.go
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2026-07-23 14:45:35 +02:00

188 lines
6.8 KiB
Go

package api
import (
"context"
"crypto/subtle"
"encoding/json"
"fmt"
"html/template"
"log"
"net/http"
"strconv"
"strings"
"time"
"example.com/siem-greenfield/internal/clickhouse"
"example.com/siem-greenfield/internal/config"
"example.com/siem-greenfield/internal/postgres"
)
func Run(ctx context.Context, cfg config.Config) error {
pg, e := postgres.Open(ctx, cfg.PostgresURL)
if e != nil {
return e
}
defer pg.Close()
ch := clickhouse.New(cfg)
tpl, e := template.ParseFiles("/app/web/index.html")
if e != nil {
return e
}
mux := http.NewServeMux()
mux.HandleFunc("/healthz", func(w http.ResponseWriter, _ *http.Request) { j(w, 200, map[string]string{"status": "ok"}) })
mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
cctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
defer cancel()
if e := pg.Pool.Ping(cctx); e != nil {
j(w, 503, map[string]string{"status": "not_ready", "component": "postgres"})
return
}
if e := ch.Exec(cctx, "SELECT 1"); e != nil {
j(w, 503, map[string]string{"status": "not_ready", "component": "clickhouse"})
return
}
j(w, 200, map[string]string{"status": "ready"})
})
mux.HandleFunc("/ui", func(w http.ResponseWriter, r *http.Request) {
_ = tpl.Execute(w, map[string]string{"Tenant": cfg.TenantID})
})
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/" {
http.Redirect(w, r, "/ui", http.StatusFound)
return
}
http.NotFound(w, r)
})
mux.HandleFunc("/api/summary", func(w http.ResponseWriter, r *http.Request) { summary(w, r, cfg, pg, ch) })
mux.HandleFunc("/api/events", func(w http.ResponseWriter, r *http.Request) { events(w, r, cfg, ch) })
mux.HandleFunc("/api/detections", func(w http.ResponseWriter, r *http.Request) { detections(w, r, cfg, pg) })
mux.HandleFunc("/api/detections/status", func(w http.ResponseWriter, r *http.Request) { detectionStatus(w, r, cfg, pg) })
mux.HandleFunc("/api/agents", func(w http.ResponseWriter, r *http.Request) {
x, e := pg.ListAgents(r.Context(), cfg.TenantID)
if e != nil {
j(w, 500, map[string]string{"error": e.Error()})
return
}
j(w, 200, x)
})
srv := &http.Server{Addr: cfg.ServiceAddr, Handler: security(basicAuth(mux, cfg.UIUsername, cfg.UIPassword)), ReadHeaderTimeout: 5 * time.Second, ReadTimeout: 15 * time.Second, WriteTimeout: 30 * time.Second, IdleTimeout: 60 * time.Second}
go func() {
<-ctx.Done()
c, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
_ = srv.Shutdown(c)
}()
log.Printf("api/ui listening on %s", cfg.ServiceAddr)
e = srv.ListenAndServe()
if e == http.ErrServerClosed {
return nil
}
return e
}
func summary(w http.ResponseWriter, r *http.Request, cfg config.Config, pg *postgres.Store, ch *clickhouse.Client) {
ctx, cancel := context.WithTimeout(r.Context(), 8*time.Second)
defer cancel()
q := fmt.Sprintf(`SELECT uniqExactMerge(cnt_state) events_24h, uniqExact(host_name) active_hosts FROM siem.events_5m WHERE tenant_id=%s AND bucket>=now()-INTERVAL 24 HOUR`, clickhouse.Q(cfg.TenantID))
rows, e := ch.QueryJSON(ctx, q)
if e != nil {
j(w, 500, map[string]string{"error": e.Error()})
return
}
out := map[string]any{"events_24h": 0, "active_hosts": 0}
if len(rows) > 0 {
for k, v := range rows[0] {
out[k] = v
}
}
dc, _ := pg.DetectionCounts(ctx, cfg.TenantID)
out["detections"] = dc
j(w, 200, out)
}
func events(w http.ResponseWriter, r *http.Request, cfg config.Config, ch *clickhouse.Client) {
limit := cfg.UIQueryLimit
if n, e := strconv.Atoi(r.URL.Query().Get("limit")); e == nil && n > 0 && n <= 2000 {
limit = n
}
hours := 24
if n, e := strconv.Atoi(r.URL.Query().Get("hours")); e == nil && n > 0 && n <= 2160 {
hours = n
}
where := []string{"tenant_id=" + clickhouse.Q(cfg.TenantID), fmt.Sprintf("event_time>=now()-INTERVAL %d HOUR", hours)}
for key, col := range map[string]string{"host": "host_name", "user": "user_name", "ip": "source_ip", "channel": "channel", "action": "action"} {
if v := strings.TrimSpace(r.URL.Query().Get(key)); v != "" {
where = append(where, col+"="+clickhouse.Q(v))
}
}
if v := strings.TrimSpace(r.URL.Query().Get("event_code")); v != "" {
if _, e := strconv.ParseUint(v, 10, 32); e == nil {
where = append(where, "event_code="+v)
}
}
q := fmt.Sprintf(`SELECT event_uid,event_time,host_name,channel,event_code,category,action,outcome,severity,user_name,subject_user,target_user,source_ip,workstation,process_path,message,raw_object_key,raw_index FROM siem.events WHERE %s ORDER BY event_time DESC, ingest_time DESC LIMIT 1 BY event_uid LIMIT %d`, strings.Join(where, " AND "), limit)
ctx, cancel := context.WithTimeout(r.Context(), 12*time.Second)
defer cancel()
rows, e := ch.QueryJSON(ctx, q)
if e != nil {
j(w, 500, map[string]string{"error": e.Error()})
return
}
j(w, 200, rows)
}
func detections(w http.ResponseWriter, r *http.Request, cfg config.Config, pg *postgres.Store) {
x, e := pg.ListDetections(r.Context(), cfg.TenantID, 500)
if e != nil {
j(w, 500, map[string]string{"error": e.Error()})
return
}
j(w, 200, x)
}
func detectionStatus(w http.ResponseWriter, r *http.Request, cfg config.Config, pg *postgres.Store) {
if r.Method != http.MethodPost {
j(w, 405, map[string]string{"error": "method not allowed"})
return
}
var v struct {
ID int64 `json:"id"`
Status string `json:"status"`
}
if e := json.NewDecoder(r.Body).Decode(&v); e != nil {
j(w, 400, map[string]string{"error": "invalid json"})
return
}
if e := pg.UpdateDetectionStatus(r.Context(), cfg.TenantID, v.ID, v.Status); e != nil {
j(w, 400, map[string]string{"error": e.Error()})
return
}
j(w, 200, map[string]string{"status": "ok"})
}
func j(w http.ResponseWriter, s int, v any) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(s)
_ = json.NewEncoder(w).Encode(v)
}
func basicAuth(next http.Handler, user, pass string) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/healthz" || r.URL.Path == "/readyz" {
next.ServeHTTP(w, r)
return
}
u, p, ok := r.BasicAuth()
if !ok || subtle.ConstantTimeCompare([]byte(u), []byte(user)) != 1 || subtle.ConstantTimeCompare([]byte(p), []byte(pass)) != 1 {
w.Header().Set("WWW-Authenticate", `Basic realm="Greenfield SIEM", charset="UTF-8"`)
http.Error(w, "Unauthorized", http.StatusUnauthorized)
return
}
next.ServeHTTP(w, r)
})
}
func security(n http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("X-Content-Type-Options", "nosniff")
w.Header().Set("X-Frame-Options", "DENY")
w.Header().Set("Referrer-Policy", "no-referrer")
w.Header().Set("Content-Security-Policy", "default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline'")
n.ServeHTTP(w, r)
})
}