Files
edgeguard-native/internal/waf/engine.go
Debian 02096c8ad8 chore(lint): golangci-lint --fix — misspell + staticcheck-Autofixes (Backlog 142→~98)
Erster Schritt des golangci-lint-Rollouts (non-blocking): 44 misspell + 4
staticcheck automatisch behoben (32 Dateien, nur Tippfehler/mechanisch).
build+test grün. Kein Runtime-Change → kein Deploy.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-05 23:25:22 +02:00

105 lines
3.0 KiB
Go

// Package waf implements the per-domain WAF engine for EdgeGuard.
// It wraps Coraza v3 (OWASP Core Rule Set) and exposes a simple
// hostname-keyed engine manager that the SPOE agent uses.
package waf
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/corazawaf/coraza/v3"
"git.netcell-it.de/projekte/edgeguard-native/internal/models"
)
const (
DefaultCRSDir = "/usr/share/edgeguard/waf/crs"
DefaultSPOEAddr = "127.0.0.1:9000"
)
// BuildEngine creates a Coraza WAF instance for the given domain config.
// crsDir is the path to the OWASP CRS directory (may be empty — engine
// works without CRS, using only the basic Coraza core rules).
func BuildEngine(cfg models.WafConfig, crsDir string) (coraza.WAF, error) {
directives := buildDirectives(cfg, crsDir)
wafCfg := coraza.NewWAFConfig().
WithRequestBodyAccess().
WithDirectives(directives)
return coraza.NewWAF(wafCfg)
}
// buildDirectives assembles the SecLang directives for a domain config.
func buildDirectives(cfg models.WafConfig, crsDir string) string {
var sb strings.Builder
sb.WriteString("SecRequestBodyAccess On\n")
sb.WriteString("SecResponseBodyAccess Off\n")
sb.WriteString("SecRequestBodyLimit 13107200\n") // 12.5 MB
sb.WriteString("SecRequestBodyInMemoryLimit 131072\n") // 128 KB
fmt.Fprintf(&sb, "SecRuleEngine %s\n", ruleEngineMode(cfg.Mode))
if crsDir != "" && crsAvailable(crsDir) {
// Paranoia level MUST be set before CRS rules are included.
pl := cfg.ParanoiaLevel
if pl < 1 || pl > 4 {
pl = 1
}
fmt.Fprintf(&sb, "SecAction \"id:900000,phase:1,nolog,pass,t:none,setvar:tx.paranoia_level=%d\"\n", pl)
setupConf := filepath.Join(crsDir, "crs-setup.conf")
if _, err := os.Stat(setupConf); err == nil {
fmt.Fprintf(&sb, "Include %s\n", setupConf)
}
rulesGlob := filepath.Join(crsDir, "rules", "*.conf")
fmt.Fprintf(&sb, "Include %s\n", rulesGlob)
}
// Rule exclusions (applied after CRS load so they override CRS).
for _, id := range cfg.RuleExclusions {
id = strings.TrimSpace(id)
if id != "" {
fmt.Fprintf(&sb, "SecRuleRemoveById %s\n", id)
}
}
// Trusted proxies are NOT a SecLang directive — they are applied in the
// SPOE agent (spoe.go): when the connection source is a trusted proxy,
// the real client IP is taken from X-Forwarded-For before Coraza sees
// it. (Previously this loop emitted a bogus, unrelated directive.)
// Custom rules (appended last so they can override CRS).
if strings.TrimSpace(cfg.CustomRules) != "" {
sb.WriteString(cfg.CustomRules)
sb.WriteString("\n")
}
return sb.String()
}
func ruleEngineMode(mode string) string {
switch mode {
case "blocking":
return "On"
default: // "detection"
return "DetectionOnly"
}
}
// crsAvailable returns true when the CRS rules directory exists and
// contains at least one .conf file.
func crsAvailable(crsDir string) bool {
rulesDir := filepath.Join(crsDir, "rules")
entries, err := os.ReadDir(rulesDir)
if err != nil {
return false
}
for _, e := range entries {
if strings.HasSuffix(e.Name(), ".conf") {
return true
}
}
return false
}