switch to properly compiled regexp to be able to bail out early

pkg/acquisition/modules/waf/utils.go

@@ -2,7 +2,6 @@ package wafacquisition
 
 import (
 	"fmt"
-	"regexp"
 	"time"
 
 	"github.com/crowdsecurity/coraza/v3/collection"
@@ -104,16 +103,12 @@ func (r *WafRunner) AccumulateTxToEvent(tx experimental.FullTransaction, kind st
 				continue
 			}
 			for _, collectionToKeep := range r.VariablesTracking {
-				match, err := regexp.MatchString("(?i)"+collectionToKeep, key)
-				if err != nil {
-					r.logger.Warningf("error matching %s with %s: %s", key, collectionToKeep, err)
-					continue
-				}
+				match := collectionToKeep.MatchString(key)
 				if match {
 					evt.Waap.Vars[key] = variable.Value()
 					r.logger.Infof("%s.%s = %s", variable.Variable().Name(), variable.Key(), variable.Value())
 				} else {
-					r.logger.Infof("%s.%s != %s (%s) (not kept)", variable.Variable().Name(), variable.Key(), collectionToKeep, variable.Value())
+					r.logger.Debugf("%s.%s != %s (%s) (not kept)", variable.Variable().Name(), variable.Key(), collectionToKeep, variable.Value())
 				}
 			}
 		}

pkg/acquisition/modules/waf/waf.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"regexp"
 	"strings"
 	"time"
 
@@ -38,7 +39,7 @@ type WafRunner struct {
 	UUID              string
 	RulesCollections  []*waf.WafRulesCollection
 	logger            *log.Entry
-	VariablesTracking []string
+	VariablesTracking []*regexp.Regexp
 }
 
 type WafSourceConfig struct {
@@ -251,6 +252,16 @@ func (w *WafSource) Configure(yamlConfig []byte, logger *log.Entry) error {
 			})
 		}
 
+		var compiledVariableRules []*regexp.Regexp
+
+		for _, variable := range w.config.VariablesTracking {
+			compiledVariableRule, err := regexp.Compile(variable)
+			if err != nil {
+				return fmt.Errorf("cannot compile variable regexp %s: %w", variable, err)
+			}
+			compiledVariableRules = append(compiledVariableRules, compiledVariableRule)
+		}
+
 		runner := WafRunner{
 			outOfBandWaf:      outofbandwaf,
 			inBandWaf:         inbandwaf,
@@ -258,7 +269,7 @@ func (w *WafSource) Configure(yamlConfig []byte, logger *log.Entry) error {
 			UUID:              wafUUID,
 			RulesCollections:  rulesCollections,
 			logger:            wafLogger,
-			VariablesTracking: w.config.VariablesTracking,
+			VariablesTracking: compiledVariableRules,
 		}
 		w.WafRunners[nbRoutine] = runner
 	}