getRootCAs() - add mutex for concurrency safety (kedacore#5299)

Signed-off-by: Zbynek Roubalik <zroubalik@gmail.com>
Signed-off-by: anton.lysina <alysina@gmail.com>

pkg/util/certificates.go

@@ -22,8 +22,9 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
-	"path"
+	"path/filepath"
 	"strings"
+	"sync"
 
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 )
@@ -32,18 +33,29 @@ const customCAPath = "/custom/ca"
 
 var logger = logf.Log.WithName("certificates")
 
-var rootCAs *x509.CertPool
+var (
+	rootCAs     *x509.CertPool
+	rootCAsLock sync.Mutex
+)
 
 func getRootCAs() *x509.CertPool {
+	rootCAsLock.Lock()
+	defer rootCAsLock.Unlock()
+
 	if rootCAs != nil {
 		return rootCAs
 	}
 
-	rootCAs, _ = x509.SystemCertPool()
+	var err error
+	rootCAs, err = x509.SystemCertPool()
 	if rootCAs == nil {
 		rootCAs = x509.NewCertPool()
+		if err != nil {
+			logger.Error(err, "failed to load system cert pool, using new cert pool instead")
+		} else {
+			logger.V(1).Info("system cert pool not available, using new cert pool instead")
+		}
 	}
-
 	if _, err := os.Stat(customCAPath); errors.Is(err, fs.ErrNotExist) {
 		logger.V(1).Info(fmt.Sprintf("the path %s doesn't exist, skipping custom CA registrations", customCAPath))
 		return rootCAs
@@ -56,22 +68,24 @@ func getRootCAs() *x509.CertPool {
 	}
 
 	for _, file := range files {
-		if file.IsDir() || strings.HasPrefix(file.Name(), "..") {
-			logger.V(1).Info(fmt.Sprintf("%s isn't a valid certificate", file.Name()))
-			continue
+		filename := file.Name()
+		if file.IsDir() || strings.HasPrefix(filename, "..") {
+			logger.V(1).Info(fmt.Sprintf("%s isn't a valid certificate", filename))
+			continue // Skip directories and special files
 		}
 
-		certs, err := os.ReadFile(path.Join(customCAPath, file.Name()))
+		filePath := filepath.Join(customCAPath, filename)
+		certs, err := os.ReadFile(filePath)
 		if err != nil {
-			logger.Error(err, fmt.Sprintf("error reading %q", file.Name()))
+			logger.Error(err, fmt.Sprintf("error reading %q", filename))
 			continue
 		}
 
 		if ok := rootCAs.AppendCertsFromPEM(certs); !ok {
-			logger.Error(fmt.Errorf("no certs appended"), fmt.Sprintf("the certificate %s hasn't been added to the pool", file.Name()))
+			logger.Error(fmt.Errorf("no certs appended"), "filename", filename)
 			continue
 		}
-		logger.V(1).Info(fmt.Sprintf("the certificate %s has been added to the pool", file.Name()))
+		logger.V(1).Info(fmt.Sprintf("the certificate %s has been added to the pool", filename))
 	}
 
 	return rootCAs