envconf: use crypto/rand for random name generator

pkg/envconf/config.go

@@ -17,11 +17,10 @@ limitations under the License.
 package envconf
 
 import (
+	"crypto/rand"
 	"encoding/hex"
 	"fmt"
-	"math/rand"
 	"regexp"
-	"time"
 
 	log "k8s.io/klog/v2"
 
@@ -303,9 +302,13 @@ func RandomName(prefix string, n int) string {
 	if len(prefix) >= n {
 		return prefix
 	}
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+
 	p := make([]byte, n)
-	r.Read(p)
+	_, err := rand.Read(p)
+	if err != nil {
+		log.ErrorS(err, "failed to generate random name. falling back to prefix directly")
+		return prefix
+	}
 	if prefix == "" {
 		return hex.EncodeToString(p)[:n]
 	}

pkg/envconf/config_test.go

@@ -102,3 +102,15 @@ func TestRandomName(t *testing.T) {
 		}
 	})
 }
+
+func TestRandomGeneratorIsIndeedGeneratingRandom(t *testing.T) {
+	randomValues := make(map[string]int)
+	for attempt := 0; attempt < 10; attempt++ {
+		randomValues[RandomName("test-randomness", 32)]++
+	}
+	for key, val := range randomValues {
+		if val > 1 {
+			t.Errorf("random name %q was generated %d times", key, val)
+		}
+	}
+}