all: use global rand to seed random generators

Global random generator is automatically seeded since go1.20,
see https://go.dev/doc/go1.20#math/rand and golang/go#54880

This change uses global generator to seed random sources instead of time.Now().UnixNano().

Signed-off-by: Alexander Yastrebov <alexander.yastrebov@zalando.de>

filters/auth/oidc_test.go

@@ -1002,7 +1002,7 @@ func parseFilter(def, oidcServerURL, redirectURL string) ([]*eskip.Filter, error
 }
 
 func TestChunkAndMergerCookie(t *testing.T) {
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	r := rand.New(rand.NewSource(rand.Int63()))
 	tinyCookie := http.Cookie{
 		Name:     "skipperOauthOidcHASHHASH-",
 		Value:    "eyJ0eXAiOiJKV1QiLCJhbGciO",

filters/builtin/compress_test.go

@@ -36,7 +36,7 @@ type errorReader struct {
 var testContent []byte
 
 func init() {
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	r := rand.New(rand.NewSource(rand.Int63()))
 	testContent = make([]byte, maxTestContent)
 	n, err := r.Read(testContent)
 

filters/diag/absorb_test.go

@@ -38,7 +38,7 @@ func testAbsorb(t *testing.T, silent bool) {
 		"POST",
 		p.URL,
 		io.LimitReader(
-			rand.New(rand.NewSource(time.Now().UnixNano())),
+			rand.New(rand.NewSource(rand.Int63())),
 			bodySize,
 		),
 	)

filters/diag/diag.go

@@ -224,7 +224,7 @@ func (r *random) CreateFilter(args []interface{}) (filters.Filter, error) {
 	}
 
 	if l, ok := args[0].(float64); ok {
-		return &random{rand: rand.New(rand.NewSource(time.Now().UnixNano())), len: int64(l)}, nil // #nosec
+		return &random{rand: rand.New(rand.NewSource(rand.Int63())), len: int64(l)}, nil // #nosec
 	} else {
 		return nil, filters.ErrInvalidFilterParameters
 	}

filters/flowid/ulid.go

@@ -5,7 +5,6 @@ import (
 	"math/rand"
 	"regexp"
 	"sync"
-	"time"
 
 	"github.com/oklog/ulid"
 )
@@ -26,7 +25,7 @@ var ulidFlowIDRegex = regexp.MustCompile(`^[0123456789ABCDEFGHJKMNPQRSTVWXYZ]{26
 // It uses a shared, pseudo-random source of entropy, seeded with the current timestamp.
 // It is safe for concurrent usage.
 func NewULIDGenerator() Generator {
-	return NewULIDGeneratorWithEntropyProvider(rand.New(rand.NewSource(time.Now().UTC().UnixNano()))) // #nosec
+	return NewULIDGeneratorWithEntropyProvider(rand.New(rand.NewSource(rand.Int63()))) // #nosec
 }
 
 // NewULIDGeneratorWithEntropyProvider behaves like NewULIDGenerator but allows you to specify your own source of

loadbalancer/fadein_test.go

@@ -77,7 +77,7 @@ func testFadeIn(
 			})
 		}
 
-		rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
+		rnd := rand.New(rand.NewSource(rand.Int63()))
 		t.Log("test start", time.Now())
 		var stats []string
 		stop := time.After(fadeInDuration)
@@ -232,7 +232,7 @@ func benchmarkFadeIn(
 			go func(i int) {
 				defer wg.Done()
 
-				rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
+				rnd := rand.New(rand.NewSource(rand.Int63()))
 				ctx := &routing.LBContext{
 					Params: map[string]interface{}{},
 					Route:  route,

loadbalancer/locked_source.go

@@ -3,7 +3,6 @@ package loadbalancer
 import (
 	"math/rand"
 	"sync"
-	"time"
 )
 
 type lockedSource struct {
@@ -12,7 +11,7 @@ type lockedSource struct {
 }
 
 func newLockedSource() *lockedSource {
-	return &lockedSource{r: rand.NewSource(time.Now().UnixNano())}
+	return &lockedSource{r: rand.NewSource(rand.Int63())} // #nosec
 }
 
 func (s *lockedSource) Int63() int64 {

predicates/source/source_test.go

@@ -5,7 +5,6 @@ import (
 	"math/rand"
 	"net/http"
 	"testing"
-	"time"
 
 	"github.com/zalando/skipper/predicates"
 	"github.com/zalando/skipper/routing"
@@ -314,7 +313,7 @@ func TestMatchingClientIP(t *testing.T) {
 	}
 }
 
-var random = rand.New(rand.NewSource(time.Now().UnixNano()))
+var random = rand.New(rand.NewSource(rand.Int63()))
 
 func generateIPCidr() string {
 	if m := random.Int(); m%10 == 0 {

proxy/idle_test.go

@@ -32,7 +32,7 @@ func hasArg(arg string) bool {
 // This test is unpredictable, and occasionally fails on certain OSes.
 // To run this test, set `-args idle` for the test command.
 func TestIdleConns(t *testing.T) {
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	r := rand.New(rand.NewSource(rand.Int63()))
 	if !hasArg("idle") {
 		t.Skip()
 	}