Isolated X.509 Certificate Chain Validation with Custom Verification Options

package main
 
import (
	"crypto/x509"
	"fmt"
	"time"
)
 
func ValidateCertChain(leaf, root *x509.Certificate, dnsName string) error {
	roots := x509.NewCertPool()
	roots.AddCert(root)
 
	opts := x509.VerifyOptions{
		DNSName:     dnsName,
		Roots:       roots,
		CurrentTime: time.Now(),
		KeyUsages:   []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
	}
 
	chains, err := leaf.Verify(opts)
	if err != nil {
		return fmt.Errorf("certificate verification failed: %w", err)
	}
 
	fmt.Printf("Verified %d valid trust chain(s)\n", len(chains))
	return nil
}