kubernetes/kops · error

failed to parse certificate: %w

Error message

failed to parse certificate: %w

What it means

BuildChallengeServerCertificate wraps an error from x509.ParseCertificate after the certificate DER bytes were just created. Since the bytes come directly from CreateCertificate, this should be impossible in practice; if it fires, the crypto backend produced malformed DER or memory corruption/patched crypto layers are in play.

Source

Thrown at pkg/bootstrap/challenge.go:92

		},
		NotBefore: notBefore,
		NotAfter:  notAfter,

		KeyUsage:              keyUsage,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
	}

	template.DNSNames = append(template.DNSNames, serverName)

	der, err := x509.CreateCertificate(cryptorand.Reader, &template, &template, privateKey.Key.Public(), privateKey.Key)
	if err != nil {
		return nil, fmt.Errorf("failed to create certificate: %w", err)
	}

	parsed, err := x509.ParseCertificate(der)
	if err != nil {
		return nil, fmt.Errorf("failed to parse certificate: %w", err)
	}
	tlsCertificate := &tls.Certificate{
		PrivateKey:  privateKey.Key,
		Certificate: [][]byte{parsed.Raw},
		Leaf:        parsed,
	}

	return tlsCertificate, nil
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Confirm the Go toolchain is official/unpatched (go version) and rebuild kops
2. Check for FIPS or crypto replacement modules (e.g. boringcrypto) in the build (go env GOEXPERIMENT, build tags)
3. Log hex.Dump(der) and inspect whether the bytes are a plausible certificate
4. Report to kops with the environment details if reproducible with a stock build

cert, err := BuildChallengeServerCertificate(clusterName)
if err != nil {
  return fmt.Errorf("challenge server startup failed: %w", err)
}

When it happens

Trigger: NewChallengeServer builds the challenge certificate; x509.ParseCertificate(der) fails on freshly generated DER bytes — essentially only under a broken/patched Go crypto stack or corrupted memory.

Common situations: Custom Go toolchains with crypto patches; FIPS-mode builds altering encoding; observing this in stock kops strongly suggests a bug report-worthy environment problem.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.
• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• failed to create certificate: %w
• parsing key: %v
• error creating certificate: %w
• error loading certificate pool
• unable to build client-cert CA pools

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/ff7704d0e3103ca5. Report an issue: GitHub.