/
generate_csr.go
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/
generate_csr.go
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// Copyright 2017 Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Provides utility methods to generate X.509 certificates with different
// options. This implementation is Largely inspired from
// https://golang.org/src/crypto/tls/generate_cert.go.
package util
import (
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"fmt"
"istio.io/istio/pkg/log"
)
// GenCSR generates a X.509 certificate sign request and private key with the given options.
func GenCSR(options CertOptions) ([]byte, []byte, error) {
// Generates a CSR
priv, err := rsa.GenerateKey(rand.Reader, options.RSAKeySize)
if err != nil {
return nil, nil, fmt.Errorf("RSA key generation failed (%v)", err)
}
template, err := GenCSRTemplate(options)
if err != nil {
return nil, nil, fmt.Errorf("CSR template creation failed (%v)", err)
}
csrBytes, err := x509.CreateCertificateRequest(rand.Reader, template, crypto.PrivateKey(priv))
if err != nil {
return nil, nil, fmt.Errorf("CSR creation failed (%v)", err)
}
csr, privKey := encodePem(true, csrBytes, priv)
return csr, privKey, nil
}
// GenCSRTemplate generates a certificateRequest template with the given options.
func GenCSRTemplate(options CertOptions) (*x509.CertificateRequest, error) {
template := &x509.CertificateRequest{
Subject: pkix.Name{
Organization: []string{options.Org},
},
}
if h := options.Host; len(h) > 0 {
s, err := BuildSubjectAltNameExtension(h)
if err != nil {
return nil, err
}
if options.IsDualUse {
cn, err := DualUseCommonName(h)
if err != nil {
// log and continue
log.Errorf("dual-use failed for CSR template - omitting CN (%v)", err)
} else {
template.Subject.CommonName = cn
}
}
template.ExtraExtensions = []pkix.Extension{*s}
}
return template, nil
}