63 lines
1.8 KiB
Go
63 lines
1.8 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cert
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import (
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cryptorand "crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/pem"
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"net"
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)
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// MakeCSR generates a PEM-encoded CSR using the supplied private key, subject, and SANs.
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// All key types that are implemented via crypto.Signer are supported (This includes *rsa.PrivateKey and *ecdsa.PrivateKey.)
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func MakeCSR(privateKey interface{}, subject *pkix.Name, dnsSANs []string, ipSANs []net.IP) (csr []byte, err error) {
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// Customize the signature for RSA keys, depending on the key size
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var sigType x509.SignatureAlgorithm
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if privateKey, ok := privateKey.(*rsa.PrivateKey); ok {
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keySize := privateKey.N.BitLen()
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switch {
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case keySize >= 4096:
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sigType = x509.SHA512WithRSA
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case keySize >= 3072:
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sigType = x509.SHA384WithRSA
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default:
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sigType = x509.SHA256WithRSA
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}
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}
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template := &x509.CertificateRequest{
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Subject: *subject,
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SignatureAlgorithm: sigType,
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DNSNames: dnsSANs,
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IPAddresses: ipSANs,
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}
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csr, err = x509.CreateCertificateRequest(cryptorand.Reader, template, privateKey)
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if err != nil {
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return nil, err
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}
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csrPemBlock := &pem.Block{
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Type: "CERTIFICATE REQUEST",
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Bytes: csr,
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}
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return pem.EncodeToMemory(csrPemBlock), nil
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}
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