consul/agent/connect/csr.go

69 lines
1.7 KiB
Go

package connect
import (
"bytes"
"crypto"
"crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"net/url"
)
// CreateCSR returns a CSR to sign the given service along with the PEM-encoded
// private key for this certificate.
func CreateCSR(uri CertURI, commonName string, privateKey crypto.Signer, extensions ...pkix.Extension) (string, error) {
template := &x509.CertificateRequest{
Subject: pkix.Name{CommonName: commonName},
URIs: []*url.URL{uri.URI()},
SignatureAlgorithm: x509.ECDSAWithSHA256,
ExtraExtensions: extensions,
}
// Create the CSR itself
var csrBuf bytes.Buffer
bs, err := x509.CreateCertificateRequest(rand.Reader, template, privateKey)
if err != nil {
return "", err
}
err = pem.Encode(&csrBuf, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: bs})
if err != nil {
return "", err
}
return csrBuf.String(), nil
}
// CreateCSR returns a CA CSR to sign the given service along with the PEM-encoded
// private key for this certificate.
func CreateCACSR(uri CertURI, commonName string, privateKey crypto.Signer) (string, error) {
ext, err := CreateCAExtension()
if err != nil {
return "", err
}
return CreateCSR(uri, commonName, privateKey, ext)
}
// CreateCAExtension creates a pkix.Extension for the x509 Basic Constraints
// IsCA field ()
func CreateCAExtension() (pkix.Extension, error) {
type basicConstraints struct {
IsCA bool `asn1:"optional"`
MaxPathLen int `asn1:"optional"`
}
basicCon := basicConstraints{IsCA: true, MaxPathLen: 0}
bitstr, err := asn1.Marshal(basicCon)
if err != nil {
return pkix.Extension{}, err
}
return pkix.Extension{
Id: []int{2, 5, 29, 19}, // from x509 package
Critical: true,
Value: bitstr,
}, nil
}