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package cert
import (
"crypto/x509"
stdlibb64 "encoding/base64"
"fmt"
"io"
"github.com/lestrrat-go/jwx/v2/internal/base64"
)
// Create is a wrapper around x509.CreateCertificate, but it additionally
// encodes it in base64 so that it can be easily added to `x5c` fields
func Create(rand io.Reader, template, parent *x509.Certificate, pub, priv interface{}) ([]byte, error) {
der, err := x509.CreateCertificate(rand, template, parent, pub, priv)
if err != nil {
return nil, fmt.Errorf(`failed to create x509 certificate: %w`, err)
}
return EncodeBase64(der)
}
// EncodeBase64 is a utility function to encode ASN.1 DER certificates
// using base64 encoding. This operation is normally done by `pem.Encode`
// but since PEM would include the markers (`-----BEGIN`, and the like)
// while `x5c` fields do not need this, this function can be used to
// shave off a few lines
func EncodeBase64(der []byte) ([]byte, error) {
enc := stdlibb64.StdEncoding
dst := make([]byte, enc.EncodedLen(len(der)))
enc.Encode(dst, der)
return dst, nil
}
// Parse is a utility function to decode a base64 encoded
// ASN.1 DER format certificate, and to parse the byte sequence.
// The certificate must be in PKIX format, and it must not contain PEM markers
func Parse(src []byte) (*x509.Certificate, error) {
dst, err := base64.Decode(src)
if err != nil {
return nil, fmt.Errorf(`failed to base64 decode the certificate: %w`, err)
}
cert, err := x509.ParseCertificate(dst)
if err != nil {
return nil, fmt.Errorf(`failed to parse x509 certificate: %w`, err)
}
return cert, nil
}
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