go语言生成自签证书文件（SM2）

package main

import (
	"crypto/rand"
	"crypto/x509/pkix"
	"encoding/pem"
	"github.com/tjfoc/gmsm/sm2"
	"github.com/tjfoc/gmsm/x509"
	"math/big"
	"net"
	"os"
	"time"
)

func GenerateCertKeySM2(host, commonName string, alternateIPs []net.IP, alternateDNS []string){
	priv, err := sm2.GenerateKey(rand.Reader)
	if err != nil {
		panic(err)
	}

	max := new(big.Int).Lsh(big.NewInt(1), 128)
	serialNumber, _ := rand.Int(rand.Reader, max)
	template := x509.Certificate{
		SerialNumber: serialNumber,
		Issuer: pkix.Name{},
		Subject: pkix.Name{
			CommonName:   commonName,
			Organization: []string{"Test"},
			Country:      []string{"CN"},
			ExtraNames: []pkix.AttributeTypeAndValue{
				{
					Type:  []int{2, 5, 4, 42},
					Value: "Gopher",
				},
				{
					Type:  []int{2, 5, 4, 6},
					Value: "NL",
				},
			},
		},
		NotBefore:             time.Now(),
		NotAfter:              time.Now().Add(time.Hour * 24 * 365),
		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
		BasicConstraintsValid: true,
		IsCA:                  true,
		SignatureAlgorithm:    x509.SM2WithSM3,
	}

	if ip := net.ParseIP(host); ip != nil {
		template.IPAddresses = append(template.IPAddresses, ip)
	}else {
		template.DNSNames = append(template.DNSNames, host)
	}

	template.IPAddresses = append(template.IPAddresses, alternateIPs...)
	template.DNSNames = append(template.DNSNames, alternateDNS...)

	publicKey := priv.Public().(*sm2.PublicKey)
	certificateToPem, err := x509.CreateCertificateToPem(&template, &template, publicKey, priv)
	if err != nil {
		panic(err)
	}

	file, err := os.Create("caSM2.crt")
	if err != nil {
		panic(err)
	}
	defer file.Close()
	file.Write(certificateToPem)

	privateKey, err := x509.MarshalSm2PrivateKey(priv, []byte("jjjjjj"))
	if err != nil {
		panic(err)
	}
	block := pem.Block{
		Type:    "SM2 PRIVATE KEY",
		Headers: nil,
		Bytes:   privateKey,
	}
	file, err = os.Create("caSM2.key")
	if err != nil {
		panic(err)
	}
	defer file.Close()
	err = pem.Encode(file, &block)
	if err != nil {
		panic(err)
	}
}

func main(){
	ip := []byte("127.0.0.1")
	alternateDNS := []string{"localhost"}
	GenerateCertKeySM2("192.168.0.1", "www.example.com", []net.IP{net.ParseIP(string(ip))}, alternateDNS)
}

查看证书信息，用该库生成的证书Signature Algorithm字段解析出来的值与template中设置的不一致，已在GitHub提交了issue

$ openssl x509 -in caSM2.crt -noout -text
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ed:e3:0a:34:c5:8f:49:09:13:e4:7b:77:ec:45:87:c8
        Signature Algorithm: 1.2.156.10197.1.501
        Issuer: O = Test, CN = www.example.com, GN = Gopher, C = NL
        Validity
            Not Before: May 28 13:20:58 2021 GMT
            Not After : May 28 13:20:58 2022 GMT
        Subject: O = Test, CN = www.example.com, GN = Gopher, C = NL
        Subject Public Key Info:
            Public Key Algorithm: id-ecPublicKey
                Public-Key: (256 bit)
                pub:
                    04:85:a3:bf:57:67:23:40:fb:81:c4:3f:14:c9:96:
                    31:a7:76:68:2b:c7:2b:56:b4:9d:3e:f8:9b:69:ff:
                    97:60:97:97:5d:09:ad:fe:95:28:d1:75:59:bf:00:
                    f8:cb:8f:27:d9:af:4d:4d:57:07:d8:dd:20:a7:eb:
                    d0:6e:2d:25:8f
                ASN1 OID: SM2
        X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment, Certificate Sign
            X509v3 Basic Constraints: critical
                CA:TRUE
            X509v3 Subject Alternative Name:
                DNS:localhost, IP Address:192.168.0.1, IP Address:127.0.0.1
    Signature Algorithm: 1.2.156.10197.1.501
         30:45:02:20:7f:27:cf:23:2e:53:15:e7:0c:23:3a:6d:3b:23:
         f8:6a:8e:6d:cb:ed:6a:af:e5:a3:46:d3:2a:2d:f0:21:1e:d6:
         02:21:00:bf:81:4e:74:19:e2:fe:bc:25:86:1b:39:12:8f:b5:
         f5:15:76:14:29:f1:5f:9b:32:da:13:b1:1c:bb:3a:f4:8f