Update Go API to version 1.2

Add Certificate Object, support parse, check and access (very limited)
attributes of an X.509 certificate in PEM format.

go/gmssl/certificate.go

@@ -0,0 +1,127 @@
+/* +build cgo */
+package gmssl
+
+/*
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <openssl/ec.h>
+#include <openssl/sm2.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/engine.h>
+#include <openssl/objects.h>
+#include <openssl/opensslconf.h>
+
+void _OPENSSL_free(void *p) {
+	OPENSSL_free(p);
+}
+
+long _BIO_get_mem_data(BIO *b, char **pp) {
+	return BIO_get_mem_data(b, pp);
+}
+
+*/
+import "C"
+
+import (
+	"fmt"
+	"unsafe"
+	"runtime"
+)
+
+type Certificate struct {
+	x509 *C.X509
+}
+
+func ReadCertificateFromPEM(pem string, pass string) (*Certificate, error) {
+	cpem := C.CString(pem)
+	defer C.free(unsafe.Pointer(cpem))
+	cpass := C.CString(pass)
+	defer C.free(unsafe.Pointer(cpass))
+
+	bio := C.BIO_new_mem_buf(unsafe.Pointer(cpem), -1)
+	if bio == nil {
+		return nil, GetErrors()
+	}
+	defer C.BIO_free(bio)
+
+	x509 := C.PEM_read_bio_X509(bio, nil, nil, unsafe.Pointer(cpass))
+	if x509 == nil {
+		return nil, GetErrors()
+	}
+	ret := &Certificate{x509}
+	runtime.SetFinalizer(ret, func(ret *Certificate) {
+		C.X509_free(ret.x509)
+	})
+
+	return ret, nil
+}
+
+func (cert *Certificate) GetSubject() (string, error) {
+	name := C.X509_get_subject_name(cert.x509)
+	if name == nil {
+		return "", GetErrors()
+	}
+	str := C.X509_NAME_oneline(name, nil, 0)
+	if str == nil {
+		return "", GetErrors()
+	}
+	defer C._OPENSSL_free(unsafe.Pointer(str))
+	return C.GoString(str), nil
+}
+
+func (cert *Certificate) GetIssuer() (string, error) {
+	name := C.X509_get_issuer_name(cert.x509)
+	if name == nil {
+		return "", GetErrors()
+	}
+	str := C.X509_NAME_oneline(name, nil, 0)
+	if str == nil {
+		return "", GetErrors()
+	}
+	defer C._OPENSSL_free(unsafe.Pointer(str))
+	return C.GoString(str), nil
+}
+
+func (cert *Certificate) GetSerialNumber() (string, error) {
+	serial := C.X509_get0_serialNumber(cert.x509)
+	if serial == nil {
+		return "", GetErrors()
+	}
+	bn := C.ASN1_INTEGER_to_BN(serial, nil)
+	if bn == nil {
+		return "", GetErrors()
+	}
+	defer C.BN_free(bn)
+	hex := C.BN_bn2hex(bn)
+	if hex == nil {
+		return "", GetErrors()
+	}
+	defer C._OPENSSL_free(unsafe.Pointer(hex))
+	return C.GoString(hex), nil
+}
+
+func (cert *Certificate) GetPublicKey() (*PublicKey, error) {
+	pkey := C.X509_get_pubkey(cert.x509)
+	if pkey == nil {
+		return nil, GetErrors()
+	}
+	ret := &PublicKey{pkey}
+	runtime.SetFinalizer(ret, func(ret *PublicKey) {
+		C.EVP_PKEY_free(ret.pkey)
+	})
+	return ret, nil
+}
+func (cert *Certificate) CheckPrivateKey(skey *PrivateKey) error {
+	if 1 != C.X509_check_private_key(cert.x509, skey.pkey) {
+		err := GetErrors()
+		if err == nil {
+			return fmt.Errorf("failure")
+		}
+		return err
+	}
+	return nil
+}
+