我希望现在还不算太晚，我的回答会有所帮助:)
我正在提供我的解决方案，我在大约三年前研究了 openssl 源代码后实施了该解决方案。生成的证书非常简单 - 查看您需要的字段并调整功能。
openssl req -new -key cert.key -out cert.csr
通过以下方式实现：
X509_REQ *generate_cert_req(const char *p_path) {
FILE *p_file = NULL;
EVP_PKEY *p_key = NULL;
X509_REQ *p_x509_req = NULL;
if (NULL == (p_file = fopen(p_path, "r"))) {
printf("failed to open the private key file\n");
goto CLEANUP;
}
if (NULL == (p_key = PEM_read_PrivateKey(p_file, NULL, NULL, NULL))) {
printf("failed to read the private key file\n");
goto CLEANUP;
}
if (NULL == (p_x509_req = X509_REQ_new())) {
printf("failed to create a new X509 REQ\n");
goto CLEANUP;
}
if (0 > X509_REQ_set_pubkey(p_x509_req, p_key)) {
printf("failed to set pub key\n");
X509_REQ_free(p_x509_req);
p_x509_req = NULL;
goto CLEANUP;
}
if (0 > X509_REQ_sign(p_x509_req, p_key, EVP_sha256())) {
printf("failed to sign the certificate\n");
X509_REQ_free(p_x509_req);
p_x509_req = NULL;
goto CLEANUP;
}
CLEANUP:
fclose(p_file);
EVP_PKEY_free(p_key);
return p_x509_req;
}
该函数只有一个参数，它是密钥文件的路径（上面 openssl 命令 sn-p 中的 cert.key），其结果返回一个指向生成的证书请求的指针。
openssl x509 -req -in cert.csr -CA rootCA.crt -CAkey rootCA.key -CAcreateserial -out cert.crt -days 5000
作为“generate_cert”函数实现
int randSerial(ASN1_INTEGER *ai) {
BIGNUM *p_bignum = NULL;
int ret = -1;
if (NULL == (p_bignum = BN_new())) {
goto CLEANUP;
}
if (!BN_pseudo_rand(p_bignum, 64, 0, 0)) {
goto CLEANUP;
}
if (ai && !BN_to_ASN1_INTEGER(p_bignum, ai)) {
goto CLEANUP;
}
ret = 1;
CLEANUP:
BN_free(p_bignum);
return ret;
}
X509 *generate_cert(X509_REQ *pCertReq, const char *p_ca_path, const char *p_ca_key_path) {
FILE *p_ca_file = NULL;
X509 *p_ca_cert = NULL;
EVP_PKEY *p_ca_pkey = NULL;
FILE *p_ca_key_file = NULL;
EVP_PKEY *p_ca_key_pkey = NULL;
X509 *p_generated_cert = NULL;
ASN1_INTEGER *p_serial_number = NULL;
EVP_PKEY *p_cert_req_pkey = NULL;
if (NULL == (p_ca_file = fopen(p_ca_path, "r"))) {
printf("failed to open the ca file\n");
goto CLEANUP;
}
if (NULL == (p_ca_cert = PEM_read_X509(p_ca_file, NULL, 0, NULL))) {
printf("failed to read X509 CA certificate\n");
goto CLEANUP;
}
if (NULL == (p_ca_pkey = X509_get_pubkey(p_ca_cert))) {
printf("failed to get X509 CA pkey\n");
goto CLEANUP;
}
if (NULL == (p_ca_key_file = fopen(p_ca_key_path, "r"))) {
printf("failed to open the private key file\n");
goto CLEANUP;
}
if (NULL == (p_ca_key_pkey = PEM_read_PrivateKey(p_ca_key_file, NULL, NULL, NULL))) {
printf("failed to read the private key file\n");
goto CLEANUP;
}
if (NULL == (p_generated_cert = X509_new())) {
printf("failed to allocate a new X509\n");
goto CLEANUP;
}
p_serial_number = ASN1_INTEGER_new();
randSerial(p_serial_number);
X509_set_serialNumber(p_generated_cert, p_serial_number);
X509_set_issuer_name(p_generated_cert, X509_REQ_get_subject_name(pCertReq));
X509_set_subject_name(p_generated_cert, X509_REQ_get_subject_name(pCertReq));
X509_gmtime_adj(X509_get_notBefore(p_generated_cert), 0L);
X509_gmtime_adj(X509_get_notAfter(p_generated_cert), 31536000L);
if (NULL == (p_cert_req_pkey = X509_REQ_get_pubkey(pCertReq))) {
printf("failed to get certificate req pkey\n");
X509_free(p_generated_cert);
p_generated_cert = NULL;
goto CLEANUP;
}
if (0 > X509_set_pubkey(p_generated_cert, p_cert_req_pkey)) {
printf("failed to set pkey\n");
X509_free(p_generated_cert);
p_generated_cert = NULL;
goto CLEANUP;
}
if (0 > EVP_PKEY_copy_parameters(p_ca_pkey, p_ca_key_pkey)) {
printf("failed to copy parameters\n");
X509_free(p_generated_cert);
p_generated_cert = NULL;
goto CLEANUP;
}
X509_set_issuer_name(p_generated_cert, X509_get_subject_name(p_ca_cert));
if (0 > X509_sign(p_generated_cert, p_ca_key_pkey, EVP_sha256())) {
printf("failed to sign the certificate\n");
X509_free(p_generated_cert);
p_generated_cert = NULL;
goto CLEANUP;
}
CLEANUP:
fclose(p_ca_file);
X509_free(p_ca_cert);
EVP_PKEY_free(p_ca_pkey);
fclose(p_ca_key_file);
EVP_PKEY_free(p_ca_key_pkey);
ASN1_INTEGER_free(p_serial_number);
EVP_PKEY_free(p_cert_req_pkey);
return p_generated_cert;
}
函数有三个参数：
1：指向一个证书请求（在第一步中生成）
2：ca的路径（上面sn -p命令中的-CA rootCA.crt）
3：ca key的路径（-CAkey rootCA.key）
函数可以通过以下方式使用：
int save_cert_req(X509_REQ *p_cert_req, const char *path) {
FILE *p_file = NULL;
if (NULL == (p_file = fopen(path, "w"))) {
printf("failed to open file for saving csr\n");
return -1;
}
PEM_write_X509_REQ(p_file, p_cert_req);
fclose(p_file);
return 0;
}
int save_cert(X509 *p_generated_cert, const char *path) {
FILE *p_file = NULL;
if (NULL == (p_file = fopen(path, "w"))) {
printf("failed to open file for saving csr\n");
return -1;
}
PEM_write_X509(p_file, p_generated_cert);
fclose(p_file);
return 0;
}
int main() {
int ret = 0;
X509_REQ *p_cert_req = NULL;
X509 *p_generated_cert = NULL;
p_cert_req = generate_cert_req(CERT_REQUEST_KEY_PATH);
if (NULL == p_cert_req) {
printf("failed to generate cert req\n");
ret = -1;
goto CLEANUP;
}
if (save_cert_req(p_cert_req, GENERATED_CERT_REQUEST_SAVE_PATH)) {
printf("failed to save generated cert request\n");
ret = -1;
goto CLEANUP;
}
p_generated_cert = generate_cert(p_cert_req, CERT_CA_PATH, CERT_CA_KEY_PATH);
if (NULL == p_generated_cert) {
printf("failed to generate cert\n");
ret = -1;
goto CLEANUP;
}
if (save_cert(p_generated_cert, GENERATED_CERT_SAVE_PATH)) {
printf("failed to save generated cert\n");
ret = -1;
goto CLEANUP;
}
printf("the certificates have been generated.");
CLEANUP:
X509_REQ_free(p_cert_req);
X509_free(p_generated_cert);
return ret;
}
您可以从 github 存储库下载可以编译和测试的整个解决方案：
https://github.com/egorovandreyrm/openssl_cert_req