C++ OpenSSL 之三：生成CSR文件

1.等同于使用： openssl req -new -key "key_path" -out "save_path" -subj "/emailAddress=email/CN=name/C=country"

2.代码如下：keyFilePath为RSA private key 文件。

bool MakeCsrSSL(const  char * keyFilePath, const  char *email, const  char *name, const  char *country, const  char *saveCsrFilePath) {
    int             ret = 0;
    RSA             *r = NULL;
    BIGNUM          *bne = NULL;

    int             nVersion = 1;
    int             bits = 2048;
    unsigned long   e = RSA_F4;

    X509_REQ        *x509_req = NULL;
    X509_NAME       *x509_name = NULL;
    EVP_PKEY        *pKey = NULL;
    RSA             *tem = NULL;
    BIO             *out = NULL, *keyFileBIO = NULL;
    FILE            *pubKeyFile = NULL;

    if (strlen(saveCsrFilePath) == 0) {
        fprintf(stderr, "MakeLocalCsrSSLApi save path is empty\n");
        return false;
    }

    //not exists public key file, create one immediately.
    if (strlen(keyFilePath) == 0) {
        // 1. generate rsa key
        bne = BN_new();
        ret = BN_set_word(bne, e);
        if (ret != 1) {
            fprintf(stderr, "MakeLocalCsrSSLApi BN_set_word err\n");
            goto free_all;
        }

        r = RSA_new();
        ret = RSA_generate_key_ex(r, bits, bne, NULL);
        if (ret != 1) {
            fprintf(stderr, "MakeLocalCsrSSLApi RSA_generate_key_ex err\n");
            goto free_all;
        }
    } else { //open it
        pubKeyFile = fopen(keyFilePath, "r");
        if (pubKeyFile == NULL) {
            fprintf(stderr, "MakeLocalCsrSSLApi opening file %s err\n", keyFilePath);
            goto free_all;
        }

        keyFileBIO = BIO_new_file(keyFilePath, "r");
        if (keyFileBIO == NULL) {
            fprintf(stderr, "MakeLocalCsrSSLApi BIO_new_file err %s\n", keyFilePath);
            goto free_all;
        }

        r = PEM_read_bio_RSAPrivateKey(keyFileBIO, NULL, NULL, NULL);
        if (r == NULL) {
            fprintf(stderr, "MakeLocalCsrSSLApi PEM_read_bio_RSAPrivateKey err\n");
            goto free_all;
        }

        /*
        //从csr文件中获取私钥
        BIO* bio = bio_open_default(csrFilePath, "r", 1);
        r = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, NULL);
        if (r == NULL) {
            fprintf(stderr, "Error PEM_read_RSAPublicKey file %s\n", savePrivateKeyFilePath);
            return false;
        }*/
    }

    // 2. set version of x509 req
    x509_req = X509_REQ_new();
    ret = X509_REQ_set_version(x509_req, nVersion);
    if (ret != 1) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_REQ_set_version err\n");
        goto free_all;
    }

    // 3. set subject of x509 req
    x509_name = X509_REQ_get_subject_name(x509_req); //x509_req->req_info.subject;

    ret = X509_NAME_add_entry_by_txt(x509_name, "emailAddress", MBSTRING_ASC, (const unsigned char*)email, -1, -1, 0);
    if (ret != 1) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_NAME_add_entry_by_txt emailAddress err\n");
        goto free_all;
    }

    ret = X509_NAME_add_entry_by_txt(x509_name, "CN", MBSTRING_ASC, (const unsigned char*)name, -1, -1, 0);
    if (ret != 1) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_NAME_add_entry_by_txt CN err\n");
        goto free_all;
    }

    ret = X509_NAME_add_entry_by_txt(x509_name, "C", MBSTRING_ASC, (const unsigned char*)country, -1, -1, 0);
    if (ret != 1) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_NAME_add_entry_by_txt C err\n");
        goto free_all;
    }

    // 4. set public key of x509 req
    pKey = EVP_PKEY_new();
    EVP_PKEY_assign_RSA(pKey, r);
    r = NULL;   // will be free rsa when EVP_PKEY_free(pKey)

    ret = X509_REQ_set_pubkey(x509_req, pKey);
    if (ret != 1) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_REQ_set_pubkey err\n");
        goto free_all;
    }

    // 5. set sign key of x509 req
    ret = X509_REQ_sign(x509_req, pKey, EVP_sha1());    // return x509_req->signature->length
    if (ret <= 0) {
        fprintf(stderr, "MakeLocalCsrSSLApi X509_REQ_sign err\n");
        goto free_all;
    }

    out = BIO_new_file(saveCsrFilePath, "w");
    ret = PEM_write_bio_X509_REQ(out, x509_req);

    // 6. free
free_all:
    BIO_free_all(keyFileBIO);
    X509_REQ_free(x509_req);
    BIO_free_all(out);

    EVP_PKEY_free(pKey);
    BN_free(bne);
    if (pubKeyFile) fclose(pubKeyFile);

    return (ret == 1);
}

以上。

 

《C++ OpenSSL 之一：编译和使用》
《C++ OpenSSL 之二：生成RSA文件》
《C++ OpenSSL 之三：生成CSR文件》
《C++ OpenSSL 之四：CER转换为PEM》
《C++ OpenSSL 之五：生成P12文件》