使用 OpenSSL 从内存中读取证书文件而不是文件

Question

我有一个使用 OpenSSL 侦听 HTTPS 的服务器。为此，我必须提供要使用的证书。但是，当前的实现使用提供给 OpenSSL API 的文件名。

我希望从内存中读取证书信息，这样我就不必发送打开的证书文件。我尝试用谷歌搜索，但没有找到任何选项。

有可能吗？如果是这样，如何从内存中读取证书文件而不是使用 OpenSSL 的文件？

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编辑：以下内容已从评论移至问题。

// CURRENT
void start_server()
{
    const char *fileName = "cert_and_key.pem";
    set_server_ssl_file(fileName);
}
set_server_ssl_file(const char *fileName)
{
    //initialize context
    SSL_CTX_use_certificate_file(CTX, pem, SSL_FILETYPE_PEM); 
    SSL_CTX_use_PrivateKey_file(CTX, pem, SSL_FILETYPE_PEM);
}

//REQUIRED
void start_server()
{
    const char *cert = "--BEGIN CERTIFICATE--............";
    const char *key = "--BEGIN RSA PRIVATE KEY--.......";
    set_server_ssl_options(cert, key);
}
set_server_ssl_options(const char *cert, const char *key)
{
    //IMPLEMENTATION REQUIRED
}

Answer 1

其他片段将仅加载一个证书。 http://curl.haxx.se/ca/cacert.pem 包含许多不同的证书需要一种新方法。这是改编自openssl 1.0.1p（主要是openssl-1.0.1p\crypto\x509\by_file.c，char* buf包含*.pem文件的内容，ctx是boost::asio::ssl::context ），自行添加错误处理：

BIO *cbio = BIO_new_mem_buf((void*)buf, (int)length);
X509_STORE  *cts = SSL_CTX_get_cert_store(ctx.native_handle());
if(!cts || !cbio)
   return false;
X509_INFO *itmp;
int i, count = 0, type = X509_FILETYPE_PEM;
STACK_OF(X509_INFO) *inf = PEM_X509_INFO_read_bio(cbio, NULL, NULL, NULL);

if (!inf)
{
    BIO_free(cbio);//cleanup
    return false;
}
//itterate over all entries from the pem file, add them to the x509_store one by one
for (i = 0; i < sk_X509_INFO_num(inf); i++) {
    itmp = sk_X509_INFO_value(inf, i);
    if (itmp->x509) {
          X509_STORE_add_cert(cts, itmp->x509);
          count++;
    }
    if (itmp->crl) {
          X509_STORE_add_crl(cts, itmp->crl);
          count++;
    }
}
sk_X509_INFO_pop_free(inf, X509_INFO_free); //cleanup
BIO_free(cbio);//cleanup

Answer 2

unsigned char *cert_data = (....);
int cert_len = (....);

X509 *cert = d2i_X509(NULL, &cert_data, cert_len);
SSL_CTX_use_certificate(ctx, cert);

unsigned char *pkey_data = /* ... */;
int pkey_len = /* ... */;

RSA *pkey = d2i_RSAPrivateKey(NULL, &pkey_data, pkey_len);
SSL_CTX_use_RSAPrivateKey(ctx, pkey);

不要忘记 cert_data 和 pkey_data 之前的 & - 请注意 OpenSSL 会修改这些指针。

Answer 3

还有另一个使用 X509_STORE_add_cert 的响应，该响应已被投票但不正确。该答案是在内存中执行 SSL_CTX_load_verify_locations 的方法，但不会加载服务器证书链。对该评论的回复也表明它不起作用。

以下代码是基于 OpenSSL 中该函数实现的 SSL_CTX_use_certificate_chain_file 从内存加载实现：

bool load_cert_chain_from_shared_mem(SSL_CTX *context, const char *cert_buffer)
{
    BIO *cbio = BIO_new_mem_buf((void*)cert_buffer, -1);
    if (!cbio)
        return false;

    X509_INFO *itmp;
    int i, count = 0, type = X509_FILETYPE_PEM;
    STACK_OF(X509_INFO) *inf = PEM_X509_INFO_read_bio(cbio, NULL, NULL, NULL);

    if (!inf)
    {
        BIO_free(cbio);
        return false;
    }

    /* Iterate over contents of the PEM buffer, and add certs. */
    BOOL first = TRUE;
    for (i = 0; i < sk_X509_INFO_num(inf); i++) {
        itmp = sk_X509_INFO_value(inf, i);
        if (itmp->x509)
        {
            /* First cert is server cert. Remaining, if any, are intermediate certs. */
            if (first)
            {
                first = FALSE;

                /*
                 * Set server certificate. Note that this operation increments the
                 * reference count, which means that it is okay for cleanup to free it.
                 */
                if (!SSL_CTX_use_certificate(context, itmp->x509))
                    goto Error;

                if (ERR_peek_error() != 0)
                    goto Error;

                /* Get ready to store intermediate certs, if any. */
                SSL_CTX_clear_chain_certs(context);
            }
            else
            {
                /* Add intermediate cert to chain. */
                if (!SSL_CTX_add0_chain_cert(context, itmp->x509))
                    goto Error;

                /*
                 * Above function doesn't increment cert reference count. NULL the info
                 * reference to it in order to prevent it from being freed during cleanup.
                 */
                itmp->x509 = NULL;
            }
        }
    }

    sk_X509_INFO_pop_free(inf, X509_INFO_free);
    BIO_free(cbio);

    return true;

Error:
    sk_X509_INFO_pop_free(inf, X509_INFO_free);
    BIO_free(cbio);

    return false;
}

Answer 4

以下代码为我完成了这项工作：

 
SSL_CTX *CTX;
X509 *cert = NULL;
RSA *rsa = NULL;
BIO *cbio, *kbio;
const char *cert_buffer = "";
const char *key_buffer = "";

cbio = BIO_new_mem_buf((void*)cert_buffer, -1);
cert = PEM_read_bio_X509(cbio, NULL, 0, NULL);
assert(cert != NULL);
SSL_CTX_use_certificate(CTX, cert);

kbio = BIO_new_mem_buf((void*)key_buffer, -1);
rsa = PEM_read_bio_RSAPrivateKey(kbio, NULL, 0, NULL);
assert(rsa != NULL);
SSL_CTX_use_RSAPrivateKey(CTX, rsa);