int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
unsigned char output_buf[4096];
size_t olen = 0;
if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf),
f_rng, p_rng ) ) < 0 )
{
return( ret );
}
if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,
output_buf + sizeof(output_buf) - ret,
ret, buf, size, &olen ) ) != 0 )
{
return( ret );
}
return( 0 );
}
/*
* CSR is output formatted as b64url(DER)
* Private key is output as a PEM in memory
*/
LWS_VISIBLE LWS_EXTERN int
lws_tls_acme_sni_csr_create(struct lws_context *context, const char *elements[],
uint8_t *dcsr, size_t csr_len, char **privkey_pem,
size_t *privkey_len)
{
mbedtls_x509write_csr csr;
char subject[200];
mbedtls_pk_context mpk;
int buf_size = 4096, n;
uint8_t *buf = malloc(buf_size); /* malloc because given to user code */
if (!buf)
return -1;
mbedtls_x509write_csr_init(&csr);
mbedtls_pk_init(&mpk);
if (mbedtls_pk_setup(&mpk, mbedtls_pk_info_from_type(MBEDTLS_PK_RSA))) {
lwsl_notice("%s: pk_setup failed\n", __func__);
goto fail;
}
n = mbedtls_rsa_gen_key(mbedtls_pk_rsa(mpk), _rngf, context,
lws_plat_recommended_rsa_bits(), 65537);
if (n) {
lwsl_notice("%s: failed to generate keys\n", __func__);
goto fail1;
}
/* subject must be formatted like "C=TW,O=warmcat,CN=myserver" */
lws_snprintf(subject, sizeof(subject) - 1,
"C=%s,ST=%s,L=%s,O=%s,CN=%s",
elements[LWS_TLS_REQ_ELEMENT_COUNTRY],
elements[LWS_TLS_REQ_ELEMENT_STATE],
elements[LWS_TLS_REQ_ELEMENT_LOCALITY],
elements[LWS_TLS_REQ_ELEMENT_ORGANIZATION],
elements[LWS_TLS_REQ_ELEMENT_COMMON_NAME]);
if (mbedtls_x509write_csr_set_subject_name(&csr, subject))
goto fail1;
mbedtls_x509write_csr_set_key(&csr, &mpk);
mbedtls_x509write_csr_set_md_alg(&csr, MBEDTLS_MD_SHA256);
/*
* data is written at the end of the buffer! Use the
* return value to determine where you should start
* using the buffer
*/
n = mbedtls_x509write_csr_der(&csr, buf, buf_size, _rngf, context);
if (n < 0) {
lwsl_notice("%s: write csr der failed\n", __func__);
goto fail1;
}
/* we have it in DER, we need it in b64URL */
n = lws_jws_base64_enc((char *)(buf + buf_size) - n, n,
(char *)dcsr, csr_len);
if (n < 0)
goto fail1;
/*
* okay, the CSR is done, last we need the private key in PEM
* re-use the DER CSR buf as the result buffer since we cn do it in
* one step
*/
if (mbedtls_pk_write_key_pem(&mpk, buf, buf_size)) {
lwsl_notice("write key pem failed\n");
goto fail1;
}
*privkey_pem = (char *)buf;
*privkey_len = strlen((const char *)buf);
mbedtls_pk_free(&mpk);
mbedtls_x509write_csr_free(&csr);
return n;
fail1:
mbedtls_pk_free(&mpk);
fail:
mbedtls_x509write_csr_free(&csr);
free(buf);
return -1;
}
