Man page - curlopt_ssl_ctx_data(3)

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Manual

CURLOPT_SSL_CTX_DATA(3)

Library Functions Manual

CURLOPT_SSL_CTX_DATA(3)

NAME

CURLOPT_SSL_CTX_DATA - pointer passed to SSL context callback

SYNOPSIS

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CTX_DATA, void *pointer);

DESCRIPTION

Data pointer to pass to the ssl context callback set by the option CURLOPT_SSL_CTX_FUNCTION(3), this is the pointer you get as third parameter.

DEFAULT

NULL

PROTOCOLS

This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

This option works only with the following TLS backends: BearSSL, OpenSSL, mbedTLS and wolfSSL

EXAMPLE

/* OpenSSL specific */
#include <openssl/ssl.h>
#include <curl/curl.h>
#include <stdio.h>
static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
{


  X509_STORE *store;


  X509 *cert = NULL;


  BIO *bio;


  char *mypem = parm;


  /* get a BIO */


  bio = BIO_new_mem_buf(mypem, -1);


  /* use it to read the PEM formatted certificate from memory into an


   * X509 structure that SSL can use


   */


  PEM_read_bio_X509(bio, &cert, 0, NULL);


  if(!cert)


    printf("PEM_read_bio_X509 failed...\n");


  /* get a pointer to the X509 certificate store (which may be empty) */


  store = SSL_CTX_get_cert_store((SSL_CTX *)sslctx);


  /* add our certificate to this store */


  if(X509_STORE_add_cert(store, cert) == 0)


    printf("error adding certificate\n");


  /* decrease reference counts */


  X509_free(cert);


  BIO_free(bio);


  /* all set to go */


  return CURLE_OK;
}
int main(void)
{


  CURL *ch;


  CURLcode rv;


  char *mypem = /* example CA cert PEM - shortened */


    "-----BEGIN CERTIFICATE-----\n"


    "MIIHPTCCBSWgAwIBAgIBADANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290\n"


    "IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNB\n"


    "IENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRA\n"


    "Y2FjZXJ0Lm9yZzAeFw0wMzAzMzAxMjI5NDlaFw0zMzAzMjkxMjI5NDlaMHkxEDAO\n"


    "GCSNe9FINSkYQKyTYOGWhlC0elnYjyELn8+CkcY7v2vcB5G5l1YjqrZslMZIBjzk\n"


    "zk6q5PYvCdxTby78dOs6Y5nCpqyJvKeyRKANihDjbPIky/qbn3BHLt4Ui9SyIAmW\n"


    "omTxJBzcoTWcFbLUvFUufQb1nA5V9FrWk9p2rSVzTMVD\n"


    "-----END CERTIFICATE-----\n";


  curl_global_init(CURL_GLOBAL_ALL);


  ch = curl_easy_init();


  curl_easy_setopt(ch, CURLOPT_SSLCERTTYPE, "PEM");


  curl_easy_setopt(ch, CURLOPT_SSL_VERIFYPEER, 1L);


  curl_easy_setopt(ch, CURLOPT_URL, "https://www.example.com/");


  curl_easy_setopt(ch, CURLOPT_SSL_CTX_FUNCTION, *sslctx_function);


  curl_easy_setopt(ch, CURLOPT_SSL_CTX_DATA, mypem);


  rv = curl_easy_perform(ch);


  if(!rv)


    printf("*** transfer succeeded ***\n");


  else


    printf("*** transfer failed ***\n");


  curl_easy_cleanup(ch);


  curl_global_cleanup();


  return rv;
}

HISTORY

Added in 7.11.0 for OpenSSL, in 7.42.0 for wolfSSL, in 7.54.0 for mbedTLS, in 7.83.0 in BearSSL.

AVAILABILITY

Added in curl 7.10.6

RETURN VALUE

CURLE_OK if supported; or an error such as:

CURLE_NOT_BUILT_IN - Not supported by the SSL backend

CURLE_UNKNOWN_OPTION