Man pages sections > man3 > CURLOPT_SSL_CTX_DATA

CURLOPT_SSL_CTX_DATA - custom pointer passed to ssl_ctx callback

CURLOPT_SSL_CTX_DATA(3) curl_easy_setopt options CURLOPT_SSL_CTX_DATA(3)

NAME

CURLOPT_SSL_CTX_DATA - custom pointer passed to ssl_ctx 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'll get as third parameter.

DEFAULT

NULL

PROTOCOLS

All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

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 = (char *)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 == NULL) 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";
rv=curl_global_init(CURL_GLOBAL_ALL); ch=curl_easy_init(); rv=curl_easy_setopt(ch, CURLOPT_SSLCERTTYPE, "PEM"); rv=curl_easy_setopt(ch, CURLOPT_SSL_VERIFYPEER, 1L); rv=curl_easy_setopt(ch, CURLOPT_URL, "https://www.example.com/");
/* Retrieve page using cacerts' certificate -> will succeed * load the certificate by installing a function doing the necessary * "modifications" to the SSL CONTEXT just before link init */ rv=curl_easy_setopt(ch, CURLOPT_SSL_CTX_FUNCTION, *sslctx_function); rv=curl_easy_setopt(ch, CURLOPT_SSL_CTX_DATA, mypem); rv=curl_easy_perform(ch); if(rv==CURLE_OK) printf("*** transfer succeeded ***\n"); else printf("*** transfer failed ***\n");
curl_easy_cleanup(ch); curl_global_cleanup(); return rv; }

AVAILABILITY

Added in 7.11.0 for OpenSSL. Added in 7.42.0 for wolfSSL/CyaSSL. Other SSL backends not supported.

RETURN VALUE

CURLE_OK if supported; or an error such as:
 
CURLE_NOT_BUILT_IN - Not supported by the SSL backend
 
CURLE_UNKNOWN_OPTION

SEE ALSO

CURLOPT_SSL_CTX_FUNCTION(3), CURLOPT_SSLVERSION(3),
May 31, 2017 libcurl 7.55.1