CURLOPT_PROXY_CRLFILE(3) Library Functions Manual CURLOPT_PROXY_CRLFILE(3)
NAME
CURLOPT_PROXY_CRLFILE - HTTPS proxy Certificate Revocation List file
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CRLFILE, char *file);
DESCRIPTION
This option is for connecting to an HTTPS proxy, not an HTTPS server.
Pass a char pointer to a null-terminated string naming a file with the
concatenation of CRL (in PEM format) to use in the certificate valida-
tion that occurs during the SSL exchange.
When curl is built to use GnuTLS, there is no way to influence the use
of CRL passed to help in the verification process. When libcurl is built
with OpenSSL support, X509_V_FLAG_CRL_CHECK and
X509_V_FLAG_CRL_CHECK_ALL are both set, requiring CRL check against all
the elements of the certificate chain if a CRL file is passed.
This option makes sense only when used in combination with the CUR-
LOPT_PROXY_SSL_VERIFYPEER(3) option.
A specific error code (CURLE_SSL_CRL_BADFILE) is defined with the op-
tion. It is returned when the SSL exchange fails because the CRL file
cannot be loaded. A failure in certificate verification due to a revo-
cation information found in the CRL does not trigger this specific er-
ror.
The application does not have to keep the string around after setting
this option.
Using this option multiple times makes the last set string override the
previous ones. Set it to NULL to disable its use again.
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: GnuTLS, OpenSSL
and mbedTLS
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:80");
curl_easy_setopt(curl, CURLOPT_PROXY_CRLFILE, "/etc/certs/crl.pem");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.52.0
RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error.
CURLE_OK (0) means everything was OK, non-zero means an error occurred,
see libcurl-errors(3).
SEE ALSO
CURLOPT_PROXY_SSL_VERIFYHOST(3), CURLOPT_PROXY_SSL_VERIFYPEER(3), CUR-
LOPT_SSL_VERIFYHOST(3), CURLOPT_SSL_VERIFYPEER(3)
libcurl 2026-07-12 CURLOPT_PROXY_CRLFILE(3)
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