GNURLOPT_CRLFILE(3)

💖 CURLOPT_CRLFILE — specify a Certificate Revocation List file 💖

Okay bestie, you're on the GNURLOPT_CRLFILE(3) page from the gnurl/curl_easy_setopt options manual. This is the CRL-file option, and we're gonna get you comfy with it. No cap. ✨

🌸 NAME 🌸

CURLOPT_CRLFILE — specify a Certificate Revocation List file. 🎀

✨ SYNOPSIS ✨

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CRLFILE, char *file);

That's the whole spell, friend. 💅

🦋 DESCRIPTION 🦋

You're passing a char * that points at a null-terminated string. That string names a file with the concatenation of CRL (in PEM format), and it gets used in the certificate validation that happens during the SSL exchange. Slay. 🫶

When curl is built to use NSS or GnuTLS, there is no way to influence the use of CRL passed to help in the verification process. That's just how it is, bestie. 😭

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. Also note that CURLOPT_CRLFILE(3) will imply CURLSSLOPT_NO_PARTIALCHAIN (see CURLOPT_SSL_OPTIONS(3)) since curl 7.71.0 due to an OpenSSL bug. 🔥

This option makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER(3) option. Like, that's the combo, iykyk.

A specific error code (CURLE_SSL_CRL_BADFILE) is defined with the option. It is returned when the SSL exchange fails because the CRL file cannot be loaded. A failure in certificate verification due to a revocation information found in the CRL does not trigger this specific error. Important distinction, bestie. 💀

The application does not have to keep the string around after setting this option. So you can let that string go live its life. 🧚

🎀 DEFAULT 🎀

NULL

🌈 PROTOCOLS 🌈

All TLS-based protocols. Periodt. 👑

⭐ EXAMPLE ⭐

CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  curl_easy_setopt(curl, CURLOPT_CRLFILE, "/etc/certs/crl.pem");
  ret = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}

💜 AVAILABILITY 💜

Added in 7.19.0. Iconic. ✨

🍓 RETURN VALUE 🍓

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space. Gotta watch that heap, bestie. 😭

🌸 SEE ALSO 🌸

• CURLOPT_SSL_VERIFYPEER(3)
• CURLOPT_SSL_VERIFYHOST(3)
• CURLOPT_PROXY_CRLFILE(3),

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That's the tea, bestie: libcurl 7.37.0, 19 Jun 2014, page GNURLOPT_CRLFILE(3). Byeee 💖