Provided by: libcurl4-doc_8.9.1-2ubuntu2.1_all bug

NAME

       CURLOPT_SSL_VERIFYPEER - verify the peer's SSL certificate

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYPEER, long verify);

DESCRIPTION

       Pass a long as parameter to enable or disable.

       This option determines whether curl verifies the authenticity of the peer's certificate. A
       value of 1 means curl verifies; 0 (zero) means it does not.

       When negotiating a TLS or SSL connection, the server sends a  certificate  indicating  its
       identity. Curl verifies whether the certificate is authentic, i.e. that you can trust that
       the server is who the certificate says it is.  This trust is based on a chain  of  digital
       signatures,  rooted  in  certification authority (CA) certificates you supply. curl uses a
       default bundle of CA certificates (the path for that is determined at build time) and  you
       can   specify   alternate   certificates   with   the   CURLOPT_CAINFO(3)  option  or  the
       CURLOPT_CAPATH(3) option.

       When CURLOPT_SSL_VERIFYPEER(3) is enabled, and the verification fails to  prove  that  the
       certificate is signed by a CA, the connection fails.

       When  this  option  is  disabled (set to zero), the CA certificates are not loaded and the
       peer certificate verification is simply skipped.

       Authenticating the certificate is not enough to be sure about the  server.  You  typically
       also  want  to  ensure  that  the  server  is  the  server  you mean to be talking to. Use
       CURLOPT_SSL_VERIFYHOST(3) for that. The check that the host name  in  the  certificate  is
       valid   for   the   hostname   you   are  connecting  to  is  done  independently  of  the
       CURLOPT_SSL_VERIFYPEER(3) option.

       WARNING: disabling verification of the certificate allows bad  guys  to  man-in-the-middle
       the  communication  without you knowing it. Disabling verification makes the communication
       insecure. Just having encryption on a transfer is not enough as you cannot  be  sure  that
       you are communicating with the correct end-point.

       When  libcurl  uses  secure  protocols it trusts responses and allows for example HSTS and
       Alt-Svc information to be stored and used subsequently. Disabling certificate verification
       can make libcurl trust and use such information from malicious servers.

DEFAULT

       1 - enabled

PROTOCOLS

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

       All TLS backends support this option.

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* Set the default value: strict certificate check please */
           curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);

           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in curl 7.4.2

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       CURLINFO_CAINFO(3),                 CURLINFO_CAPATH(3),                 CURLOPT_CAINFO(3),
       CURLOPT_PROXY_SSL_VERIFYHOST(3),                          CURLOPT_PROXY_SSL_VERIFYPEER(3),
       CURLOPT_SSL_VERIFYHOST(3)