plucky (3) CURLOPT_SSL_VERIFYPEER.3.gz

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

       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

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