Tribblix: manual page: CURLOPT_PROXY_SSL

CURLOPT_PROXY_SSL_VERIFYHOST(3) Introduction to Library Functions

NAME

CURLOPT_PROXY_SSL_VERIFYHOST - verify the proxy certificate's name
against host

SYNOPSIS

#include <curl/curl.h>

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

DESCRIPTION

Pass a long set to 2L as asking curl to verify in the HTTPS proxy's
certificate name fields against the proxy name.

This option determines whether libcurl verifies that the proxy cert
contains the correct name for the name it is known as.

When CURLOPT_PROXY_SSL_VERIFYHOST(3) is 2, the proxy certificate must
indicate that the server is the proxy to which you meant to connect
to, or the connection fails.

curl considers the proxy the intended one when the Common Name field
or a Subject Alternate Name field in the certificate matches the
hostname in the proxy string which you told curl to use.

If verify value is set to 1:

In 7.28.0 and earlier: treated as a debug option of some sorts, not
supported anymore due to frequently leading to programmer mistakes.

From 7.28.1 to 7.65.3: setting it to 1 made curl_easy_setopt(3)
return an error and leaving the flag untouched.

From 7.66.0: treats 1 and 2 the same.

When the verify value is 0L, the connection succeeds regardless of
the names used in the certificate. Use that ability with caution.

See also CURLOPT_PROXY_SSL_VERIFYPEER(3) to verify the digital
signature of the proxy certificate.

DEFAULT

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 name check please */
curl_easy_setopt(curl, CURLOPT_PROXY_SSL_VERIFYHOST, 2L);

curl_easy_perform(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).