curl/docs/libcurl/opts/CURLOPT_PROXY_SSL_VERIFYHOST.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

2.2 KiB

c SPDX-License-Identifier Title Section Source See-also
Copyright (C) Daniel Stenberg, <daniel.se>, et al. curl CURLOPT_PROXY_SSL_VERIFYHOST 3 libcurl
CURLOPT_CAINFO (3)
CURLOPT_PROXY_CAINFO (3)
CURLOPT_PROXY_SSL_VERIFYPEER (3)
CURLOPT_SSL_VERIFYPEER (3)

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 host name 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

2

PROTOCOLS

All protocols when used over an HTTPS proxy.

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 7.52.0.

If built TLS enabled.

RETURN VALUE

Returns CURLE_OK if TLS is supported, and CURLE_UNKNOWN_OPTION if not.

If 1 is set as argument, CURLE_BAD_FUNCTION_ARGUMENT is returned.