103 lines
2.9 KiB
Markdown
103 lines
2.9 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLOPT_DOH_SSL_VERIFYPEER
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Section: 3
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Source: libcurl
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See-also:
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- CURLOPT_CAINFO (3)
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- CURLOPT_CAPATH (3)
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- CURLOPT_DOH_SSL_VERIFYHOST (3)
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- CURLOPT_PROXY_SSL_VERIFYHOST (3)
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- CURLOPT_PROXY_SSL_VERIFYPEER (3)
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- CURLOPT_SSL_VERIFYHOST (3)
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- CURLOPT_SSL_VERIFYPEER (3)
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---
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# NAME
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CURLOPT_DOH_SSL_VERIFYPEER - verify the DoH SSL certificate
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DOH_SSL_VERIFYPEER,
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long verify);
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~~~
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# DESCRIPTION
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Pass a long as parameter set to 1L to enable or 0L to disable.
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This option tells curl to verify the authenticity of the DoH (DNS-over-HTTPS)
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server's certificate. A value of 1 means curl verifies; 0 (zero) means it
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does not.
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This option is the DoH equivalent of CURLOPT_SSL_VERIFYPEER(3) and
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only affects requests to the DoH server.
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When negotiating a TLS or SSL connection, the server sends a certificate
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indicating its identity. Curl verifies whether the certificate is authentic,
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i.e. that you can trust that the server is who the certificate says it is.
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This trust is based on a chain of digital signatures, rooted in certification
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authority (CA) certificates you supply. curl uses a default bundle of CA
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certificates (the path for that is determined at build time) and you can
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specify alternate certificates with the CURLOPT_CAINFO(3) option or the
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CURLOPT_CAPATH(3) option.
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When CURLOPT_DOH_SSL_VERIFYPEER(3) is enabled, and the verification fails to
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prove that the certificate is authentic, the connection fails. When the option
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is zero, the peer certificate verification succeeds regardless.
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Authenticating the certificate is not enough to be sure about the server. You
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typically also want to ensure that the server is the server you mean to be
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talking to. Use CURLOPT_DOH_SSL_VERIFYHOST(3) for that. The check that the
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hostname in the certificate is valid for the hostname you are connecting to
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is done independently of the CURLOPT_DOH_SSL_VERIFYPEER(3) option.
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WARNING: disabling verification of the certificate allows bad guys to
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man-in-the-middle the communication without you knowing it. Disabling
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verification makes the communication insecure. Just having encryption on a
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transfer is not enough as you cannot be sure that you are communicating with
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the correct end-point.
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# DEFAULT
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1
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# PROTOCOLS
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DoH
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURL *curl = curl_easy_init();
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if(curl) {
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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curl_easy_setopt(curl, CURLOPT_DOH_URL,
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"https://cloudflare-dns.com/dns-query");
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/* Disable certificate verification of the DoH server */
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curl_easy_setopt(curl, CURLOPT_DOH_SSL_VERIFYPEER, 0L);
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curl_easy_perform(curl);
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}
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}
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~~~
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# AVAILABILITY
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Added in 7.76.0
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If built TLS enabled.
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# RETURN VALUE
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Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
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