1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_PROXY_SSL_VERIFYPEER 5Section: 3 6Source: libcurl 7See-also: 8 - CURLOPT_PROXY_SSL_VERIFYHOST (3) 9 - CURLOPT_SSL_VERIFYHOST (3) 10 - CURLOPT_SSL_VERIFYPEER (3) 11Protocol: 12 - TLS 13TLS-backend: 14 - All 15--- 16 17# NAME 18 19CURLOPT_PROXY_SSL_VERIFYPEER - verify the proxy's SSL certificate 20 21# SYNOPSIS 22 23~~~c 24#include <curl/curl.h> 25 26CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSL_VERIFYPEER, 27 long verify); 28~~~ 29 30# DESCRIPTION 31 32Pass a long as parameter set to 1L to enable or 0L to disable. 33 34This option tells curl to verify the authenticity of the HTTPS proxy's 35certificate. A value of 1 means curl verifies; 0 (zero) means it does not. 36 37This is the proxy version of CURLOPT_SSL_VERIFYPEER(3) that is used for 38ordinary HTTPS servers. 39 40When negotiating a TLS or SSL connection, the server sends a certificate 41indicating its identity. Curl verifies whether the certificate is authentic, 42i.e. that you can trust that the server is who the certificate says it is. 43This trust is based on a chain of digital signatures, rooted in certification 44authority (CA) certificates you supply. curl uses a default bundle of CA 45certificates (the path for that is determined at build time) and you can 46specify alternate certificates with the CURLOPT_PROXY_CAINFO(3) option or 47the CURLOPT_PROXY_CAPATH(3) option. 48 49When CURLOPT_PROXY_SSL_VERIFYPEER(3) is enabled, and the verification 50fails to prove that the certificate is authentic, the connection fails. When 51the option is zero, the peer certificate verification succeeds regardless. 52 53Authenticating the certificate is not enough to be sure about the server. You 54typically also want to ensure that the server is the server you mean to be 55talking to. Use CURLOPT_PROXY_SSL_VERIFYHOST(3) for that. The check that the 56hostname in the certificate is valid for the hostname you are connecting to is 57done independently of the CURLOPT_PROXY_SSL_VERIFYPEER(3) option. 58 59WARNING: disabling verification of the certificate allows bad guys to 60man-in-the-middle the communication without you knowing it. Disabling 61verification makes the communication insecure. Just having encryption on a 62transfer is not enough as you cannot be sure that you are communicating with 63the correct end-point. 64 65# DEFAULT 66 671 68 69# EXAMPLE 70 71~~~c 72int main(void) 73{ 74 CURL *curl = curl_easy_init(); 75 if(curl) { 76 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); 77 78 /* Set the default value: strict certificate check please */ 79 curl_easy_setopt(curl, CURLOPT_PROXY_SSL_VERIFYPEER, 1L); 80 81 curl_easy_perform(curl); 82 } 83} 84~~~ 85 86# AVAILABILITY 87 88Added in 7.52.0 89 90If built TLS enabled. 91 92# RETURN VALUE 93 94Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. 95