1CURLOPT_SSL_VERIFYPEER(3) curl_easy_setopt options CURLOPT_SSL_VERIFYPEER(3)
2
3
4
6 CURLOPT_SSL_VERIFYPEER - verify the peer's SSL certificate
7
9 #include <curl/curl.h>
10
11 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYPEER, long
12 verify);
13
15 Pass a long as parameter to enable or disable.
16
17 This option determines whether curl verifies the authenticity of the
18 peer's certificate. A value of 1 means curl verifies; 0 (zero) means it
19 doesn't.
20
21 When negotiating a TLS or SSL connection, the server sends a certifi‐
22 cate indicating its identity. Curl verifies whether the certificate is
23 authentic, i.e. that you can trust that the server is who the certifi‐
24 cate says it is. This trust is based on a chain of digital signatures,
25 rooted in certification authority (CA) certificates you supply. curl
26 uses a default bundle of CA certificates (the path for that is deter‐
27 mined at build time) and you can specify alternate certificates with
28 the CURLOPT_CAINFO(3) option or the CURLOPT_CAPATH(3) option.
29
30 When CURLOPT_SSL_VERIFYPEER(3) is enabled, and the verification fails
31 to prove that the certificate is authentic, the connection fails. When
32 the option is zero, the peer certificate verification succeeds regard‐
33 less.
34
35 Authenticating the certificate is not enough to be sure about the
36 server. You typically also want to ensure that the server is the server
37 you mean to be talking to. Use CURLOPT_SSL_VERIFYHOST(3) for that. The
38 check that the host name in the certificate is valid for the host name
39 you're connecting to is done independently of the CURLOPT_SSL_VERI‐
40 FYPEER(3) option.
41
42 WARNING: disabling verification of the certificate allows bad guys to
43 man-in-the-middle the communication without you knowing it. Disabling
44 verification makes the communication insecure. Just having encryption
45 on a transfer is not enough as you cannot be sure that you are communi‐
46 cating with the correct end-point.
47
48 NOTE: even when this option is disabled, depending on the used TLS
49 backend, curl may still load the certificate file specified in CUR‐
50 LOPT_CAINFO(3). curl default settings in some distributions might use
51 quite a large file as a default setting for CURLOPT_CAINFO(3), so load‐
52 ing the file can be quite expensive, especially when dealing with many
53 connections. Thus, in some situations, you might want to disable veri‐
54 fication fully to save resources by setting CURLOPT_CAINFO(3) to NULL -
55 but please also consider the warning above!
56
58 By default, curl assumes a value of 1.
59
61 All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
62
64 CURL *curl = curl_easy_init();
65 if(curl) {
66 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
67
68 /* Set the default value: strict certificate check please */
69 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);
70
71 curl_easy_perform(curl);
72 }
73
75 If built TLS enabled.
76
78 Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
79 if not.
80
82 CURLOPT_SSL_VERIFYHOST(3), CURLOPT_PROXY_SSL_VERIFYPEER(3), CUR‐
83 LOPT_PROXY_SSL_VERIFYHOST(3), CURLOPT_CAINFO(3),
84
85
86
87libcurl 7.69.1 June 24, 2018 CURLOPT_SSL_VERIFYPEER(3)