Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_SSL_VERIFYPEER.3, revision 1.1.1.1
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23: .TH CURLOPT_SSL_VERIFYPEER 3 "June 24, 2018" "libcurl 7.70.0" "curl_easy_setopt options"
24:
25: .SH NAME
26: CURLOPT_SSL_VERIFYPEER \- verify the peer's SSL certificate
27: .SH SYNOPSIS
28: #include <curl/curl.h>
29:
30: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYPEER, long verify);
31: .SH DESCRIPTION
32: Pass a long as parameter to enable or disable.
33:
34: This option determines whether curl verifies the authenticity of the peer's
35: certificate. A value of 1 means curl verifies; 0 (zero) means it doesn't.
36:
37: When negotiating a TLS or SSL connection, the server sends a certificate
38: indicating its identity. Curl verifies whether the certificate is authentic,
39: i.e. that you can trust that the server is who the certificate says it is.
40: This trust is based on a chain of digital signatures, rooted in certification
41: authority (CA) certificates you supply. curl uses a default bundle of CA
42: certificates (the path for that is determined at build time) and you can
43: specify alternate certificates with the \fICURLOPT_CAINFO(3)\fP option or the
44: \fICURLOPT_CAPATH(3)\fP option.
45:
46: When \fICURLOPT_SSL_VERIFYPEER(3)\fP is enabled, and the verification fails to
47: prove that the certificate is authentic, the connection fails. When the
48: option is zero, the peer certificate verification succeeds regardless.
49:
50: Authenticating the certificate is not enough to be sure about the server. You
51: typically also want to ensure that the server is the server you mean to be
52: talking to. Use \fICURLOPT_SSL_VERIFYHOST(3)\fP for that. The check that the
53: host name in the certificate is valid for the host name you're connecting to
54: is done independently of the \fICURLOPT_SSL_VERIFYPEER(3)\fP option.
55:
56: WARNING: disabling verification of the certificate allows bad guys to
57: man-in-the-middle the communication without you knowing it. Disabling
58: verification makes the communication insecure. Just having encryption on a
59: transfer is not enough as you cannot be sure that you are communicating with
60: the correct end-point.
61:
62: NOTE: even when this option is disabled, depending on the used TLS backend,
63: curl may still load the certificate file specified in
64: \fICURLOPT_CAINFO(3)\fP. curl default settings in some distributions might use
65: quite a large file as a default setting for \fICURLOPT_CAINFO(3)\fP, so
66: loading the file can be quite expensive, especially when dealing with many
67: connections. Thus, in some situations, you might want to disable verification
68: fully to save resources by setting \fICURLOPT_CAINFO(3)\fP to NULL - but
69: please also consider the warning above!
70: .SH DEFAULT
71: By default, curl assumes a value of 1.
72: .SH PROTOCOLS
73: All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
74: .SH EXAMPLE
75: .nf
76: CURL *curl = curl_easy_init();
77: if(curl) {
78: curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
79:
80: /* Set the default value: strict certificate check please */
81: curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);
82:
83: curl_easy_perform(curl);
84: }
85: .fi
86: .SH AVAILABILITY
87: If built TLS enabled.
88: .SH RETURN VALUE
89: Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
90: .SH "SEE ALSO"
91: .BR CURLOPT_SSL_VERIFYHOST "(3), "
92: .BR CURLOPT_PROXY_SSL_VERIFYPEER "(3), "
93: .BR CURLOPT_PROXY_SSL_VERIFYHOST "(3), "
94: .BR CURLOPT_CAINFO "(3), "
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