1=pod
2
3=head1 NAME
4
5SSL_CTX_set_tlsext_status_cb,
6SSL_CTX_get_tlsext_status_cb,
7SSL_CTX_set_tlsext_status_arg,
8SSL_CTX_get_tlsext_status_arg,
9SSL_CTX_set_tlsext_status_type,
10SSL_CTX_get_tlsext_status_type,
11SSL_set_tlsext_status_type,
12SSL_get_tlsext_status_type,
13SSL_get_tlsext_status_ocsp_resp,
14SSL_set_tlsext_status_ocsp_resp
15- OCSP Certificate Status Request functions
16
17=head1 SYNOPSIS
18
19 #include <openssl/tls1.h>
20
21 long SSL_CTX_set_tlsext_status_cb(SSL_CTX *ctx, int (*callback)(SSL *, void *));
22 long SSL_CTX_get_tlsext_status_cb(SSL_CTX *ctx, int (**callback)(SSL *, void *));
23
24 long SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg);
25 long SSL_CTX_get_tlsext_status_arg(SSL_CTX *ctx, void **arg);
26
27 long SSL_CTX_set_tlsext_status_type(SSL_CTX *ctx, int type);
28 long SSL_CTX_get_tlsext_status_type(SSL_CTX *ctx);
29
30 long SSL_set_tlsext_status_type(SSL *s, int type);
31 long SSL_get_tlsext_status_type(SSL *s);
32
33 long SSL_get_tlsext_status_ocsp_resp(ssl, unsigned char **resp);
34 long SSL_set_tlsext_status_ocsp_resp(ssl, unsigned char *resp, int len);
35
36=head1 DESCRIPTION
37
38A client application may request that a server send back an OCSP status response
39(also known as OCSP stapling). To do so the client should call the
40SSL_CTX_set_tlsext_status_type() function prior to the creation of any SSL
41objects. Alternatively an application can call the SSL_set_tlsext_status_type()
42function on an individual SSL object prior to the start of the handshake.
43Currently the only supported type is B<TLSEXT_STATUSTYPE_ocsp>. This value
44should be passed in the B<type> argument. Calling
45SSL_CTX_get_tlsext_status_type() will return the type B<TLSEXT_STATUSTYPE_ocsp>
46previously set via SSL_CTX_set_tlsext_status_type() or -1 if not set.
47
48The client should additionally provide a callback function to decide what to do
49with the returned OCSP response by calling SSL_CTX_set_tlsext_status_cb(). The
50callback function should determine whether the returned OCSP response is
51acceptable or not. The callback will be passed as an argument the value
52previously set via a call to SSL_CTX_set_tlsext_status_arg(). Note that the
53callback will not be called in the event of a handshake where session resumption
54occurs (because there are no Certificates exchanged in such a handshake).
55The callback previously set via SSL_CTX_set_tlsext_status_cb() can be retrieved
56by calling SSL_CTX_get_tlsext_status_cb(), and the argument by calling
57SSL_CTX_get_tlsext_status_arg().
58
59On the client side SSL_get_tlsext_status_type() can be used to determine whether
60the client has previously called SSL_set_tlsext_status_type(). It will return
61B<TLSEXT_STATUSTYPE_ocsp> if it has been called or -1 otherwise. On the server
62side SSL_get_tlsext_status_type() can be used to determine whether the client
63requested OCSP stapling. If the client requested it then this function will
64return B<TLSEXT_STATUSTYPE_ocsp>, or -1 otherwise.
65
66The response returned by the server can be obtained via a call to
67SSL_get_tlsext_status_ocsp_resp(). The value B<*resp> will be updated to point
68to the OCSP response data and the return value will be the length of that data.
69Typically a callback would obtain an OCSP_RESPONSE object from this data via a
70call to the d2i_OCSP_RESPONSE() function. If the server has not provided any
71response data then B<*resp> will be NULL and the return value from
72SSL_get_tlsext_status_ocsp_resp() will be -1.
73
74A server application must also call the SSL_CTX_set_tlsext_status_cb() function
75if it wants to be able to provide clients with OCSP Certificate Status
76responses. Typically the server callback would obtain the server certificate
77that is being sent back to the client via a call to SSL_get_certificate();
78obtain the OCSP response to be sent back; and then set that response data by
79calling SSL_set_tlsext_status_ocsp_resp(). A pointer to the response data should
80be provided in the B<resp> argument, and the length of that data should be in
81the B<len> argument.
82
83=head1 RETURN VALUES
84
85The callback when used on the client side should return a negative value on
86error; 0 if the response is not acceptable (in which case the handshake will
87fail) or a positive value if it is acceptable.
88
89The callback when used on the server side should return with either
90SSL_TLSEXT_ERR_OK (meaning that the OCSP response that has been set should be
91returned), SSL_TLSEXT_ERR_NOACK (meaning that an OCSP response should not be
92returned) or SSL_TLSEXT_ERR_ALERT_FATAL (meaning that a fatal error has
93occurred).
94
95SSL_CTX_set_tlsext_status_cb(), SSL_CTX_set_tlsext_status_arg(),
96SSL_CTX_set_tlsext_status_type(), SSL_set_tlsext_status_type() and
97SSL_set_tlsext_status_ocsp_resp() return 0 on error or 1 on success.
98
99SSL_CTX_get_tlsext_status_type() returns the value previously set by
100SSL_CTX_set_tlsext_status_type(), or -1 if not set.
101
102SSL_get_tlsext_status_ocsp_resp() returns the length of the OCSP response data
103or -1 if there is no OCSP response data.
104
105SSL_get_tlsext_status_type() returns B<TLSEXT_STATUSTYPE_ocsp> on the client
106side if SSL_set_tlsext_status_type() was previously called, or on the server
107side if the client requested OCSP stapling. Otherwise -1 is returned.
108
109=head1 HISTORY
110
111The SSL_get_tlsext_status_type(), SSL_CTX_get_tlsext_status_type()
112and SSL_CTX_set_tlsext_status_type() functions were added in OpenSSL 1.1.0.
113
114=head1 COPYRIGHT
115
116Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
117
118Licensed under the OpenSSL license (the "License").  You may not use
119this file except in compliance with the License.  You can obtain a copy
120in the file LICENSE in the source distribution or at
121L<https://www.openssl.org/source/license.html>.
122
123=cut
124