openssl/doc/man3/SSL_CTX_use_serverinfo.pod
Matt Caswell f233a9d181 Clarify serverinfo usage with Certificate messages
Ensure that serverinfo only gets added for the first Certificate in a list.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3298)
2017-05-03 14:37:42 +01:00

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3.2 KiB
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=pod
=head1 NAME
SSL_CTX_use_serverinfo_ex,
SSL_CTX_use_serverinfo,
SSL_CTX_use_serverinfo_file
- use serverinfo extension
=head1 SYNOPSIS
#include <openssl/ssl.h>
int SSL_CTX_use_serverinfo_ex(SSL_CTX *ctx, unsigned int version,
const unsigned char *serverinfo,
size_t serverinfo_length);
int SSL_CTX_use_serverinfo(SSL_CTX *ctx, const unsigned char *serverinfo,
size_t serverinfo_length);
int SSL_CTX_use_serverinfo_file(SSL_CTX *ctx, const char *file);
=head1 DESCRIPTION
These functions load "serverinfo" TLS extensions into the SSL_CTX. A
"serverinfo" extension is returned in response to an empty ClientHello
Extension.
SSL_CTX_use_serverinfo_ex() loads one or more serverinfo extensions from
a byte array into B<ctx>. The B<version> parameter specifies the format of the
byte array provided in B<*serverinfo> which is of length B<serverinfo_length>.
If B<version> is B<SSL_SERVERINFOV2> then the extensions in the array must
consist of a 4-byte context, a 2-byte Extension Type, a 2-byte length, and then
length bytes of extension_data. The context and type values have the same
meaning as for L<SSL_CTX_add_custom_ext(3)>. If serverinfo is being loaded for
extensions to be added to a Certificate message, then the extension will only
be added for the first Certificate in the message.
If B<version> is B<SSL_SERVERINFOV1> then the extensions in the array must
consist of a 2-byte Extension Type, a 2-byte length, and then length bytes of
extension_data. The type value has the same meaning as for
L<SSL_CTX_add_custom_ext(3)>. The following default context value will be used
in this case:
SSL_EXT_TLS1_2_AND_BELOW_ONLY | SSL_EXT_CLIENT_HELLO
| SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_IGNORE_ON_RESUMPTION
SSL_CTX_use_serverinfo() does the same thing as SSL_CTX_use_serverinfo_ex()
except that there is no B<version> parameter so a default version of
SSL_SERVERINFOV1 is used instead.
SSL_CTX_use_serverinfo_file() loads one or more serverinfo extensions from
B<file> into B<ctx>. The extensions must be in PEM format. Each extension
must be in a format as described above for SSL_CTX_use_serverinfo_ex(). Each
PEM extension name must begin with the phrase "BEGIN SERVERINFOV2 FOR " for
SSL_SERVERINFOV2 data or "BEGIN SERVERINFO FOR " for SSL_SERVERINFOV1 data.
If more than one certificate (RSA/DSA) is installed using
SSL_CTX_use_certificate(), the serverinfo extension will be loaded into the
last certificate installed. If e.g. the last item was a RSA certificate, the
loaded serverinfo extension data will be loaded for that certificate. To
use the serverinfo extension for multiple certificates,
SSL_CTX_use_serverinfo() needs to be called multiple times, once B<after>
each time a certificate is loaded.
=head1 RETURN VALUES
On success, the functions return 1.
On failure, the functions return 0. Check out the error stack to find out
the reason.
=head1 COPYRIGHT
Copyright 2013-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut