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.\" $OpenBSD: d2i_SSL_SESSION.3,v 1.7 2019/06/08 15:25:43 schwarze Exp $
.\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
.\"
.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>.
.\" Copyright (c) 2001, 2005, 2014 The OpenSSL Project. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\" software must display the following acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\" endorse or promote products derived from this software without
.\" prior written permission. For written permission, please contact
.\" openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\" nor may "OpenSSL" appear in their names without prior written
.\" permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\" acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: June 8 2019 $
.Dt D2I_SSL_SESSION 3
.Os
.Sh NAME
.Nm d2i_SSL_SESSION ,
.Nm i2d_SSL_SESSION
.Nd convert SSL_SESSION object from/to ASN1 representation
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft SSL_SESSION *
.Fn d2i_SSL_SESSION "SSL_SESSION **a" "const unsigned char **pp" "long length"
.Ft int
.Fn i2d_SSL_SESSION "SSL_SESSION *in" "unsigned char **pp"
.Sh DESCRIPTION
.Fn d2i_SSL_SESSION
transforms the external ASN1 representation of an SSL/TLS session,
stored as binary data at location
.Fa pp
with length
.Fa length ,
into
an
.Vt SSL_SESSION
object.
.Pp
.Fn i2d_SSL_SESSION
transforms the
.Vt SSL_SESSION
object
.Fa in
into the ASN1 representation and stores it into the memory location pointed to
by
.Fa pp .
The length of the resulting ASN1 representation is returned.
If
.Fa pp
is the
.Dv NULL
pointer, only the length is calculated and returned.
.Pp
The
.Vt SSL_SESSION
object is built from several
.Xr malloc 3 Ns
-ed parts; it can therefore not be moved, copied or stored directly.
In order to store session data on disk or into a database,
it must be transformed into a binary ASN1 representation.
.Pp
When using
.Fn d2i_SSL_SESSION ,
the
.Vt SSL_SESSION
object is automatically allocated.
The reference count is 1, so that the session must be explicitly removed using
.Xr SSL_SESSION_free 3 ,
unless the
.Vt SSL_SESSION
object is completely taken over, when being called inside the
.Fn get_session_cb ,
see
.Xr SSL_CTX_sess_set_get_cb 3 .
.Pp
.Vt SSL_SESSION
objects keep internal link information about the session cache list when being
inserted into one
.Vt SSL_CTX
object's session cache.
One
.Vt SSL_SESSION
object, regardless of its reference count, must therefore only be used with one
.Vt SSL_CTX
object (and the
.Vt SSL
objects created from this
.Vt SSL_CTX
object).
.Pp
When using
.Fn i2d_SSL_SESSION ,
the memory location pointed to by
.Fa pp
must be large enough to hold the binary representation of the session.
There is no known limit on the size of the created ASN1 representation,
so call
.Fn i2d_SSL_SESSION
first with
.Fa pp Ns = Ns Dv NULL
to obtain the encoded size, before allocating the required amount of memory and
calling
.Fn i2d_SSL_SESSION
again.
Note that this will advance the value contained in
.Fa *pp
so it is necessary to save a copy of the original allocation.
For example:
.Bd -literal -offset indent
char *p, *pp;
int elen, len;
elen = i2d_SSL_SESSION(sess, NULL);
p = pp = malloc(elen);
if (p != NULL) {
len = i2d_SSL_SESSION(sess, &pp);
assert(elen == len);
assert(p + len == pp);
}
.Ed
.Sh RETURN VALUES
.Fn d2i_SSL_SESSION
returns a pointer to the newly allocated
.Vt SSL_SESSION
object.
In case of failure a
.Dv NULL
pointer is returned and the error message can be retrieved from the error
stack.
.Pp
.Fn i2d_SSL_SESSION
returns the size of the ASN1 representation in bytes.
When the session is not valid, 0 is returned and no operation is performed.
.Sh SEE ALSO
.Xr d2i_X509 3 ,
.Xr ssl 3 ,
.Xr SSL_CTX_sess_set_get_cb 3 ,
.Xr SSL_SESSION_free 3
.Sh HISTORY
.Fn d2i_SSL_SESSION
and
.Fn i2d_SSL_SESSION
first appeared in SSLeay 0.5.2 and have been available since
.Ox 2.4 .
|
