path: root/lib/libcrypto/man/ASN1_TIME_set.3

.\"	$OpenBSD: ASN1_TIME_set.3,v 1.8 2018/03/22 21:08:22 schwarze Exp $
.\"	OpenSSL ASN1_TIME_set.pod cf37aaa3 Aug 4 11:24:03 2017 +1000
.\"	OpenSSL ASN1_TIME_set.pod e9b77246 Jan 20 19:58:49 2017 +0100
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>
.\" and Todd Short <tshort@akamai.com>.
.\" Copyright (c) 2015, 2017 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: March 22 2018 $
.Dt ASN1_TIME_SET 3
.Os
.Sh NAME
.Nm ASN1_TIME_set ,
.Nm ASN1_UTCTIME_set ,
.Nm ASN1_GENERALIZEDTIME_set ,
.Nm ASN1_TIME_adj ,
.Nm ASN1_UTCTIME_adj ,
.Nm ASN1_GENERALIZEDTIME_adj ,
.Nm ASN1_TIME_set_string ,
.Nm ASN1_UTCTIME_set_string ,
.Nm ASN1_GENERALIZEDTIME_set_string ,
.Nm ASN1_TIME_check ,
.Nm ASN1_UTCTIME_check ,
.Nm ASN1_GENERALIZEDTIME_check ,
.Nm ASN1_TIME_print ,
.Nm ASN1_UTCTIME_print ,
.Nm ASN1_GENERALIZEDTIME_print ,
.Nm ASN1_UTCTIME_cmp_time_t ,
.Nm ASN1_TIME_to_generalizedtime
.Nd ASN.1 Time functions
.Sh SYNOPSIS
.Ft ASN1_TIME *
.Fo ASN1_TIME_set
.Fa "ASN1_TIME *s"
.Fa "time_t t"
.Fc
.Ft ASN1_UTCTIME *
.Fo ASN1_UTCTIME_set
.Fa "ASN1_UTCTIME *s"
.Fa "time_t t"
.Fc
.Ft ASN1_GENERALIZEDTIME *
.Fo ASN1_GENERALIZEDTIME_set
.Fa "ASN1_GENERALIZEDTIME *s"
.Fa "time_t t"
.Fc
.Ft ASN1_TIME *
.Fo ASN1_TIME_adj
.Fa "ASN1_TIME *s"
.Fa "time_t t"
.Fa "int offset_day"
.Fa "long offset_sec"
.Fc
.Ft ASN1_UTCTIME *
.Fo ASN1_UTCTIME_adj
.Fa "ASN1_UTCTIME *s"
.Fa "time_t t"
.Fa "int offset_day"
.Fa "long offset_sec"
.Fc
.Ft ASN1_GENERALIZEDTIME *
.Fo ASN1_GENERALIZEDTIME_adj
.Fa "ASN1_GENERALIZEDTIME *s"
.Fa "time_t t"
.Fa "int offset_day"
.Fa "long offset_sec"
.Fc
.Ft int
.Fo ASN1_TIME_set_string
.Fa "ASN1_TIME *s"
.Fa "const char *str"
.Fc
.Ft int
.Fo ASN1_UTCTIME_set_string
.Fa "ASN1_UTCTIME *s"
.Fa "const char *str"
.Fc
.Ft int
.Fo ASN1_GENERALIZEDTIME_set_string
.Fa "ASN1_GENERALIZEDTIME *s"
.Fa "const char *str"
.Fc
.Ft int
.Fo ASN1_TIME_check
.Fa "const ASN1_TIME *t"
.Fc
.Ft int
.Fo ASN1_UTCTIME_check
.Fa "const ASN1_UTCTIME *t"
.Fc
.Ft int
.Fo ASN1_GENERALIZEDTIME_check
.Fa "const ASN1_GENERALIZEDTIME *t"
.Fc
.Ft int
.Fo ASN1_TIME_print
.Fa "BIO *b"
.Fa "const ASN1_TIME *s"
.Fc
.Ft int
.Fo ASN1_UTCTIME_print
.Fa "BIO *b"
.Fa "const ASN1_UTCTIME *s"
.Fc
.Ft int
.Fo ASN1_GENERALIZEDTIME_print
.Fa "BIO *b"
.Fa "const ASN1_GENERALIZEDTIME *s"
.Fc
.Ft int
.Fo ASN1_UTCTIME_cmp_time_t
.Fa "const ASN1_UTCTIME *s"
.Fa "time_t t"
.Fc
.Ft ASN1_GENERALIZEDTIME *
.Fo ASN1_TIME_to_generalizedtime
.Fa "ASN1_TIME *t"
.Fa "ASN1_GENERALIZEDTIME **out"
.Fc
.Sh DESCRIPTION
The functions
.Fn ASN1_TIME_set ,
.Fn ASN1_UTCTIME_set ,
and
.Fn ASN1_GENERALIZEDTIME_set
set the time structure
.Fa s
to the time represented by the
.Vt time_t
value
.Fa t .
If
.Fa s
is
.Dv NULL ,
a new time structure is allocated and returned.
.Pp
The functions
.Fn ASN1_TIME_adj ,
.Fn ASN1_UTCTIME_adj ,
and
.Fn ASN1_GENERALIZEDTIME_adj
set the time structure
.Fa s
to the time represented by the time
.Fa offset_day
and
.Fa offset_sec
after the
.Vt time_t
value
.Fa t .
The values of
.Fa offset_day
or
.Fa offset_sec
can be negative to set a time before
.Fa t .
The
.Fa offset_sec
value can also exceed the number of seconds in a day.
If
.Fa s
is
.Dv NULL ,
a new time structure is allocated and returned.
.Pp
.Fn ASN1_TIME_adj
may change the type from
.Vt ASN1_GENERALIZEDTIME
to
.Vt ASN1_UTCTIME
or vise-versa depending on the resulting year.
The functions
.Fn ASN1_UTCTIME_adj
and
.Fn ASN1_GENERALIZEDTIME_adj
do not modify the type of the return structure.
.Pp
The functions
.Fn ASN1_TIME_set_string ,
.Fn ASN1_UTCTIME_set_string ,
and
.Fn ASN1_GENERALIZEDTIME_set_string
set the time structure
.Fa s
to the time represented by the string
.Fa str ,
which must be in appropriate ASN.1 time format (for example
YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ).
The string
.Fa str
is copied into
.Fa s .
If
.Fa s
is
.Dv NULL ,
these functions only perform a format check on
.Fa str .
.Pp
The functions
.Fn ASN1_TIME_check ,
.Fn ASN1_UTCTIME_check ,
and
.Fn ASN1_GENERALIZEDTIME_check
check the syntax of the time structure
.Fa s .
.Pp
The functions
.Fn ASN1_TIME_print ,
.Fn ASN1_UTCTIME_print ,
and
.Fn ASN1_GENERALIZEDTIME_print
print out the time
.Fa s
to
.Vt BIO
.Fa b
in human readable format.
It will be of the format MMM DD HH:MM:SS YYYY [GMT], for example "Feb 3
00:55:52 2015 GMT".
It does not include a newline.
If the time structure has an invalid format,
it prints out "Bad time value" and returns an error.
The output of
.Fn ASN1_GENERALIZEDTIME_print
may include a fractional part following the second.
.Pp
The function
.Fn ASN1_UTCTIME_cmp_time_t
compares the two times represented by
.Fa s
and
.Fa t .
.Pp
The function
.Fn ASN1_TIME_to_generalizedtime
converts the
.Vt ASN1_TIME
.Fa t
to an
.Vt ASN1_GENERALIZEDTIME ,
regardless of year.
If either
.Fa out
or
.Pf * Fa out
is
.Dv NULL ,
then a new object is allocated and must be freed after use.
.Pp
The
.Vt ASN1_TIME
structure corresponds to the ASN.1 structure
.Sy Time
defined in RFC 5280 et al.
The time setting functions obey the rules outlined in RFC 5280: if the
date can be represented by UTCTime it is used, otherwise GeneralizedTime is
used.
.Pp
The
.Vt ASN1_TIME ,
.Vt ASN1_UTCTIME ,
and
.Vt ASN1_GENERALIZEDTIME
structures are represented as
.Vt ASN1_STRING
structures internally and can be freed using
.Xr ASN1_STRING_free 3 .
.Pp
The
.Vt ASN1_TIME
structure can represent years from 0000 to 9999 but no attempt is
made to correct ancient calendar changes (for example from Julian
to Gregorian calendars).
.Pp
.Vt ASN1_UTCTIME
is limited to a year range of 1950 through 2049.
.Pp
It is recommended that
.Vt ASN1_TIME
functions be used instead of
.Vt ASN1_UTCTIME
or
.Vt ASN1_GENERALIZEDTIME
functions because the
.Vt ASN1_UTCTIME
and
.Vt ASN1_GENERALIZEDTIME
functions act only on that specific time format, while the
.Vt ASN1_TIME
functions operate on either format.
.Sh RETURN VALUES
.Fn ASN1_TIME_set ,
.Fn ASN1_UTCTIME_set ,
.Fn ASN1_GENERALIZEDTIME_set ,
.Fn ASN1_TIME_adj ,
.Fn ASN1_UTCTIME_adj ,
.Fn ASN1_GENERALIZEDTIME_adj ,
and
.Fn ASN1_TIME_to_generalizedtime
return a pointer to a time structure or
.Dv NULL
if an error occurred.
.Pp
.Fn ASN1_TIME_set_string ,
.Fn ASN1_UTCTIME_set_string ,
and
.Fn ASN1_GENERALIZEDTIME_set_string
return 1 if the time value is successfully set or 0 otherwise.
.Pp
.Fn ASN1_TIME_check ,
.Fn ASN1_UTCTIME_check ,
and
.Fn ASN1_GENERALIZEDTIME_check
return 1 if the time structure is syntactically correct or 0 otherwise.
.Pp
.Fn ASN1_TIME_print ,
.Fn ASN1_UTCTIME_print ,
and
.Fn ASN1_GENERALIZEDTIME_print
return 1 if the time is successfully printed or 0 if an error
occurred (I/O error or invalid time format).
.Pp
.Fn ASN1_UTCTIME_cmp_time_t
returns \-1 if
.Fa s
is earlier than
.Fa t ,
0 if both are equal, 1 if
.Fa s
is later than
.Fa t ,
or \-2 on error.
.Sh EXAMPLES
Set a time structure to one hour after the current time and print it
out:
.Bd -literal -offset indent
#include <time.h>
#include <openssl/asn1.h>

ASN1_TIME *tm;
time_t t;
BIO *b;

t = time(NULL);
tm = ASN1_TIME_adj(NULL, t, 0, 60 * 60);
b = BIO_new_fp(stdout, BIO_NOCLOSE);
ASN1_TIME_print(b, tm);
ASN1_STRING_free(tm);
BIO_free(b);
.Ed
.Sh HISTORY
.Fn ASN1_UTCTIME_set ,
.Fn ASN1_UTCTIME_check ,
and
.Fn ASN1_UTCTIME_print
appeared in SSLeay 0.8.1b or earlier.
.Fn ASN1_UTCTIME_set_string
first appeared in SSLeay 0.9.0.
All these functions have been available since
.Ox 2.4 .
.Pp
.Fn ASN1_TIME_set ,
.Fn ASN1_GENERALIZEDTIME_set ,
.Fn ASN1_GENERALIZEDTIME_set_string ,
.Fn ASN1_GENERALIZEDTIME_check ,
.Fn ASN1_TIME_print ,
and
.Fn ASN1_GENERALIZEDTIME_print
first appeared in OpenSSL 0.9.2b and have been available since
.Ox 2.6 .
.Pp
.Fn ASN1_UTCTIME_cmp_time_t
first appeared in OpenSSL 0.9.6 and has been available since
.Ox 2.9 .
.Pp
.Fn ASN1_TIME_check
and
.Fn ASN1_TIME_to_generalizedtime
first appeared in OpenSSL 0.9.7 and have been available since
.Ox 3.2 .
.Pp
.Fn ASN1_TIME_cmp_time_t
first appeared in OpenSSL 1.1.1.
.Sh CAVEATS
Some applications add offset times directly to a
.Vt time_t
value and pass the results to
.Fn ASN1_TIME_set
(or equivalent).
This can cause problems as the
.Vt time_t
value can overflow on some systems resulting in unexpected results.
New applications should use
.Fn ASN1_TIME_adj
instead and pass the offset value in the
.Fa offset_sec
and
.Fa offset_day
parameters instead of directly manipulating a
.Vt time_t
value.
.Sh BUGS
.Fn ASN1_TIME_print ,
.Fn ASN1_UTCTIME_print ,
and
.Fn ASN1_GENERALIZEDTIME_print
do not print the time zone: they either print "GMT" or nothing.
But all certificates complying with RFC 5280 et al use GMT anyway.