1/*
2 * Copyright (c) 2011-12 Apple Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23/*
24 * Copyright (c) 1997 Kungliga Tekniska Högskolan
25 * (Royal Institute of Technology, Stockholm, Sweden).
26 * All rights reserved.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 *
32 * 1. Redistributions of source code must retain the above copyright
33 *    notice, this list of conditions and the following disclaimer.
34 *
35 * 2. Redistributions in binary form must reproduce the above copyright
36 *    notice, this list of conditions and the following disclaimer in the
37 *    documentation and/or other materials provided with the distribution.
38 *
39 * 3. Neither the name of the Institute nor the names of its contributors
40 *    may be used to endorse or promote products derived from this software
41 *    without specific prior written permission.
42 *
43 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * SUCH DAMAGE.
54 */
55
56#include "asn1-der_locl.h"
57
58#define ASN1_MAX_YEAR	2000
59
60static int
61is_leap(unsigned y)
62{
63    y += 1900;
64    return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
65}
66
67static const unsigned ndays[2][12] ={
68    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
69    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
70
71/*
72 * This is a simplifed version of timegm(3) that doesn't accept out of
73 * bound values that timegm(3) normally accepts but those are not
74 * valid in asn1 encodings.
75 */
76
77time_t
78_der_timegm (struct tm *tm)
79{
80  time_t res = 0;
81  int i;
82
83  /*
84   * See comment in _der_gmtime
85   */
86  if (tm->tm_year > ASN1_MAX_YEAR)
87      return 0;
88
89  if (tm->tm_year < 0)
90      return -1;
91  if (tm->tm_mon < 0 || tm->tm_mon > 11)
92      return -1;
93  if (tm->tm_mday < 1 || tm->tm_mday > (int)ndays[is_leap(tm->tm_year)][tm->tm_mon])
94      return -1;
95  if (tm->tm_hour < 0 || tm->tm_hour > 23)
96      return -1;
97  if (tm->tm_min < 0 || tm->tm_min > 59)
98      return -1;
99  if (tm->tm_sec < 0 || tm->tm_sec > 59)
100      return -1;
101
102  for (i = 70; i < tm->tm_year; ++i)
103    res += is_leap(i) ? 366 : 365;
104
105  for (i = 0; i < tm->tm_mon; ++i)
106    res += ndays[is_leap(tm->tm_year)][i];
107  res += tm->tm_mday - 1;
108  res *= 24;
109  res += tm->tm_hour;
110  res *= 60;
111  res += tm->tm_min;
112  res *= 60;
113  res += tm->tm_sec;
114  return res;
115}
116
117struct tm *
118_der_gmtime(time_t t, struct tm *tm)
119{
120    time_t secday = t % (3600 * 24);
121    time_t days = t / (3600 * 24);
122
123    memset(tm, 0, sizeof(*tm));
124
125    tm->tm_sec = secday % 60;
126    tm->tm_min = (secday % 3600) / 60;
127    tm->tm_hour = secday / 3600;
128
129    /*
130     * Refuse to calculate time ~ 2000 years into the future, this is
131     * not possible for systems where time_t is a int32_t, however,
132     * when time_t is a int64_t, that can happen, and this becomes a
133     * denial of sevice.
134     */
135    if (days > (ASN1_MAX_YEAR * 365))
136	return NULL;
137
138    tm->tm_year = 70;
139    while(1) {
140	unsigned dayinyear = (is_leap(tm->tm_year) ? 366 : 365);
141	if (days < dayinyear)
142	    break;
143	tm->tm_year += 1;
144	days -= dayinyear;
145    }
146    tm->tm_mon = 0;
147
148    while (1) {
149	unsigned daysinmonth = ndays[is_leap(tm->tm_year)][tm->tm_mon];
150	if (days < daysinmonth)
151	    break;
152	days -= daysinmonth;
153	tm->tm_mon++;
154    }
155    tm->tm_mday = days + 1;
156
157    return tm;
158}
159