crypto/external/bsd/heimdal/dist/lib/asn1/timegm.c

   1 /*      $NetBSD: timegm.c,v 1.1.1.2 2014/04/24 12:45:28 pettai Exp $    */
   2
   3 /*
   4  * Copyright (c) 1997 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "der_locl.h"
  37
  38 #define ASN1_MAX_YEAR   2000
  39
  40 static int
  41 is_leap(unsigned y)
  42 {
  43     y += 1900;
  44     return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0);
  45 }
  46
  47 static const unsigned ndays[2][12] ={
  48     {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
  49     {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
  50
  51 /*
  52  * This is a simplifed version of timegm(3) that doesn't accept out of
  53  * bound values that timegm(3) normally accepts but those are not
  54  * valid in asn1 encodings.
  55  */
  56
  57 time_t
  58 _der_timegm (struct tm *tm)
  59 {
  60   time_t res = 0;
  61   int i;
  62
  63   /*
  64    * See comment in _der_gmtime
  65    */
  66   if (tm->tm_year > ASN1_MAX_YEAR)
  67       return 0;
  68
  69   if (tm->tm_year < 0)
  70       return -1;
  71   if (tm->tm_mon < 0 || tm->tm_mon > 11)
  72       return -1;
  73   if (tm->tm_mday < 1 || tm->tm_mday > (int)ndays[is_leap(tm->tm_year)][tm->tm_mon])
  74       return -1;
  75   if (tm->tm_hour < 0 || tm->tm_hour > 23)
  76       return -1;
  77   if (tm->tm_min < 0 || tm->tm_min > 59)
  78       return -1;
  79   if (tm->tm_sec < 0 || tm->tm_sec > 59)
  80       return -1;
  81
  82   for (i = 70; i < tm->tm_year; ++i)
  83     res += is_leap(i) ? 366 : 365;
  84
  85   for (i = 0; i < tm->tm_mon; ++i)
  86     res += ndays[is_leap(tm->tm_year)][i];
  87   res += tm->tm_mday - 1;
  88   res *= 24;
  89   res += tm->tm_hour;
  90   res *= 60;
  91   res += tm->tm_min;
  92   res *= 60;
  93   res += tm->tm_sec;
  94   return res;
  95 }
  96
  97 struct tm *
  98 _der_gmtime(time_t t, struct tm *tm)
  99 {
 100     time_t secday = t % (3600 * 24);
 101     time_t days = t / (3600 * 24);
 102
 103     memset(tm, 0, sizeof(*tm));
 104
 105     tm->tm_sec = secday % 60;
 106     tm->tm_min = (secday % 3600) / 60;
 107     tm->tm_hour = secday / 3600;
 108
 109     /*
 110      * Refuse to calculate time ~ 2000 years into the future, this is
 111      * not possible for systems where time_t is a int32_t, however,
 112      * when time_t is a int64_t, that can happen, and this becomes a
 113      * denial of sevice.
 114      */
 115     if (days > (ASN1_MAX_YEAR * 365))
 116         return NULL;
 117
 118     tm->tm_year = 70;
 119     while(1) {
 120         unsigned dayinyear = (is_leap(tm->tm_year) ? 366 : 365);
 121         if (days < dayinyear)
 122             break;
 123         tm->tm_year += 1;
 124         days -= dayinyear;
 125     }
 126     tm->tm_mon = 0;
 127
 128     while (1) {
 129         unsigned daysinmonth = ndays[is_leap(tm->tm_year)][tm->tm_mon];
 130         if (days < daysinmonth)
 131             break;
 132         days -= daysinmonth;
 133         tm->tm_mon++;
 134     }
 135     tm->tm_mday = days + 1;
 136
 137     return tm;
 138 }