1/* $NetBSD: timegm.c,v 1.2 2017/01/28 21:31:45 christos Exp $ */ 2 3/* 4 * Copyright (c) 1997 Kungliga Tekniska H��gskolan 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 40static int 41is_leap(unsigned y) 42{ 43 y += 1900; 44 return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0); 45} 46 47static 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 57time_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 97struct 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 = (int)(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 = (int)(days + 1); 136 137 return tm; 138} 139