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