1 =pod 2 3 =head1 NAME 4 5 ASN1_TIME_set, ASN1_UTCTIME_set, ASN1_GENERALIZEDTIME_set, 6 ASN1_TIME_adj, ASN1_UTCTIME_adj, ASN1_GENERALIZEDTIME_adj, 7 ASN1_TIME_check, ASN1_UTCTIME_check, ASN1_GENERALIZEDTIME_check, 8 ASN1_TIME_set_string, ASN1_UTCTIME_set_string, ASN1_GENERALIZEDTIME_set_string, 9 ASN1_TIME_set_string_X509, 10 ASN1_TIME_normalize, 11 ASN1_TIME_to_tm, 12 ASN1_TIME_print, ASN1_TIME_print_ex, ASN1_UTCTIME_print, ASN1_GENERALIZEDTIME_print, 13 ASN1_TIME_diff, 14 ASN1_TIME_cmp_time_t, ASN1_UTCTIME_cmp_time_t, 15 ASN1_TIME_compare, 16 ASN1_TIME_to_generalizedtime, 17 ASN1_TIME_dup, ASN1_UTCTIME_dup, ASN1_GENERALIZEDTIME_dup - ASN.1 Time functions 18 19 =head1 SYNOPSIS 20 21 ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t); 22 ASN1_UTCTIME *ASN1_UTCTIME_set(ASN1_UTCTIME *s, time_t t); 23 ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_set(ASN1_GENERALIZEDTIME *s, 24 time_t t); 25 26 ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t, int offset_day, 27 long offset_sec); 28 ASN1_UTCTIME *ASN1_UTCTIME_adj(ASN1_UTCTIME *s, time_t t, 29 int offset_day, long offset_sec); 30 ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_adj(ASN1_GENERALIZEDTIME *s, 31 time_t t, int offset_day, 32 long offset_sec); 33 34 int ASN1_TIME_set_string(ASN1_TIME *s, const char *str); 35 int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str); 36 int ASN1_UTCTIME_set_string(ASN1_UTCTIME *s, const char *str); 37 int ASN1_GENERALIZEDTIME_set_string(ASN1_GENERALIZEDTIME *s, 38 const char *str); 39 40 int ASN1_TIME_normalize(ASN1_TIME *s); 41 42 int ASN1_TIME_check(const ASN1_TIME *t); 43 int ASN1_UTCTIME_check(const ASN1_UTCTIME *t); 44 int ASN1_GENERALIZEDTIME_check(const ASN1_GENERALIZEDTIME *t); 45 46 int ASN1_TIME_print(BIO *b, const ASN1_TIME *s); 47 int ASN1_TIME_print_ex(BIO *bp, const ASN1_TIME *tm, unsigned long flags); 48 int ASN1_UTCTIME_print(BIO *b, const ASN1_UTCTIME *s); 49 int ASN1_GENERALIZEDTIME_print(BIO *b, const ASN1_GENERALIZEDTIME *s); 50 51 int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm); 52 int ASN1_TIME_diff(int *pday, int *psec, const ASN1_TIME *from, 53 const ASN1_TIME *to); 54 55 int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t); 56 int ASN1_UTCTIME_cmp_time_t(const ASN1_UTCTIME *s, time_t t); 57 58 int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b); 59 60 ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(ASN1_TIME *t, 61 ASN1_GENERALIZEDTIME **out); 62 63 ASN1_TIME *ASN1_TIME_dup(const ASN1_TIME *t); 64 ASN1_UTCTIME *ASN1_UTCTIME_dup(const ASN1_UTCTIME *t); 65 ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_dup(const ASN1_GENERALIZEDTIME *t); 66 67 =head1 DESCRIPTION 68 69 The ASN1_TIME_set(), ASN1_UTCTIME_set() and ASN1_GENERALIZEDTIME_set() 70 functions set the structure I<s> to the time represented by the time_t 71 value I<t>. If I<s> is NULL a new time structure is allocated and returned. 72 73 The ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_adj() 74 functions set the time structure I<s> to the time represented 75 by the time I<offset_day> and I<offset_sec> after the time_t value I<t>. 76 The values of I<offset_day> or I<offset_sec> can be negative to set a 77 time before I<t>. The I<offset_sec> value can also exceed the number of 78 seconds in a day. If I<s> is NULL a new structure is allocated 79 and returned. 80 81 The ASN1_TIME_set_string(), ASN1_UTCTIME_set_string() and 82 ASN1_GENERALIZEDTIME_set_string() functions set the time structure I<s> 83 to the time represented by string I<str> which must be in appropriate ASN.1 84 time format (for example YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ). If I<s> is NULL 85 this function performs a format check on I<str> only. The string I<str> 86 is copied into I<s>. 87 88 ASN1_TIME_set_string_X509() sets B<ASN1_TIME> structure I<s> to the time 89 represented by string I<str> which must be in appropriate time format 90 that RFC 5280 requires, which means it only allows YYMMDDHHMMSSZ and 91 YYYYMMDDHHMMSSZ (leap second is rejected), all other ASN.1 time format 92 are not allowed. If I<s> is NULL this function performs a format check 93 on I<str> only. 94 95 The ASN1_TIME_normalize() function converts an B<ASN1_GENERALIZEDTIME> or 96 B<ASN1_UTCTIME> into a time value that can be used in a certificate. It 97 should be used after the ASN1_TIME_set_string() functions and before 98 ASN1_TIME_print() functions to get consistent (i.e. GMT) results. 99 100 The ASN1_TIME_check(), ASN1_UTCTIME_check() and ASN1_GENERALIZEDTIME_check() 101 functions check the syntax of the time structure I<s>. 102 103 The ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() 104 functions print the time structure I<s> to BIO I<b> in human readable 105 format. It will be of the format MMM DD HH:MM:SS[.s*] YYYY GMT, for example 106 "Feb E<32>3 00:55:52 2015 GMT", which does not include a newline. 107 If the time structure has invalid format it prints out "Bad time value" and 108 returns an error. The output for generalized time may include a fractional part 109 following the second. 110 111 ASN1_TIME_print_ex() provides I<flags> to specify the output format of the 112 datetime. This can be either B<ASN1_DTFLGS_RFC822> or B<ASN1_DTFLGS_ISO8601>. 113 114 ASN1_TIME_to_tm() converts the time I<s> to the standard I<tm> structure. 115 If I<s> is NULL, then the current time is converted. The output time is GMT. 116 The I<tm_sec>, I<tm_min>, I<tm_hour>, I<tm_mday>, I<tm_wday>, I<tm_yday>, 117 I<tm_mon> and I<tm_year> fields of I<tm> structure are set to proper values, 118 whereas all other fields are set to 0. If I<tm> is NULL this function performs 119 a format check on I<s> only. If I<s> is in Generalized format with fractional 120 seconds, e.g. YYYYMMDDHHMMSS.SSSZ, the fractional seconds will be lost while 121 converting I<s> to I<tm> structure. 122 123 ASN1_TIME_diff() sets I<*pday> and I<*psec> to the time difference between 124 I<from> and I<to>. If I<to> represents a time later than I<from> then 125 one or both (depending on the time difference) of I<*pday> and I<*psec> 126 will be positive. If I<to> represents a time earlier than I<from> then 127 one or both of I<*pday> and I<*psec> will be negative. If I<to> and I<from> 128 represent the same time then I<*pday> and I<*psec> will both be zero. 129 If both I<*pday> and I<*psec> are nonzero they will always have the same 130 sign. The value of I<*psec> will always be less than the number of seconds 131 in a day. If I<from> or I<to> is NULL the current time is used. 132 133 The ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() functions compare 134 the two times represented by the time structure I<s> and the time_t I<t>. 135 136 The ASN1_TIME_compare() function compares the two times represented by the 137 time structures I<a> and I<b>. 138 139 The ASN1_TIME_to_generalizedtime() function converts an B<ASN1_TIME> to an 140 B<ASN1_GENERALIZEDTIME>, regardless of year. If either I<out> or 141 I<*out> are NULL, then a new object is allocated and must be freed after use. 142 143 The ASN1_TIME_dup(), ASN1_UTCTIME_dup() and ASN1_GENERALIZEDTIME_dup() functions 144 duplicate the time structure I<t> and return the duplicated result 145 correspondingly. 146 147 =head1 NOTES 148 149 The B<ASN1_TIME> structure corresponds to the ASN.1 structure B<Time> 150 defined in RFC5280 et al. The time setting functions obey the rules outlined 151 in RFC5280: if the date can be represented by UTCTime it is used, else 152 GeneralizedTime is used. 153 154 The B<ASN1_TIME>, B<ASN1_UTCTIME> and B<ASN1_GENERALIZEDTIME> structures are 155 represented as an B<ASN1_STRING> internally and can be freed up using 156 ASN1_STRING_free(). 157 158 The B<ASN1_TIME> structure can represent years from 0000 to 9999 but no attempt 159 is made to correct ancient calendar changes (for example from Julian to 160 Gregorian calendars). 161 162 B<ASN1_UTCTIME> is limited to a year range of 1950 through 2049. 163 164 Some applications add offset times directly to a time_t value and pass the 165 results to ASN1_TIME_set() (or equivalent). This can cause problems as the 166 time_t value can overflow on some systems resulting in unexpected results. 167 New applications should use ASN1_TIME_adj() instead and pass the offset value 168 in the I<offset_sec> and I<offset_day> parameters instead of directly 169 manipulating a time_t value. 170 171 ASN1_TIME_adj() may change the type from B<ASN1_GENERALIZEDTIME> to 172 B<ASN1_UTCTIME>, or vice versa, based on the resulting year. 173 ASN1_GENERALIZEDTIME_adj() and ASN1_UTCTIME_adj() will not modify the type 174 of the return structure. 175 176 It is recommended that functions starting with B<ASN1_TIME> be used instead of 177 those starting with B<ASN1_UTCTIME> or B<ASN1_GENERALIZEDTIME>. The functions 178 starting with B<ASN1_UTCTIME> and B<ASN1_GENERALIZEDTIME> act only on that 179 specific time format. The functions starting with B<ASN1_TIME> will operate on 180 either format. 181 182 Users familiar with RFC822 should note that when specifying the flag 183 B<ASN1_DTFLGS_RFC822> the year will be formatted as documented above, 184 i.e., using 4 digits, not 2 as specified in RFC822. 185 186 =head1 BUGS 187 188 ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() do 189 not print out the timezone: it either prints out "GMT" or nothing. But all 190 certificates complying with RFC5280 et al use GMT anyway. 191 192 ASN1_TIME_print(), ASN1_TIME_print_ex(), ASN1_UTCTIME_print() and 193 ASN1_GENERALIZEDTIME_print() do not distinguish if they fail because 194 of an I/O error or invalid time format. 195 196 Use the ASN1_TIME_normalize() function to normalize the time value before 197 printing to get GMT results. 198 199 =head1 RETURN VALUES 200 201 ASN1_TIME_set(), ASN1_UTCTIME_set(), ASN1_GENERALIZEDTIME_set(), 202 ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_set() return 203 a pointer to a time structure or NULL if an error occurred. 204 205 ASN1_TIME_set_string(), ASN1_UTCTIME_set_string(), 206 ASN1_GENERALIZEDTIME_set_string() and ASN1_TIME_set_string_X509() return 207 1 if the time value is successfully set and 0 otherwise. 208 209 ASN1_TIME_normalize() returns 1 on success, and 0 on error. 210 211 ASN1_TIME_check(), ASN1_UTCTIME_check and ASN1_GENERALIZEDTIME_check() return 1 212 if the structure is syntactically correct and 0 otherwise. 213 214 ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() 215 return 1 if the time is successfully printed out and 216 0 if an I/O error occurred an error occurred (I/O error or invalid time format). 217 218 ASN1_TIME_to_tm() returns 1 if the time is successfully parsed and 0 if an 219 error occurred (invalid time format). 220 221 ASN1_TIME_diff() returns 1 for success and 0 for failure. It can fail if the 222 passed-in time structure has invalid syntax, for example. 223 224 ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() return -1 if I<s> is 225 before I<t>, 0 if I<s> equals I<t>, or 1 if I<s> is after I<t>. -2 is returned 226 on error. 227 228 ASN1_TIME_compare() returns -1 if I<a> is before I<b>, 0 if I<a> equals I<b>, 229 or 1 if I<a> is after I<b>. -2 is returned on error. 230 231 ASN1_TIME_to_generalizedtime() returns a pointer to the appropriate time 232 structure on success or NULL if an error occurred. 233 234 ASN1_TIME_dup(), ASN1_UTCTIME_dup() and ASN1_GENERALIZEDTIME_dup() return a 235 pointer to a time structure or NULL if an error occurred. 236 237 =head1 EXAMPLES 238 239 Set a time structure to one hour after the current time and print it out: 240 241 #include <time.h> 242 #include <openssl/asn1.h> 243 244 ASN1_TIME *tm; 245 time_t t; 246 BIO *b; 247 248 t = time(NULL); 249 tm = ASN1_TIME_adj(NULL, t, 0, 60 * 60); 250 b = BIO_new_fp(stdout, BIO_NOCLOSE); 251 ASN1_TIME_print(b, tm); 252 ASN1_STRING_free(tm); 253 BIO_free(b); 254 255 Determine if one time is later or sooner than the current time: 256 257 int day, sec; 258 259 if (!ASN1_TIME_diff(&day, &sec, NULL, to)) 260 /* Invalid time format */ 261 262 if (day > 0 || sec > 0) 263 printf("Later\n"); 264 else if (day < 0 || sec < 0) 265 printf("Sooner\n"); 266 else 267 printf("Same\n"); 268 269 =head1 HISTORY 270 271 The ASN1_TIME_to_tm() function was added in OpenSSL 1.1.1. 272 The ASN1_TIME_set_string_X509() function was added in OpenSSL 1.1.1. 273 The ASN1_TIME_normalize() function was added in OpenSSL 1.1.1. 274 The ASN1_TIME_cmp_time_t() function was added in OpenSSL 1.1.1. 275 The ASN1_TIME_compare() function was added in OpenSSL 1.1.1. 276 277 =head1 COPYRIGHT 278 279 Copyright 2015-2025 The OpenSSL Project Authors. All Rights Reserved. 280 281 Licensed under the Apache License 2.0 (the "License"). You may not use 282 this file except in compliance with the License. You can obtain a copy 283 in the file LICENSE in the source distribution or at 284 L<https://www.openssl.org/source/license.html>. 285 286 =cut 287
Indexes created Sat Feb 28 05:31:39 UTC 2026