1 /*
2  * Copyright 1999-2019 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 /*-
11  * This is an implementation of the ASN1 Time structure which is:
12  *    Time ::= CHOICE {
13  *      utcTime        UTCTime,
14  *      generalTime    GeneralizedTime }
15  */
16 
17 #include <stdio.h>
18 #include <time.h>
19 #include "crypto/ctype.h"
20 #include "internal/cryptlib.h"
21 #include <openssl/asn1t.h>
22 #include "asn1_local.h"
23 
IMPLEMENT_ASN1_MSTRING(ASN1_TIME,B_ASN1_TIME)24 IMPLEMENT_ASN1_MSTRING(ASN1_TIME, B_ASN1_TIME)
25 
26 IMPLEMENT_ASN1_FUNCTIONS(ASN1_TIME)
27 
28 static int is_utc(const int year)
29 {
30     if (50 <= year && year <= 149)
31         return 1;
32     return 0;
33 }
34 
leap_year(const int year)35 static int leap_year(const int year)
36 {
37     if (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
38         return 1;
39     return 0;
40 }
41 
42 /*
43  * Compute the day of the week and the day of the year from the year, month
44  * and day.  The day of the year is straightforward, the day of the week uses
45  * a form of Zeller's congruence.  For this months start with March and are
46  * numbered 4 through 15.
47  */
determine_days(struct tm * tm)48 static void determine_days(struct tm *tm)
49 {
50     static const int ydays[12] = {
51         0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
52     };
53     int y = tm->tm_year + 1900;
54     int m = tm->tm_mon;
55     int d = tm->tm_mday;
56     int c;
57 
58     tm->tm_yday = ydays[m] + d - 1;
59     if (m >= 2) {
60         /* March and onwards can be one day further into the year */
61         tm->tm_yday += leap_year(y);
62         m += 2;
63     } else {
64         /* Treat January and February as part of the previous year */
65         m += 14;
66         y--;
67     }
68     c = y / 100;
69     y %= 100;
70     /* Zeller's congruence */
71     tm->tm_wday = (d + (13 * m) / 5 + y + y / 4 + c / 4 + 5 * c + 6) % 7;
72 }
73 
asn1_time_to_tm(struct tm * tm,const ASN1_TIME * d)74 int asn1_time_to_tm(struct tm *tm, const ASN1_TIME *d)
75 {
76     static const int min[9] = { 0, 0, 1, 1, 0, 0, 0, 0, 0 };
77     static const int max[9] = { 99, 99, 12, 31, 23, 59, 59, 12, 59 };
78     static const int mdays[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
79     char *a;
80     int n, i, i2, l, o, min_l = 11, strict = 0, end = 6, btz = 5, md;
81     struct tm tmp;
82 #if defined(CHARSET_EBCDIC)
83     const char upper_z = 0x5A, num_zero = 0x30, period = 0x2E, minus = 0x2D, plus = 0x2B;
84 #else
85     const char upper_z = 'Z', num_zero = '0', period = '.', minus = '-', plus = '+';
86 #endif
87     /*
88      * ASN1_STRING_FLAG_X509_TIME is used to enforce RFC 5280
89      * time string format, in which:
90      *
91      * 1. "seconds" is a 'MUST'
92      * 2. "Zulu" timezone is a 'MUST'
93      * 3. "+|-" is not allowed to indicate a time zone
94      */
95     if (d->type == V_ASN1_UTCTIME) {
96         if (d->flags & ASN1_STRING_FLAG_X509_TIME) {
97             min_l = 13;
98             strict = 1;
99         }
100     } else if (d->type == V_ASN1_GENERALIZEDTIME) {
101         end = 7;
102         btz = 6;
103         if (d->flags & ASN1_STRING_FLAG_X509_TIME) {
104             min_l = 15;
105             strict = 1;
106         } else {
107             min_l = 13;
108         }
109     } else {
110         return 0;
111     }
112 
113     l = d->length;
114     a = (char *)d->data;
115     o = 0;
116     memset(&tmp, 0, sizeof(tmp));
117 
118     /*
119      * GENERALIZEDTIME is similar to UTCTIME except the year is represented
120      * as YYYY. This stuff treats everything as a two digit field so make
121      * first two fields 00 to 99
122      */
123 
124     if (l < min_l)
125         goto err;
126     for (i = 0; i < end; i++) {
127         if (!strict && (i == btz) && ((a[o] == upper_z) || (a[o] == plus) || (a[o] == minus))) {
128             i++;
129             break;
130         }
131         if (!ascii_isdigit(a[o]))
132             goto err;
133         n = a[o] - num_zero;
134         /* incomplete 2-digital number */
135         if (++o == l)
136             goto err;
137 
138         if (!ascii_isdigit(a[o]))
139             goto err;
140         n = (n * 10) + a[o] - num_zero;
141         /* no more bytes to read, but we haven't seen time-zone yet */
142         if (++o == l)
143             goto err;
144 
145         i2 = (d->type == V_ASN1_UTCTIME) ? i + 1 : i;
146 
147         if ((n < min[i2]) || (n > max[i2]))
148             goto err;
149         switch (i2) {
150         case 0:
151             /* UTC will never be here */
152             tmp.tm_year = n * 100 - 1900;
153             break;
154         case 1:
155             if (d->type == V_ASN1_UTCTIME)
156                 tmp.tm_year = n < 50 ? n + 100 : n;
157             else
158                 tmp.tm_year += n;
159             break;
160         case 2:
161             tmp.tm_mon = n - 1;
162             break;
163         case 3:
164             /* check if tm_mday is valid in tm_mon */
165             if (tmp.tm_mon == 1) {
166                 /* it's February */
167                 md = mdays[1] + leap_year(tmp.tm_year + 1900);
168             } else {
169                 md = mdays[tmp.tm_mon];
170             }
171             if (n > md)
172                 goto err;
173             tmp.tm_mday = n;
174             determine_days(&tmp);
175             break;
176         case 4:
177             tmp.tm_hour = n;
178             break;
179         case 5:
180             tmp.tm_min = n;
181             break;
182         case 6:
183             tmp.tm_sec = n;
184             break;
185         }
186     }
187 
188     /*
189      * Optional fractional seconds: decimal point followed by one or more
190      * digits.
191      */
192     if (d->type == V_ASN1_GENERALIZEDTIME && a[o] == period) {
193         if (strict)
194             /* RFC 5280 forbids fractional seconds */
195             goto err;
196         if (++o == l)
197             goto err;
198         i = o;
199         while ((o < l) && ascii_isdigit(a[o]))
200             o++;
201         /* Must have at least one digit after decimal point */
202         if (i == o)
203             goto err;
204         /* no more bytes to read, but we haven't seen time-zone yet */
205         if (o == l)
206             goto err;
207     }
208 
209     /*
210      * 'o' will never point to '\0' at this point, the only chance
211      * 'o' can point to '\0' is either the subsequent if or the first
212      * else if is true.
213      */
214     if (a[o] == upper_z) {
215         o++;
216     } else if (!strict && ((a[o] == plus) || (a[o] == minus))) {
217         int offsign = a[o] == minus ? 1 : -1;
218         int offset = 0;
219 
220         o++;
221         /*
222          * if not equal, no need to do subsequent checks
223          * since the following for-loop will add 'o' by 4
224          * and the final return statement will check if 'l'
225          * and 'o' are equal.
226          */
227         if (o + 4 != l)
228             goto err;
229         for (i = end; i < end + 2; i++) {
230             if (!ascii_isdigit(a[o]))
231                 goto err;
232             n = a[o] - num_zero;
233             o++;
234             if (!ascii_isdigit(a[o]))
235                 goto err;
236             n = (n * 10) + a[o] - num_zero;
237             i2 = (d->type == V_ASN1_UTCTIME) ? i + 1 : i;
238             if ((n < min[i2]) || (n > max[i2]))
239                 goto err;
240             /* if tm is NULL, no need to adjust */
241             if (tm != NULL) {
242                 if (i == end)
243                     offset = n * 3600;
244                 else if (i == end + 1)
245                     offset += n * 60;
246             }
247             o++;
248         }
249         if (offset && !OPENSSL_gmtime_adj(&tmp, 0, offset * offsign))
250             goto err;
251     } else {
252         /* not Z, or not +/- in non-strict mode */
253         goto err;
254     }
255     if (o == l) {
256         /* success, check if tm should be filled */
257         if (tm != NULL)
258             *tm = tmp;
259         return 1;
260     }
261  err:
262     return 0;
263 }
264 
asn1_time_from_tm(ASN1_TIME * s,struct tm * ts,int type)265 ASN1_TIME *asn1_time_from_tm(ASN1_TIME *s, struct tm *ts, int type)
266 {
267     char* p;
268     ASN1_TIME *tmps = NULL;
269     const size_t len = 20;
270 
271     if (type == V_ASN1_UNDEF) {
272         if (is_utc(ts->tm_year))
273             type = V_ASN1_UTCTIME;
274         else
275             type = V_ASN1_GENERALIZEDTIME;
276     } else if (type == V_ASN1_UTCTIME) {
277         if (!is_utc(ts->tm_year))
278             goto err;
279     } else if (type != V_ASN1_GENERALIZEDTIME) {
280         goto err;
281     }
282 
283     if (s == NULL)
284         tmps = ASN1_STRING_new();
285     else
286         tmps = s;
287     if (tmps == NULL)
288         return NULL;
289 
290     if (!ASN1_STRING_set(tmps, NULL, len))
291         goto err;
292 
293     tmps->type = type;
294     p = (char*)tmps->data;
295 
296     if (type == V_ASN1_GENERALIZEDTIME)
297         tmps->length = BIO_snprintf(p, len, "%04d%02d%02d%02d%02d%02dZ",
298                                     ts->tm_year + 1900, ts->tm_mon + 1,
299                                     ts->tm_mday, ts->tm_hour, ts->tm_min,
300                                     ts->tm_sec);
301     else
302         tmps->length = BIO_snprintf(p, len, "%02d%02d%02d%02d%02d%02dZ",
303                                     ts->tm_year % 100, ts->tm_mon + 1,
304                                     ts->tm_mday, ts->tm_hour, ts->tm_min,
305                                     ts->tm_sec);
306 
307 #ifdef CHARSET_EBCDIC
308     ebcdic2ascii(tmps->data, tmps->data, tmps->length);
309 #endif
310     return tmps;
311  err:
312     if (tmps != s)
313         ASN1_STRING_free(tmps);
314     return NULL;
315 }
316 
ASN1_TIME_set(ASN1_TIME * s,time_t t)317 ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t)
318 {
319     return ASN1_TIME_adj(s, t, 0, 0);
320 }
321 
ASN1_TIME_adj(ASN1_TIME * s,time_t t,int offset_day,long offset_sec)322 ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t,
323                          int offset_day, long offset_sec)
324 {
325     struct tm *ts;
326     struct tm data;
327 
328     ts = OPENSSL_gmtime(&t, &data);
329     if (ts == NULL) {
330         ASN1err(ASN1_F_ASN1_TIME_ADJ, ASN1_R_ERROR_GETTING_TIME);
331         return NULL;
332     }
333     if (offset_day || offset_sec) {
334         if (!OPENSSL_gmtime_adj(ts, offset_day, offset_sec))
335             return NULL;
336     }
337     return asn1_time_from_tm(s, ts, V_ASN1_UNDEF);
338 }
339 
ASN1_TIME_check(const ASN1_TIME * t)340 int ASN1_TIME_check(const ASN1_TIME *t)
341 {
342     if (t->type == V_ASN1_GENERALIZEDTIME)
343         return ASN1_GENERALIZEDTIME_check(t);
344     else if (t->type == V_ASN1_UTCTIME)
345         return ASN1_UTCTIME_check(t);
346     return 0;
347 }
348 
349 /* Convert an ASN1_TIME structure to GeneralizedTime */
ASN1_TIME_to_generalizedtime(const ASN1_TIME * t,ASN1_GENERALIZEDTIME ** out)350 ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(const ASN1_TIME *t,
351                                                    ASN1_GENERALIZEDTIME **out)
352 {
353     ASN1_GENERALIZEDTIME *ret = NULL;
354     struct tm tm;
355 
356     if (!ASN1_TIME_to_tm(t, &tm))
357         return NULL;
358 
359     if (out != NULL)
360         ret = *out;
361 
362     ret = asn1_time_from_tm(ret, &tm, V_ASN1_GENERALIZEDTIME);
363 
364     if (out != NULL && ret != NULL)
365         *out = ret;
366 
367     return ret;
368 }
369 
ASN1_TIME_set_string(ASN1_TIME * s,const char * str)370 int ASN1_TIME_set_string(ASN1_TIME *s, const char *str)
371 {
372     /* Try UTC, if that fails, try GENERALIZED */
373     if (ASN1_UTCTIME_set_string(s, str))
374         return 1;
375     return ASN1_GENERALIZEDTIME_set_string(s, str);
376 }
377 
ASN1_TIME_set_string_X509(ASN1_TIME * s,const char * str)378 int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str)
379 {
380     ASN1_TIME t;
381     struct tm tm;
382     int rv = 0;
383 
384     t.length = strlen(str);
385     t.data = (unsigned char *)str;
386     t.flags = ASN1_STRING_FLAG_X509_TIME;
387 
388     t.type = V_ASN1_UTCTIME;
389 
390     if (!ASN1_TIME_check(&t)) {
391         t.type = V_ASN1_GENERALIZEDTIME;
392         if (!ASN1_TIME_check(&t))
393             goto out;
394     }
395 
396     /*
397      * Per RFC 5280 (section 4.1.2.5.), the valid input time
398      * strings should be encoded with the following rules:
399      *
400      * 1. UTC: YYMMDDHHMMSSZ, if YY < 50 (20YY) --> UTC: YYMMDDHHMMSSZ
401      * 2. UTC: YYMMDDHHMMSSZ, if YY >= 50 (19YY) --> UTC: YYMMDDHHMMSSZ
402      * 3. G'd: YYYYMMDDHHMMSSZ, if YYYY >= 2050 --> G'd: YYYYMMDDHHMMSSZ
403      * 4. G'd: YYYYMMDDHHMMSSZ, if YYYY < 2050 --> UTC: YYMMDDHHMMSSZ
404      *
405      * Only strings of the 4th rule should be reformatted, but since a
406      * UTC can only present [1950, 2050), so if the given time string
407      * is less than 1950 (e.g. 19230419000000Z), we do nothing...
408      */
409 
410     if (s != NULL && t.type == V_ASN1_GENERALIZEDTIME) {
411         if (!asn1_time_to_tm(&tm, &t))
412             goto out;
413         if (is_utc(tm.tm_year)) {
414             t.length -= 2;
415             /*
416              * it's OK to let original t.data go since that's assigned
417              * to a piece of memory allocated outside of this function.
418              * new t.data would be freed after ASN1_STRING_copy is done.
419              */
420             t.data = OPENSSL_zalloc(t.length + 1);
421             if (t.data == NULL)
422                 goto out;
423             memcpy(t.data, str + 2, t.length);
424             t.type = V_ASN1_UTCTIME;
425         }
426     }
427 
428     if (s == NULL || ASN1_STRING_copy((ASN1_STRING *)s, (ASN1_STRING *)&t))
429         rv = 1;
430 
431     if (t.data != (unsigned char *)str)
432         OPENSSL_free(t.data);
433 out:
434     return rv;
435 }
436 
ASN1_TIME_to_tm(const ASN1_TIME * s,struct tm * tm)437 int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm)
438 {
439     if (s == NULL) {
440         time_t now_t;
441 
442         time(&now_t);
443         memset(tm, 0, sizeof(*tm));
444         if (OPENSSL_gmtime(&now_t, tm) != NULL)
445             return 1;
446         return 0;
447     }
448 
449     return asn1_time_to_tm(tm, s);
450 }
451 
ASN1_TIME_diff(int * pday,int * psec,const ASN1_TIME * from,const ASN1_TIME * to)452 int ASN1_TIME_diff(int *pday, int *psec,
453                    const ASN1_TIME *from, const ASN1_TIME *to)
454 {
455     struct tm tm_from, tm_to;
456 
457     if (!ASN1_TIME_to_tm(from, &tm_from))
458         return 0;
459     if (!ASN1_TIME_to_tm(to, &tm_to))
460         return 0;
461     return OPENSSL_gmtime_diff(pday, psec, &tm_from, &tm_to);
462 }
463 
464 static const char _asn1_mon[12][4] = {
465     "Jan", "Feb", "Mar", "Apr", "May", "Jun",
466     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
467 };
468 
ASN1_TIME_print(BIO * bp,const ASN1_TIME * tm)469 int ASN1_TIME_print(BIO *bp, const ASN1_TIME *tm)
470 {
471     char *v;
472     int gmt = 0, l;
473     struct tm stm;
474     const char upper_z = 0x5A, period = 0x2E;
475 
476     if (!asn1_time_to_tm(&stm, tm)) {
477         /* asn1_time_to_tm will check the time type */
478         goto err;
479     }
480 
481     l = tm->length;
482     v = (char *)tm->data;
483     if (v[l - 1] == upper_z)
484         gmt = 1;
485 
486     if (tm->type == V_ASN1_GENERALIZEDTIME) {
487         char *f = NULL;
488         int f_len = 0;
489 
490         /*
491          * Try to parse fractional seconds. '14' is the place of
492          * 'fraction point' in a GeneralizedTime string.
493          */
494         if (tm->length > 15 && v[14] == period) {
495             f = &v[14];
496             f_len = 1;
497             while (14 + f_len < l && ascii_isdigit(f[f_len]))
498                 ++f_len;
499         }
500 
501         return BIO_printf(bp, "%s %2d %02d:%02d:%02d%.*s %d%s",
502                           _asn1_mon[stm.tm_mon], stm.tm_mday, stm.tm_hour,
503                           stm.tm_min, stm.tm_sec, f_len, f, stm.tm_year + 1900,
504                           (gmt ? " GMT" : "")) > 0;
505     } else {
506         return BIO_printf(bp, "%s %2d %02d:%02d:%02d %d%s",
507                           _asn1_mon[stm.tm_mon], stm.tm_mday, stm.tm_hour,
508                           stm.tm_min, stm.tm_sec, stm.tm_year + 1900,
509                           (gmt ? " GMT" : "")) > 0;
510     }
511  err:
512     BIO_write(bp, "Bad time value", 14);
513     return 0;
514 }
515 
ASN1_TIME_cmp_time_t(const ASN1_TIME * s,time_t t)516 int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t)
517 {
518     struct tm stm, ttm;
519     int day, sec;
520 
521     if (!ASN1_TIME_to_tm(s, &stm))
522         return -2;
523 
524     if (!OPENSSL_gmtime(&t, &ttm))
525         return -2;
526 
527     if (!OPENSSL_gmtime_diff(&day, &sec, &ttm, &stm))
528         return -2;
529 
530     if (day > 0 || sec > 0)
531         return 1;
532     if (day < 0 || sec < 0)
533         return -1;
534     return 0;
535 }
536 
ASN1_TIME_normalize(ASN1_TIME * t)537 int ASN1_TIME_normalize(ASN1_TIME *t)
538 {
539     struct tm tm;
540 
541     if (!ASN1_TIME_to_tm(t, &tm))
542         return 0;
543 
544     return asn1_time_from_tm(t, &tm, V_ASN1_UNDEF) != NULL;
545 }
546 
ASN1_TIME_compare(const ASN1_TIME * a,const ASN1_TIME * b)547 int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b)
548 {
549     int day, sec;
550 
551     if (!ASN1_TIME_diff(&day, &sec, b, a))
552         return -2;
553     if (day > 0 || sec > 0)
554         return 1;
555     if (day < 0 || sec < 0)
556         return -1;
557     return 0;
558 }
559