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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
11  * you should have received as part of this distribution. The terms
12  * are also available at https://curl.haxx.se/docs/copyright.html.
13  *
14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15  * copies of the Software, and permit persons to whom the Software is
16  * furnished to do so, under the terms of the COPYING file.
17  *
18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  ***************************************************************************/
22 /*
23   A brief summary of the date string formats this parser groks:
24 
25   RFC 2616 3.3.1
26 
27   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
28   Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
29   Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
30 
31   we support dates without week day name:
32 
33   06 Nov 1994 08:49:37 GMT
34   06-Nov-94 08:49:37 GMT
35   Nov  6 08:49:37 1994
36 
37   without the time zone:
38 
39   06 Nov 1994 08:49:37
40   06-Nov-94 08:49:37
41 
42   weird order:
43 
44   1994 Nov 6 08:49:37  (GNU date fails)
45   GMT 08:49:37 06-Nov-94 Sunday
46   94 6 Nov 08:49:37    (GNU date fails)
47 
48   time left out:
49 
50   1994 Nov 6
51   06-Nov-94
52   Sun Nov 6 94
53 
54   unusual separators:
55 
56   1994.Nov.6
57   Sun/Nov/6/94/GMT
58 
59   commonly used time zone names:
60 
61   Sun, 06 Nov 1994 08:49:37 CET
62   06 Nov 1994 08:49:37 EST
63 
64   time zones specified using RFC822 style:
65 
66   Sun, 12 Sep 2004 15:05:58 -0700
67   Sat, 11 Sep 2004 21:32:11 +0200
68 
69   compact numerical date strings:
70 
71   20040912 15:05:58 -0700
72   20040911 +0200
73 
74 */
75 
76 #include "curl_setup.h"
77 
78 #include <limits.h>
79 
80 #include <curl/curl.h>
81 #include "strcase.h"
82 #include "warnless.h"
83 #include "parsedate.h"
84 
85 /*
86  * parsedate()
87  *
88  * Returns:
89  *
90  * PARSEDATE_OK     - a fine conversion
91  * PARSEDATE_FAIL   - failed to convert
92  * PARSEDATE_LATER  - time overflow at the far end of time_t
93  * PARSEDATE_SOONER - time underflow at the low end of time_t
94  */
95 
96 static int parsedate(const char *date, time_t *output);
97 
98 #define PARSEDATE_OK     0
99 #define PARSEDATE_FAIL   -1
100 #define PARSEDATE_LATER  1
101 #define PARSEDATE_SOONER 2
102 
103 #if !defined(CURL_DISABLE_PARSEDATE) || !defined(CURL_DISABLE_FTP) || \
104   !defined(CURL_DISABLE_FILE)
105 /* These names are also used by FTP and FILE code */
106 const char * const Curl_wkday[] =
107 {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
108 const char * const Curl_month[]=
109 { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
110   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
111 #endif
112 
113 #ifndef CURL_DISABLE_PARSEDATE
114 static const char * const weekday[] =
115 { "Monday", "Tuesday", "Wednesday", "Thursday",
116   "Friday", "Saturday", "Sunday" };
117 
118 struct tzinfo {
119   char name[5];
120   int offset; /* +/- in minutes */
121 };
122 
123 /* Here's a bunch of frequently used time zone names. These were supported
124    by the old getdate parser. */
125 #define tDAYZONE -60       /* offset for daylight savings time */
126 static const struct tzinfo tz[]= {
127   {"GMT", 0},              /* Greenwich Mean */
128   {"UT",  0},              /* Universal Time */
129   {"UTC", 0},              /* Universal (Coordinated) */
130   {"WET", 0},              /* Western European */
131   {"BST", 0 tDAYZONE},     /* British Summer */
132   {"WAT", 60},             /* West Africa */
133   {"AST", 240},            /* Atlantic Standard */
134   {"ADT", 240 tDAYZONE},   /* Atlantic Daylight */
135   {"EST", 300},            /* Eastern Standard */
136   {"EDT", 300 tDAYZONE},   /* Eastern Daylight */
137   {"CST", 360},            /* Central Standard */
138   {"CDT", 360 tDAYZONE},   /* Central Daylight */
139   {"MST", 420},            /* Mountain Standard */
140   {"MDT", 420 tDAYZONE},   /* Mountain Daylight */
141   {"PST", 480},            /* Pacific Standard */
142   {"PDT", 480 tDAYZONE},   /* Pacific Daylight */
143   {"YST", 540},            /* Yukon Standard */
144   {"YDT", 540 tDAYZONE},   /* Yukon Daylight */
145   {"HST", 600},            /* Hawaii Standard */
146   {"HDT", 600 tDAYZONE},   /* Hawaii Daylight */
147   {"CAT", 600},            /* Central Alaska */
148   {"AHST", 600},           /* Alaska-Hawaii Standard */
149   {"NT",  660},            /* Nome */
150   {"IDLW", 720},           /* International Date Line West */
151   {"CET", -60},            /* Central European */
152   {"MET", -60},            /* Middle European */
153   {"MEWT", -60},           /* Middle European Winter */
154   {"MEST", -60 tDAYZONE},  /* Middle European Summer */
155   {"CEST", -60 tDAYZONE},  /* Central European Summer */
156   {"MESZ", -60 tDAYZONE},  /* Middle European Summer */
157   {"FWT", -60},            /* French Winter */
158   {"FST", -60 tDAYZONE},   /* French Summer */
159   {"EET", -120},           /* Eastern Europe, USSR Zone 1 */
160   {"WAST", -420},          /* West Australian Standard */
161   {"WADT", -420 tDAYZONE}, /* West Australian Daylight */
162   {"CCT", -480},           /* China Coast, USSR Zone 7 */
163   {"JST", -540},           /* Japan Standard, USSR Zone 8 */
164   {"EAST", -600},          /* Eastern Australian Standard */
165   {"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */
166   {"GST", -600},           /* Guam Standard, USSR Zone 9 */
167   {"NZT", -720},           /* New Zealand */
168   {"NZST", -720},          /* New Zealand Standard */
169   {"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */
170   {"IDLE", -720},          /* International Date Line East */
171   /* Next up: Military timezone names. RFC822 allowed these, but (as noted in
172      RFC 1123) had their signs wrong. Here we use the correct signs to match
173      actual military usage.
174    */
175   {"A",  1 * 60},         /* Alpha */
176   {"B",  2 * 60},         /* Bravo */
177   {"C",  3 * 60},         /* Charlie */
178   {"D",  4 * 60},         /* Delta */
179   {"E",  5 * 60},         /* Echo */
180   {"F",  6 * 60},         /* Foxtrot */
181   {"G",  7 * 60},         /* Golf */
182   {"H",  8 * 60},         /* Hotel */
183   {"I",  9 * 60},         /* India */
184   /* "J", Juliet is not used as a timezone, to indicate the observer's local
185      time */
186   {"K", 10 * 60},         /* Kilo */
187   {"L", 11 * 60},         /* Lima */
188   {"M", 12 * 60},         /* Mike */
189   {"N",  -1 * 60},         /* November */
190   {"O",  -2 * 60},         /* Oscar */
191   {"P",  -3 * 60},         /* Papa */
192   {"Q",  -4 * 60},         /* Quebec */
193   {"R",  -5 * 60},         /* Romeo */
194   {"S",  -6 * 60},         /* Sierra */
195   {"T",  -7 * 60},         /* Tango */
196   {"U",  -8 * 60},         /* Uniform */
197   {"V",  -9 * 60},         /* Victor */
198   {"W", -10 * 60},         /* Whiskey */
199   {"X", -11 * 60},         /* X-ray */
200   {"Y", -12 * 60},         /* Yankee */
201   {"Z", 0},                /* Zulu, zero meridian, a.k.a. UTC */
202 };
203 
204 /* returns:
205    -1 no day
206    0 monday - 6 sunday
207 */
208 
checkday(const char * check,size_t len)209 static int checkday(const char *check, size_t len)
210 {
211   int i;
212   const char * const *what;
213   bool found = FALSE;
214   if(len > 3)
215     what = &weekday[0];
216   else
217     what = &Curl_wkday[0];
218   for(i = 0; i<7; i++) {
219     if(strcasecompare(check, what[0])) {
220       found = TRUE;
221       break;
222     }
223     what++;
224   }
225   return found?i:-1;
226 }
227 
checkmonth(const char * check)228 static int checkmonth(const char *check)
229 {
230   int i;
231   const char * const *what;
232   bool found = FALSE;
233 
234   what = &Curl_month[0];
235   for(i = 0; i<12; i++) {
236     if(strcasecompare(check, what[0])) {
237       found = TRUE;
238       break;
239     }
240     what++;
241   }
242   return found?i:-1; /* return the offset or -1, no real offset is -1 */
243 }
244 
245 /* return the time zone offset between GMT and the input one, in number
246    of seconds or -1 if the timezone wasn't found/legal */
247 
checktz(const char * check)248 static int checktz(const char *check)
249 {
250   unsigned int i;
251   const struct tzinfo *what;
252   bool found = FALSE;
253 
254   what = tz;
255   for(i = 0; i< sizeof(tz)/sizeof(tz[0]); i++) {
256     if(strcasecompare(check, what->name)) {
257       found = TRUE;
258       break;
259     }
260     what++;
261   }
262   return found?what->offset*60:-1;
263 }
264 
skip(const char ** date)265 static void skip(const char **date)
266 {
267   /* skip everything that aren't letters or digits */
268   while(**date && !ISALNUM(**date))
269     (*date)++;
270 }
271 
272 enum assume {
273   DATE_MDAY,
274   DATE_YEAR,
275   DATE_TIME
276 };
277 
278 /*
279  * time2epoch: time stamp to seconds since epoch in GMT time zone.  Similar to
280  * mktime but for GMT only.
281  */
time2epoch(int sec,int min,int hour,int mday,int mon,int year)282 static time_t time2epoch(int sec, int min, int hour,
283                          int mday, int mon, int year)
284 {
285   static const int month_days_cumulative [12] =
286     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
287   int leap_days = year - (mon <= 1);
288   leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
289                - (1969 / 4) + (1969 / 100) - (1969 / 400));
290   return ((((time_t) (year - 1970) * 365
291             + leap_days + month_days_cumulative[mon] + mday - 1) * 24
292            + hour) * 60 + min) * 60 + sec;
293 }
294 
295 /*
296  * parsedate()
297  *
298  * Returns:
299  *
300  * PARSEDATE_OK     - a fine conversion
301  * PARSEDATE_FAIL   - failed to convert
302  * PARSEDATE_LATER  - time overflow at the far end of time_t
303  * PARSEDATE_SOONER - time underflow at the low end of time_t
304  */
305 
parsedate(const char * date,time_t * output)306 static int parsedate(const char *date, time_t *output)
307 {
308   time_t t = 0;
309   int wdaynum = -1;  /* day of the week number, 0-6 (mon-sun) */
310   int monnum = -1;   /* month of the year number, 0-11 */
311   int mdaynum = -1; /* day of month, 1 - 31 */
312   int hournum = -1;
313   int minnum = -1;
314   int secnum = -1;
315   int yearnum = -1;
316   int tzoff = -1;
317   enum assume dignext = DATE_MDAY;
318   const char *indate = date; /* save the original pointer */
319   int part = 0; /* max 6 parts */
320 
321   while(*date && (part < 6)) {
322     bool found = FALSE;
323 
324     skip(&date);
325 
326     if(ISALPHA(*date)) {
327       /* a name coming up */
328       char buf[32]="";
329       size_t len;
330       if(sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZ"
331                           "abcdefghijklmnopqrstuvwxyz]", buf))
332         len = strlen(buf);
333       else
334         len = 0;
335 
336       if(wdaynum == -1) {
337         wdaynum = checkday(buf, len);
338         if(wdaynum != -1)
339           found = TRUE;
340       }
341       if(!found && (monnum == -1)) {
342         monnum = checkmonth(buf);
343         if(monnum != -1)
344           found = TRUE;
345       }
346 
347       if(!found && (tzoff == -1)) {
348         /* this just must be a time zone string */
349         tzoff = checktz(buf);
350         if(tzoff != -1)
351           found = TRUE;
352       }
353 
354       if(!found)
355         return PARSEDATE_FAIL; /* bad string */
356 
357       date += len;
358     }
359     else if(ISDIGIT(*date)) {
360       /* a digit */
361       int val;
362       char *end;
363       int len = 0;
364       if((secnum == -1) &&
365          (3 == sscanf(date, "%02d:%02d:%02d%n",
366                       &hournum, &minnum, &secnum, &len))) {
367         /* time stamp! */
368         date += len;
369       }
370       else if((secnum == -1) &&
371               (2 == sscanf(date, "%02d:%02d%n", &hournum, &minnum, &len))) {
372         /* time stamp without seconds */
373         date += len;
374         secnum = 0;
375       }
376       else {
377         long lval;
378         int error;
379         int old_errno;
380 
381         old_errno = errno;
382         errno = 0;
383         lval = strtol(date, &end, 10);
384         error = errno;
385         if(errno != old_errno)
386           errno = old_errno;
387 
388         if(error)
389           return PARSEDATE_FAIL;
390 
391 #if LONG_MAX != INT_MAX
392         if((lval > (long)INT_MAX) || (lval < (long)INT_MIN))
393           return PARSEDATE_FAIL;
394 #endif
395 
396         val = curlx_sltosi(lval);
397 
398         if((tzoff == -1) &&
399            ((end - date) == 4) &&
400            (val <= 1400) &&
401            (indate< date) &&
402            ((date[-1] == '+' || date[-1] == '-'))) {
403           /* four digits and a value less than or equal to 1400 (to take into
404              account all sorts of funny time zone diffs) and it is preceded
405              with a plus or minus. This is a time zone indication.  1400 is
406              picked since +1300 is frequently used and +1400 is mentioned as
407              an edge number in the document "ISO C 200X Proposal: Timezone
408              Functions" at http://david.tribble.com/text/c0xtimezone.html If
409              anyone has a more authoritative source for the exact maximum time
410              zone offsets, please speak up! */
411           found = TRUE;
412           tzoff = (val/100 * 60 + val%100)*60;
413 
414           /* the + and - prefix indicates the local time compared to GMT,
415              this we need their reversed math to get what we want */
416           tzoff = date[-1]=='+'?-tzoff:tzoff;
417         }
418 
419         if(((end - date) == 8) &&
420            (yearnum == -1) &&
421            (monnum == -1) &&
422            (mdaynum == -1)) {
423           /* 8 digits, no year, month or day yet. This is YYYYMMDD */
424           found = TRUE;
425           yearnum = val/10000;
426           monnum = (val%10000)/100-1; /* month is 0 - 11 */
427           mdaynum = val%100;
428         }
429 
430         if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {
431           if((val > 0) && (val<32)) {
432             mdaynum = val;
433             found = TRUE;
434           }
435           dignext = DATE_YEAR;
436         }
437 
438         if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
439           yearnum = val;
440           found = TRUE;
441           if(yearnum < 100) {
442             if(yearnum > 70)
443               yearnum += 1900;
444             else
445               yearnum += 2000;
446           }
447           if(mdaynum == -1)
448             dignext = DATE_MDAY;
449         }
450 
451         if(!found)
452           return PARSEDATE_FAIL;
453 
454         date = end;
455       }
456     }
457 
458     part++;
459   }
460 
461   if(-1 == secnum)
462     secnum = minnum = hournum = 0; /* no time, make it zero */
463 
464   if((-1 == mdaynum) ||
465      (-1 == monnum) ||
466      (-1 == yearnum))
467     /* lacks vital info, fail */
468     return PARSEDATE_FAIL;
469 
470 #ifdef HAVE_TIME_T_UNSIGNED
471   if(yearnum < 1970) {
472     /* only positive numbers cannot return earlier */
473     *output = TIME_T_MIN;
474     return PARSEDATE_SOONER;
475   }
476 #endif
477 
478 #if (SIZEOF_TIME_T < 5)
479 
480 #ifdef HAVE_TIME_T_UNSIGNED
481   /* an unsigned 32 bit time_t can only hold dates to 2106 */
482   if(yearnum > 2105) {
483     *output = TIME_T_MAX;
484     return PARSEDATE_LATER;
485   }
486 #else
487   /* a signed 32 bit time_t can only hold dates to the beginning of 2038 */
488   if(yearnum > 2037) {
489     *output = TIME_T_MAX;
490     return PARSEDATE_LATER;
491   }
492   if(yearnum < 1903) {
493     *output = TIME_T_MIN;
494     return PARSEDATE_SOONER;
495   }
496 #endif
497 
498 #else
499   /* The Gregorian calendar was introduced 1582 */
500   if(yearnum < 1583)
501     return PARSEDATE_FAIL;
502 #endif
503 
504   if((mdaynum > 31) || (monnum > 11) ||
505      (hournum > 23) || (minnum > 59) || (secnum > 60))
506     return PARSEDATE_FAIL; /* clearly an illegal date */
507 
508   /* time2epoch() returns a time_t. time_t is often 32 bits, sometimes even on
509      architectures that feature 64 bit 'long' but ultimately time_t is the
510      correct data type to use.
511   */
512   t = time2epoch(secnum, minnum, hournum, mdaynum, monnum, yearnum);
513 
514   /* Add the time zone diff between local time zone and GMT. */
515   if(tzoff == -1)
516     tzoff = 0;
517 
518   if((tzoff > 0) && (t > TIME_T_MAX - tzoff)) {
519     *output = TIME_T_MAX;
520     return PARSEDATE_LATER; /* time_t overflow */
521   }
522 
523   t += tzoff;
524 
525   *output = t;
526 
527   return PARSEDATE_OK;
528 }
529 #else
530 /* disabled */
parsedate(const char * date,time_t * output)531 static int parsedate(const char *date, time_t *output)
532 {
533   (void)date;
534   *output = 0;
535   return PARSEDATE_OK; /* a lie */
536 }
537 #endif
538 
curl_getdate(const char * p,const time_t * now)539 time_t curl_getdate(const char *p, const time_t *now)
540 {
541   time_t parsed = -1;
542   int rc = parsedate(p, &parsed);
543   (void)now; /* legacy argument from the past that we ignore */
544 
545   if(rc == PARSEDATE_OK) {
546     if(parsed == -1)
547       /* avoid returning -1 for a working scenario */
548       parsed++;
549     return parsed;
550   }
551   /* everything else is fail */
552   return -1;
553 }
554 
555 /* Curl_getdate_capped() differs from curl_getdate() in that this will return
556    TIME_T_MAX in case the parsed time value was too big, instead of an
557    error. */
558 
Curl_getdate_capped(const char * p)559 time_t Curl_getdate_capped(const char *p)
560 {
561   time_t parsed = -1;
562   int rc = parsedate(p, &parsed);
563 
564   switch(rc) {
565   case PARSEDATE_OK:
566     if(parsed == -1)
567       /* avoid returning -1 for a working scenario */
568       parsed++;
569     return parsed;
570   case PARSEDATE_LATER:
571     /* this returns the maximum time value */
572     return parsed;
573   default:
574     return -1; /* everything else is fail */
575   }
576   /* UNREACHABLE */
577 }
578 
579 /*
580  * Curl_gmtime() is a gmtime() replacement for portability. Do not use the
581  * gmtime_r() or gmtime() functions anywhere else but here.
582  *
583  */
584 
Curl_gmtime(time_t intime,struct tm * store)585 CURLcode Curl_gmtime(time_t intime, struct tm *store)
586 {
587   const struct tm *tm;
588 #ifdef HAVE_GMTIME_R
589   /* thread-safe version */
590   tm = (struct tm *)gmtime_r(&intime, store);
591 #else
592   /* !checksrc! disable BANNEDFUNC 1 */
593   tm = gmtime(&intime);
594   if(tm)
595     *store = *tm; /* copy the pointed struct to the local copy */
596 #endif
597 
598   if(!tm)
599     return CURLE_BAD_FUNCTION_ARGUMENT;
600   return CURLE_OK;
601 }
602