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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel (at) 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 #ifdef HAVE_LIMITS_H
     79 #include <limits.h>
     80 #endif
     81 
     82 #include <curl/curl.h>
     83 #include "strcase.h"
     84 #include "warnless.h"
     85 #include "parsedate.h"
     86 
     87 const char * const Curl_wkday[] =
     88 {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
     89 static const char * const weekday[] =
     90 { "Monday", "Tuesday", "Wednesday", "Thursday",
     91   "Friday", "Saturday", "Sunday" };
     92 const char * const Curl_month[]=
     93 { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
     94   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
     95 
     96 struct tzinfo {
     97   char name[5];
     98   int offset; /* +/- in minutes */
     99 };
    100 
    101 /*
    102  * parsedate()
    103  *
    104  * Returns:
    105  *
    106  * PARSEDATE_OK     - a fine conversion
    107  * PARSEDATE_FAIL   - failed to convert
    108  * PARSEDATE_LATER  - time overflow at the far end of time_t
    109  * PARSEDATE_SOONER - time underflow at the low end of time_t
    110  */
    111 
    112 static int parsedate(const char *date, time_t *output);
    113 
    114 #define PARSEDATE_OK     0
    115 #define PARSEDATE_FAIL   -1
    116 #define PARSEDATE_LATER  1
    117 #define PARSEDATE_SOONER 2
    118 
    119 /* Here's a bunch of frequently used time zone names. These were supported
    120    by the old getdate parser. */
    121 #define tDAYZONE -60       /* offset for daylight savings time */
    122 static const struct tzinfo tz[]= {
    123   {"GMT", 0},              /* Greenwich Mean */
    124   {"UTC", 0},              /* Universal (Coordinated) */
    125   {"WET", 0},              /* Western European */
    126   {"BST", 0 tDAYZONE},     /* British Summer */
    127   {"WAT", 60},             /* West Africa */
    128   {"AST", 240},            /* Atlantic Standard */
    129   {"ADT", 240 tDAYZONE},   /* Atlantic Daylight */
    130   {"EST", 300},            /* Eastern Standard */
    131   {"EDT", 300 tDAYZONE},   /* Eastern Daylight */
    132   {"CST", 360},            /* Central Standard */
    133   {"CDT", 360 tDAYZONE},   /* Central Daylight */
    134   {"MST", 420},            /* Mountain Standard */
    135   {"MDT", 420 tDAYZONE},   /* Mountain Daylight */
    136   {"PST", 480},            /* Pacific Standard */
    137   {"PDT", 480 tDAYZONE},   /* Pacific Daylight */
    138   {"YST", 540},            /* Yukon Standard */
    139   {"YDT", 540 tDAYZONE},   /* Yukon Daylight */
    140   {"HST", 600},            /* Hawaii Standard */
    141   {"HDT", 600 tDAYZONE},   /* Hawaii Daylight */
    142   {"CAT", 600},            /* Central Alaska */
    143   {"AHST", 600},           /* Alaska-Hawaii Standard */
    144   {"NT",  660},            /* Nome */
    145   {"IDLW", 720},           /* International Date Line West */
    146   {"CET", -60},            /* Central European */
    147   {"MET", -60},            /* Middle European */
    148   {"MEWT", -60},           /* Middle European Winter */
    149   {"MEST", -60 tDAYZONE},  /* Middle European Summer */
    150   {"CEST", -60 tDAYZONE},  /* Central European Summer */
    151   {"MESZ", -60 tDAYZONE},  /* Middle European Summer */
    152   {"FWT", -60},            /* French Winter */
    153   {"FST", -60 tDAYZONE},   /* French Summer */
    154   {"EET", -120},           /* Eastern Europe, USSR Zone 1 */
    155   {"WAST", -420},          /* West Australian Standard */
    156   {"WADT", -420 tDAYZONE}, /* West Australian Daylight */
    157   {"CCT", -480},           /* China Coast, USSR Zone 7 */
    158   {"JST", -540},           /* Japan Standard, USSR Zone 8 */
    159   {"EAST", -600},          /* Eastern Australian Standard */
    160   {"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */
    161   {"GST", -600},           /* Guam Standard, USSR Zone 9 */
    162   {"NZT", -720},           /* New Zealand */
    163   {"NZST", -720},          /* New Zealand Standard */
    164   {"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */
    165   {"IDLE", -720},          /* International Date Line East */
    166   /* Next up: Military timezone names. RFC822 allowed these, but (as noted in
    167      RFC 1123) had their signs wrong. Here we use the correct signs to match
    168      actual military usage.
    169    */
    170   {"A",  +1 * 60},         /* Alpha */
    171   {"B",  +2 * 60},         /* Bravo */
    172   {"C",  +3 * 60},         /* Charlie */
    173   {"D",  +4 * 60},         /* Delta */
    174   {"E",  +5 * 60},         /* Echo */
    175   {"F",  +6 * 60},         /* Foxtrot */
    176   {"G",  +7 * 60},         /* Golf */
    177   {"H",  +8 * 60},         /* Hotel */
    178   {"I",  +9 * 60},         /* India */
    179   /* "J", Juliet is not used as a timezone, to indicate the observer's local
    180      time */
    181   {"K", +10 * 60},         /* Kilo */
    182   {"L", +11 * 60},         /* Lima */
    183   {"M", +12 * 60},         /* Mike */
    184   {"N",  -1 * 60},         /* November */
    185   {"O",  -2 * 60},         /* Oscar */
    186   {"P",  -3 * 60},         /* Papa */
    187   {"Q",  -4 * 60},         /* Quebec */
    188   {"R",  -5 * 60},         /* Romeo */
    189   {"S",  -6 * 60},         /* Sierra */
    190   {"T",  -7 * 60},         /* Tango */
    191   {"U",  -8 * 60},         /* Uniform */
    192   {"V",  -9 * 60},         /* Victor */
    193   {"W", -10 * 60},         /* Whiskey */
    194   {"X", -11 * 60},         /* X-ray */
    195   {"Y", -12 * 60},         /* Yankee */
    196   {"Z", 0},                /* Zulu, zero meridian, a.k.a. UTC */
    197 };
    198 
    199 /* returns:
    200    -1 no day
    201    0 monday - 6 sunday
    202 */
    203 
    204 static int checkday(const char *check, size_t len)
    205 {
    206   int i;
    207   const char * const *what;
    208   bool found= FALSE;
    209   if(len > 3)
    210     what = &weekday[0];
    211   else
    212     what = &Curl_wkday[0];
    213   for(i=0; i<7; i++) {
    214     if(strcasecompare(check, what[0])) {
    215       found=TRUE;
    216       break;
    217     }
    218     what++;
    219   }
    220   return found?i:-1;
    221 }
    222 
    223 static int checkmonth(const char *check)
    224 {
    225   int i;
    226   const char * const *what;
    227   bool found= FALSE;
    228 
    229   what = &Curl_month[0];
    230   for(i=0; i<12; i++) {
    231     if(strcasecompare(check, what[0])) {
    232       found=TRUE;
    233       break;
    234     }
    235     what++;
    236   }
    237   return found?i:-1; /* return the offset or -1, no real offset is -1 */
    238 }
    239 
    240 /* return the time zone offset between GMT and the input one, in number
    241    of seconds or -1 if the timezone wasn't found/legal */
    242 
    243 static int checktz(const char *check)
    244 {
    245   unsigned int i;
    246   const struct tzinfo *what;
    247   bool found= FALSE;
    248 
    249   what = tz;
    250   for(i=0; i< sizeof(tz)/sizeof(tz[0]); i++) {
    251     if(strcasecompare(check, what->name)) {
    252       found=TRUE;
    253       break;
    254     }
    255     what++;
    256   }
    257   return found?what->offset*60:-1;
    258 }
    259 
    260 static void skip(const char **date)
    261 {
    262   /* skip everything that aren't letters or digits */
    263   while(**date && !ISALNUM(**date))
    264     (*date)++;
    265 }
    266 
    267 enum assume {
    268   DATE_MDAY,
    269   DATE_YEAR,
    270   DATE_TIME
    271 };
    272 
    273 /* this is a clone of 'struct tm' but with all fields we don't need or use
    274    cut out */
    275 struct my_tm {
    276   int tm_sec;
    277   int tm_min;
    278   int tm_hour;
    279   int tm_mday;
    280   int tm_mon;
    281   int tm_year;
    282 };
    283 
    284 /* struct tm to time since epoch in GMT time zone.
    285  * This is similar to the standard mktime function but for GMT only, and
    286  * doesn't suffer from the various bugs and portability problems that
    287  * some systems' implementations have.
    288  */
    289 static time_t my_timegm(struct my_tm *tm)
    290 {
    291   static const int month_days_cumulative [12] =
    292     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
    293   int month, year, leap_days;
    294 
    295   if(tm->tm_year < 70)
    296     /* we don't support years before 1970 as they will cause this function
    297        to return a negative value */
    298     return -1;
    299 
    300   year = tm->tm_year + 1900;
    301   month = tm->tm_mon;
    302   if(month < 0) {
    303     year += (11 - month) / 12;
    304     month = 11 - (11 - month) % 12;
    305   }
    306   else if(month >= 12) {
    307     year -= month / 12;
    308     month = month % 12;
    309   }
    310 
    311   leap_days = year - (tm->tm_mon <= 1);
    312   leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
    313                - (1969 / 4) + (1969 / 100) - (1969 / 400));
    314 
    315   return ((((time_t) (year - 1970) * 365
    316             + leap_days + month_days_cumulative [month] + tm->tm_mday - 1) * 24
    317            + tm->tm_hour) * 60 + tm->tm_min) * 60 + tm->tm_sec;
    318 }
    319 
    320 /*
    321  * parsedate()
    322  *
    323  * Returns:
    324  *
    325  * PARSEDATE_OK     - a fine conversion
    326  * PARSEDATE_FAIL   - failed to convert
    327  * PARSEDATE_LATER  - time overflow at the far end of time_t
    328  * PARSEDATE_SOONER - time underflow at the low end of time_t
    329  */
    330 
    331 static int parsedate(const char *date, time_t *output)
    332 {
    333   time_t t = 0;
    334   int wdaynum=-1;  /* day of the week number, 0-6 (mon-sun) */
    335   int monnum=-1;   /* month of the year number, 0-11 */
    336   int mdaynum=-1; /* day of month, 1 - 31 */
    337   int hournum=-1;
    338   int minnum=-1;
    339   int secnum=-1;
    340   int yearnum=-1;
    341   int tzoff=-1;
    342   struct my_tm tm;
    343   enum assume dignext = DATE_MDAY;
    344   const char *indate = date; /* save the original pointer */
    345   int part = 0; /* max 6 parts */
    346 
    347   while(*date && (part < 6)) {
    348     bool found=FALSE;
    349 
    350     skip(&date);
    351 
    352     if(ISALPHA(*date)) {
    353       /* a name coming up */
    354       char buf[32]="";
    355       size_t len;
    356       if(sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    357                           "abcdefghijklmnopqrstuvwxyz]", buf))
    358         len = strlen(buf);
    359       else
    360         len = 0;
    361 
    362       if(wdaynum == -1) {
    363         wdaynum = checkday(buf, len);
    364         if(wdaynum != -1)
    365           found = TRUE;
    366       }
    367       if(!found && (monnum == -1)) {
    368         monnum = checkmonth(buf);
    369         if(monnum != -1)
    370           found = TRUE;
    371       }
    372 
    373       if(!found && (tzoff == -1)) {
    374         /* this just must be a time zone string */
    375         tzoff = checktz(buf);
    376         if(tzoff != -1)
    377           found = TRUE;
    378       }
    379 
    380       if(!found)
    381         return PARSEDATE_FAIL; /* bad string */
    382 
    383       date += len;
    384     }
    385     else if(ISDIGIT(*date)) {
    386       /* a digit */
    387       int val;
    388       char *end;
    389       int len=0;
    390       if((secnum == -1) &&
    391          (3 == sscanf(date, "%02d:%02d:%02d%n",
    392                       &hournum, &minnum, &secnum, &len))) {
    393         /* time stamp! */
    394         date += len;
    395       }
    396       else if((secnum == -1) &&
    397               (2 == sscanf(date, "%02d:%02d%n", &hournum, &minnum, &len))) {
    398         /* time stamp without seconds */
    399         date += len;
    400         secnum = 0;
    401       }
    402       else {
    403         long lval;
    404         int error;
    405         int old_errno;
    406 
    407         old_errno = ERRNO;
    408         SET_ERRNO(0);
    409         lval = strtol(date, &end, 10);
    410         error = ERRNO;
    411         if(error != old_errno)
    412           SET_ERRNO(old_errno);
    413 
    414         if(error)
    415           return PARSEDATE_FAIL;
    416 
    417 #if LONG_MAX != INT_MAX
    418         if((lval > (long)INT_MAX) || (lval < (long)INT_MIN))
    419           return PARSEDATE_FAIL;
    420 #endif
    421 
    422         val = curlx_sltosi(lval);
    423 
    424         if((tzoff == -1) &&
    425            ((end - date) == 4) &&
    426            (val <= 1400) &&
    427            (indate< date) &&
    428            ((date[-1] == '+' || date[-1] == '-'))) {
    429           /* four digits and a value less than or equal to 1400 (to take into
    430              account all sorts of funny time zone diffs) and it is preceded
    431              with a plus or minus. This is a time zone indication.  1400 is
    432              picked since +1300 is frequently used and +1400 is mentioned as
    433              an edge number in the document "ISO C 200X Proposal: Timezone
    434              Functions" at http://david.tribble.com/text/c0xtimezone.html If
    435              anyone has a more authoritative source for the exact maximum time
    436              zone offsets, please speak up! */
    437           found = TRUE;
    438           tzoff = (val/100 * 60 + val%100)*60;
    439 
    440           /* the + and - prefix indicates the local time compared to GMT,
    441              this we need ther reversed math to get what we want */
    442           tzoff = date[-1]=='+'?-tzoff:tzoff;
    443         }
    444 
    445         if(((end - date) == 8) &&
    446            (yearnum == -1) &&
    447            (monnum == -1) &&
    448            (mdaynum == -1)) {
    449           /* 8 digits, no year, month or day yet. This is YYYYMMDD */
    450           found = TRUE;
    451           yearnum = val/10000;
    452           monnum = (val%10000)/100-1; /* month is 0 - 11 */
    453           mdaynum = val%100;
    454         }
    455 
    456         if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {
    457           if((val > 0) && (val<32)) {
    458             mdaynum = val;
    459             found = TRUE;
    460           }
    461           dignext = DATE_YEAR;
    462         }
    463 
    464         if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
    465           yearnum = val;
    466           found = TRUE;
    467           if(yearnum < 1900) {
    468             if(yearnum > 70)
    469               yearnum += 1900;
    470             else
    471               yearnum += 2000;
    472           }
    473           if(mdaynum == -1)
    474             dignext = DATE_MDAY;
    475         }
    476 
    477         if(!found)
    478           return PARSEDATE_FAIL;
    479 
    480         date = end;
    481       }
    482     }
    483 
    484     part++;
    485   }
    486 
    487   if(-1 == secnum)
    488     secnum = minnum = hournum = 0; /* no time, make it zero */
    489 
    490   if((-1 == mdaynum) ||
    491      (-1 == monnum) ||
    492      (-1 == yearnum))
    493     /* lacks vital info, fail */
    494     return PARSEDATE_FAIL;
    495 
    496   /* 32 bit time_t can only hold dates to the beginning of 2038 */
    497   if(sizeof(time_t) < 5 && yearnum > 2037) {
    498     *output = 0x7fffffff;
    499     return PARSEDATE_LATER;
    500   }
    501 
    502   if(yearnum < 1970) {
    503     *output = 0;
    504     return PARSEDATE_SOONER;
    505   }
    506 
    507   if((mdaynum > 31) || (monnum > 11) ||
    508      (hournum > 23) || (minnum > 59) || (secnum > 60))
    509     return PARSEDATE_FAIL; /* clearly an illegal date */
    510 
    511   tm.tm_sec = secnum;
    512   tm.tm_min = minnum;
    513   tm.tm_hour = hournum;
    514   tm.tm_mday = mdaynum;
    515   tm.tm_mon = monnum;
    516   tm.tm_year = yearnum - 1900;
    517 
    518   /* my_timegm() returns a time_t. time_t is often 32 bits, even on many
    519      architectures that feature 64 bit 'long'.
    520 
    521      Some systems have 64 bit time_t and deal with years beyond 2038. However,
    522      even on some of the systems with 64 bit time_t mktime() returns -1 for
    523      dates beyond 03:14:07 UTC, January 19, 2038. (Such as AIX 5100-06)
    524   */
    525   t = my_timegm(&tm);
    526 
    527   /* time zone adjust (cast t to int to compare to negative one) */
    528   if(-1 != (int)t) {
    529 
    530     /* Add the time zone diff between local time zone and GMT. */
    531     long delta = (long)(tzoff!=-1?tzoff:0);
    532 
    533     if((delta>0) && (t > LONG_MAX - delta)) {
    534       *output = 0x7fffffff;
    535       return PARSEDATE_LATER; /* time_t overflow */
    536     }
    537 
    538     t += delta;
    539   }
    540 
    541   *output = t;
    542 
    543   return PARSEDATE_OK;
    544 }
    545 
    546 time_t curl_getdate(const char *p, const time_t *now)
    547 {
    548   time_t parsed = -1;
    549   int rc = parsedate(p, &parsed);
    550   (void)now; /* legacy argument from the past that we ignore */
    551 
    552   switch(rc) {
    553   case PARSEDATE_OK:
    554   case PARSEDATE_LATER:
    555   case PARSEDATE_SOONER:
    556     return parsed;
    557   }
    558   /* everything else is fail */
    559   return -1;
    560 }
    561 
    562 /*
    563  * Curl_gmtime() is a gmtime() replacement for portability. Do not use the
    564  * gmtime_r() or gmtime() functions anywhere else but here.
    565  *
    566  */
    567 
    568 CURLcode Curl_gmtime(time_t intime, struct tm *store)
    569 {
    570   const struct tm *tm;
    571 #ifdef HAVE_GMTIME_R
    572   /* thread-safe version */
    573   tm = (struct tm *)gmtime_r(&intime, store);
    574 #else
    575   tm = gmtime(&intime);
    576   if(tm)
    577     *store = *tm; /* copy the pointed struct to the local copy */
    578 #endif
    579 
    580   if(!tm)
    581     return CURLE_BAD_FUNCTION_ARGUMENT;
    582   return CURLE_OK;
    583 }
    584