utilities/src/der_date.c

   1 //
   2 //  SecCFDER_CFDate.c
   3 //  utilities
   4 //
   5 //  Created by Michael Brouwer on 7/7/12.
   6 //  Copyright (c) 2012 Apple Inc. All rights reserved.
   7 //
   8
   9 #include "utilities/SecCFRelease.h"
  10 #include "utilities/der_date.h"
  11 #include "utilities/der_plist.h"
  12 #include "utilities/der_plist_internal.h"
  13
  14 #include <corecrypto/ccder.h>
  15 #include <CoreFoundation/CoreFoundation.h>
  16
  17 #include <math.h>
  18
  19 #define NULL_TIME NAN
  20
  21 CFAbsoluteTime SecCFGregorianDateGetAbsoluteTime(CFGregorianDate g, CFTimeInterval timeZoneOffset, CFErrorRef *error);
  22 CFGregorianDate SecCFAbsoluteTimeGetGregorianDate(CFAbsoluteTime at, CFTimeInterval timeZoneOffset, CFErrorRef *error);
  23
  24 /* Cumalitive number of days in the year for months up to month i.  */
  25 static int mdays[13] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
  26
  27 CFAbsoluteTime SecCFGregorianDateGetAbsoluteTime(CFGregorianDate g, CFTimeInterval timeZoneOffset, CFErrorRef *error) {
  28     int day = g.day;
  29     int is_leap_year = g.year % 4 == 0 && (g.year % 100 != 0 || g.year % 400 == 0) ? 1 : 0;
  30     if (g.month < 1 || g.month > 12 || day < 1 || day > 31 || g.hour >= 24 || g.minute >= 60 || g.second >= 60.0
  31         || (g.month == 2 && day > mdays[g.month] - mdays[g.month - 1] + is_leap_year)
  32         || (g.month != 2 && day > mdays[g.month] - mdays[g.month - 1])) {
  33         /* Invalid date. */
  34         SecCFDERCreateError(-1000, CFSTR("Invalid date."), 0, error);
  35         return NULL_TIME;
  36     }
  37
  38     int dy = g.year - 2001;
  39     if (dy < 0) {
  40         dy += 1;
  41         day -= 1;
  42     }
  43
  44     int leap_days = dy / 4 - dy / 100 + dy / 400;
  45     day += ((g.year - 2001) * 365 + leap_days) + mdays[g.month - 1] - 1;
  46     if (g.month > 2)
  47         day += is_leap_year;
  48
  49 #if 0
  50     int64_t time = day;
  51     time *= 24;
  52     time += g.hour;
  53     time *= 60;
  54     time += g.minute;
  55     time *= 60;
  56     time += lrint(g.second);
  57     time -= lrint(timeZoneOffset);
  58     return time;
  59 #else
  60     CFAbsoluteTime absTime = (CFAbsoluteTime)((day * 24 + g.hour) * 60 + g.minute) * 60 + g.second;
  61         return absTime - timeZoneOffset;
  62 #endif
  63 }
  64
  65 CFGregorianDate SecCFAbsoluteTimeGetGregorianDate(CFAbsoluteTime at, CFTimeInterval timeZoneOffset, CFErrorRef *error) {
  66     CFTimeZoneRef tz = CFTimeZoneCreateWithTimeIntervalFromGMT(0, timeZoneOffset);
  67     if (!tz) {
  68         SecCFDERCreateError(-1000, CFSTR("timezone creation failed."), 0, error);
  69         CFGregorianDate g = {};
  70         return g;
  71     } else {
  72         CFGregorianDate g = CFAbsoluteTimeGetGregorianDate(at, tz);
  73         CFRelease(tz);
  74         return g;
  75     }
  76 }
  77
  78
  79 static int der_get_char(const uint8_t **der_p, const uint8_t *der_end,
  80                          CFErrorRef *error) {
  81     const uint8_t *der = *der_p;
  82     if (!der) {
  83         /* Don't create a new error in this case. */
  84         return -1;
  85     }
  86
  87     if (der >= der_end) {
  88         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
  89                             CFSTR("Unexpected end of datetime"), 0, error);
  90         *der_p = NULL;
  91         return -1;
  92     }
  93
  94     int ch = *der++;
  95     *der_p = der;
  96     return ch;
  97 }
  98
  99
 100 static int der_decode_decimal(const uint8_t **der_p, const uint8_t *der_end,
 101                              CFErrorRef *error) {
 102     char ch = der_get_char(der_p, der_end, error);
 103     if (ch < '0' || ch > '9') {
 104         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 105                             CFSTR("Not a decimal digit"), 0, error);
 106         *der_p = NULL;
 107         return -1;
 108     }
 109     return ch - '0';
 110 }
 111
 112 static int der_decode_decimal_pair(const uint8_t **der_p, const uint8_t *der_end,
 113                             CFErrorRef *error) {
 114     return (10 * der_decode_decimal(der_p, der_end, error))
 115         + der_decode_decimal(der_p, der_end, error);
 116 }
 117
 118 static int der_peek_byte(const uint8_t *der, const uint8_t *der_end) {
 119     if (!der || der >= der_end)
 120         return -1;
 121
 122     return *der;
 123 }
 124
 125 static const uint8_t *der_decode_decimal_fraction(double *fraction, CFErrorRef *error,
 126                                                   const uint8_t* der, const uint8_t *der_end) {
 127     int ch = der_peek_byte(der, der_end);
 128     if (ch == -1) {
 129         der = NULL;
 130     } else if (ch == '.') {
 131         uint64_t divisor = 1;
 132         uint64_t value = 0;
 133         int last = -1;
 134         while (++der < der_end) {
 135             last = ch;
 136             ch = *der;
 137             if (ch < '0' || ch > '9') {
 138                 break;
 139             }
 140             if (divisor < UINT64_MAX / 10) {
 141                 divisor *= 10;
 142                 value *= 10;
 143                 value += (ch - '0');
 144             }
 145         }
 146         if (der >= der_end)
 147             der = NULL;
 148         else if (last == '0') {
 149             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 150                                 CFSTR("fraction ends in 0"), 0, error);
 151             der = NULL;
 152         } else if (last == '.') {
 153             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 154                                 CFSTR("fraction without digits"), 0, error);
 155             der = NULL;
 156         } else {
 157             *fraction = (double)value / divisor;
 158         }
 159     } else {
 160         *fraction = 0.0;
 161     }
 162
 163     return der;
 164 }
 165
 166 static const CFTimeInterval der_decode_timezone_offset(const uint8_t **der_p,
 167                                                        const uint8_t *der_end,
 168                                                        CFErrorRef *error) {
 169     CFTimeInterval timeZoneOffset;
 170     int ch = der_get_char(der_p, der_end, error);
 171     if (ch == 'Z') {
 172         /* Zulu time. */
 173         timeZoneOffset = 0.0;
 174     } else {
 175                 /* ZONE INDICATOR */
 176         int multiplier;
 177         if (ch == '-')
 178             multiplier = -60;
 179         else if (ch == '+')
 180             multiplier = +60;
 181         else {
 182             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 183                                 CFSTR("Invalid datetime character"), 0, error);
 184             timeZoneOffset = NULL_TIME;
 185         }
 186
 187         timeZoneOffset = multiplier *
 188             (der_decode_decimal_pair(der_p, der_end, error)
 189              * 60 + der_decode_decimal_pair(der_p, der_end, error));
 190     }
 191     return timeZoneOffset;
 192 }
 193
 194 static const uint8_t* der_decode_commontime_body(CFAbsoluteTime *at, CFErrorRef *error, SInt32 year,
 195                                                  const uint8_t* der, const uint8_t *der_end)
 196 {
 197     CFGregorianDate g;
 198     g.year = year;
 199         g.month = der_decode_decimal_pair(&der, der_end, error);
 200         g.day = der_decode_decimal_pair(&der, der_end, error);
 201         g.hour = der_decode_decimal_pair(&der, der_end, error);
 202         g.minute = der_decode_decimal_pair(&der, der_end, error);
 203     g.second = der_decode_decimal_pair(&der, der_end, error);
 204     double fraction;
 205     der = der_decode_decimal_fraction(&fraction, error, der, der_end);
 206
 207         CFTimeInterval timeZoneOffset = der_decode_timezone_offset(&der, der_end, error);
 208
 209 #if 0
 210     secdebug("dateparse",
 211              "date %.*s year: %04d%02d%02d%02d%02d%02d%+05g",
 212              length, bytes, g.year, g.month,
 213              g.day, g.hour, g.minute, g.second,
 214              timeZoneOffset / 60);
 215 #endif
 216
 217     if (der) {
 218         if (der != der_end) {
 219             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 220                                 CFSTR("trailing garbage at end of datetime"), 0, error);
 221             return NULL;
 222         }
 223
 224         *at = SecCFGregorianDateGetAbsoluteTime(g, timeZoneOffset, error) + fraction;
 225         if (*at == NULL_TIME)
 226             return NULL;
 227     }
 228
 229     return der;
 230 }
 231
 232 const uint8_t* der_decode_generalizedtime_body(CFAbsoluteTime *at, CFErrorRef *error,
 233                                                const uint8_t* der, const uint8_t *der_end)
 234 {
 235     SInt32 year = 100 * der_decode_decimal_pair(&der, der_end, error) + der_decode_decimal_pair(&der, der_end, error);
 236     return der_decode_commontime_body(at, error, year, der, der_end);
 237 }
 238
 239 const uint8_t* der_decode_universaltime_body(CFAbsoluteTime *at, CFErrorRef *error,
 240                                              const uint8_t* der, const uint8_t *der_end)
 241 {
 242     SInt32 year = der_decode_decimal_pair(&der, der_end, error);
 243     if (year < 50) {
 244         /* 0  <= year <  50 : assume century 21 */
 245         year += 2000;
 246     } else if (year < 70) {
 247         /* 50 <= year <  70 : illegal per PKIX */
 248         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 249                             CFSTR("Invalid universal time year between 50 and 70"), 0, error);
 250         der = NULL;
 251     } else {
 252         /* 70 <  year <= 99 : assume century 20 */
 253         year += 1900;
 254     }
 255
 256     return der_decode_commontime_body(at, error, year, der, der_end);
 257 }
 258
 259 const uint8_t* der_decode_date(CFAllocatorRef allocator, CFOptionFlags mutability,
 260                                CFDateRef* date, CFErrorRef *error,
 261                                const uint8_t* der, const uint8_t *der_end)
 262 {
 263     if (NULL == der)
 264         return NULL;
 265
 266     der = ccder_decode_constructed_tl(CCDER_GENERALIZED_TIME, &der_end, der, der_end);
 267     CFAbsoluteTime at;
 268     der = der_decode_generalizedtime_body(&at, error, der, der_end);
 269     if (der) {
 270         *date = CFDateCreate(allocator, at);
 271         if (NULL == *date) {
 272             SecCFDERCreateError(kSecDERErrorUnderlyingError, CFSTR("Failed to create date"), NULL, error);
 273             return NULL;
 274         }
 275     }
 276     return der;
 277 }
 278
 279 extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
 280 extern void  __freedtoa(char *);
 281
 282 static size_t ccder_sizeof_nanoseconds(CFAbsoluteTime at) {
 283     int dotoff;
 284     int sign;
 285     char *end;
 286     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 287     ptrdiff_t len = end - str;
 288     __freedtoa(str);
 289     return len < dotoff ? 0 : len - dotoff;
 290     //return len < dotoff ? 0 : len - dotoff > 9 ? 9 : len - dotoff;
 291 }
 292
 293 size_t der_sizeof_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error)
 294 {
 295     size_t subsec_digits = ccder_sizeof_nanoseconds(at);
 296
 297     /* Generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 298     return subsec_digits ? 16 + subsec_digits : 15;
 299 }
 300
 301 size_t der_sizeof_generalizedtime(CFAbsoluteTime at, CFErrorRef *error)
 302 {
 303     return ccder_sizeof(CCDER_GENERALIZED_TIME,
 304                         der_sizeof_generalizedtime_body(at, error));
 305 }
 306
 307 size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
 308 {
 309     return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
 310 }
 311
 312
 313 static uint8_t *ccder_encode_byte(uint8_t byte,
 314                                   const uint8_t *der, uint8_t *der_end) {
 315     if (der + 1 > der_end) {
 316         return NULL;
 317     }
 318     *--der_end = byte;
 319     return der_end;
 320 }
 321
 322 static uint8_t *ccder_encode_decimal_pair(int v, const uint8_t *der,
 323                                           uint8_t *der_end) {
 324     if (der + 2 > der_end) {
 325         return NULL;
 326     }
 327     assert(v < 100);
 328     *--der_end = '0' + v % 10;
 329     *--der_end = '0' + v / 10;
 330     return der_end;
 331 }
 332
 333 static uint8_t *ccder_encode_decimal_quad(int v, const uint8_t *der,
 334                                           uint8_t *der_end) {
 335     return ccder_encode_decimal_pair(v / 100, der,
 336            ccder_encode_decimal_pair(v % 100, der, der_end));
 337 }
 338
 339 static uint8_t *ccder_encode_nanoseconds(CFAbsoluteTime at, const uint8_t *der,
 340                                          uint8_t *der_end) {
 341     int dotoff;
 342     int sign;
 343     char *end;
 344     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 345     char *begin = str + (dotoff < 0 ? 0 : dotoff);
 346     // Compute 1.0000000 - fraction in ascii space
 347     if (at < 0.0 && begin < end) {
 348         char *p = end - 1;
 349         // Borrow for last digit
 350         *p = ('9' + 1) - (*p - '0');
 351         while (p-- > begin) {
 352             // Every other digit is a 9 since we borrowed from the last one
 353             *p = '9' - (*p - '0');
 354         }
 355     }
 356
 357     ptrdiff_t len = end - str;
 358     if (len > dotoff) {
 359         if (dotoff < 0) {
 360             assert(-1.0 < at && at < 1.0);
 361             der_end = ccder_encode_body(len, (const uint8_t *)str, der, der_end);
 362             der_end = ccder_encode_body_nocopy(-dotoff, der, der_end);
 363             if (der_end)
 364                 memset(der_end, at < 0.0 ? '9' : '0', -dotoff);
 365         } else {
 366             der_end = ccder_encode_body(len - dotoff, (const uint8_t *)(str + dotoff), der, der_end);
 367         }
 368         der_end = ccder_encode_byte('.', der, der_end);
 369     }
 370     __freedtoa(str);
 371
 372     return der_end;
 373 }
 374
 375 /* Encode generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 376 uint8_t* der_encode_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error,
 377                                          const uint8_t *der, uint8_t *der_end)
 378 {
 379     CFGregorianDate g = SecCFAbsoluteTimeGetGregorianDate(floor(at), 0.0, error);
 380     if (g.year == 0)
 381         return NULL;
 382
 383     return ccder_encode_decimal_quad(g.year, der,
 384            ccder_encode_decimal_pair(g.month, der,
 385            ccder_encode_decimal_pair(g.day, der,
 386            ccder_encode_decimal_pair(g.hour, der,
 387            ccder_encode_decimal_pair(g.minute, der,
 388            ccder_encode_decimal_pair(g.second, der,
 389            ccder_encode_nanoseconds(at, der,
 390            ccder_encode_byte('Z', der, der_end))))))));
 391 }
 392
 393 uint8_t* der_encode_generalizedtime(CFAbsoluteTime at, CFErrorRef *error,
 394                                     const uint8_t *der, uint8_t *der_end)
 395 {
 396     return ccder_encode_constructed_tl(CCDER_GENERALIZED_TIME, der_end, der,
 397            der_encode_generalizedtime_body(at, error, der, der_end));
 398 }
 399
 400
 401 uint8_t* der_encode_date(CFDateRef date, CFErrorRef *error,
 402                          const uint8_t *der, uint8_t *der_end)
 403 {
 404     return der_encode_generalizedtime(CFDateGetAbsoluteTime(date), error,
 405                                       der, der_end);
 406 }