Security/utilities/src/der_date.c

   1 /*
   2  * Copyright (c) 2012-2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24
  25 #include "utilities/SecCFRelease.h"
  26 #include "utilities/SecCFWrappers.h"
  27 #include "utilities/der_date.h"
  28 #include "utilities/der_plist.h"
  29 #include "utilities/der_plist_internal.h"
  30
  31 #include <corecrypto/ccder.h>
  32 #include <CoreFoundation/CoreFoundation.h>
  33 #include <CoreFoundation/CFCalendar.h>
  34 #include <math.h>
  35
  36 #define NULL_TIME NAN
  37
  38 /* Cumulative number of days in the year for months up to month i.  */
  39 static int mdays[13] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
  40
  41 static CFAbsoluteTime SecGregorianDateGetAbsoluteTime(int year, int month, int day, int hour, int minute, int second, CFTimeInterval timeZoneOffset, CFErrorRef *error) {
  42     int is_leap_year = year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) ? 1 : 0;
  43     if (month < 1 || month > 12 || day < 1 || day > 31 || hour >= 24 || minute >= 60 || second >= 60.0
  44         || (month == 2 && day > mdays[month] - mdays[month - 1] + is_leap_year)
  45         || (month != 2 && day > mdays[month] - mdays[month - 1])) {
  46         /* Invalid date. */
  47         SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Invalid date."), 0, error);
  48         return NULL_TIME;
  49     }
  50
  51     int dy = year - 2001;
  52     if (dy < 0) {
  53         dy += 1;
  54         day -= 1;
  55     }
  56
  57     int leap_days = dy / 4 - dy / 100 + dy / 400;
  58     day += ((year - 2001) * 365 + leap_days) + mdays[month - 1] - 1;
  59     if (month > 2)
  60         day += is_leap_year;
  61
  62     CFAbsoluteTime absTime = (CFAbsoluteTime)((day * 24 + hour) * 60 + minute) * 60 + second;
  63         return absTime - timeZoneOffset;
  64 }
  65
  66 static bool SecAbsoluteTimeGetGregorianDate(CFTimeInterval at, int *year, int *month, int *day, int *hour, int *minute, int *second, CFErrorRef *error) {
  67     // TODO: Remove CFCalendarDecomposeAbsoluteTime dependancy because CFTimeZoneCreateWithTimeIntervalFromGMT is expensive and requires filesystem access to timezone files when we are only doing zulu time anyway
  68     if (!CFCalendarDecomposeAbsoluteTime(SecCFCalendarGetZulu(), at, "yMdHms", year, month, day, hour, minute, second)) {
  69         SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Failed to encode date."), 0, error);
  70         return false;
  71     }
  72     return true;
  73 }
  74
  75 static int der_get_char(const uint8_t **der_p, const uint8_t *der_end,
  76                          CFErrorRef *error) {
  77     const uint8_t *der = *der_p;
  78     if (!der) {
  79         /* Don't create a new error in this case. */
  80         return -1;
  81     }
  82
  83     if (der >= der_end) {
  84         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
  85                             CFSTR("Unexpected end of datetime"), 0, error);
  86         *der_p = NULL;
  87         return -1;
  88     }
  89
  90     int ch = *der++;
  91     *der_p = der;
  92     return ch;
  93 }
  94
  95
  96 static int der_decode_decimal(const uint8_t **der_p, const uint8_t *der_end,
  97                              CFErrorRef *error) {
  98     char ch = der_get_char(der_p, der_end, error);
  99     if (ch < '0' || ch > '9') {
 100         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 101                             CFSTR("Not a decimal digit"), 0, error);
 102         *der_p = NULL;
 103         return -1;
 104     }
 105     return ch - '0';
 106 }
 107
 108 static int der_decode_decimal_pair(const uint8_t **der_p, const uint8_t *der_end,
 109                             CFErrorRef *error) {
 110     return (10 * der_decode_decimal(der_p, der_end, error))
 111         + der_decode_decimal(der_p, der_end, error);
 112 }
 113
 114 static int der_peek_byte(const uint8_t *der, const uint8_t *der_end) {
 115     if (!der || der >= der_end)
 116         return -1;
 117
 118     return *der;
 119 }
 120
 121 static const uint8_t *der_decode_decimal_fraction(double *fraction, CFErrorRef *error,
 122                                                   const uint8_t* der, const uint8_t *der_end) {
 123     int ch = der_peek_byte(der, der_end);
 124     if (ch == -1) {
 125         der = NULL;
 126     } else if (ch == '.') {
 127         uint64_t divisor = 1;
 128         uint64_t value = 0;
 129         int last = -1;
 130         while (++der < der_end) {
 131             last = ch;
 132             ch = *der;
 133             if (ch < '0' || ch > '9') {
 134                 break;
 135             }
 136             if (divisor < UINT64_MAX / 10) {
 137                 divisor *= 10;
 138                 value *= 10;
 139                 value += (ch - '0');
 140             }
 141         }
 142         if (der >= der_end)
 143             der = NULL;
 144         else if (last == '0') {
 145             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 146                                 CFSTR("fraction ends in 0"), 0, error);
 147             der = NULL;
 148         } else if (last == '.') {
 149             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 150                                 CFSTR("fraction without digits"), 0, error);
 151             der = NULL;
 152         } else {
 153             *fraction = (double)value / divisor;
 154         }
 155     } else {
 156         *fraction = 0.0;
 157     }
 158
 159     return der;
 160 }
 161
 162 static const CFTimeInterval der_decode_timezone_offset(const uint8_t **der_p,
 163                                                        const uint8_t *der_end,
 164                                                        CFErrorRef *error) {
 165     CFTimeInterval timeZoneOffset;
 166     int ch = der_get_char(der_p, der_end, error);
 167     if (ch == 'Z') {
 168         /* Zulu time. */
 169         timeZoneOffset = 0.0;
 170     } else {
 171                 /* ZONE INDICATOR */
 172         int multiplier;
 173         if (ch == '-')
 174             multiplier = -60;
 175         else if (ch == '+')
 176             multiplier = +60;
 177         else {
 178             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 179                                 CFSTR("Invalid datetime character"), 0, error);
 180             return NULL_TIME;
 181         }
 182
 183         timeZoneOffset = multiplier *
 184             (der_decode_decimal_pair(der_p, der_end, error)
 185              * 60 + der_decode_decimal_pair(der_p, der_end, error));
 186     }
 187     return timeZoneOffset;
 188 }
 189
 190 static const uint8_t* der_decode_commontime_body(CFAbsoluteTime *at, CFErrorRef *error, int year,
 191                                                  const uint8_t* der, const uint8_t *der_end)
 192 {
 193         int month = der_decode_decimal_pair(&der, der_end, error);
 194         int day = der_decode_decimal_pair(&der, der_end, error);
 195         int hour = der_decode_decimal_pair(&der, der_end, error);
 196         int minute = der_decode_decimal_pair(&der, der_end, error);
 197     int second = der_decode_decimal_pair(&der, der_end, error);
 198     double fraction;
 199     der = der_decode_decimal_fraction(&fraction, error, der, der_end);
 200
 201         CFTimeInterval timeZoneOffset = der_decode_timezone_offset(&der, der_end, error);
 202
 203 #if 0
 204     secdebug("dateparse",
 205              "date %.*s year: %04d%02d%02d%02d%02d%02d%+05g",
 206              length, bytes, g.year, g.month,
 207              g.day, g.hour, g.minute, g.second,
 208              timeZoneOffset / 60);
 209 #endif
 210
 211     if (der) {
 212         if (der != der_end) {
 213             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 214                                 CFSTR("trailing garbage at end of datetime"), 0, error);
 215             return NULL;
 216         }
 217
 218         *at = SecGregorianDateGetAbsoluteTime(year, month, day, hour, minute, second, timeZoneOffset, error) + fraction;
 219         if (*at == NULL_TIME)
 220             return NULL;
 221     }
 222
 223     return der;
 224 }
 225
 226 const uint8_t* der_decode_generalizedtime_body(CFAbsoluteTime *at, CFErrorRef *error,
 227                                                const uint8_t* der, const uint8_t *der_end)
 228 {
 229     int year = 100 * der_decode_decimal_pair(&der, der_end, error) + der_decode_decimal_pair(&der, der_end, error);
 230     return der_decode_commontime_body(at, error, year, der, der_end);
 231 }
 232
 233 const uint8_t* der_decode_universaltime_body(CFAbsoluteTime *at, CFErrorRef *error,
 234                                              const uint8_t* der, const uint8_t *der_end)
 235 {
 236     SInt32 year = der_decode_decimal_pair(&der, der_end, error);
 237     if (year < 50) {
 238         /* 0  <= year <  50 : assume century 21 */
 239         year += 2000;
 240     } else if (year < 70) {
 241         /* 50 <= year <  70 : illegal per PKIX */
 242         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 243                             CFSTR("Invalid universal time year between 50 and 70"), 0, error);
 244         der = NULL;
 245     } else {
 246         /* 70 <  year <= 99 : assume century 20 */
 247         year += 1900;
 248     }
 249
 250     return der_decode_commontime_body(at, error, year, der, der_end);
 251 }
 252
 253 const uint8_t* der_decode_date(CFAllocatorRef allocator, CFOptionFlags mutability,
 254                                CFDateRef* date, CFErrorRef *error,
 255                                const uint8_t* der, const uint8_t *der_end)
 256 {
 257     if (NULL == der)
 258         return NULL;
 259
 260     der = ccder_decode_constructed_tl(CCDER_GENERALIZED_TIME, &der_end, der, der_end);
 261     CFAbsoluteTime at = 0;
 262     der = der_decode_generalizedtime_body(&at, error, der, der_end);
 263     if (der) {
 264         *date = CFDateCreate(allocator, at);
 265         if (NULL == *date) {
 266             SecCFDERCreateError(kSecDERErrorAllocationFailure, CFSTR("Failed to create date"), NULL, error);
 267             return NULL;
 268         }
 269     }
 270     return der;
 271 }
 272
 273 extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
 274 extern void  __freedtoa(char *);
 275
 276 static size_t ccder_sizeof_nanoseconds(CFAbsoluteTime at) {
 277     int dotoff;
 278     int sign;
 279     char *end;
 280     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 281     ptrdiff_t len = end - str;
 282     __freedtoa(str);
 283     return len < dotoff ? 0 : len - dotoff;
 284     //return len < dotoff ? 0 : len - dotoff > 9 ? 9 : len - dotoff;
 285 }
 286
 287 size_t der_sizeof_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error)
 288 {
 289     size_t subsec_digits = ccder_sizeof_nanoseconds(at);
 290
 291     /* Generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 292     return subsec_digits ? 16 + subsec_digits : 15;
 293 }
 294
 295 size_t der_sizeof_generalizedtime(CFAbsoluteTime at, CFErrorRef *error)
 296 {
 297     return ccder_sizeof(CCDER_GENERALIZED_TIME,
 298                         der_sizeof_generalizedtime_body(at, error));
 299 }
 300
 301 size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
 302 {
 303     return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
 304 }
 305
 306
 307 static uint8_t *ccder_encode_byte(uint8_t byte,
 308                                   const uint8_t *der, uint8_t *der_end) {
 309     if (der + 1 > der_end) {
 310         return NULL;
 311     }
 312     *--der_end = byte;
 313     return der_end;
 314 }
 315
 316 static uint8_t *ccder_encode_decimal_pair(int v, const uint8_t *der,
 317                                           uint8_t *der_end) {
 318     if (der_end == NULL || der + 2 > der_end) {
 319         return NULL;
 320     }
 321     assert(v < 100);
 322     *--der_end = '0' + v % 10;
 323     *--der_end = '0' + v / 10;
 324     return der_end;
 325 }
 326
 327 static uint8_t *ccder_encode_decimal_quad(int v, const uint8_t *der,
 328                                           uint8_t *der_end) {
 329     return ccder_encode_decimal_pair(v / 100, der,
 330            ccder_encode_decimal_pair(v % 100, der, der_end));
 331 }
 332
 333 static uint8_t *ccder_encode_nanoseconds(CFAbsoluteTime at, const uint8_t *der,
 334                                          uint8_t *der_end) {
 335     int dotoff;
 336     int sign;
 337     char *end;
 338     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 339     char *begin = str + (dotoff < 0 ? 0 : dotoff);
 340     // Compute 1.0000000 - fraction in ascii space
 341     if (at < 0.0 && begin < end) {
 342         char *p = end - 1;
 343         // Borrow for last digit
 344         *p = ('9' + 1) - (*p - '0');
 345         while (p-- > begin) {
 346             // Every other digit is a 9 since we borrowed from the last one
 347             *p = '9' - (*p - '0');
 348         }
 349     }
 350
 351     ptrdiff_t len = end - str;
 352     if (len > dotoff) {
 353         if (dotoff < 0) {
 354             assert(-1.0 < at && at < 1.0);
 355             der_end = ccder_encode_body(len, (const uint8_t *)str, der, der_end);
 356             der_end = ccder_encode_body_nocopy(-dotoff, der, der_end);
 357             if (der_end)
 358                 memset(der_end, at < 0.0 ? '9' : '0', -dotoff);
 359         } else {
 360             der_end = ccder_encode_body(len - dotoff, (const uint8_t *)(str + dotoff), der, der_end);
 361         }
 362         der_end = ccder_encode_byte('.', der, der_end);
 363     }
 364     __freedtoa(str);
 365
 366     return der_end;
 367 }
 368
 369 /* Encode generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 370 uint8_t* der_encode_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error,
 371                                          const uint8_t *der, uint8_t *der_end)
 372 {
 373     int year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0;
 374     if (!SecAbsoluteTimeGetGregorianDate(at, &year, &month, &day, &hour, &minute, &second, error))
 375         return NULL;
 376
 377     return ccder_encode_decimal_quad(year, der,
 378            ccder_encode_decimal_pair(month, der,
 379            ccder_encode_decimal_pair(day, der,
 380            ccder_encode_decimal_pair(hour, der,
 381            ccder_encode_decimal_pair(minute, der,
 382            ccder_encode_decimal_pair(second, der,
 383            ccder_encode_nanoseconds(at, der,
 384            ccder_encode_byte('Z', der, der_end))))))));
 385 }
 386
 387 uint8_t* der_encode_generalizedtime(CFAbsoluteTime at, CFErrorRef *error,
 388                                     const uint8_t *der, uint8_t *der_end)
 389 {
 390     return ccder_encode_constructed_tl(CCDER_GENERALIZED_TIME, der_end, der,
 391            der_encode_generalizedtime_body(at, error, der, der_end));
 392 }
 393
 394
 395 uint8_t* der_encode_date(CFDateRef date, CFErrorRef *error,
 396                          const uint8_t *der, uint8_t *der_end)
 397 {
 398     return der_encode_generalizedtime(CFDateGetAbsoluteTime(date), error,
 399                                       der, der_end);
 400 }