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 #define IS_NULL_TIME(x) isnan(x)
  38
  39 /* Cumulative number of days in the year for months up to month i.  */
  40 static int mdays[13] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
  41
  42 static CFAbsoluteTime SecGregorianDateGetAbsoluteTime(int year, int month, int day, int hour, int minute, int second, CFTimeInterval timeZoneOffset, CFErrorRef *error) {
  43     int is_leap_year = year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) ? 1 : 0;
  44     if (month < 1 || month > 12 || day < 1 || day > 31 || hour >= 24 || minute >= 60 || second >= 60.0
  45         || (month == 2 && day > mdays[month] - mdays[month - 1] + is_leap_year)
  46         || (month != 2 && day > mdays[month] - mdays[month - 1])) {
  47         /* Invalid date. */
  48         SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Invalid date."), 0, error);
  49         return NULL_TIME;
  50     }
  51
  52     int dy = year - 2001;
  53     if (dy < 0) {
  54         dy += 1;
  55         day -= 1;
  56     }
  57
  58     int leap_days = dy / 4 - dy / 100 + dy / 400;
  59     day += ((year - 2001) * 365 + leap_days) + mdays[month - 1] - 1;
  60     if (month > 2)
  61         day += is_leap_year;
  62
  63     CFAbsoluteTime absTime = (CFAbsoluteTime)((day * 24 + hour) * 60 + minute) * 60 + second;
  64         return absTime - timeZoneOffset;
  65 }
  66
  67 static bool SecAbsoluteTimeGetGregorianDate(CFTimeInterval at, int *year, int *month, int *day, int *hour, int *minute, int *second, CFErrorRef *error) {
  68     // TODO: Remove CFCalendarDecomposeAbsoluteTime dependancy because
  69     // CFTimeZoneCreateWithTimeIntervalFromGMT is expensive and requires
  70     // filesystem access to timezone files when we are only doing zulu time anyway
  71     __block bool result;
  72     SecCFCalendarDoWithZuluCalendar(^(CFCalendarRef zuluCalendar) {
  73         result = CFCalendarDecomposeAbsoluteTime(zuluCalendar, at, "yMdHms", year, month, day, hour, minute, second);
  74     });
  75     if (!result)
  76         SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Failed to encode date."), 0, error);
  77     return result;
  78 }
  79
  80 static int der_get_char(const uint8_t **der_p, const uint8_t *der_end,
  81                          CFErrorRef *error) {
  82     const uint8_t *der = *der_p;
  83     if (!der) {
  84         /* Don't create a new error in this case. */
  85         return -1;
  86     }
  87
  88     if (der >= der_end) {
  89         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
  90                             CFSTR("Unexpected end of datetime"), 0, error);
  91         *der_p = NULL;
  92         return -1;
  93     }
  94
  95     int ch = *der++;
  96     *der_p = der;
  97     return ch;
  98 }
  99
 100
 101 static int der_decode_decimal(const uint8_t **der_p, const uint8_t *der_end,
 102                              CFErrorRef *error) {
 103     char ch = der_get_char(der_p, der_end, error);
 104     if (ch < '0' || ch > '9') {
 105         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 106                             CFSTR("Not a decimal digit"), 0, error);
 107         *der_p = NULL;
 108         return -1;
 109     }
 110     return ch - '0';
 111 }
 112
 113 static int der_decode_decimal_pair(const uint8_t **der_p, const uint8_t *der_end,
 114                             CFErrorRef *error) {
 115     return (10 * der_decode_decimal(der_p, der_end, error))
 116         + der_decode_decimal(der_p, der_end, error);
 117 }
 118
 119 static int der_peek_byte(const uint8_t *der, const uint8_t *der_end) {
 120     if (!der || der >= der_end)
 121         return -1;
 122
 123     return *der;
 124 }
 125
 126 static const uint8_t *der_decode_decimal_fraction(double *fraction, CFErrorRef *error,
 127                                                   const uint8_t* der, const uint8_t *der_end) {
 128     int ch = der_peek_byte(der, der_end);
 129     if (ch == -1) {
 130         der = NULL;
 131     } else if (ch == '.') {
 132         uint64_t divisor = 1;
 133         uint64_t value = 0;
 134         int last = -1;
 135         while (++der < der_end) {
 136             last = ch;
 137             ch = *der;
 138             if (ch < '0' || ch > '9') {
 139                 break;
 140             }
 141             if (divisor < UINT64_MAX / 10) {
 142                 divisor *= 10;
 143                 value *= 10;
 144                 value += (ch - '0');
 145             }
 146         }
 147         if (der >= der_end)
 148             der = NULL;
 149         else if (last == '0') {
 150             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 151                                 CFSTR("fraction ends in 0"), 0, error);
 152             der = NULL;
 153         } else if (last == '.') {
 154             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 155                                 CFSTR("fraction without digits"), 0, error);
 156             der = NULL;
 157         } else {
 158             *fraction = (double)value / divisor;
 159         }
 160     } else {
 161         *fraction = 0.0;
 162     }
 163
 164     return der;
 165 }
 166
 167 static const CFTimeInterval der_decode_timezone_offset(const uint8_t **der_p,
 168                                                        const uint8_t *der_end,
 169                                                        CFErrorRef *error) {
 170     CFTimeInterval timeZoneOffset;
 171     int ch = der_get_char(der_p, der_end, error);
 172     if (ch == 'Z') {
 173         /* Zulu time. */
 174         timeZoneOffset = 0.0;
 175     } else {
 176                 /* ZONE INDICATOR */
 177         int multiplier;
 178         if (ch == '-')
 179             multiplier = -60;
 180         else if (ch == '+')
 181             multiplier = +60;
 182         else {
 183             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 184                                 CFSTR("Invalid datetime character"), 0, error);
 185             return NULL_TIME;
 186         }
 187
 188         timeZoneOffset = multiplier *
 189             (der_decode_decimal_pair(der_p, der_end, error)
 190              * 60 + der_decode_decimal_pair(der_p, der_end, error));
 191     }
 192     return timeZoneOffset;
 193 }
 194
 195 static const uint8_t* der_decode_commontime_body(CFAbsoluteTime *at, CFErrorRef *error, int year,
 196                                                  const uint8_t* der, const uint8_t *der_end)
 197 {
 198         int month = der_decode_decimal_pair(&der, der_end, error);
 199         int day = der_decode_decimal_pair(&der, der_end, error);
 200         int hour = der_decode_decimal_pair(&der, der_end, error);
 201         int minute = der_decode_decimal_pair(&der, der_end, error);
 202     int second = der_decode_decimal_pair(&der, der_end, error);
 203     double fraction;
 204     der = der_decode_decimal_fraction(&fraction, error, der, der_end);
 205
 206         CFTimeInterval timeZoneOffset = der_decode_timezone_offset(&der, der_end, error);
 207
 208 #if 0
 209     secdebug("dateparse",
 210              "date %.*s year: %04d%02d%02d%02d%02d%02d%+05g",
 211              length, bytes, g.year, g.month,
 212              g.day, g.hour, g.minute, g.second,
 213              timeZoneOffset / 60);
 214 #endif
 215
 216     if (der) {
 217         if (der != der_end) {
 218             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 219                                 CFSTR("trailing garbage at end of datetime"), 0, error);
 220             return NULL;
 221         }
 222
 223         *at = SecGregorianDateGetAbsoluteTime(year, month, day, hour, minute, second, timeZoneOffset, error);
 224         if (IS_NULL_TIME(*at))
 225             return NULL;
 226
 227         *at += fraction;
 228     }
 229
 230     return der;
 231 }
 232
 233 const uint8_t* der_decode_generalizedtime_body(CFAbsoluteTime *at, CFErrorRef *error,
 234                                                const uint8_t* der, const uint8_t *der_end)
 235 {
 236     int year = 100 * der_decode_decimal_pair(&der, der_end, error) + der_decode_decimal_pair(&der, der_end, error);
 237     return der_decode_commontime_body(at, error, year, der, der_end);
 238 }
 239
 240 const uint8_t* der_decode_universaltime_body(CFAbsoluteTime *at, CFErrorRef *error,
 241                                              const uint8_t* der, const uint8_t *der_end)
 242 {
 243     SInt32 year = der_decode_decimal_pair(&der, der_end, error);
 244     if (year < 50) {
 245         /* 0  <= year <  50 : assume century 21 */
 246         year += 2000;
 247     } else if (year < 70) {
 248         /* 50 <= year <  70 : illegal per PKIX */
 249         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 250                             CFSTR("Invalid universal time year between 50 and 70"), 0, error);
 251         der = NULL;
 252     } else {
 253         /* 70 <  year <= 99 : assume century 20 */
 254         year += 1900;
 255     }
 256
 257     return der_decode_commontime_body(at, error, year, der, der_end);
 258 }
 259
 260 const uint8_t* der_decode_date(CFAllocatorRef allocator, CFOptionFlags mutability,
 261                                CFDateRef* date, CFErrorRef *error,
 262                                const uint8_t* der, const uint8_t *der_end)
 263 {
 264     if (NULL == der)
 265         return NULL;
 266
 267     der = ccder_decode_constructed_tl(CCDER_GENERALIZED_TIME, &der_end, der, der_end);
 268     CFAbsoluteTime at = 0;
 269     der = der_decode_generalizedtime_body(&at, error, der, der_end);
 270     if (der) {
 271         *date = CFDateCreate(allocator, at);
 272         if (NULL == *date) {
 273             SecCFDERCreateError(kSecDERErrorAllocationFailure, CFSTR("Failed to create date"), NULL, error);
 274             return NULL;
 275         }
 276     }
 277     return der;
 278 }
 279
 280 extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
 281 extern void  __freedtoa(char *);
 282
 283 static size_t ccder_sizeof_nanoseconds(CFAbsoluteTime at) {
 284     int dotoff;
 285     int sign;
 286     char *end;
 287     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 288     ptrdiff_t len = end - str;
 289     __freedtoa(str);
 290     return len < dotoff ? 0 : len - dotoff;
 291     //return len < dotoff ? 0 : len - dotoff > 9 ? 9 : len - dotoff;
 292 }
 293
 294 size_t der_sizeof_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error)
 295 {
 296     size_t subsec_digits = ccder_sizeof_nanoseconds(at);
 297
 298     /* Generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 299     return subsec_digits ? 16 + subsec_digits : 15;
 300 }
 301
 302 size_t der_sizeof_generalizedtime(CFAbsoluteTime at, CFErrorRef *error)
 303 {
 304     return ccder_sizeof(CCDER_GENERALIZED_TIME,
 305                         der_sizeof_generalizedtime_body(at, error));
 306 }
 307
 308 size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
 309 {
 310     return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
 311 }
 312
 313
 314 static uint8_t *ccder_encode_byte(uint8_t byte,
 315                                   const uint8_t *der, uint8_t *der_end) {
 316     if (der + 1 > der_end) {
 317         return NULL;
 318     }
 319     *--der_end = byte;
 320     return der_end;
 321 }
 322
 323 static uint8_t *ccder_encode_decimal_pair(int v, const uint8_t *der,
 324                                           uint8_t *der_end) {
 325     if (der_end == NULL || der + 2 > der_end) {
 326         return NULL;
 327     }
 328     assert(v < 100);
 329     *--der_end = '0' + v % 10;
 330     *--der_end = '0' + v / 10;
 331     return der_end;
 332 }
 333
 334 static uint8_t *ccder_encode_decimal_quad(int v, const uint8_t *der,
 335                                           uint8_t *der_end) {
 336     return ccder_encode_decimal_pair(v / 100, der,
 337            ccder_encode_decimal_pair(v % 100, der, der_end));
 338 }
 339
 340 static uint8_t *ccder_encode_nanoseconds(CFAbsoluteTime at, const uint8_t *der,
 341                                          uint8_t *der_end) {
 342     int dotoff;
 343     int sign;
 344     char *end;
 345     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 346     char *begin = str + (dotoff < 0 ? 0 : dotoff);
 347     // Compute 1.0000000 - fraction in ascii space
 348     if (at < 0.0 && begin < end) {
 349         char *p = end - 1;
 350         // Borrow for last digit
 351         *p = ('9' + 1) - (*p - '0');
 352         while (p-- > begin) {
 353             // Every other digit is a 9 since we borrowed from the last one
 354             *p = '9' - (*p - '0');
 355         }
 356     }
 357
 358     ptrdiff_t len = end - str;
 359     if (len > dotoff) {
 360         if (dotoff < 0) {
 361             assert(-1.0 < at && at < 1.0);
 362             der_end = ccder_encode_body(len, (const uint8_t *)str, der, der_end);
 363             der_end = ccder_encode_body_nocopy(-dotoff, der, der_end);
 364             if (der_end)
 365                 memset(der_end, at < 0.0 ? '9' : '0', -dotoff);
 366         } else {
 367             der_end = ccder_encode_body(len - dotoff, (const uint8_t *)(str + dotoff), der, der_end);
 368         }
 369         der_end = ccder_encode_byte('.', der, der_end);
 370     }
 371     __freedtoa(str);
 372
 373     return der_end;
 374 }
 375
 376 /* Encode generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 377 uint8_t* der_encode_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error,
 378                                          const uint8_t *der, uint8_t *der_end)
 379 {
 380     int year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0;
 381     if (!SecAbsoluteTimeGetGregorianDate(at, &year, &month, &day, &hour, &minute, &second, error))
 382         return NULL;
 383
 384     uint8_t * result = ccder_encode_decimal_quad(year, der,
 385            ccder_encode_decimal_pair(month, der,
 386            ccder_encode_decimal_pair(day, der,
 387            ccder_encode_decimal_pair(hour, der,
 388            ccder_encode_decimal_pair(minute, der,
 389            ccder_encode_decimal_pair(second, der,
 390            ccder_encode_nanoseconds(at, der,
 391            ccder_encode_byte('Z', der, der_end))))))));
 392
 393     return result;
 394 }
 395
 396 uint8_t* der_encode_generalizedtime(CFAbsoluteTime at, CFErrorRef *error,
 397                                     const uint8_t *der, uint8_t *der_end)
 398 {
 399     return ccder_encode_constructed_tl(CCDER_GENERALIZED_TIME, der_end, der,
 400            der_encode_generalizedtime_body(at, error, der, der_end));
 401 }
 402
 403
 404 uint8_t* der_encode_date(CFDateRef date, CFErrorRef *error,
 405                          const uint8_t *der, uint8_t *der_end)
 406 {
 407     return der_encode_generalizedtime(CFDateGetAbsoluteTime(date), error,
 408                                       der, der_end);
 409 }