OSX/utilities/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 bool validateDateComponents(int year, int month, int day, int hour, int minute, int second, int *is_leap_year, CFErrorRef* error)
  43 {
  44     int leapyear = year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) ? 1 : 0;
  45     if (is_leap_year) {
  46         *is_leap_year = leapyear;
  47     }
  48     if (month < 1 || month > 12 || day < 1 || day > 31 || hour >= 24 || minute >= 60 || second > 61
  49         || (month == 2 && day > mdays[month] - mdays[month - 1] + leapyear)
  50         || (month != 2 && day > mdays[month] - mdays[month - 1]))
  51     {
  52         SecError(kSecDERErrorUnknownEncoding, error, CFSTR("Invalid date: %i, %i, %i, %i, %i, %i, %i"), year, month, day, hour, minute, second, leapyear);
  53         return false;
  54     }
  55
  56     return true;
  57 }
  58
  59 static CFAbsoluteTime SecGregorianDateGetAbsoluteTime(int year, int month, int day, int hour, int minute, int second, CFTimeInterval timeZoneOffset, CFErrorRef *error) {
  60     int is_leap_year = 0;
  61     if (!validateDateComponents(year, month, day, hour, minute, second, &is_leap_year, error)) {
  62         return NULL_TIME;
  63     }
  64
  65     int dy = year - 2001;
  66     if (dy < 0) {
  67         dy += 1;
  68         day -= 1;
  69     }
  70
  71     int leap_days = dy / 4 - dy / 100 + dy / 400;
  72     day += ((year - 2001) * 365 + leap_days) + mdays[month - 1] - 1;
  73     if (month > 2)
  74         day += is_leap_year;
  75
  76     CFAbsoluteTime absTime = (CFAbsoluteTime)((day * 24 + hour) * 60 + minute) * 60 + second;
  77         return absTime - timeZoneOffset;
  78 }
  79
  80 static bool SecAbsoluteTimeGetGregorianDate(CFTimeInterval at, int *year, int *month, int *day, int *hour, int *minute, int *second, CFErrorRef *error) {
  81     // TODO: Remove CFCalendarDecomposeAbsoluteTime dependancy because
  82     // CFTimeZoneCreateWithTimeIntervalFromGMT is expensive and requires
  83     // filesystem access to timezone files when we are only doing zulu time anyway
  84     __block bool result;
  85     SecCFCalendarDoWithZuluCalendar(^(CFCalendarRef zuluCalendar) {
  86         result = CFCalendarDecomposeAbsoluteTime(zuluCalendar, at, "yMdHms", year, month, day, hour, minute, second);
  87     });
  88     if (!result) {
  89         SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Failed to encode date."), 0, error);
  90     }
  91
  92     return result;
  93 }
  94
  95 static int der_get_char(const uint8_t **der_p, const uint8_t *der_end,
  96                          CFErrorRef *error) {
  97     const uint8_t *der = *der_p;
  98     if (!der) {
  99         /* Don't create a new error in this case. */
 100         return -1;
 101     }
 102
 103     if (der >= der_end) {
 104         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 105                             CFSTR("Unexpected end of datetime"), 0, error);
 106         *der_p = NULL;
 107         return -1;
 108     }
 109
 110     int ch = *der++;
 111     *der_p = der;
 112     return ch;
 113 }
 114
 115
 116 static int der_decode_decimal(const uint8_t **der_p, const uint8_t *der_end,
 117                              CFErrorRef *error) {
 118     char ch = der_get_char(der_p, der_end, error);
 119     if (ch < '0' || ch > '9') {
 120         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 121                             CFSTR("Not a decimal digit"), 0, error);
 122         *der_p = NULL;
 123         return -1;
 124     }
 125     return ch - '0';
 126 }
 127
 128 static int der_decode_decimal_pair(const uint8_t **der_p, const uint8_t *der_end,
 129                             CFErrorRef *error) {
 130     return (10 * der_decode_decimal(der_p, der_end, error))
 131         + der_decode_decimal(der_p, der_end, error);
 132 }
 133
 134 static int der_peek_byte(const uint8_t *der, const uint8_t *der_end) {
 135     if (!der || der >= der_end)
 136         return -1;
 137
 138     return *der;
 139 }
 140
 141 static const uint8_t *der_decode_decimal_fraction(double *fraction, CFErrorRef *error,
 142                                                   const uint8_t* der, const uint8_t *der_end) {
 143     int ch = der_peek_byte(der, der_end);
 144     if (ch == -1) {
 145         der = NULL;
 146     } else if (ch == '.') {
 147         uint64_t divisor = 1;
 148         uint64_t value = 0;
 149         int last = -1;
 150         while (++der < der_end) {
 151             last = ch;
 152             ch = *der;
 153             if (ch < '0' || ch > '9') {
 154                 break;
 155             }
 156             if (divisor < UINT64_MAX / 10) {
 157                 divisor *= 10;
 158                 value *= 10;
 159                 value += (ch - '0');
 160             }
 161         }
 162         if (der >= der_end) {
 163             SecCFDERCreateError(kSecDERErrorOverflow,
 164                                 CFSTR("overflow"), 0, error);
 165             der = NULL;
 166         } else if (last == '0') {
 167             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 168                                 CFSTR("fraction ends in 0"), 0, error);
 169             der = NULL;
 170         } else if (last == '.') {
 171             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 172                                 CFSTR("fraction without digits"), 0, error);
 173             der = NULL;
 174         } else {
 175             *fraction = (double)value / divisor;
 176         }
 177     } else {
 178         *fraction = 0.0;
 179     }
 180
 181     return der;
 182 }
 183
 184 static CFTimeInterval der_decode_timezone_offset(const uint8_t **der_p,
 185                                                        const uint8_t *der_end,
 186                                                        CFErrorRef *error) {
 187     CFTimeInterval timeZoneOffset;
 188     int ch = der_get_char(der_p, der_end, error);
 189     if (ch == 'Z') {
 190         /* Zulu time. */
 191         timeZoneOffset = 0.0;
 192     } else {
 193                 /* ZONE INDICATOR */
 194         int multiplier;
 195         if (ch == '-')
 196             multiplier = -60;
 197         else if (ch == '+')
 198             multiplier = +60;
 199         else {
 200             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 201                                 CFSTR("Invalid datetime character"), 0, error);
 202             return NULL_TIME;
 203         }
 204
 205         timeZoneOffset = multiplier *
 206             (der_decode_decimal_pair(der_p, der_end, error)
 207              * 60 + der_decode_decimal_pair(der_p, der_end, error));
 208     }
 209     return timeZoneOffset;
 210 }
 211
 212 static const uint8_t* der_decode_commontime_body(CFAbsoluteTime *at, CFErrorRef *error, int year,
 213                                                  const uint8_t* der, const uint8_t *der_end)
 214 {
 215         int month = der_decode_decimal_pair(&der, der_end, error);
 216         int day = der_decode_decimal_pair(&der, der_end, error);
 217         int hour = der_decode_decimal_pair(&der, der_end, error);
 218         int minute = der_decode_decimal_pair(&der, der_end, error);
 219     int second = der_decode_decimal_pair(&der, der_end, error);
 220     double fraction;
 221     der = der_decode_decimal_fraction(&fraction, error, der, der_end);
 222
 223         CFTimeInterval timeZoneOffset = der_decode_timezone_offset(&der, der_end, error);
 224
 225     if (der) {
 226         if (der != der_end) {
 227             SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 228                                 CFSTR("trailing garbage at end of datetime"), 0, error);
 229             return NULL;
 230         }
 231
 232         *at = SecGregorianDateGetAbsoluteTime(year, month, day, hour, minute, second, timeZoneOffset, error);
 233         if (IS_NULL_TIME(*at))
 234             return NULL;
 235
 236         *at += fraction;
 237     }
 238
 239     return der;
 240 }
 241
 242 const uint8_t* der_decode_generalizedtime_body(CFAbsoluteTime *at, CFErrorRef *error,
 243                                                const uint8_t* der, const uint8_t *der_end)
 244 {
 245     int year = 100 * der_decode_decimal_pair(&der, der_end, error) + der_decode_decimal_pair(&der, der_end, error);
 246     return der_decode_commontime_body(at, error, year, der, der_end);
 247 }
 248
 249 const uint8_t* der_decode_universaltime_body(CFAbsoluteTime *at, CFErrorRef *error,
 250                                              const uint8_t* der, const uint8_t *der_end)
 251 {
 252     SInt32 year = der_decode_decimal_pair(&der, der_end, error);
 253     if (year < 50) {
 254         /* 0  <= year <  50 : assume century 21 */
 255         year += 2000;
 256     } else if (year < 70) {
 257         /* 50 <= year <  70 : illegal per PKIX */
 258         SecCFDERCreateError(kSecDERErrorUnknownEncoding,
 259                             CFSTR("Invalid universal time year between 50 and 70"), 0, error);
 260         der = NULL;
 261     } else {
 262         /* 70 <  year <= 99 : assume century 20 */
 263         year += 1900;
 264     }
 265
 266     return der_decode_commontime_body(at, error, year, der, der_end);
 267 }
 268
 269 const uint8_t* der_decode_date(CFAllocatorRef allocator,
 270                                CFDateRef* date, CFErrorRef *error,
 271                                const uint8_t* der, const uint8_t *der_end)
 272 {
 273     if (NULL == der) {
 274         SecCFDERCreateError(kSecDERErrorNullInput, CFSTR("null input"), NULL, error);
 275         return NULL;
 276     }
 277
 278     der = ccder_decode_constructed_tl(CCDER_GENERALIZED_TIME, &der_end, der, der_end);
 279     CFAbsoluteTime at = 0;
 280     der = der_decode_generalizedtime_body(&at, error, der, der_end);
 281     if (der) {
 282         *date = CFDateCreate(allocator, at);
 283         if (NULL == *date) {
 284             SecCFDERCreateError(kSecDERErrorAllocationFailure, CFSTR("Failed to create date"), NULL, error);
 285             return NULL;
 286         }
 287     }
 288     return der;
 289 }
 290
 291 extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
 292 extern void  __freedtoa(char *);
 293
 294 static size_t ccder_sizeof_nanoseconds(CFAbsoluteTime at) {
 295     int dotoff;
 296     int sign;
 297     char *end;
 298     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 299     ptrdiff_t len = end - str;
 300     __freedtoa(str);
 301     return len < dotoff ? 0 : len - dotoff;
 302     //return len < dotoff ? 0 : len - dotoff > 9 ? 9 : len - dotoff;
 303 }
 304
 305 size_t der_sizeof_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error)
 306 {
 307     size_t subsec_digits = ccder_sizeof_nanoseconds(at);
 308
 309     /* Generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 310     return subsec_digits ? 16 + subsec_digits : 15;
 311 }
 312
 313 size_t der_sizeof_generalizedtime(CFAbsoluteTime at, CFErrorRef *error)
 314 {
 315     return ccder_sizeof(CCDER_GENERALIZED_TIME,
 316                         der_sizeof_generalizedtime_body(at, error));
 317 }
 318
 319 size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
 320 {
 321     return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
 322 }
 323
 324
 325 static uint8_t *ccder_encode_byte(uint8_t byte,
 326                                   const uint8_t *der, uint8_t *der_end) {
 327     if (der + 1 > der_end) {
 328         return NULL;
 329     }
 330     *--der_end = byte;
 331     return der_end;
 332 }
 333
 334 static uint8_t *ccder_encode_decimal_pair(int v, const uint8_t *der,
 335                                           uint8_t *der_end) {
 336     if (der_end == NULL || der + 2 > der_end) {
 337         return NULL;
 338     }
 339     assert(v < 100);
 340     *--der_end = '0' + v % 10;
 341     *--der_end = '0' + v / 10;
 342     return der_end;
 343 }
 344
 345 static uint8_t *ccder_encode_decimal_quad(int v, const uint8_t *der,
 346                                           uint8_t *der_end) {
 347     return ccder_encode_decimal_pair(v / 100, der,
 348            ccder_encode_decimal_pair(v % 100, der, der_end));
 349 }
 350
 351 static uint8_t *ccder_encode_nanoseconds(CFAbsoluteTime at, const uint8_t *der,
 352                                          uint8_t *der_end) {
 353     int dotoff;
 354     int sign;
 355     char *end;
 356     char *str = __dtoa(at, 0, 0, &dotoff, &sign, &end);
 357     char *begin = str + (dotoff < 0 ? 0 : dotoff);
 358     // Compute 1.0000000 - fraction in ascii space
 359     if (at < 0.0 && begin < end) {
 360         char *p = end - 1;
 361         // Borrow for last digit
 362         *p = ('9' + 1) - (*p - '0');
 363         while (p-- > begin) {
 364             // Every other digit is a 9 since we borrowed from the last one
 365             *p = '9' - (*p - '0');
 366         }
 367     }
 368
 369     ptrdiff_t len = end - str;
 370     if (len > dotoff) {
 371         if (dotoff < 0) {
 372             assert(-1.0 < at && at < 1.0);
 373             der_end = ccder_encode_body(len, (const uint8_t *)str, der, der_end);
 374             der_end = ccder_encode_body_nocopy(-dotoff, der, der_end);
 375             if (der_end)
 376                 memset(der_end, at < 0.0 ? '9' : '0', -dotoff);
 377         } else {
 378             der_end = ccder_encode_body(len - dotoff, (const uint8_t *)(str + dotoff), der, der_end);
 379         }
 380         der_end = ccder_encode_byte('.', der, der_end);
 381     }
 382     __freedtoa(str);
 383
 384     return der_end;
 385 }
 386
 387 uint8_t* der_encode_generalizedtime_body(CFAbsoluteTime at, CFErrorRef *error,
 388                                          const uint8_t *der, uint8_t *der_end)
 389 {
 390     return der_encode_generalizedtime_body_repair(at, error, false, der, der_end);
 391 }
 392
 393 /* Encode generalized zulu time YYYYMMDDhhmmss[.ssss]Z */
 394 uint8_t* der_encode_generalizedtime_body_repair(CFAbsoluteTime at, CFErrorRef *error, bool repair,
 395                                          const uint8_t *der, uint8_t *der_end)
 396 {
 397     int year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0;
 398     if (!SecAbsoluteTimeGetGregorianDate(at, &year, &month, &day, &hour, &minute, &second, error)) {
 399         secerror("der: unable to encode date: %@", error ? *error : NULL);
 400         return NULL;
 401     }
 402
 403     // Without repair flag, do not let validation change result so we do not change existing behavior
 404     CFErrorRef localError = NULL;
 405     if (!validateDateComponents(year, month, day, hour, minute, second, 0, &localError)) {
 406         CFStringRef desc = CFErrorCopyDescription(localError);
 407         __security_simulatecrash(desc, __sec_exception_code_CorruptItem);
 408         CFReleaseNull(desc);
 409         secerror("der: invalid date: %@; %s", localError, repair ? "setting default value" : "continuing");
 410         CFReleaseNull(localError);
 411         if (repair) {
 412             year = 2001;
 413             month = 1;
 414             day = 1;
 415             // I don't think this is required but I don't want any funny business with exactly midnight in any timezone
 416             minute = 1;
 417         }
 418     }
 419
 420     uint8_t * result = ccder_encode_decimal_quad(year, der,
 421            ccder_encode_decimal_pair(month, der,
 422            ccder_encode_decimal_pair(day, der,
 423            ccder_encode_decimal_pair(hour, der,
 424            ccder_encode_decimal_pair(minute, der,
 425            ccder_encode_decimal_pair(second, der,
 426            ccder_encode_nanoseconds(at, der,    // Uses original "at" even after repair because DER length calculations depend on its exact value
 427            ccder_encode_byte('Z', der, der_end))))))));
 428
 429     return SecCCDEREncodeHandleResult(result, error);
 430 }
 431
 432 uint8_t* der_encode_generalizedtime(CFAbsoluteTime at, CFErrorRef *error,
 433                                     const uint8_t *der, uint8_t *der_end)
 434 {
 435     return SecCCDEREncodeHandleResult(ccder_encode_constructed_tl(CCDER_GENERALIZED_TIME, der_end, der,
 436                                                                   der_encode_generalizedtime_body(at, error, der, der_end)),
 437                                       error);
 438 }
 439
 440
 441 uint8_t* der_encode_date(CFDateRef date, CFErrorRef *error,
 442                          const uint8_t *der, uint8_t *der_end)
 443 {
 444     return der_encode_generalizedtime(CFDateGetAbsoluteTime(date), error,
 445                                       der, der_end);
 446 }
 447
 448 uint8_t* der_encode_date_repair(CFDateRef date, CFErrorRef *error,
 449                                 bool repair, const uint8_t *der, uint8_t *der_end)
 450 {
 451     return SecCCDEREncodeHandleResult(ccder_encode_constructed_tl(CCDER_GENERALIZED_TIME, der_end, der,
 452                                                                   der_encode_generalizedtime_body_repair(CFDateGetAbsoluteTime(date), error, repair, der, der_end)),
 453                                       error);
 454 }