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.  */
39static int mdays[13] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
40
41static 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
66static 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
75static 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
96static 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
108static 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
114static 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
121static 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
162static 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
190static 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
226const 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
233const 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
253const 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
273extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
274extern void  __freedtoa(char *);
275
276static 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
287size_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
295size_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
301size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
302{
303    return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
304}
305
306
307static 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
316static 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
327static 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
333static 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 */
370uint8_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
387uint8_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
395uint8_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}
401