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
21CFAbsoluteTime SecCFGregorianDateGetAbsoluteTime(CFGregorianDate g, CFTimeInterval timeZoneOffset, CFErrorRef *error);
22CFGregorianDate SecCFAbsoluteTimeGetGregorianDate(CFAbsoluteTime at, CFTimeInterval timeZoneOffset, CFErrorRef *error);
23
24/* Cumalitive number of days in the year for months up to month i.  */
25static int mdays[13] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
26
27CFAbsoluteTime 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
65CFGregorianDate 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
79static 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
100static 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
112static 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
118static 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
125static 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
166static 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
194static 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
232const 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
239const 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
259const 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
279extern char *__dtoa(double _d, int mode, int ndigits, int *decpt, int *sign, char **rve);
280extern void  __freedtoa(char *);
281
282static 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
293size_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
301size_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
307size_t der_sizeof_date(CFDateRef date, CFErrorRef *error)
308{
309    return der_sizeof_generalizedtime(CFDateGetAbsoluteTime(date), error);
310}
311
312
313static 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
322static 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
333static 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
339static 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 */
376uint8_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
393uint8_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
401uint8_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}
407