1 /*
2  * parseutil.c - parse utilities for string and wire conversion
3  *
4  * (c) NLnet Labs, 2004-2006
5  *
6  * See the file LICENSE for the license
7  */
8 /**
9  * \file
10  *
11  * Utility functions for parsing, base32(DNS variant) and base64 encoding
12  * and decoding, Hex, Time units, Escape codes.
13  */
14 
15 #include "config.h"
16 #include "sldns/parseutil.h"
17 #include <sys/time.h>
18 #include <time.h>
19 #include <ctype.h>
20 
21 sldns_lookup_table *
sldns_lookup_by_name(sldns_lookup_table * table,const char * name)22 sldns_lookup_by_name(sldns_lookup_table *table, const char *name)
23 {
24         while (table->name != NULL) {
25                 if (strcasecmp(name, table->name) == 0)
26                         return table;
27                 table++;
28         }
29         return NULL;
30 }
31 
32 sldns_lookup_table *
sldns_lookup_by_id(sldns_lookup_table * table,int id)33 sldns_lookup_by_id(sldns_lookup_table *table, int id)
34 {
35         while (table->name != NULL) {
36                 if (table->id == id)
37                         return table;
38                 table++;
39         }
40         return NULL;
41 }
42 
43 /* Number of days per month (except for February in leap years). */
44 static const int mdays[] = {
45 	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
46 };
47 
48 #define LDNS_MOD(x,y) (((x) % (y) < 0) ? ((x) % (y) + (y)) : ((x) % (y)))
49 #define LDNS_DIV(x,y) (((x) % (y) < 0) ? ((x) / (y) -  1 ) : ((x) / (y)))
50 
51 static int
is_leap_year(int year)52 is_leap_year(int year)
53 {
54 	return LDNS_MOD(year,   4) == 0 && (LDNS_MOD(year, 100) != 0
55 	    || LDNS_MOD(year, 400) == 0);
56 }
57 
58 static int
leap_days(int y1,int y2)59 leap_days(int y1, int y2)
60 {
61 	--y1;
62 	--y2;
63 	return (LDNS_DIV(y2,   4) - LDNS_DIV(y1,   4)) -
64 	       (LDNS_DIV(y2, 100) - LDNS_DIV(y1, 100)) +
65 	       (LDNS_DIV(y2, 400) - LDNS_DIV(y1, 400));
66 }
67 
68 /*
69  * Code adapted from Python 2.4.1 sources (Lib/calendar.py).
70  */
71 time_t
sldns_mktime_from_utc(const struct tm * tm)72 sldns_mktime_from_utc(const struct tm *tm)
73 {
74 	int year = 1900 + tm->tm_year;
75 	time_t days = 365 * ((time_t) year - 1970) + leap_days(1970, year);
76 	time_t hours;
77 	time_t minutes;
78 	time_t seconds;
79 	int i;
80 
81 	for (i = 0; i < tm->tm_mon; ++i) {
82 		days += mdays[i];
83 	}
84 	if (tm->tm_mon > 1 && is_leap_year(year)) {
85 		++days;
86 	}
87 	days += tm->tm_mday - 1;
88 
89 	hours = days * 24 + tm->tm_hour;
90 	minutes = hours * 60 + tm->tm_min;
91 	seconds = minutes * 60 + tm->tm_sec;
92 
93 	return seconds;
94 }
95 
96 #if SIZEOF_TIME_T <= 4
97 
98 static void
sldns_year_and_yday_from_days_since_epoch(int64_t days,struct tm * result)99 sldns_year_and_yday_from_days_since_epoch(int64_t days, struct tm *result)
100 {
101 	int year = 1970;
102 	int new_year;
103 
104 	while (days < 0 || days >= (int64_t) (is_leap_year(year) ? 366 : 365)) {
105 		new_year = year + (int) LDNS_DIV(days, 365);
106 		days -= (new_year - year) * 365;
107 		days -= leap_days(year, new_year);
108 		year  = new_year;
109 	}
110 	result->tm_year = year;
111 	result->tm_yday = (int) days;
112 }
113 
114 /* Number of days per month in a leap year. */
115 static const int leap_year_mdays[] = {
116 	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
117 };
118 
119 static void
sldns_mon_and_mday_from_year_and_yday(struct tm * result)120 sldns_mon_and_mday_from_year_and_yday(struct tm *result)
121 {
122 	int idays = result->tm_yday;
123 	const int *mon_lengths = is_leap_year(result->tm_year) ?
124 					leap_year_mdays : mdays;
125 
126 	result->tm_mon = 0;
127 	while  (idays >= mon_lengths[result->tm_mon]) {
128 		idays -= mon_lengths[result->tm_mon++];
129 	}
130 	result->tm_mday = idays + 1;
131 }
132 
133 static void
sldns_wday_from_year_and_yday(struct tm * result)134 sldns_wday_from_year_and_yday(struct tm *result)
135 {
136 	result->tm_wday = 4 /* 1-1-1970 was a thursday */
137 			+ LDNS_MOD((result->tm_year - 1970), 7) * LDNS_MOD(365, 7)
138 			+ leap_days(1970, result->tm_year)
139 			+ result->tm_yday;
140 	result->tm_wday = LDNS_MOD(result->tm_wday, 7);
141 	if (result->tm_wday < 0) {
142 		result->tm_wday += 7;
143 	}
144 }
145 
146 static struct tm *
sldns_gmtime64_r(int64_t clock,struct tm * result)147 sldns_gmtime64_r(int64_t clock, struct tm *result)
148 {
149 	result->tm_isdst = 0;
150 	result->tm_sec   = (int) LDNS_MOD(clock, 60);
151 	clock            =       LDNS_DIV(clock, 60);
152 	result->tm_min   = (int) LDNS_MOD(clock, 60);
153 	clock            =       LDNS_DIV(clock, 60);
154 	result->tm_hour  = (int) LDNS_MOD(clock, 24);
155 	clock            =       LDNS_DIV(clock, 24);
156 
157 	sldns_year_and_yday_from_days_since_epoch(clock, result);
158 	sldns_mon_and_mday_from_year_and_yday(result);
159 	sldns_wday_from_year_and_yday(result);
160 	result->tm_year -= 1900;
161 
162 	return result;
163 }
164 
165 #endif /* SIZEOF_TIME_T <= 4 */
166 
167 static int64_t
sldns_serial_arithmetics_time(int32_t time,time_t now)168 sldns_serial_arithmetics_time(int32_t time, time_t now)
169 {
170 	int32_t offset = (int32_t)((uint32_t) time - (uint32_t) now);
171 	return (int64_t) now + offset;
172 }
173 
174 struct tm *
sldns_serial_arithmetics_gmtime_r(int32_t time,time_t now,struct tm * result)175 sldns_serial_arithmetics_gmtime_r(int32_t time, time_t now, struct tm *result)
176 {
177 #if SIZEOF_TIME_T <= 4
178 	int64_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);
179 	return  sldns_gmtime64_r(secs_since_epoch, result);
180 #else
181 	time_t  secs_since_epoch = sldns_serial_arithmetics_time(time, now);
182 	return  gmtime_r(&secs_since_epoch, result);
183 #endif
184 }
185 
186 int
sldns_hexdigit_to_int(char ch)187 sldns_hexdigit_to_int(char ch)
188 {
189 	switch (ch) {
190 	case '0': return 0;
191 	case '1': return 1;
192 	case '2': return 2;
193 	case '3': return 3;
194 	case '4': return 4;
195 	case '5': return 5;
196 	case '6': return 6;
197 	case '7': return 7;
198 	case '8': return 8;
199 	case '9': return 9;
200 	case 'a': case 'A': return 10;
201 	case 'b': case 'B': return 11;
202 	case 'c': case 'C': return 12;
203 	case 'd': case 'D': return 13;
204 	case 'e': case 'E': return 14;
205 	case 'f': case 'F': return 15;
206 	default:
207 		return -1;
208 	}
209 }
210 
211 uint32_t
sldns_str2period(const char * nptr,const char ** endptr)212 sldns_str2period(const char *nptr, const char **endptr)
213 {
214 	int sign = 0;
215 	uint32_t i = 0;
216 	uint32_t seconds = 0;
217 
218 	for(*endptr = nptr; **endptr; (*endptr)++) {
219 		switch (**endptr) {
220 			case ' ':
221 			case '\t':
222 				break;
223 			case '-':
224 				if(sign == 0) {
225 					sign = -1;
226 				} else {
227 					return seconds;
228 				}
229 				break;
230 			case '+':
231 				if(sign == 0) {
232 					sign = 1;
233 				} else {
234 					return seconds;
235 				}
236 				break;
237 			case 's':
238 			case 'S':
239 				seconds += i;
240 				i = 0;
241 				break;
242 			case 'm':
243 			case 'M':
244 				seconds += i * 60;
245 				i = 0;
246 				break;
247 			case 'h':
248 			case 'H':
249 				seconds += i * 60 * 60;
250 				i = 0;
251 				break;
252 			case 'd':
253 			case 'D':
254 				seconds += i * 60 * 60 * 24;
255 				i = 0;
256 				break;
257 			case 'w':
258 			case 'W':
259 				seconds += i * 60 * 60 * 24 * 7;
260 				i = 0;
261 				break;
262 			case '0':
263 			case '1':
264 			case '2':
265 			case '3':
266 			case '4':
267 			case '5':
268 			case '6':
269 			case '7':
270 			case '8':
271 			case '9':
272 				i *= 10;
273 				i += (**endptr - '0');
274 				break;
275 			default:
276 				seconds += i;
277 				/* disregard signedness */
278 				return seconds;
279 		}
280 	}
281 	seconds += i;
282 	/* disregard signedness */
283 	return seconds;
284 }
285 
286 int
sldns_parse_escape(uint8_t * ch_p,const char ** str_p)287 sldns_parse_escape(uint8_t *ch_p, const char** str_p)
288 {
289 	uint16_t val;
290 
291 	if ((*str_p)[0] && isdigit((unsigned char)(*str_p)[0]) &&
292 	    (*str_p)[1] && isdigit((unsigned char)(*str_p)[1]) &&
293 	    (*str_p)[2] && isdigit((unsigned char)(*str_p)[2])) {
294 
295 		val = (uint16_t)(((*str_p)[0] - '0') * 100 +
296 				 ((*str_p)[1] - '0') *  10 +
297 				 ((*str_p)[2] - '0'));
298 
299 		if (val > 255) {
300 			goto error;
301 		}
302 		*ch_p = (uint8_t)val;
303 		*str_p += 3;
304 		return 1;
305 
306 	} else if ((*str_p)[0] && !isdigit((unsigned char)(*str_p)[0])) {
307 
308 		*ch_p = (uint8_t)*(*str_p)++;
309 		return 1;
310 	}
311 error:
312 	*str_p = NULL;
313 	return 0; /* LDNS_WIREPARSE_ERR_SYNTAX_BAD_ESCAPE */
314 }
315 
316 /** parse one character, with escape codes */
317 int
sldns_parse_char(uint8_t * ch_p,const char ** str_p)318 sldns_parse_char(uint8_t *ch_p, const char** str_p)
319 {
320 	switch (**str_p) {
321 
322 	case '\0':	return 0;
323 
324 	case '\\':	*str_p += 1;
325 			return sldns_parse_escape(ch_p, str_p);
326 
327 	default:	*ch_p = (uint8_t)*(*str_p)++;
328 			return 1;
329 	}
330 }
331 
sldns_b32_ntop_calculate_size(size_t src_data_length)332 size_t sldns_b32_ntop_calculate_size(size_t src_data_length)
333 {
334 	return src_data_length == 0 ? 0 : ((src_data_length - 1) / 5 + 1) * 8;
335 }
336 
sldns_b32_ntop_calculate_size_no_padding(size_t src_data_length)337 size_t sldns_b32_ntop_calculate_size_no_padding(size_t src_data_length)
338 {
339 	return ((src_data_length + 3) * 8 / 5) - 4;
340 }
341 
342 static int
sldns_b32_ntop_base(const uint8_t * src,size_t src_sz,char * dst,size_t dst_sz,int extended_hex,int add_padding)343 sldns_b32_ntop_base(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz,
344 	int extended_hex, int add_padding)
345 {
346 	size_t ret_sz;
347 	const char* b32 = extended_hex ?  "0123456789abcdefghijklmnopqrstuv"
348 					: "abcdefghijklmnopqrstuvwxyz234567";
349 
350 	size_t c = 0; /* c is used to carry partial base32 character over
351 		       * byte boundaries for sizes with a remainder.
352 		       * (i.e. src_sz % 5 != 0)
353 		       */
354 
355 	ret_sz = add_padding ? sldns_b32_ntop_calculate_size(src_sz)
356 			     : sldns_b32_ntop_calculate_size_no_padding(src_sz);
357 
358 	/* Do we have enough space? */
359 	if (dst_sz < ret_sz + 1)
360 		return -1;
361 
362 	/* We know the size; terminate the string */
363 	dst[ret_sz] = '\0';
364 
365 	/* First process all chunks of five */
366 	while (src_sz >= 5) {
367 		/* 00000... ........ ........ ........ ........ */
368 		dst[0] = b32[(src[0]       ) >> 3];
369 
370 		/* .....111 11...... ........ ........ ........ */
371 		dst[1] = b32[(src[0] & 0x07) << 2 | src[1] >> 6];
372 
373 		/* ........ ..22222. ........ ........ ........ */
374 		dst[2] = b32[(src[1] & 0x3e) >> 1];
375 
376 		/* ........ .......3 3333.... ........ ........ */
377 		dst[3] = b32[(src[1] & 0x01) << 4 | src[2] >> 4];
378 
379 		/* ........ ........ ....4444 4....... ........ */
380 		dst[4] = b32[(src[2] & 0x0f) << 1 | src[3] >> 7];
381 
382 		/* ........ ........ ........ .55555.. ........ */
383 		dst[5] = b32[(src[3] & 0x7c) >> 2];
384 
385 		/* ........ ........ ........ ......66 666..... */
386 		dst[6] = b32[(src[3] & 0x03) << 3 | src[4] >> 5];
387 
388 		/* ........ ........ ........ ........ ...77777 */
389 		dst[7] = b32[(src[4] & 0x1f)     ];
390 
391 		src_sz -= 5;
392 		src    += 5;
393 		dst    += 8;
394 	}
395 	/* Process what remains */
396 	switch (src_sz) {
397 	case 4: /* ........ ........ ........ ......66 666..... */
398 		dst[6] = b32[(src[3] & 0x03) << 3];
399 
400 		/* ........ ........ ........ .55555.. ........ */
401 		dst[5] = b32[(src[3] & 0x7c) >> 2];
402 
403 		/* ........ ........ ....4444 4....... ........ */
404 			 c =  src[3]         >> 7 ;
405 		/* fallthrough */
406 	case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];
407 
408 		/* ........ .......3 3333.... ........ ........ */
409 			 c =  src[2]         >> 4 ;
410 		/* fallthrough */
411 	case 2:	dst[3] = b32[(src[1] & 0x01) << 4 | c];
412 
413 		/* ........ ..22222. ........ ........ ........ */
414 		dst[2] = b32[(src[1] & 0x3e) >> 1];
415 
416 		/* .....111 11...... ........ ........ ........ */
417 			 c =  src[1]         >> 6 ;
418 		/* fallthrough */
419 	case 1:	dst[1] = b32[(src[0] & 0x07) << 2 | c];
420 
421 		/* 00000... ........ ........ ........ ........ */
422 		dst[0] = b32[ src[0]         >> 3];
423 	}
424 	/* Add padding */
425 	if (add_padding) {
426 		switch (src_sz) {
427 			case 1: dst[2] = '=';
428 				dst[3] = '=';
429 				/* fallthrough */
430 			case 2: dst[4] = '=';
431 				/* fallthrough */
432 			case 3: dst[5] = '=';
433 				dst[6] = '=';
434 				/* fallthrough */
435 			case 4: dst[7] = '=';
436 		}
437 	}
438 	return (int)ret_sz;
439 }
440 
441 int
sldns_b32_ntop(const uint8_t * src,size_t src_sz,char * dst,size_t dst_sz)442 sldns_b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
443 {
444 	return sldns_b32_ntop_base(src, src_sz, dst, dst_sz, 0, 1);
445 }
446 
447 int
sldns_b32_ntop_extended_hex(const uint8_t * src,size_t src_sz,char * dst,size_t dst_sz)448 sldns_b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
449 		char* dst, size_t dst_sz)
450 {
451 	return sldns_b32_ntop_base(src, src_sz, dst, dst_sz, 1, 1);
452 }
453 
sldns_b32_pton_calculate_size(size_t src_text_length)454 size_t sldns_b32_pton_calculate_size(size_t src_text_length)
455 {
456 	return src_text_length * 5 / 8;
457 }
458 
459 static int
sldns_b32_pton_base(const char * src,size_t src_sz,uint8_t * dst,size_t dst_sz,int extended_hex,int check_padding)460 sldns_b32_pton_base(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz,
461 	int extended_hex, int check_padding)
462 {
463 	size_t i = 0;
464 	char ch = '\0';
465 	uint8_t buf[8];
466 	uint8_t* start = dst;
467 
468 	while (src_sz) {
469 		/* Collect 8 characters in buf (if possible) */
470 		for (i = 0; i < 8; i++) {
471 
472 			do {
473 				ch = *src++;
474 				--src_sz;
475 
476 			} while (isspace((unsigned char)ch) && src_sz > 0);
477 
478 			if (ch == '=' || ch == '\0')
479 				break;
480 
481 			else if (extended_hex)
482 
483 				if (ch >= '0' && ch <= '9')
484 					buf[i] = (uint8_t)ch - '0';
485 				else if (ch >= 'a' && ch <= 'v')
486 					buf[i] = (uint8_t)ch - 'a' + 10;
487 				else if (ch >= 'A' && ch <= 'V')
488 					buf[i] = (uint8_t)ch - 'A' + 10;
489 				else
490 					return -1;
491 
492 			else if (ch >= 'a' && ch <= 'z')
493 				buf[i] = (uint8_t)ch - 'a';
494 			else if (ch >= 'A' && ch <= 'Z')
495 				buf[i] = (uint8_t)ch - 'A';
496 			else if (ch >= '2' && ch <= '7')
497 				buf[i] = (uint8_t)ch - '2' + 26;
498 			else
499 				return -1;
500 		}
501 		/* Less that 8 characters. We're done. */
502 		if (i < 8)
503 			break;
504 
505 		/* Enough space available at the destination? */
506 		if (dst_sz < 5)
507 			return -1;
508 
509 		/* 00000... ........ ........ ........ ........ */
510 		/* .....111 11...... ........ ........ ........ */
511 		dst[0] = buf[0] << 3 | buf[1] >> 2;
512 
513 		/* .....111 11...... ........ ........ ........ */
514 		/* ........ ..22222. ........ ........ ........ */
515 		/* ........ .......3 3333.... ........ ........ */
516 		dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
517 
518 		/* ........ .......3 3333.... ........ ........ */
519 		/* ........ ........ ....4444 4....... ........ */
520 		dst[2] = buf[3] << 4 | buf[4] >> 1;
521 
522 		/* ........ ........ ....4444 4....... ........ */
523 		/* ........ ........ ........ .55555.. ........ */
524 		/* ........ ........ ........ ......66 666..... */
525 		dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
526 
527 		/* ........ ........ ........ ......66 666..... */
528 		/* ........ ........ ........ ........ ...77777 */
529 		dst[4] = buf[6] << 5 | buf[7];
530 
531 		dst += 5;
532 		dst_sz -= 5;
533 	}
534 	/* Not ending on a eight byte boundary? */
535 	if (i > 0 && i < 8) {
536 
537 		/* Enough space available at the destination? */
538 		if (dst_sz < (i + 1) / 2)
539 			return -1;
540 
541 		switch (i) {
542 		case 7: /* ........ ........ ........ ......66 666..... */
543 			/* ........ ........ ........ .55555.. ........ */
544 			/* ........ ........ ....4444 4....... ........ */
545 			dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
546 			/* fallthrough */
547 
548 		case 5: /* ........ ........ ....4444 4....... ........ */
549 			/* ........ .......3 3333.... ........ ........ */
550 			dst[2] = buf[3] << 4 | buf[4] >> 1;
551 			/* fallthrough */
552 
553 		case 4: /* ........ .......3 3333.... ........ ........ */
554 			/* ........ ..22222. ........ ........ ........ */
555 			/* .....111 11...... ........ ........ ........ */
556 			dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
557 			/* fallthrough */
558 
559 		case 2: /* .....111 11...... ........ ........ ........ */
560 			/* 00000... ........ ........ ........ ........ */
561 			dst[0] = buf[0] << 3 | buf[1] >> 2;
562 
563 			break;
564 
565 		default:
566 			return -1;
567 		}
568 		dst += (i + 1) / 2;
569 
570 		if (check_padding) {
571 			/* Check remaining padding characters */
572 			if (ch != '=')
573 				return -1;
574 
575 			/* One down, 8 - i - 1 more to come... */
576 			for (i = 8 - i - 1; i > 0; i--) {
577 
578 				do {
579 					if (src_sz == 0)
580 						return -1;
581 					ch = *src++;
582 					src_sz--;
583 
584 				} while (isspace((unsigned char)ch));
585 
586 				if (ch != '=')
587 					return -1;
588 			}
589 		}
590 	}
591 	return dst - start;
592 }
593 
594 int
sldns_b32_pton(const char * src,size_t src_sz,uint8_t * dst,size_t dst_sz)595 sldns_b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
596 {
597 	return sldns_b32_pton_base(src, src_sz, dst, dst_sz, 0, 1);
598 }
599 
600 int
sldns_b32_pton_extended_hex(const char * src,size_t src_sz,uint8_t * dst,size_t dst_sz)601 sldns_b32_pton_extended_hex(const char* src, size_t src_sz,
602 		uint8_t* dst, size_t dst_sz)
603 {
604 	return sldns_b32_pton_base(src, src_sz, dst, dst_sz, 1, 1);
605 }
606 
sldns_b64_ntop_calculate_size(size_t srcsize)607 size_t sldns_b64_ntop_calculate_size(size_t srcsize)
608 {
609 	return ((((srcsize + 2) / 3) * 4) + 1);
610 }
611 
612 /* RFC 1521, section 5.2.
613  *
614  * The encoding process represents 24-bit groups of input bits as output
615  * strings of 4 encoded characters. Proceeding from left to right, a
616  * 24-bit input group is formed by concatenating 3 8-bit input groups.
617  * These 24 bits are then treated as 4 concatenated 6-bit groups, each
618  * of which is translated into a single digit in the base64 alphabet.
619  *
620  * This routine does not insert spaces or linebreaks after 76 characters.
621  */
sldns_b64_ntop_base(uint8_t const * src,size_t srclength,char * target,size_t targsize,int base64url,int padding)622 static int sldns_b64_ntop_base(uint8_t const *src, size_t srclength,
623 	char *target, size_t targsize, int base64url, int padding)
624 {
625 	char* b64;
626 	const char pad64 = '=';
627 	size_t i = 0, o = 0;
628 	if(base64url)
629 		b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123"
630 			"456789-_";
631 	else
632 		b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123"
633 			"456789+/";
634 	if(targsize < sldns_b64_ntop_calculate_size(srclength))
635 		return -1;
636 	/* whole chunks: xxxxxxyy yyyyzzzz zzwwwwww */
637 	while(i+3 <= srclength) {
638 		if(o+4 > targsize) return -1;
639 		target[o] = b64[src[i] >> 2];
640 		target[o+1] = b64[ ((src[i]&0x03)<<4) | (src[i+1]>>4) ];
641 		target[o+2] = b64[ ((src[i+1]&0x0f)<<2) | (src[i+2]>>6) ];
642 		target[o+3] = b64[ (src[i+2]&0x3f) ];
643 		i += 3;
644 		o += 4;
645 	}
646 	/* remainder */
647 	switch(srclength - i) {
648 	case 2:
649 		/* two at end, converted into A B C = */
650 		target[o] = b64[src[i] >> 2];
651 		target[o+1] = b64[ ((src[i]&0x03)<<4) | (src[i+1]>>4) ];
652 		target[o+2] = b64[ ((src[i+1]&0x0f)<<2) ];
653 		if(padding) {
654 			target[o+3] = pad64;
655 			/* i += 2; */
656 			o += 4;
657 		} else {
658 			o += 3;
659 		}
660 		break;
661 	case 1:
662 		/* one at end, converted into A B = = */
663 		target[o] = b64[src[i] >> 2];
664 		target[o+1] = b64[ ((src[i]&0x03)<<4) ];
665 		if(padding) {
666 			target[o+2] = pad64;
667 			target[o+3] = pad64;
668 			/* i += 1; */
669 			o += 4;
670 		} else {
671 			o += 2;
672 		}
673 		break;
674 	case 0:
675 	default:
676 		/* nothing */
677 		break;
678 	}
679 	/* assert: i == srclength */
680 	if(o+1 > targsize) return -1;
681 	target[o] = 0;
682 	return (int)o;
683 }
684 
sldns_b64_ntop(uint8_t const * src,size_t srclength,char * target,size_t targsize)685 int sldns_b64_ntop(uint8_t const *src, size_t srclength, char *target,
686 	size_t targsize)
687 {
688 	return sldns_b64_ntop_base(src, srclength, target, targsize,
689 		0 /* no base64url */, 1 /* padding */);
690 }
691 
sldns_b64url_ntop(uint8_t const * src,size_t srclength,char * target,size_t targsize)692 int sldns_b64url_ntop(uint8_t const *src, size_t srclength, char *target,
693 	size_t targsize)
694 {
695 	return sldns_b64_ntop_base(src, srclength, target, targsize,
696 		1 /* base64url */, 0 /* no padding */);
697 }
698 
sldns_b64_pton_calculate_size(size_t srcsize)699 size_t sldns_b64_pton_calculate_size(size_t srcsize)
700 {
701 	return (((((srcsize + 3) / 4) * 3)) + 1);
702 }
703 
704 /* padding not required if srcsize is set */
sldns_b64_pton_base(char const * src,size_t srcsize,uint8_t * target,size_t targsize,int base64url)705 static int sldns_b64_pton_base(char const *src, size_t srcsize, uint8_t *target,
706 	size_t targsize, int base64url)
707 {
708 	const uint8_t pad64 = 64; /* is 64th in the b64 array */
709 	const char* s = src;
710 	uint8_t in[4];
711 	size_t o = 0, incount = 0;
712 	int check_padding = (srcsize) ? 0 : 1;
713 
714 	while(*s && (check_padding || srcsize)) {
715 		/* skip any character that is not base64 */
716 		/* conceptually we do:
717 		const char* b64 =      pad'=' is appended to array
718 		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
719 		const char* d = strchr(b64, *s++);
720 		and use d-b64;
721 		*/
722 		char d = *s++;
723 		srcsize--;
724 		if(d <= 'Z' && d >= 'A')
725 			d -= 'A';
726 		else if(d <= 'z' && d >= 'a')
727 			d = d - 'a' + 26;
728 		else if(d <= '9' && d >= '0')
729 			d = d - '0' + 52;
730 		else if(!base64url && d == '+')
731 			d = 62;
732 		else if(base64url && d == '-')
733 			d = 62;
734 		else if(!base64url && d == '/')
735 			d = 63;
736 		else if(base64url && d == '_')
737 			d = 63;
738 		else if(d == '=') {
739 			if(!check_padding)
740 				continue;
741 			d = 64;
742 		} else	continue;
743 
744 		in[incount++] = (uint8_t)d;
745 		/* work on block of 4, unless padding is not used and there are
746 		 * less than 4 chars left */
747 		if(incount != 4 && (check_padding || srcsize))
748 			continue;
749 		assert(!check_padding || incount==4);
750 		/* process whole block of 4 characters into 3 output bytes */
751 		if((incount == 2 ||
752 			(incount == 4 && in[3] == pad64 && in[2] == pad64))) { /* A B = = */
753 			if(o+1 > targsize)
754 				return -1;
755 			target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
756 			o += 1;
757 			break; /* we are done */
758 		} else if(incount == 3 ||
759 			(incount == 4 && in[3] == pad64)) { /* A B C = */
760 			if(o+2 > targsize)
761 				return -1;
762 			target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
763 			target[o+1]= ((in[1]&0x0f)<<4) | ((in[2]&0x3c)>>2);
764 			o += 2;
765 			break; /* we are done */
766 		} else {
767 			if(incount != 4 || o+3 > targsize)
768 				return -1;
769 			/* write xxxxxxyy yyyyzzzz zzwwwwww */
770 			target[o] = (in[0]<<2) | ((in[1]&0x30)>>4);
771 			target[o+1]= ((in[1]&0x0f)<<4) | ((in[2]&0x3c)>>2);
772 			target[o+2]= ((in[2]&0x03)<<6) | in[3];
773 			o += 3;
774 		}
775 		incount = 0;
776 	}
777 	return (int)o;
778 }
779 
sldns_b64_pton(char const * src,uint8_t * target,size_t targsize)780 int sldns_b64_pton(char const *src, uint8_t *target, size_t targsize)
781 {
782 	return sldns_b64_pton_base(src, 0, target, targsize, 0);
783 }
784 
sldns_b64url_pton(char const * src,size_t srcsize,uint8_t * target,size_t targsize)785 int sldns_b64url_pton(char const *src, size_t srcsize, uint8_t *target,
786 	size_t targsize)
787 {
788 	if(!srcsize) {
789 		return 0;
790 	}
791 	return sldns_b64_pton_base(src, srcsize, target, targsize, 1);
792 }
793 
sldns_b64_contains_nonurl(char const * src,size_t srcsize)794 int sldns_b64_contains_nonurl(char const *src, size_t srcsize)
795 {
796 	const char* s = src;
797 	while(*s && srcsize) {
798 		char d = *s++;
799 		srcsize--;
800 		/* the '+' and the '/' and padding '=' is not allowed in b64
801 		 * url encoding */
802 		if(d == '+' || d == '/' || d == '=') {
803 			return 1;
804 		}
805 	}
806 	return 0;
807 }
808