1 /*
2 * JavaScript Object Notation (JSON) parser (RFC7159)
3 * Copyright (c) 2017, Qualcomm Atheros, Inc.
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10
11 #include "common.h"
12 #include "base64.h"
13 #include "json.h"
14
15 #define JSON_MAX_DEPTH 10
16 #define JSON_MAX_TOKENS 500
17
18
json_escape_string(char * txt,size_t maxlen,const char * data,size_t len)19 void json_escape_string(char *txt, size_t maxlen, const char *data, size_t len)
20 {
21 char *end = txt + maxlen;
22 size_t i;
23
24 for (i = 0; i < len; i++) {
25 if (txt + 4 >= end)
26 break;
27
28 switch (data[i]) {
29 case '\"':
30 *txt++ = '\\';
31 *txt++ = '\"';
32 break;
33 case '\\':
34 *txt++ = '\\';
35 *txt++ = '\\';
36 break;
37 case '\n':
38 *txt++ = '\\';
39 *txt++ = 'n';
40 break;
41 case '\r':
42 *txt++ = '\\';
43 *txt++ = 'r';
44 break;
45 case '\t':
46 *txt++ = '\\';
47 *txt++ = 't';
48 break;
49 default:
50 if (data[i] >= 32 && data[i] <= 126) {
51 *txt++ = data[i];
52 } else {
53 txt += os_snprintf(txt, end - txt, "\\u%04x",
54 (unsigned char) data[i]);
55 }
56 break;
57 }
58 }
59
60 *txt = '\0';
61 }
62
63
json_parse_string(const char ** json_pos,const char * end)64 static char * json_parse_string(const char **json_pos, const char *end)
65 {
66 const char *pos = *json_pos;
67 char *str, *spos, *s_end;
68 size_t max_len, buf_len;
69 u8 bin[2];
70
71 pos++; /* skip starting quote */
72
73 max_len = end - pos + 1;
74 buf_len = max_len > 10 ? 10 : max_len;
75 str = os_malloc(buf_len);
76 if (!str)
77 return NULL;
78 spos = str;
79 s_end = str + buf_len;
80
81 for (; pos < end; pos++) {
82 if (buf_len < max_len && s_end - spos < 3) {
83 char *tmp;
84 int idx;
85
86 idx = spos - str;
87 buf_len *= 2;
88 if (buf_len > max_len)
89 buf_len = max_len;
90 tmp = os_realloc(str, buf_len);
91 if (!tmp)
92 goto fail;
93 str = tmp;
94 spos = str + idx;
95 s_end = str + buf_len;
96 }
97
98 switch (*pos) {
99 case '\"': /* end string */
100 *spos = '\0';
101 /* caller will move to the next position */
102 *json_pos = pos;
103 return str;
104 case '\\':
105 pos++;
106 if (pos >= end) {
107 wpa_printf(MSG_DEBUG,
108 "JSON: Truncated \\ escape");
109 goto fail;
110 }
111 switch (*pos) {
112 case '"':
113 case '\\':
114 case '/':
115 *spos++ = *pos;
116 break;
117 case 'n':
118 *spos++ = '\n';
119 break;
120 case 'r':
121 *spos++ = '\r';
122 break;
123 case 't':
124 *spos++ = '\t';
125 break;
126 case 'u':
127 if (end - pos < 5 ||
128 hexstr2bin(pos + 1, bin, 2) < 0 ||
129 bin[1] == 0x00) {
130 wpa_printf(MSG_DEBUG,
131 "JSON: Invalid \\u escape");
132 goto fail;
133 }
134 if (bin[0] == 0x00) {
135 *spos++ = bin[1];
136 } else {
137 *spos++ = bin[0];
138 *spos++ = bin[1];
139 }
140 pos += 4;
141 break;
142 default:
143 wpa_printf(MSG_DEBUG,
144 "JSON: Unknown escape '%c'", *pos);
145 goto fail;
146 }
147 break;
148 default:
149 *spos++ = *pos;
150 break;
151 }
152 }
153
154 fail:
155 os_free(str);
156 return NULL;
157 }
158
159
json_parse_number(const char ** json_pos,const char * end,int * ret_val)160 static int json_parse_number(const char **json_pos, const char *end,
161 int *ret_val)
162 {
163 const char *pos = *json_pos;
164 size_t len;
165 char *str;
166
167 for (; pos < end; pos++) {
168 if (*pos != '-' && (*pos < '0' || *pos > '9')) {
169 pos--;
170 break;
171 }
172 }
173 if (pos == end)
174 pos--;
175 if (pos < *json_pos)
176 return -1;
177 len = pos - *json_pos + 1;
178 str = os_malloc(len + 1);
179 if (!str)
180 return -1;
181 os_memcpy(str, *json_pos, len);
182 str[len] = '\0';
183
184 *ret_val = atoi(str);
185 os_free(str);
186 *json_pos = pos;
187 return 0;
188 }
189
190
json_check_tree_state(struct json_token * token)191 static int json_check_tree_state(struct json_token *token)
192 {
193 if (!token)
194 return 0;
195 if (json_check_tree_state(token->child) < 0 ||
196 json_check_tree_state(token->sibling) < 0)
197 return -1;
198 if (token->state != JSON_COMPLETED) {
199 wpa_printf(MSG_DEBUG,
200 "JSON: Unexpected token state %d (name=%s type=%d)",
201 token->state, token->name ? token->name : "N/A",
202 token->type);
203 return -1;
204 }
205 return 0;
206 }
207
208
json_alloc_token(unsigned int * tokens)209 static struct json_token * json_alloc_token(unsigned int *tokens)
210 {
211 (*tokens)++;
212 if (*tokens > JSON_MAX_TOKENS) {
213 wpa_printf(MSG_DEBUG, "JSON: Maximum token limit exceeded");
214 return NULL;
215 }
216 return os_zalloc(sizeof(struct json_token));
217 }
218
219
json_parse(const char * data,size_t data_len)220 struct json_token * json_parse(const char *data, size_t data_len)
221 {
222 struct json_token *root = NULL, *curr_token = NULL, *token = NULL;
223 const char *pos, *end;
224 char *str;
225 int num;
226 unsigned int depth = 0;
227 unsigned int tokens = 0;
228
229 pos = data;
230 end = data + data_len;
231
232 for (; pos < end; pos++) {
233 switch (*pos) {
234 case '[': /* start array */
235 case '{': /* start object */
236 if (!curr_token) {
237 token = json_alloc_token(&tokens);
238 if (!token)
239 goto fail;
240 if (!root)
241 root = token;
242 } else if (curr_token->state == JSON_WAITING_VALUE) {
243 token = curr_token;
244 } else if (curr_token->parent &&
245 curr_token->parent->type == JSON_ARRAY &&
246 curr_token->parent->state == JSON_STARTED &&
247 curr_token->state == JSON_EMPTY) {
248 token = curr_token;
249 } else {
250 wpa_printf(MSG_DEBUG,
251 "JSON: Invalid state for start array/object");
252 goto fail;
253 }
254 depth++;
255 if (depth > JSON_MAX_DEPTH) {
256 wpa_printf(MSG_DEBUG,
257 "JSON: Max depth exceeded");
258 goto fail;
259 }
260 token->type = *pos == '[' ? JSON_ARRAY : JSON_OBJECT;
261 token->state = JSON_STARTED;
262 token->child = json_alloc_token(&tokens);
263 if (!token->child)
264 goto fail;
265 curr_token = token->child;
266 curr_token->parent = token;
267 curr_token->state = JSON_EMPTY;
268 break;
269 case ']': /* end array */
270 case '}': /* end object */
271 if (!curr_token || !curr_token->parent ||
272 curr_token->parent->state != JSON_STARTED) {
273 wpa_printf(MSG_DEBUG,
274 "JSON: Invalid state for end array/object");
275 goto fail;
276 }
277 depth--;
278 curr_token = curr_token->parent;
279 if ((*pos == ']' &&
280 curr_token->type != JSON_ARRAY) ||
281 (*pos == '}' &&
282 curr_token->type != JSON_OBJECT)) {
283 wpa_printf(MSG_DEBUG,
284 "JSON: Array/Object mismatch");
285 goto fail;
286 }
287 if (curr_token->child->state == JSON_EMPTY &&
288 !curr_token->child->child &&
289 !curr_token->child->sibling) {
290 /* Remove pending child token since the
291 * array/object was empty. */
292 json_free(curr_token->child);
293 curr_token->child = NULL;
294 }
295 curr_token->state = JSON_COMPLETED;
296 break;
297 case '\"': /* string */
298 str = json_parse_string(&pos, end);
299 if (!str)
300 goto fail;
301 if (!curr_token) {
302 token = json_alloc_token(&tokens);
303 if (!token) {
304 os_free(str);
305 goto fail;
306 }
307 token->type = JSON_STRING;
308 token->string = str;
309 token->state = JSON_COMPLETED;
310 } else if (curr_token->parent &&
311 curr_token->parent->type == JSON_ARRAY &&
312 curr_token->parent->state == JSON_STARTED &&
313 curr_token->state == JSON_EMPTY) {
314 curr_token->string = str;
315 curr_token->state = JSON_COMPLETED;
316 curr_token->type = JSON_STRING;
317 wpa_printf(MSG_MSGDUMP,
318 "JSON: String value: '%s'",
319 curr_token->string);
320 } else if (curr_token->state == JSON_EMPTY) {
321 curr_token->type = JSON_VALUE;
322 curr_token->name = str;
323 curr_token->state = JSON_STARTED;
324 } else if (curr_token->state == JSON_WAITING_VALUE) {
325 curr_token->string = str;
326 curr_token->state = JSON_COMPLETED;
327 curr_token->type = JSON_STRING;
328 wpa_printf(MSG_MSGDUMP,
329 "JSON: String value: '%s' = '%s'",
330 curr_token->name,
331 curr_token->string);
332 } else {
333 wpa_printf(MSG_DEBUG,
334 "JSON: Invalid state for a string");
335 os_free(str);
336 goto fail;
337 }
338 break;
339 case ' ':
340 case '\t':
341 case '\r':
342 case '\n':
343 /* ignore whitespace */
344 break;
345 case ':': /* name/value separator */
346 if (!curr_token || curr_token->state != JSON_STARTED)
347 goto fail;
348 curr_token->state = JSON_WAITING_VALUE;
349 break;
350 case ',': /* member separator */
351 if (!curr_token)
352 goto fail;
353 curr_token->sibling = json_alloc_token(&tokens);
354 if (!curr_token->sibling)
355 goto fail;
356 curr_token->sibling->parent = curr_token->parent;
357 curr_token = curr_token->sibling;
358 curr_token->state = JSON_EMPTY;
359 break;
360 case 't': /* true */
361 case 'f': /* false */
362 case 'n': /* null */
363 if (!((end - pos >= 4 &&
364 os_strncmp(pos, "true", 4) == 0) ||
365 (end - pos >= 5 &&
366 os_strncmp(pos, "false", 5) == 0) ||
367 (end - pos >= 4 &&
368 os_strncmp(pos, "null", 4) == 0))) {
369 wpa_printf(MSG_DEBUG,
370 "JSON: Invalid literal name");
371 goto fail;
372 }
373 if (!curr_token) {
374 token = json_alloc_token(&tokens);
375 if (!token)
376 goto fail;
377 curr_token = token;
378 } else if (curr_token->state == JSON_WAITING_VALUE) {
379 wpa_printf(MSG_MSGDUMP,
380 "JSON: Literal name: '%s' = %c",
381 curr_token->name, *pos);
382 } else if (curr_token->parent &&
383 curr_token->parent->type == JSON_ARRAY &&
384 curr_token->parent->state == JSON_STARTED &&
385 curr_token->state == JSON_EMPTY) {
386 wpa_printf(MSG_MSGDUMP,
387 "JSON: Literal name: %c", *pos);
388 } else {
389 wpa_printf(MSG_DEBUG,
390 "JSON: Invalid state for a literal name");
391 goto fail;
392 }
393 switch (*pos) {
394 case 't':
395 curr_token->type = JSON_BOOLEAN;
396 curr_token->number = 1;
397 pos += 3;
398 break;
399 case 'f':
400 curr_token->type = JSON_BOOLEAN;
401 curr_token->number = 0;
402 pos += 4;
403 break;
404 case 'n':
405 curr_token->type = JSON_NULL;
406 pos += 3;
407 break;
408 }
409 curr_token->state = JSON_COMPLETED;
410 break;
411 case '-':
412 case '0':
413 case '1':
414 case '2':
415 case '3':
416 case '4':
417 case '5':
418 case '6':
419 case '7':
420 case '8':
421 case '9':
422 /* number */
423 if (json_parse_number(&pos, end, &num) < 0)
424 goto fail;
425 if (!curr_token) {
426 token = json_alloc_token(&tokens);
427 if (!token)
428 goto fail;
429 token->type = JSON_NUMBER;
430 token->number = num;
431 token->state = JSON_COMPLETED;
432 } else if (curr_token->state == JSON_WAITING_VALUE) {
433 curr_token->number = num;
434 curr_token->state = JSON_COMPLETED;
435 curr_token->type = JSON_NUMBER;
436 wpa_printf(MSG_MSGDUMP,
437 "JSON: Number value: '%s' = '%d'",
438 curr_token->name,
439 curr_token->number);
440 } else if (curr_token->parent &&
441 curr_token->parent->type == JSON_ARRAY &&
442 curr_token->parent->state == JSON_STARTED &&
443 curr_token->state == JSON_EMPTY) {
444 curr_token->number = num;
445 curr_token->state = JSON_COMPLETED;
446 curr_token->type = JSON_NUMBER;
447 wpa_printf(MSG_MSGDUMP,
448 "JSON: Number value: %d",
449 curr_token->number);
450 } else {
451 wpa_printf(MSG_DEBUG,
452 "JSON: Invalid state for a number");
453 goto fail;
454 }
455 break;
456 default:
457 wpa_printf(MSG_DEBUG,
458 "JSON: Unexpected JSON character: %c", *pos);
459 goto fail;
460 }
461
462 if (!root)
463 root = token;
464 if (!curr_token)
465 curr_token = token;
466 }
467
468 if (json_check_tree_state(root) < 0) {
469 wpa_printf(MSG_DEBUG, "JSON: Incomplete token in the tree");
470 goto fail;
471 }
472
473 return root;
474 fail:
475 wpa_printf(MSG_DEBUG, "JSON: Parsing failed");
476 json_free(root);
477 return NULL;
478 }
479
480
json_free(struct json_token * json)481 void json_free(struct json_token *json)
482 {
483 if (!json)
484 return;
485 json_free(json->child);
486 json_free(json->sibling);
487 os_free(json->name);
488 os_free(json->string);
489 os_free(json);
490 }
491
492
json_get_member(struct json_token * json,const char * name)493 struct json_token * json_get_member(struct json_token *json, const char *name)
494 {
495 struct json_token *token, *ret = NULL;
496
497 if (!json || json->type != JSON_OBJECT)
498 return NULL;
499 /* Return last matching entry */
500 for (token = json->child; token; token = token->sibling) {
501 if (token->name && os_strcmp(token->name, name) == 0)
502 ret = token;
503 }
504 return ret;
505 }
506
507
json_get_member_base64url(struct json_token * json,const char * name)508 struct wpabuf * json_get_member_base64url(struct json_token *json,
509 const char *name)
510 {
511 struct json_token *token;
512 unsigned char *buf;
513 size_t buflen;
514 struct wpabuf *ret;
515
516 token = json_get_member(json, name);
517 if (!token || token->type != JSON_STRING)
518 return NULL;
519 buf = base64_url_decode(token->string, os_strlen(token->string),
520 &buflen);
521 if (!buf)
522 return NULL;
523 ret = wpabuf_alloc_ext_data(buf, buflen);
524 if (!ret)
525 os_free(buf);
526
527 return ret;
528 }
529
530
json_type_str(enum esp_json_type type)531 static const char * json_type_str(enum esp_json_type type)
532 {
533 switch (type) {
534 case JSON_VALUE:
535 return "VALUE";
536 case JSON_OBJECT:
537 return "OBJECT";
538 case JSON_ARRAY:
539 return "ARRAY";
540 case JSON_STRING:
541 return "STRING";
542 case JSON_NUMBER:
543 return "NUMBER";
544 case JSON_BOOLEAN:
545 return "BOOLEAN";
546 case JSON_NULL:
547 return "NULL";
548 }
549 return "??";
550 }
551
552
json_print_token(struct json_token * token,int depth,char * buf,size_t buflen)553 static void json_print_token(struct json_token *token, int depth,
554 char *buf, size_t buflen)
555 {
556 size_t len;
557 int ret;
558
559 if (!token)
560 return;
561 len = os_strlen(buf);
562 ret = os_snprintf(buf + len, buflen - len, "[%d:%s:%s]",
563 depth, json_type_str(token->type),
564 token->name ? token->name : "");
565 if (os_snprintf_error(buflen - len, ret)) {
566 buf[len] = '\0';
567 return;
568 }
569 json_print_token(token->child, depth + 1, buf, buflen);
570 json_print_token(token->sibling, depth, buf, buflen);
571 }
572
573
json_print_tree(struct json_token * root,char * buf,size_t buflen)574 void json_print_tree(struct json_token *root, char *buf, size_t buflen)
575 {
576 buf[0] = '\0';
577 json_print_token(root, 1, buf, buflen);
578 }
579
580
json_add_int(struct wpabuf * json,const char * name,int val)581 void json_add_int(struct wpabuf *json, const char *name, int val)
582 {
583 wpabuf_printf(json, "\"%s\":%d", name, val);
584 }
585
586
json_add_string(struct wpabuf * json,const char * name,const char * val)587 void json_add_string(struct wpabuf *json, const char *name, const char *val)
588 {
589 wpabuf_printf(json, "\"%s\":\"%s\"", name, val);
590 }
591
592
json_add_string_escape(struct wpabuf * json,const char * name,const void * val,size_t len)593 int json_add_string_escape(struct wpabuf *json, const char *name,
594 const void *val, size_t len)
595 {
596 char *tmp;
597 size_t tmp_len = 6 * len + 1;
598
599 tmp = os_malloc(tmp_len);
600 if (!tmp)
601 return -1;
602 json_escape_string(tmp, tmp_len, val, len);
603 json_add_string(json, name, tmp);
604 bin_clear_free(tmp, tmp_len);
605 return 0;
606 }
607
608
json_add_base64url(struct wpabuf * json,const char * name,const void * val,size_t len)609 int json_add_base64url(struct wpabuf *json, const char *name, const void *val,
610 size_t len)
611 {
612 char *b64;
613
614 b64 = base64_url_encode(val, len, NULL);
615 if (!b64)
616 return -1;
617 json_add_string(json, name, b64);
618 os_free(b64);
619 return 0;
620 }
621
622
json_start_object(struct wpabuf * json,const char * name)623 void json_start_object(struct wpabuf *json, const char *name)
624 {
625 if (name)
626 wpabuf_printf(json, "\"%s\":", name);
627 wpabuf_put_u8(json, '{');
628 }
629
630
json_end_object(struct wpabuf * json)631 void json_end_object(struct wpabuf *json)
632 {
633 wpabuf_put_u8(json, '}');
634 }
635
636
json_start_array(struct wpabuf * json,const char * name)637 void json_start_array(struct wpabuf *json, const char *name)
638 {
639 if (name)
640 wpabuf_printf(json, "\"%s\":", name);
641 wpabuf_put_u8(json, '[');
642 }
643
644
json_end_array(struct wpabuf * json)645 void json_end_array(struct wpabuf *json)
646 {
647 wpabuf_put_u8(json, ']');
648 }
649
650
json_value_sep(struct wpabuf * json)651 void json_value_sep(struct wpabuf *json)
652 {
653 wpabuf_put_u8(json, ',');
654 }
655
