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 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 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 } 158 159 160 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 } 189 190 191 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 } 207 208 209 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 } 218 219 220 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 } 479 480 481 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 } 491 492 493 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 } 506 507 508 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 } 529 530 531 struct wpabuf * json_get_member_base64(struct json_token *json, 532 const char *name) 533 { 534 struct json_token *token; 535 unsigned char *buf; 536 size_t buflen; 537 struct wpabuf *ret; 538 539 token = json_get_member(json, name); 540 if (!token || token->type != JSON_STRING) 541 return NULL; 542 buf = base64_decode(token->string, os_strlen(token->string), &buflen); 543 if (!buf) 544 return NULL; 545 ret = wpabuf_alloc_ext_data(buf, buflen); 546 if (!ret) 547 os_free(buf); 548 549 return ret; 550 } 551 552 553 static const char * json_type_str(enum json_type type) 554 { 555 switch (type) { 556 case JSON_VALUE: 557 return "VALUE"; 558 case JSON_OBJECT: 559 return "OBJECT"; 560 case JSON_ARRAY: 561 return "ARRAY"; 562 case JSON_STRING: 563 return "STRING"; 564 case JSON_NUMBER: 565 return "NUMBER"; 566 case JSON_BOOLEAN: 567 return "BOOLEAN"; 568 case JSON_NULL: 569 return "NULL"; 570 } 571 return "??"; 572 } 573 574 575 static void json_print_token(struct json_token *token, int depth, 576 char *buf, size_t buflen) 577 { 578 size_t len; 579 int ret; 580 581 if (!token) 582 return; 583 len = os_strlen(buf); 584 ret = os_snprintf(buf + len, buflen - len, "[%d:%s:%s]", 585 depth, json_type_str(token->type), 586 token->name ? token->name : ""); 587 if (os_snprintf_error(buflen - len, ret)) { 588 buf[len] = '\0'; 589 return; 590 } 591 json_print_token(token->child, depth + 1, buf, buflen); 592 json_print_token(token->sibling, depth, buf, buflen); 593 } 594 595 596 void json_print_tree(struct json_token *root, char *buf, size_t buflen) 597 { 598 buf[0] = '\0'; 599 json_print_token(root, 1, buf, buflen); 600 } 601 602 603 void json_add_int(struct wpabuf *json, const char *name, int val) 604 { 605 wpabuf_printf(json, "\"%s\":%d", name, val); 606 } 607 608 609 void json_add_string(struct wpabuf *json, const char *name, const char *val) 610 { 611 wpabuf_printf(json, "\"%s\":\"%s\"", name, val); 612 } 613 614 615 int json_add_string_escape(struct wpabuf *json, const char *name, 616 const void *val, size_t len) 617 { 618 char *tmp; 619 size_t tmp_len = 6 * len + 1; 620 621 tmp = os_malloc(tmp_len); 622 if (!tmp) 623 return -1; 624 json_escape_string(tmp, tmp_len, val, len); 625 json_add_string(json, name, tmp); 626 bin_clear_free(tmp, tmp_len); 627 return 0; 628 } 629 630 631 int json_add_base64url(struct wpabuf *json, const char *name, const void *val, 632 size_t len) 633 { 634 char *b64; 635 636 b64 = base64_url_encode(val, len, NULL); 637 if (!b64) 638 return -1; 639 json_add_string(json, name, b64); 640 os_free(b64); 641 return 0; 642 } 643 644 645 int json_add_base64(struct wpabuf *json, const char *name, const void *val, 646 size_t len) 647 { 648 char *b64; 649 650 b64 = base64_encode_no_lf(val, len, NULL); 651 if (!b64) 652 return -1; 653 json_add_string(json, name, b64); 654 os_free(b64); 655 return 0; 656 } 657 658 659 void json_start_object(struct wpabuf *json, const char *name) 660 { 661 if (name) 662 wpabuf_printf(json, "\"%s\":", name); 663 wpabuf_put_u8(json, '{'); 664 } 665 666 667 void json_end_object(struct wpabuf *json) 668 { 669 wpabuf_put_u8(json, '}'); 670 } 671 672 673 void json_start_array(struct wpabuf *json, const char *name) 674 { 675 if (name) 676 wpabuf_printf(json, "\"%s\":", name); 677 wpabuf_put_u8(json, '['); 678 } 679 680 681 void json_end_array(struct wpabuf *json) 682 { 683 wpabuf_put_u8(json, ']'); 684 } 685 686 687 void json_value_sep(struct wpabuf *json) 688 { 689 wpabuf_put_u8(json, ','); 690 } 691