Add JavaScript Object Notation (JSON) parser (RFC7159)

This is needed for DPP configuration attributes/objects.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2017-06-15 21:18:00 +03:00 committed by Jouni Malinen
parent 5b52e1adc2
commit 005be3daa9
6 changed files with 603 additions and 0 deletions

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@ -941,6 +941,11 @@ ifdef NEED_BASE64
OBJS += src/utils/base64.c
endif
ifdef NEED_JSON
OBJS += src/utils/json.c
L_CFLAGS += -DCONFIG_JSON
endif
ifdef NEED_AP_MLME
OBJS += src/ap/wmm.c
OBJS += src/ap/ap_list.c

View file

@ -1035,6 +1035,11 @@ ifdef NEED_BASE64
OBJS += ../src/utils/base64.o
endif
ifdef NEED_JSON
OBJS += ../src/utils/json.o
CFLAGS += -DCONFIG_JSON
endif
ifdef NEED_AP_MLME
OBJS += ../src/ap/wmm.o
OBJS += ../src/ap/ap_list.o

541
src/utils/json.c Normal file
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@ -0,0 +1,541 @@
/*
* JavaScript Object Notation (JSON) parser (RFC7159)
* Copyright (c) 2017, Qualcomm Atheros, Inc.
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "base64.h"
#include "json.h"
#define JSON_MAX_DEPTH 10
#define JSON_MAX_TOKENS 500
void json_escape_string(char *txt, size_t maxlen, const char *data, size_t len)
{
char *end = txt + maxlen;
size_t i;
for (i = 0; i < len; i++) {
if (txt + 4 >= end)
break;
switch (data[i]) {
case '\"':
*txt++ = '\\';
*txt++ = '\"';
break;
case '\\':
*txt++ = '\\';
*txt++ = '\\';
break;
case '\n':
*txt++ = '\\';
*txt++ = 'n';
break;
case '\r':
*txt++ = '\\';
*txt++ = 'r';
break;
case '\t':
*txt++ = '\\';
*txt++ = 't';
break;
default:
if (data[i] >= 32 && data[i] <= 126) {
*txt++ = data[i];
} else {
txt += os_snprintf(txt, end - txt, "\\ux%04x",
data[i]);
}
break;
}
}
*txt = '\0';
}
static char * json_parse_string(const char **json_pos, const char *end)
{
const char *pos = *json_pos;
char *str, *spos, *s_end;
size_t max_len, buf_len;
u8 bin[2];
pos++; /* skip starting quote */
max_len = end - pos + 1;
buf_len = max_len > 10 ? 10 : max_len;
str = os_malloc(buf_len);
if (!str)
return NULL;
spos = str;
s_end = str + buf_len;
for (; pos < end; pos++) {
if (buf_len < max_len && s_end - spos < 3) {
char *tmp;
int idx;
idx = spos - str;
buf_len *= 2;
if (buf_len > max_len)
buf_len = max_len;
tmp = os_realloc(str, buf_len);
if (!tmp)
goto fail;
str = tmp;
spos = str + idx;
s_end = str + buf_len;
}
switch (*pos) {
case '\"': /* end string */
*spos = '\0';
/* caller will move to the next position */
*json_pos = pos;
return str;
case '\\':
pos++;
switch (*pos) {
case '"':
case '\\':
case '/':
*spos++ = *pos;
break;
case 'n':
*spos++ = '\n';
break;
case 'r':
*spos++ = '\r';
break;
case 't':
*spos++ = '\t';
break;
case 'u':
if (end - pos < 5 ||
hexstr2bin(pos + 1, bin, 2) < 0 ||
bin[1] == 0x00) {
wpa_printf(MSG_DEBUG,
"JSON: Invalid \\u escape");
goto fail;
}
if (bin[0] == 0x00) {
*spos++ = bin[1];
} else {
*spos++ = bin[0];
*spos++ = bin[1];
}
pos += 4;
break;
default:
wpa_printf(MSG_DEBUG,
"JSON: Unknown escape '%c'", *pos);
goto fail;
}
break;
default:
*spos++ = *pos;
break;
}
}
fail:
os_free(str);
return NULL;
}
static int json_parse_number(const char **json_pos, const char *end,
int *ret_val)
{
const char *pos = *json_pos;
size_t len;
char *str;
for (; pos < end; pos++) {
if (*pos != '-' && (*pos < '0' || *pos > '9')) {
pos--;
break;
}
}
if (pos < *json_pos)
return -1;
len = pos - *json_pos + 1;
str = os_malloc(len + 1);
if (!str)
return -1;
os_memcpy(str, *json_pos, len);
str[len] = '\0';
*ret_val = atoi(str);
os_free(str);
*json_pos = pos;
return 0;
}
static int json_check_tree_state(struct json_token *token)
{
if (!token)
return 0;
if (json_check_tree_state(token->child) < 0 ||
json_check_tree_state(token->sibling) < 0)
return -1;
if (token->state != JSON_COMPLETED) {
wpa_printf(MSG_DEBUG,
"JSON: Unexpected token state %d (name=%s type=%d)",
token->state, token->name ? token->name : "N/A",
token->type);
return -1;
}
return 0;
}
static struct json_token * json_alloc_token(unsigned int *tokens)
{
(*tokens)++;
if (*tokens > JSON_MAX_TOKENS) {
wpa_printf(MSG_DEBUG, "JSON: Maximum token limit exceeded");
return NULL;
}
return os_zalloc(sizeof(struct json_token));
}
struct json_token * json_parse(const char *data, size_t data_len)
{
struct json_token *root = NULL, *curr_token = NULL, *token = NULL;
const char *pos, *end;
char *str;
int num;
unsigned int depth = 0;
unsigned int tokens = 0;
pos = data;
end = data + data_len;
for (; pos < end; pos++) {
switch (*pos) {
case '[': /* start array */
case '{': /* start object */
if (!curr_token) {
token = json_alloc_token(&tokens);
if (!token)
goto fail;
} else if (curr_token->state == JSON_WAITING_VALUE) {
token = curr_token;
} else if (curr_token->parent &&
curr_token->parent->type == JSON_ARRAY &&
curr_token->parent->state == JSON_STARTED &&
curr_token->state == JSON_EMPTY) {
token = curr_token;
} else {
wpa_printf(MSG_DEBUG,
"JSON: Invalid state for start array/object");
goto fail;
}
depth++;
if (depth > JSON_MAX_DEPTH) {
wpa_printf(MSG_DEBUG,
"JSON: Max depth exceeded");
goto fail;
}
token->type = *pos == '[' ? JSON_ARRAY : JSON_OBJECT;
token->state = JSON_STARTED;
token->child = json_alloc_token(&tokens);
if (!token->child)
goto fail;
curr_token = token->child;
curr_token->parent = token;
curr_token->state = JSON_EMPTY;
break;
case ']': /* end array */
case '}': /* end object */
if (!curr_token || !curr_token->parent ||
curr_token->parent->state != JSON_STARTED) {
wpa_printf(MSG_DEBUG,
"JSON: Invalid state for end array/object");
goto fail;
}
depth--;
curr_token = curr_token->parent;
if ((*pos == ']' &&
curr_token->type != JSON_ARRAY) ||
(*pos == '}' &&
curr_token->type != JSON_OBJECT)) {
wpa_printf(MSG_DEBUG,
"JSON: Array/Object mismatch");
goto fail;
}
if (curr_token->child->state == JSON_EMPTY &&
!curr_token->child->child &&
!curr_token->child->sibling) {
/* Remove pending child token since the
* array/object was empty. */
json_free(curr_token->child);
curr_token->child = NULL;
}
curr_token->state = JSON_COMPLETED;
break;
case '\"': /* string */
str = json_parse_string(&pos, end);
if (!str)
goto fail;
if (!curr_token) {
token = json_alloc_token(&tokens);
if (!token)
goto fail;
token->type = JSON_STRING;
token->string = str;
token->state = JSON_COMPLETED;
} else if (curr_token->state == JSON_EMPTY) {
curr_token->type = JSON_VALUE;
curr_token->name = str;
curr_token->state = JSON_STARTED;
} else if (curr_token->state == JSON_WAITING_VALUE) {
curr_token->string = str;
curr_token->state = JSON_COMPLETED;
curr_token->type = JSON_STRING;
wpa_printf(MSG_MSGDUMP,
"JSON: String value: '%s' = '%s'",
curr_token->name,
curr_token->string);
} else {
wpa_printf(MSG_DEBUG,
"JSON: Invalid state for a string");
os_free(str);
goto fail;
}
break;
case ' ':
case '\t':
case '\r':
case '\n':
/* ignore whitespace */
break;
case ':': /* name/value separator */
if (!curr_token || curr_token->state != JSON_STARTED)
goto fail;
curr_token->state = JSON_WAITING_VALUE;
break;
case ',': /* member separator */
if (!curr_token)
goto fail;
curr_token->sibling = json_alloc_token(&tokens);
if (!curr_token->sibling)
goto fail;
curr_token->sibling->parent = curr_token->parent;
curr_token = curr_token->sibling;
curr_token->state = JSON_EMPTY;
break;
case 't': /* true */
case 'f': /* false */
case 'n': /* null */
if (!((end - pos >= 4 &&
os_strncmp(pos, "true", 4) == 0) ||
(end - pos >= 5 &&
os_strncmp(pos, "false", 5) == 0) ||
(end - pos >= 4 &&
os_strncmp(pos, "null", 4) == 0))) {
wpa_printf(MSG_DEBUG,
"JSON: Invalid literal name");
goto fail;
}
if (!curr_token) {
token = json_alloc_token(&tokens);
if (!token)
goto fail;
curr_token = token;
} else if (curr_token->state == JSON_WAITING_VALUE) {
wpa_printf(MSG_MSGDUMP,
"JSON: Literal name: '%s' = %c",
curr_token->name, *pos);
} else {
wpa_printf(MSG_DEBUG,
"JSON: Invalid state for a literal name");
goto fail;
}
switch (*pos) {
case 't':
curr_token->type = JSON_BOOLEAN;
curr_token->number = 1;
pos += 3;
break;
case 'f':
curr_token->type = JSON_BOOLEAN;
curr_token->number = 0;
pos += 4;
break;
case 'n':
curr_token->type = JSON_NULL;
pos += 3;
break;
}
curr_token->state = JSON_COMPLETED;
break;
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
/* number */
if (json_parse_number(&pos, end, &num) < 0)
goto fail;
if (!curr_token) {
token = json_alloc_token(&tokens);
if (!token)
goto fail;
token->type = JSON_NUMBER;
token->number = num;
token->state = JSON_COMPLETED;
} else if (curr_token->state == JSON_WAITING_VALUE) {
curr_token->number = num;
curr_token->state = JSON_COMPLETED;
curr_token->type = JSON_NUMBER;
wpa_printf(MSG_MSGDUMP,
"JSON: Number value: '%s' = '%d'",
curr_token->name,
curr_token->number);
} else {
wpa_printf(MSG_DEBUG,
"JSON: Invalid state for a number");
goto fail;
}
break;
default:
wpa_printf(MSG_DEBUG,
"JSON: Unexpected JSON character: %c", *pos);
goto fail;
}
if (!root)
root = token;
if (!curr_token)
curr_token = token;
}
if (json_check_tree_state(root) < 0) {
wpa_printf(MSG_DEBUG, "JSON: Incomplete token in the tree");
goto fail;
}
return root;
fail:
wpa_printf(MSG_DEBUG, "JSON: Parsing failed");
json_free(root);
return NULL;
}
void json_free(struct json_token *json)
{
if (!json)
return;
json_free(json->child);
json_free(json->sibling);
os_free(json->name);
os_free(json->string);
os_free(json);
}
struct json_token * json_get_member(struct json_token *json, const char *name)
{
struct json_token *token, *ret = NULL;
if (!json || json->type != JSON_OBJECT)
return NULL;
/* Return last matching entry */
for (token = json->child; token; token = token->sibling) {
if (token->name && os_strcmp(token->name, name) == 0)
ret = token;
}
return ret;
}
struct wpabuf * json_get_member_base64url(struct json_token *json,
const char *name)
{
struct json_token *token;
unsigned char *buf;
size_t buflen;
struct wpabuf *ret;
token = json_get_member(json, name);
if (!token || token->type != JSON_STRING)
return NULL;
buf = base64_url_decode((const unsigned char *) token->string,
os_strlen(token->string), &buflen);
if (!buf)
return NULL;
ret = wpabuf_alloc_ext_data(buf, buflen);
if (!ret)
os_free(buf);
return ret;
}
static const char * json_type_str(enum json_type type)
{
switch (type) {
case JSON_VALUE:
return "VALUE";
case JSON_OBJECT:
return "OBJECT";
case JSON_ARRAY:
return "ARRAY";
case JSON_STRING:
return "STRING";
case JSON_NUMBER:
return "NUMBER";
case JSON_BOOLEAN:
return "BOOLEAN";
case JSON_NULL:
return "NULL";
}
return "??";
}
static void json_print_token(struct json_token *token, int depth,
char *buf, size_t buflen)
{
size_t len;
int ret;
if (!token)
return;
len = os_strlen(buf);
ret = os_snprintf(buf + len, buflen - len, "[%d:%s:%s]",
depth, json_type_str(token->type),
token->name ? token->name : "");
if (os_snprintf_error(buflen - len, ret)) {
buf[len] = '\0';
return;
}
json_print_token(token->child, depth + 1, buf, buflen);
json_print_token(token->sibling, depth, buf, buflen);
}
void json_print_tree(struct json_token *root, char *buf, size_t buflen)
{
buf[0] = '\0';
json_print_token(root, 1, buf, buflen);
}

42
src/utils/json.h Normal file
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@ -0,0 +1,42 @@
/*
* JavaScript Object Notation (JSON) parser (RFC7159)
* Copyright (c) 2017, Qualcomm Atheros, Inc.
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#ifndef JSON_H
#define JSON_H
struct json_token {
enum json_type {
JSON_VALUE,
JSON_OBJECT,
JSON_ARRAY,
JSON_STRING,
JSON_NUMBER,
JSON_BOOLEAN,
JSON_NULL,
} type;
enum json_parsing_state {
JSON_EMPTY,
JSON_STARTED,
JSON_WAITING_VALUE,
JSON_COMPLETED,
} state;
char *name;
char *string;
int number;
struct json_token *parent, *child, *sibling;
};
void json_escape_string(char *txt, size_t maxlen, const char *data, size_t len);
struct json_token * json_parse(const char *data, size_t data_len);
void json_free(struct json_token *json);
struct json_token * json_get_member(struct json_token *json, const char *name);
struct wpabuf * json_get_member_base64url(struct json_token *json,
const char *name);
void json_print_tree(struct json_token *root, char *buf, size_t buflen);
#endif /* JSON_H */

View file

@ -1565,6 +1565,11 @@ OBJS += offchannel.c
L_CFLAGS += -DCONFIG_OFFCHANNEL
endif
ifdef NEED_JSON
OBJS += src/utils/json.c
L_CFLAGS += -DCONFIG_JSON
endif
OBJS += src/drivers/driver_common.c
OBJS += wpa_supplicant.c events.c blacklist.c wpas_glue.c scan.c

View file

@ -1691,6 +1691,11 @@ OBJS += offchannel.o
CFLAGS += -DCONFIG_OFFCHANNEL
endif
ifdef NEED_JSON
OBJS += ../src/utils/json.o
CFLAGS += -DCONFIG_JSON
endif
ifdef CONFIG_MODULE_TESTS
CFLAGS += -DCONFIG_MODULE_TESTS
OBJS += wpas_module_tests.o