forked from osmocom/wireshark
194 lines
7.3 KiB
C
194 lines
7.3 KiB
C
/* wsjsmn.c
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* Utility to check if a payload is json using libjsmn
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*
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* Copyright 2016, Dario Lombardo
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "wsjsmn.h"
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#include <string.h>
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#include <wsutil/jsmn.h>
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#include <wsutil/str_util.h>
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#include <wsutil/unicode-utils.h>
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#include "log.h"
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gboolean jsmn_is_json(const guint8* buf, const size_t len)
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{
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/* We expect no more than 1024 tokens */
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guint max_tokens = 1024;
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jsmntok_t* t;
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jsmn_parser p;
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gboolean ret = TRUE;
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int rcode;
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t = g_new0(jsmntok_t, max_tokens);
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if (!t)
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return FALSE;
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jsmn_init(&p);
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rcode = jsmn_parse(&p, buf, len, t, max_tokens);
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if (rcode < 0) {
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switch (rcode) {
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case JSMN_ERROR_NOMEM:
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g_log(LOG_DOMAIN_MAIN, G_LOG_LEVEL_DEBUG, "jsmn: not enough tokens were provided");
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break;
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case JSMN_ERROR_INVAL:
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g_log(LOG_DOMAIN_MAIN, G_LOG_LEVEL_DEBUG, "jsmn: invalid character inside JSON string");
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break;
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case JSMN_ERROR_PART:
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g_log(LOG_DOMAIN_MAIN, G_LOG_LEVEL_DEBUG, "jsmn: the string is not a full JSON packet, "
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"more bytes expected");
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break;
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default:
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g_log(LOG_DOMAIN_MAIN, G_LOG_LEVEL_DEBUG, "jsmn: unexpected error");
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break;
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}
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ret = FALSE;
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}
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g_free(t);
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return ret;
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}
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int wsjsmn_parse(const char *buf, jsmntok_t *tokens, unsigned int max_tokens)
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{
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jsmn_parser p;
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jsmn_init(&p);
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return jsmn_parse(&p, buf, strlen(buf), tokens, max_tokens);
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}
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gboolean wsjsmn_unescape_json_string(const char *input, char *output)
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{
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while (*input) {
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char ch = *input++;
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if (ch == '\\') {
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ch = *input++;
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switch (ch) {
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case '\"':
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case '\\':
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case '/':
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*output++ = ch;
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break;
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case 'b':
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*output++ = '\b';
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break;
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case 'f':
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*output++ = '\f';
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break;
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case 'n':
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*output++ = '\n';
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break;
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case 'r':
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*output++ = '\r';
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break;
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case 't':
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*output++ = '\t';
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break;
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case 'u':
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{
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guint32 unicode_hex = 0;
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int k;
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int bin;
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for (k = 0; k < 4; k++) {
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unicode_hex <<= 4;
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ch = *input++;
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bin = ws_xton(ch);
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if (bin == -1)
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return FALSE;
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unicode_hex |= bin;
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}
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if ((IS_LEAD_SURROGATE(unicode_hex))) {
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guint16 lead_surrogate = unicode_hex;
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guint16 trail_surrogate = 0;
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if (input[0] != '\\' || input[1] != 'u')
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return FALSE;
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input += 2;
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for (k = 0; k < 4; k++) {
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trail_surrogate <<= 4;
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ch = *input++;
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bin = ws_xton(ch);
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if (bin == -1)
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return FALSE;
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trail_surrogate |= bin;
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}
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if ((!IS_TRAIL_SURROGATE(trail_surrogate)))
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return FALSE;
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unicode_hex = SURROGATE_VALUE(lead_surrogate,trail_surrogate);
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} else if ((IS_TRAIL_SURROGATE(unicode_hex))) {
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return FALSE;
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}
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if (!g_unichar_validate(unicode_hex))
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return FALSE;
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/* Don't allow NUL byte injection. */
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if (unicode_hex == 0)
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return FALSE;
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/* \uXXXX => 6 bytes, and g_unichar_to_utf8() requires to have output buffer at least 6 bytes -> OK. */
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k = g_unichar_to_utf8(unicode_hex, output);
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output += k;
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break;
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}
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default:
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return FALSE;
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}
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} else {
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*output = ch;
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output++;
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}
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}
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*output = '\0';
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return TRUE;
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 noexpandtab:
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* :indentSize=4:tabSize=8:noTabs=false:
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*/
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