forked from osmocom/wireshark
149 lines
3.3 KiB
C
149 lines
3.3 KiB
C
/*
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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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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include "regex.h"
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#include <wsutil/ws_return.h>
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#include <pcre2.h>
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struct _ws_regex {
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pcre2_code *code;
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char *pattern;
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};
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#define ERROR_MAXLEN_IN_CODE_UNITS 128
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static char *
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get_error_msg(int errorcode)
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{
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char *buffer;
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/*
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* We have to provide a buffer and we don't know how long the
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* error message is or even the maximum size. From pcre2api(3):
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* "None of the messages are very long; a
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* buffer size of 120 code units is ample."
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*/
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/* Code unit = one byte */
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buffer = g_malloc(ERROR_MAXLEN_IN_CODE_UNITS);
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/* Message is returned with a trailing zero. */
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pcre2_get_error_message(errorcode, buffer, ERROR_MAXLEN_IN_CODE_UNITS);
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/* One more at the end for good luck. */
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buffer[ERROR_MAXLEN_IN_CODE_UNITS-1] = '\0';
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return buffer;
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}
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static pcre2_code *
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compile_pcre2(const char *patt, char **errmsg)
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{
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pcre2_code *code;
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int errorcode;
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PCRE2_SIZE erroroffset;
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/* By default UTF-8 is off. */
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code = pcre2_compile_8((PCRE2_SPTR)patt,
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PCRE2_ZERO_TERMINATED,
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PCRE2_NEVER_UTF,
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&errorcode,
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&erroroffset,
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NULL);
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if (code == NULL) {
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*errmsg = get_error_msg(errorcode);
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return NULL;
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}
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return code;
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}
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ws_regex_t *
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ws_regex_compile(const char *patt, char **errmsg)
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{
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ws_return_val_if_null(patt, NULL);
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pcre2_code *code = compile_pcre2(patt, errmsg);
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if (code == NULL)
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return NULL;
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ws_regex_t *re = g_new(ws_regex_t, 1);
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re->code = code;
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re->pattern = g_strdup(patt);
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return re;
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}
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static bool
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match_pcre2(pcre2_code *code, const char *subj, ssize_t subj_size)
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{
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PCRE2_SIZE length;
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pcre2_match_data *match_data;
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int rc;
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length = subj_size < 0 ? PCRE2_ZERO_TERMINATED : (PCRE2_SIZE)subj_size;
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/* We don't use the matched substring but pcre2_match requires
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* at least one pair of offsets. */
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match_data = pcre2_match_data_create(1, NULL);
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rc = pcre2_match(code,
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subj,
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length,
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0, /* start at offset zero of the subject */
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0, /* default options */
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match_data,
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NULL);
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pcre2_match_data_free(match_data);
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if (rc < 0) {
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/* No match */
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if (rc != PCRE2_ERROR_NOMATCH) {
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/* Error. Should not happen with UTF-8 disabled. Some huge
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* subject strings could hit some internal limit. */
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char *msg = get_error_msg(rc);
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ws_debug("Unexpected pcre2_match() error: %s.", msg);
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g_free(msg);
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}
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return FALSE;
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}
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/* Matched */
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return TRUE;
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}
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bool
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ws_regex_matches(const ws_regex_t *re, const char *subj, ssize_t subj_size)
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{
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ws_return_val_if_null(re, FALSE);
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ws_return_val_if_null(subj, FALSE);
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return match_pcre2(re->code, subj, subj_size);
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}
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void
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ws_regex_free(ws_regex_t *re)
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{
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pcre2_code_free(re->code);
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g_free(re->pattern);
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g_free(re);
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}
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const char *
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ws_regex_pattern(const ws_regex_t *re)
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{
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return re->pattern;
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}
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