lbbs/src/bwf.c

/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * bwf
 *   - bad words filter
 *
 * Copyright (C) 2004-2025  Leaflet <leaflet@leafok.com>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#define PCRE2_CODE_UNIT_WIDTH 8

#include "bwf.h"
#include "log.h"
#include <errno.h>
#include <pcre2.h>
#include <stdio.h>
#include <string.h>

enum _bwf_constant_t
{
        BWF_max_pattern_len = 64,
        BWF_max_pattern_cnt = 1000,
};

static char bwf_pattern_str[(BWF_max_pattern_len + 1) * BWF_max_pattern_cnt];
static pcre2_code *bwf_code = NULL;

int bwf_load(const char *filename)
{
        FILE *fp;
        char line[BWF_max_pattern_len + 1];
        size_t len_line;
        char *p = bwf_pattern_str;
        int line_id = 0;

        if (filename == NULL)
        {
                log_error("NULL pointer error\n");
                return -1;
        }

        if ((fp = fopen(filename, "r")) == NULL)
        {
                log_error("fopen(%s) error: %d\n", filename, errno);
                return -2;
        }

        while (fgets(line, sizeof(line), fp) != NULL)
        {
                len_line = strnlen(line, sizeof(line) - 1);
                if (!feof(fp) && line[len_line - 1] != '\n')
                {
                        log_error("Data line %d (len=%d) is truncated\n", line_id, len_line);
                        bwf_pattern_str[0] = '\0';
                        return -3;
                }

                while (len_line > 0 && (line[len_line - 1] == '\n' || line[len_line - 1] == '\r'))
                {
                        line[len_line - 1] = '\0';
                        len_line--;
                }

                if (len_line == 0)
                {
                        continue;
                }

                if (p > bwf_pattern_str)
                {
                        *p++ = '|';
                }

                if (len_line + 2 > sizeof(bwf_pattern_str) - 1 - (size_t)(p - bwf_pattern_str))
                {
                        log_error("Data in %s exceed length limit %d\n", filename, sizeof(bwf_pattern_str) - 1);
                        bwf_pattern_str[0] = '\0';
                        return -3;
                }

                *p++ = '(';
                p = mempcpy(p, line, strnlen(line, sizeof(bwf_pattern_str) - 1 - (size_t)(p - bwf_pattern_str)));
                *p++ = ')';
                line_id++;
        }

        *p = '\0';

        fclose(fp);

#ifdef _DEBUG
        log_error("Debug: bwf_pattern_str: %s\n", bwf_pattern_str);
#endif

        return 0;
}

int bwf_compile(void)
{
        int errorcode;
        PCRE2_SIZE erroroffset;

        bwf_cleanup();

        bwf_code = pcre2_compile((PCRE2_SPTR)bwf_pattern_str, PCRE2_ZERO_TERMINATED, PCRE2_CASELESS, &errorcode, &erroroffset, NULL);
        if (bwf_code == NULL)
        {
                log_error("pcre2_compile() error: %d", errorcode);
                return -1;
        }

        return 0;
}

void bwf_cleanup(void)
{
        if (bwf_code != NULL)
        {
                pcre2_code_free(bwf_code);
                bwf_code = NULL;
        }
}

int check_badwords(char *str, char c_mask)
{
        pcre2_match_data *match_data;
        PCRE2_SIZE startoffset = 0;
        PCRE2_SIZE *ovector;
        uint32_t match_count;
        int ret;
        int i;
        int total_match_count = 0;

        if (bwf_code == NULL)
        {
                log_error("BWF not loaded\n");
                return -1;
        }

        match_data = pcre2_match_data_create_from_pattern(bwf_code, NULL);

        while (1)
        {
                ret = pcre2_match(bwf_code, (PCRE2_SPTR)str, PCRE2_ZERO_TERMINATED, startoffset, 0, match_data, NULL);
                if (ret == PCRE2_ERROR_NOMATCH)
                {
                        ret = total_match_count;
                        break;
                }
                else if (ret < 0)
                {
                        log_error("pcre2_match() error: %d\n", ret);
                }
                else if (ret == 0)
                {
                        log_error("Vector of offsets is too small\n");
                }
                else // ret >= 1
                {
                        ovector = pcre2_get_ovector_pointer(match_data);
                        match_count = pcre2_get_ovector_count(match_data);

                        i = ret - 1;
                        if (ovector[i * 2] == -1 || ovector[i * 2 + 1] == -1)
                        {
                                log_error("Bug: match pattern #%d of %d with invalid offsets [%d, %d)",
                                                  i, match_count, ovector[i * 2], ovector[i * 2 + 1]);
                                ret = -2;
                        }
                        else
                        {
#ifdef _DEBUG
                                log_error("Debug: match pattern #%d of %d at offsets [%d, %d]\n",
                                                  i, match_count, ovector[i * 2], ovector[i * 2 + 1] - ovector[i * 2]);
#endif
                                memset(str + ovector[i * 2], c_mask, ovector[i * 2 + 1] - ovector[i * 2]);
                                total_match_count++;
                                startoffset = ovector[i * 2 + 1];
                        }
                }
        }

        pcre2_match_data_free(match_data);

        return ret;
}
1	sysadm	1.1	/* SPDX-License-Identifier: GPL-3.0-or-later */
2			/*
3			* bwf
4			* - bad words filter
5			*
6			* Copyright (C) 2004-2025 Leaflet <leaflet@leafok.com>
7			*/
8
9	sysadm	1.5	#ifdef HAVE_CONFIG_H
10			#include "config.h"
11			#endif
12
13	sysadm	1.1	#define PCRE2_CODE_UNIT_WIDTH 8
14
15			#include "bwf.h"
16			#include "log.h"
17			#include <errno.h>
18			#include <pcre2.h>
19			#include <stdio.h>
20			#include <string.h>
21
22			enum _bwf_constant_t
23			{
24			BWF_max_pattern_len = 64,
25			BWF_max_pattern_cnt = 1000,
26			};
27
28			static char bwf_pattern_str[(BWF_max_pattern_len + 1) * BWF_max_pattern_cnt];
29			static pcre2_code *bwf_code = NULL;
30
31			int bwf_load(const char *filename)
32			{
33			FILE *fp;
34			char line[BWF_max_pattern_len + 1];
35			size_t len_line;
36			char *p = bwf_pattern_str;
37			int line_id = 0;
38
39			if (filename == NULL)
40			{
41			log_error("NULL pointer error\n");
42			return -1;
43			}
44
45			if ((fp = fopen(filename, "r")) == NULL)
46			{
47			log_error("fopen(%s) error: %d\n", filename, errno);
48			return -2;
49			}
50
51			while (fgets(line, sizeof(line), fp) != NULL)
52			{
53			len_line = strnlen(line, sizeof(line) - 1);
54			if (!feof(fp) && line[len_line - 1] != '\n')
55			{
56			log_error("Data line %d (len=%d) is truncated\n", line_id, len_line);
57			bwf_pattern_str[0] = '\0';
58			return -3;
59			}
60
61	sysadm	1.4	while (len_line > 0 && (line[len_line - 1] == '\n' \|\| line[len_line - 1] == '\r'))
62	sysadm	1.1	{
63			line[len_line - 1] = '\0';
64	sysadm	1.4	len_line--;
65			}
66
67			if (len_line == 0)
68			{
69			continue;
70	sysadm	1.1	}
71
72			if (p > bwf_pattern_str)
73			{
74			*p++ = '\|';
75			}
76
77			if (len_line + 2 > sizeof(bwf_pattern_str) - 1 - (size_t)(p - bwf_pattern_str))
78			{
79			log_error("Data in %s exceed length limit %d\n", filename, sizeof(bwf_pattern_str) - 1);
80			bwf_pattern_str[0] = '\0';
81			return -3;
82			}
83
84			*p++ = '(';
85			p = mempcpy(p, line, strnlen(line, sizeof(bwf_pattern_str) - 1 - (size_t)(p - bwf_pattern_str)));
86			*p++ = ')';
87			line_id++;
88			}
89
90			*p = '\0';
91
92			fclose(fp);
93
94			#ifdef _DEBUG
95			log_error("Debug: bwf_pattern_str: %s\n", bwf_pattern_str);
96			#endif
97
98	sysadm	1.6	return 0;
99			}
100
101			int bwf_compile(void)
102			{
103			int errorcode;
104			PCRE2_SIZE erroroffset;
105
106			bwf_cleanup();
107	sysadm	1.3
108	sysadm	1.1	bwf_code = pcre2_compile((PCRE2_SPTR)bwf_pattern_str, PCRE2_ZERO_TERMINATED, PCRE2_CASELESS, &errorcode, &erroroffset, NULL);
109			if (bwf_code == NULL)
110			{
111			log_error("pcre2_compile() error: %d", errorcode);
112	sysadm	1.6	return -1;
113	sysadm	1.1	}
114
115			return 0;
116			}
117
118	sysadm	1.6	void bwf_cleanup(void)
119	sysadm	1.1	{
120			if (bwf_code != NULL)
121			{
122			pcre2_code_free(bwf_code);
123			bwf_code = NULL;
124			}
125			}
126
127			int check_badwords(char *str, char c_mask)
128			{
129			pcre2_match_data *match_data;
130	sysadm	1.3	PCRE2_SIZE startoffset = 0;
131	sysadm	1.1	PCRE2_SIZE *ovector;
132	sysadm	1.3	uint32_t match_count;
133	sysadm	1.1	int ret;
134			int i;
135	sysadm	1.3	int total_match_count = 0;
136	sysadm	1.1
137			if (bwf_code == NULL)
138			{
139			log_error("BWF not loaded\n");
140			return -1;
141			}
142
143			match_data = pcre2_match_data_create_from_pattern(bwf_code, NULL);
144
145	sysadm	1.3	while (1)
146	sysadm	1.1	{
147	sysadm	1.3	ret = pcre2_match(bwf_code, (PCRE2_SPTR)str, PCRE2_ZERO_TERMINATED, startoffset, 0, match_data, NULL);
148			if (ret == PCRE2_ERROR_NOMATCH)
149			{
150			ret = total_match_count;
151			break;
152			}
153			else if (ret < 0)
154			{
155			log_error("pcre2_match() error: %d\n", ret);
156			}
157			else if (ret == 0)
158	sysadm	1.1	{
159	sysadm	1.3	log_error("Vector of offsets is too small\n");
160	sysadm	1.1	}
161	sysadm	1.3	else // ret >= 1
162	sysadm	1.1	{
163	sysadm	1.3	ovector = pcre2_get_ovector_pointer(match_data);
164			match_count = pcre2_get_ovector_count(match_data);
165
166			i = ret - 1;
167			if (ovector[i * 2] == -1 \|\| ovector[i * 2 + 1] == -1)
168			{
169			log_error("Bug: match pattern #%d of %d with invalid offsets [%d, %d)",
170			i, match_count, ovector[i * 2], ovector[i * 2 + 1]);
171			ret = -2;
172			}
173			else
174			{
175	sysadm	1.1	#ifdef _DEBUG
176	sysadm	1.3	log_error("Debug: match pattern #%d of %d at offsets [%d, %d]\n",
177			i, match_count, ovector[i * 2], ovector[i * 2 + 1] - ovector[i * 2]);
178	sysadm	1.1	#endif
179	sysadm	1.3	memset(str + ovector[i * 2], c_mask, ovector[i * 2 + 1] - ovector[i * 2]);
180			total_match_count++;
181			startoffset = ovector[i * 2 + 1];
182			}
183	sysadm	1.1	}
184			}
185
186			pcre2_match_data_free(match_data);
187
188			return ret;
189			}
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