imapfilter/imapfilter/file.c

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <regex.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/stat.h>

#include "config.h"
#include "imapfilter.h"
#include "file.h"
#include "log.h"


extern char logfile[PATH_MAX];

account_t *accounts = NULL;     /* All accounts. */

filter_t *dfilters;             /* Filters of DENY type. */
filter_t *afilters;             /* Filters of ALLOW type. */

unsigned int dlimit = 0;
unsigned int alimit = 0;        /* DENY and ALLOW message size limits. */


/*
 * Finds path to configuration file, opens it and calls parse_config().
 */
int read_config(char *cfg)
{
    int r;
    FILE *fp;
    char *home = NULL;

    if (!cfg) {
        cfg = (char *) malloc(PATH_MAX * sizeof(char));


        home = getenv("HOME");

        snprintf(cfg, PATH_MAX, "%s/%s", home, ".imapfilterrc");
    }
#ifdef DEBUG
    printf("debug: configuration file: %s\n", cfg);
#endif

    check_permissions(cfg);

    fp = fopen(cfg, "r");

    if (!fp) {
        fprintf(stderr, "imapfilter: opening config file %s; %s\n",
                cfg, strerror(errno));
        return 1;
    }

    r = parse_config(fp);

    fclose(fp);

    return r;
}


/*
 * Checks the permissions of the configuration file.
 */
int check_permissions(char *cfg)
{
    struct stat fs;

    if (stat(cfg, &fs)) {
        fprintf(stderr, "imapfilter: getting file %s status; %s\n", cfg,
                strerror(errno));
        return 1;
    }

    if (!S_ISREG(fs.st_mode)) {
        fprintf(stderr, "imapfilter: file %s not a regular file\n", cfg);
        return 1;
    }

    if ((fs.st_mode & 00777) != (S_IRUSR | S_IWUSR)) {
        fprintf(stderr,
                "imapfilter: warning: bad config file %s permissions\n"
                "imapfilter: warning: file's mode should be 600 not %o\n",
                cfg, fs.st_mode & 00777);
        return 1;
    }

    return 0;
}


/*
 * Parses configuration file.
 */
int parse_config(FILE * fp)
{
    int i;
    unsigned int row = 0;
    char line[LINE_MAX];
    regex_t creg[5];
    regmatch_t match[4];
    const char *reg[5] = {
        "^[[:blank:]]*(SERVER|PORT|USERNAME|PASSWORD|LOGFILE)[[:blank:]]*=[[:blank:]]*([[:graph:]]*)[[:blank:]]*",
        "^[[:blank:]]*(DENY|ALLOW)[[:blank:]]*=[[:blank:]]*(FROM|CC|BCC|SUBJECT|TO):? ([[:print:]]*)",
        "^[[:blank:]]*(DENY|ALLOW)[[:blank:]]*=[[:blank:]]*([[:graph:]]+):? ([[:print:]]*)",
        "^[[:blank:]]*(DENY_LIMIT|ALLOW_LIMIT)[[:blank:]]*=[[:blank:]]*([[:digit:]]*)[[:blank:]]*",
        "^[[:blank:]]*#{0,1}.*"
    };

    for (i = 0; i < 5; i++)
        regcomp(&creg[i], reg[i], REG_EXTENDED);

    while (fgets(line, LINE_MAX - 1, fp)) {
        row++;
        if (!regexec(&creg[0], line, 3, match, 0)) {
            if (set_account(line, match))
                return 1;
            continue;
        } else if (!regexec(&creg[1], line, 4, match, 0)) {
            if (standard_filter(line, match))
                return 1;
            continue;
        } else if (!regexec(&creg[2], line, 4, match, 0)) {
            if (custom_filter(line, match))
                return 1;
            continue;
        } else if (!regexec(&creg[3], line, 3, match, 0)) {
            set_limits(line, match);
            continue;
        } else if (!regexec(&creg[4], line, 1, match, 0))
            continue;
        else {
            fprintf(stderr,
                    "imapfilter: parse error in config file at row %d\n",
                    row);
            return 1;
        }
    }

    /* Fail if no accounts were defined. */
    if (!accounts) {
        fprintf(stderr,
                "imapfilter: no accounts defined in config file\n");
        return 1;
    }

    /* Fail if no filters were defined. */
    if (!dfilters && !afilters) {
        fprintf(stderr, "imapfilter: no filters defined in config file\n");
        return 1;
    }

    return 0;
}


/*
 * Allocates memory for accounts, builds linked list, and NULL terminates
 * account settings.
 */
account_t *prepare_account(void)
{
    static account_t *ca;       /* Current account. */

    if (!accounts) {
        accounts = (account_t *) malloc(sizeof(account_t));
        if (!accounts) {
            error("imapfilter: allocating memory; %s\n", strerror(errno));
            return NULL;
        }
        ca = accounts;
    } else {
        ca->next = (account_t *) malloc(sizeof(account_t));
        if (!ca->next) {
            error("imapfilter: allocating memory; %s\n", strerror(errno));
            return NULL;
        }
        ca = ca->next;
    }

    ca->next = NULL;

    ca->server[0] = 0;
    ca->port = 143;
    ca->userid[0] = 0;
    ca->passwd[0] = 0;

    return ca;
}


/*
 * An account setting was found from parse_config(), changes the
 * apropriate variable.
 */
int set_account(char *line, regmatch_t * match)
{
    int s;
    char p[6];
    static account_t *ca;

    if (!strncmp(line + match[1].rm_so, "SERVER", 6)) {
        if (!(ca = prepare_account()))
            return 1;
        s = min((match[2].rm_eo - match[2].rm_so), SERVER_MAX - 1);
        strncpy(ca->server, line + match[2].rm_so, s);
        ca->server[s] = 0;
#ifdef DEBUG
        printf("debug: account setting SERVER: '%s'\n", ca->server);
#endif
    } else if (accounts) {
        if (!strncmp(line + match[1].rm_so, "PORT", 4)) {
            s = min((match[2].rm_eo - match[2].rm_so), sizeof(p));
            strncpy(p, line + match[2].rm_so, s);
            p[s] = 0;
            ca->port = strtoul(p, NULL, 0);
#ifdef DEBUG
            printf("debug: account setting PORT: '%d'\n", ca->port);
#endif
        } else if (!strncmp(line + match[1].rm_so, "USERNAME", 8)) {
            s = min((match[2].rm_eo - match[2].rm_so), USERID_MAX - 1);
            strncpy(ca->userid, line + match[2].rm_so, s);
            ca->userid[s] = 0;
#ifdef DEBUG
            printf("debug: account setting USERNAME: '%s'\n", ca->userid);
#endif
        } else if (!strncmp(line + match[1].rm_so, "PASSWORD", 8)) {
            s = min((match[2].rm_eo - match[2].rm_so), PASSWD_MAX - 1);
            strncpy(ca->passwd, line + match[2].rm_so, s);
            ca->passwd[s] = 0;
#ifdef DEBUG
            printf("debug: account setting PASSWORD: '%s'\n", ca->passwd);
#endif
        } else if (!logfile[0]
                   && !strncmp(line + match[1].rm_so, "LOGFILE", 7)) {
            s = min((match[2].rm_eo - match[2].rm_so), PATH_MAX - 1);
            strncpy(logfile, line + match[2].rm_so, s);
            logfile[s] = 0;
        }
    }

    return 0;
}


/*
 * A filter entry was found from parse_config() processes it and saves it.
 */
int set_filters(char *line, regmatch_t * match, int csm)
{
    int s;
    static filter_t *cdf, *caf;
    filter_t **cf;
    filter_t **fl;

    if (!(strncmp(line + match[1].rm_so, "DENY", 4))) {
#ifdef DEBUG
        printf("debug: filter entry: DENY");
#endif
        cf = &cdf;
        fl = &dfilters;
    } else {
#ifdef DEBUG
        printf("debug: filter entry: ALLOW");
#endif
        cf = &caf;
        fl = &afilters;
    }

    /*
     * Allocate memory for filter entry and build linked list.
     */

    if (!(*fl)) {
        *fl = (filter_t *) malloc(sizeof(filter_t));
        if (!(*fl)) {
            error("imapfilter: allocating memory; %s\n", strerror(errno));
            return 1;
        }
        *cf = *fl;
    } else {
        (*cf)->next = (filter_t *) malloc(sizeof(filter_t));
        if (!((*cf)->next)) {
            error("imapfilter: allocating memory; %s\n", strerror(errno));
            return 1;
        }
        *cf = (*cf)->next;
    }

    (*cf)->next = NULL;

    (*cf)->custom = csm;

    s = min((match[2].rm_eo - match[2].rm_so), FIELD_NAME_MAX - 1);
    strncpy((*cf)->name, line + match[2].rm_so, s);
    (*cf)->name[s] = 0;

    s = min((match[3].rm_eo - match[3].rm_so), FIELD_BODY_MAX - 1);
    strncpy((*cf)->body, line + match[3].rm_so, s);
    (*cf)->body[s] = 0;

#ifdef DEBUG
    printf(" '%s': '%s'\n", (*cf)->name, (*cf)->body);
#endif
    return 0;
}


/*
 * Sets the DENY and ALLOW limits from the values found in config file.
 */
void set_limits(char *line, regmatch_t * match)
{
    int s;
    char lim[10];

    s = min((match[2].rm_eo - match[2].rm_so), sizeof(lim));
    strncpy(lim, line + match[2].rm_so, s);
    lim[s] = 0;

    if (!strncmp(line + match[1].rm_so, "DENY_LIMIT", 10)) {
        dlimit = strtoul(lim, NULL, 0);
    } else {
        alimit = strtoul(lim, NULL, 0);
    }
}
1	lefcha	1.1	#include <stdio.h>
2			#include <errno.h>
3	lefcha	1.5	#include <sys/types.h>
4	lefcha	1.1	#include <regex.h>
5			#include <string.h>
6			#include <stdlib.h>
7			#include <limits.h>
8	lefcha	1.10	#include <sys/stat.h>
9	lefcha	1.1
10			#include "config.h"
11			#include "imapfilter.h"
12			#include "file.h"
13			#include "log.h"
14
15
16	lefcha	1.6	extern char logfile[PATH_MAX];
17	lefcha	1.8
18			account_t accounts = NULL; / All accounts. */
19
20			filter_t dfilters; / Filters of DENY type. */
21			filter_t afilters; / Filters of ALLOW type. */
22
23	lefcha	1.4	unsigned int dlimit = 0;
24			unsigned int alimit = 0; /* DENY and ALLOW message size limits. */
25	lefcha	1.1
26
27			/*
28			* Finds path to configuration file, opens it and calls parse_config().
29			*/
30			int read_config(char *cfg)
31			{
32			int r;
33			FILE *fp;
34			char *home = NULL;
35
36			if (!cfg) {
37			cfg = (char ) malloc(PATH_MAX sizeof(char));
38
39	lefcha	1.8
40	lefcha	1.1	home = getenv("HOME");
41
42			snprintf(cfg, PATH_MAX, "%s/%s", home, ".imapfilterrc");
43			}
44			#ifdef DEBUG
45			printf("debug: configuration file: %s\n", cfg);
46			#endif
47
48	lefcha	1.10	check_permissions(cfg);
49
50	lefcha	1.1	fp = fopen(cfg, "r");
51
52			if (!fp) {
53	lefcha	1.7	fprintf(stderr, "imapfilter: opening config file %s; %s\n",
54	lefcha	1.1	cfg, strerror(errno));
55	lefcha	1.8	return 1;
56	lefcha	1.1	}
57
58			r = parse_config(fp);
59
60			fclose(fp);
61
62			return r;
63			}
64
65	lefcha	1.6
66	lefcha	1.1	/*
67	lefcha	1.10	* Checks the permissions of the configuration file.
68			*/
69			int check_permissions(char *cfg)
70			{
71			struct stat fs;
72
73			if (stat(cfg, &fs)) {
74			fprintf(stderr, "imapfilter: getting file %s status; %s\n", cfg,
75			strerror(errno));
76			return 1;
77			}
78
79			if (!S_ISREG(fs.st_mode)) {
80			fprintf(stderr, "imapfilter: file %s not a regular file\n", cfg);
81			return 1;
82			}
83
84			if ((fs.st_mode & 00777) != (S_IRUSR \| S_IWUSR)) {
85			fprintf(stderr,
86			"imapfilter: warning: bad config file %s permissions\n"
87			"imapfilter: warning: file's mode should be 600 not %o\n",
88			cfg, fs.st_mode & 00777);
89			return 1;
90			}
91
92			return 0;
93			}
94
95
96			/*
97	lefcha	1.1	* Parses configuration file.
98			*/
99			int parse_config(FILE * fp)
100			{
101			int i;
102			unsigned int row = 0;
103			char line[LINE_MAX];
104	lefcha	1.8	regex_t creg[5];
105	lefcha	1.2	regmatch_t match[4];
106	lefcha	1.4	const char *reg[5] = {
107	lefcha	1.1	"^[[:blank:]](SERVER\|PORT\|USERNAME\|PASSWORD\|LOGFILE)[[:blank:]]=[[:blank:]]([[:graph:]])[[:blank:]]*",
108	lefcha	1.2	"^[[:blank:]](DENY\|ALLOW)[[:blank:]]=[[:blank:]](FROM\|CC\|BCC\|SUBJECT\|TO):? ([[:print:]])",
109			"^[[:blank:]](DENY\|ALLOW)[[:blank:]]=[[:blank:]]([[:graph:]]+):? ([[:print:]])",
110	lefcha	1.4	"^[[:blank:]](DENY_LIMIT\|ALLOW_LIMIT)[[:blank:]]=[[:blank:]]([[:digit:]])[[:blank:]]*",
111	lefcha	1.1	"^[[:blank:]]#{0,1}."
112			};
113
114	lefcha	1.4	for (i = 0; i < 5; i++)
115	lefcha	1.8	regcomp(&creg[i], reg[i], REG_EXTENDED);
116	lefcha	1.1
117			while (fgets(line, LINE_MAX - 1, fp)) {
118			row++;
119	lefcha	1.8	if (!regexec(&creg[0], line, 3, match, 0)) {
120	lefcha	1.9	if (set_account(line, match))
121			return 1;
122	lefcha	1.1	continue;
123	lefcha	1.8	} else if (!regexec(&creg[1], line, 4, match, 0)) {
124	lefcha	1.9	if (standard_filter(line, match))
125			return 1;
126	lefcha	1.1	continue;
127	lefcha	1.8	} else if (!regexec(&creg[2], line, 4, match, 0)) {
128	lefcha	1.9	if (custom_filter(line, match))
129			return 1;
130	lefcha	1.1	continue;
131	lefcha	1.8	} else if (!regexec(&creg[3], line, 3, match, 0)) {
132	lefcha	1.4	set_limits(line, match);
133			continue;
134	lefcha	1.8	} else if (!regexec(&creg[4], line, 1, match, 0))
135	lefcha	1.1	continue;
136			else {
137			fprintf(stderr,
138			"imapfilter: parse error in config file at row %d\n",
139			row);
140	lefcha	1.8	return 1;
141	lefcha	1.1	}
142			}
143	lefcha	1.3
144	lefcha	1.6	/* Fail if no accounts were defined. */
145	lefcha	1.8	if (!accounts) {
146	lefcha	1.6	fprintf(stderr,
147			"imapfilter: no accounts defined in config file\n");
148	lefcha	1.8	return 1;
149	lefcha	1.6	}
150
151	lefcha	1.8	/* Fail if no filters were defined. */
152			if (!dfilters && !afilters) {
153	lefcha	1.3	fprintf(stderr, "imapfilter: no filters defined in config file\n");
154	lefcha	1.8	return 1;
155	lefcha	1.3	}
156	lefcha	1.6
157	lefcha	1.8	return 0;
158	lefcha	1.1	}
159
160
161			/*
162	lefcha	1.9	* Allocates memory for accounts, builds linked list, and NULL terminates
163	lefcha	1.8	* account settings.
164	lefcha	1.4	*/
165	lefcha	1.8	account_t *prepare_account(void)
166	lefcha	1.4	{
167	lefcha	1.8	static account_t ca; / Current account. */
168
169			if (!accounts) {
170			accounts = (account_t *) malloc(sizeof(account_t));
171	lefcha	1.9	if (!accounts) {
172			error("imapfilter: allocating memory; %s\n", strerror(errno));
173			return NULL;
174	lefcha	1.10	}
175	lefcha	1.8	ca = accounts;
176			} else {
177			ca->next = (account_t *) malloc(sizeof(account_t));
178	lefcha	1.9	if (!ca->next) {
179			error("imapfilter: allocating memory; %s\n", strerror(errno));
180			return NULL;
181			}
182	lefcha	1.8	ca = ca->next;
183			}
184
185			ca->next = NULL;
186
187			ca->server[0] = 0;
188			ca->port = 143;
189			ca->userid[0] = 0;
190			ca->passwd[0] = 0;
191	lefcha	1.6
192	lefcha	1.8	return ca;
193	lefcha	1.4	}
194
195
196			/*
197	lefcha	1.1	* An account setting was found from parse_config(), changes the
198			* apropriate variable.
199			*/
200	lefcha	1.9	int set_account(char line, regmatch_t match)
201	lefcha	1.1	{
202			int s;
203	lefcha	1.8	char p[6];
204			static account_t *ca;
205	lefcha	1.1
206			if (!strncmp(line + match[1].rm_so, "SERVER", 6)) {
207	lefcha	1.9	if (!(ca = prepare_account()))
208			return 1;
209	lefcha	1.1	s = min((match[2].rm_eo - match[2].rm_so), SERVER_MAX - 1);
210	lefcha	1.8	strncpy(ca->server, line + match[2].rm_so, s);
211			ca->server[s] = 0;
212	lefcha	1.6	#ifdef DEBUG
213	lefcha	1.8	printf("debug: account setting SERVER: '%s'\n", ca->server);
214	lefcha	1.6	#endif
215	lefcha	1.8	} else if (accounts) {
216	lefcha	1.6	if (!strncmp(line + match[1].rm_so, "PORT", 4)) {
217	lefcha	1.8	s = min((match[2].rm_eo - match[2].rm_so), sizeof(p));
218			strncpy(p, line + match[2].rm_so, s);
219			p[s] = 0;
220			ca->port = strtoul(p, NULL, 0);
221	lefcha	1.6	#ifdef DEBUG
222	lefcha	1.8	printf("debug: account setting PORT: '%d'\n", ca->port);
223	lefcha	1.7	#endif
224	lefcha	1.6	} else if (!strncmp(line + match[1].rm_so, "USERNAME", 8)) {
225	lefcha	1.8	s = min((match[2].rm_eo - match[2].rm_so), USERID_MAX - 1);
226			strncpy(ca->userid, line + match[2].rm_so, s);
227			ca->userid[s] = 0;
228	lefcha	1.6	#ifdef DEBUG
229	lefcha	1.8	printf("debug: account setting USERNAME: '%s'\n", ca->userid);
230	lefcha	1.7	#endif
231	lefcha	1.6	} else if (!strncmp(line + match[1].rm_so, "PASSWORD", 8)) {
232	lefcha	1.8	s = min((match[2].rm_eo - match[2].rm_so), PASSWD_MAX - 1);
233			strncpy(ca->passwd, line + match[2].rm_so, s);
234			ca->passwd[s] = 0;
235	lefcha	1.6	#ifdef DEBUG
236	lefcha	1.8	printf("debug: account setting PASSWORD: '%s'\n", ca->passwd);
237	lefcha	1.6	#endif
238	lefcha	1.10	} else if (!logfile[0]
239			&& !strncmp(line + match[1].rm_so, "LOGFILE", 7)) {
240	lefcha	1.6	s = min((match[2].rm_eo - match[2].rm_so), PATH_MAX - 1);
241			strncpy(logfile, line + match[2].rm_so, s);
242			logfile[s] = 0;
243			}
244	lefcha	1.1	}
245	lefcha	1.10
246	lefcha	1.9	return 0;
247	lefcha	1.1	}
248
249
250			/*
251	lefcha	1.4	* A filter entry was found from parse_config() processes it and saves it.
252	lefcha	1.1	*/
253	lefcha	1.9	int set_filters(char line, regmatch_t match, int csm)
254	lefcha	1.1	{
255			int s;
256	lefcha	1.8	static filter_t cdf, caf;
257			filter_t **cf;
258			filter_t **fl;
259	lefcha	1.2
260			if (!(strncmp(line + match[1].rm_so, "DENY", 4))) {
261			#ifdef DEBUG
262			printf("debug: filter entry: DENY");
263			#endif
264	lefcha	1.8	cf = &cdf;
265			fl = &dfilters;
266	lefcha	1.2	} else {
267			#ifdef DEBUG
268			printf("debug: filter entry: ALLOW");
269			#endif
270	lefcha	1.8	cf = &caf;
271			fl = &afilters;
272	lefcha	1.2	}
273	lefcha	1.1
274	lefcha	1.8	/*
275			* Allocate memory for filter entry and build linked list.
276			*/
277
278			if (!(*fl)) {
279			fl = (filter_t ) malloc(sizeof(filter_t));
280	lefcha	1.9	if (!(*fl)) {
281			error("imapfilter: allocating memory; %s\n", strerror(errno));
282			return 1;
283	lefcha	1.10	}
284	lefcha	1.8	cf = fl;
285			} else {
286			(cf)->next = (filter_t ) malloc(sizeof(filter_t));
287	lefcha	1.9	if (!((*cf)->next)) {
288			error("imapfilter: allocating memory; %s\n", strerror(errno));
289			return 1;
290			}
291	lefcha	1.8	cf = (cf)->next;
292			}
293	lefcha	1.2
294	lefcha	1.8	(*cf)->next = NULL;
295	lefcha	1.2
296	lefcha	1.8	(*cf)->custom = csm;
297	lefcha	1.2
298			s = min((match[2].rm_eo - match[2].rm_so), FIELD_NAME_MAX - 1);
299	lefcha	1.8	strncpy((*cf)->name, line + match[2].rm_so, s);
300			(*cf)->name[s] = 0;
301	lefcha	1.2
302			s = min((match[3].rm_eo - match[3].rm_so), FIELD_BODY_MAX - 1);
303	lefcha	1.8	strncpy((*cf)->body, line + match[3].rm_so, s);
304			(*cf)->body[s] = 0;
305	lefcha	1.1
306			#ifdef DEBUG
307	lefcha	1.8	printf(" '%s': '%s'\n", (cf)->name, (cf)->body);
308	lefcha	1.1	#endif
309	lefcha	1.9	return 0;
310	lefcha	1.4	}
311
312
313			/*
314			* Sets the DENY and ALLOW limits from the values found in config file.
315			*/
316			void set_limits(char line, regmatch_t match)
317			{
318			int s;
319	lefcha	1.8	char lim[10];
320	lefcha	1.4
321	lefcha	1.8	s = min((match[2].rm_eo - match[2].rm_so), sizeof(lim));
322			strncpy(lim, line + match[2].rm_so, s);
323			lim[s] = 0;
324	lefcha	1.4
325			if (!strncmp(line + match[1].rm_so, "DENY_LIMIT", 10)) {
326	lefcha	1.8	dlimit = strtoul(lim, NULL, 0);
327	lefcha	1.4	} else {
328	lefcha	1.8	alimit = strtoul(lim, NULL, 0);
329	lefcha	1.4	}
330	lefcha	1.1	}