1 /*
2 * libxt_time - iptables part for xt_time
3 * Copyright © CC Computer Consultants GmbH, 2007
4 * Contact: <jengelh@computergmbh.de>
5 *
6 * libxt_time.c is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 or 3 of the License.
9 *
10 * Based on libipt_time.c.
11 */
12 #include <stdio.h>
13 #include <string.h>
14 #include <stdlib.h>
15 #include <time.h>
16 #include <linux/types.h>
17 #include <linux/netfilter/xt_time.h>
18 #include <xtables.h>
19
20 enum {
21 O_DATE_START = 0,
22 O_DATE_STOP,
23 O_TIME_START,
24 O_TIME_STOP,
25 O_TIME_CONTIGUOUS,
26 O_MONTHDAYS,
27 O_WEEKDAYS,
28 O_LOCAL_TZ,
29 O_UTC,
30 O_KERNEL_TZ,
31 F_LOCAL_TZ = 1 << O_LOCAL_TZ,
32 F_UTC = 1 << O_UTC,
33 F_KERNEL_TZ = 1 << O_KERNEL_TZ,
34 F_TIME_CONTIGUOUS = 1 << O_TIME_CONTIGUOUS,
35 };
36
37 static const char *const week_days[] = {
38 NULL, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun",
39 };
40
41 static const struct xt_option_entry time_opts[] = {
42 {.name = "datestart", .id = O_DATE_START, .type = XTTYPE_STRING},
43 {.name = "datestop", .id = O_DATE_STOP, .type = XTTYPE_STRING},
44 {.name = "timestart", .id = O_TIME_START, .type = XTTYPE_STRING},
45 {.name = "timestop", .id = O_TIME_STOP, .type = XTTYPE_STRING},
46 {.name = "contiguous", .id = O_TIME_CONTIGUOUS, .type = XTTYPE_NONE},
47 {.name = "weekdays", .id = O_WEEKDAYS, .type = XTTYPE_STRING,
48 .flags = XTOPT_INVERT},
49 {.name = "monthdays", .id = O_MONTHDAYS, .type = XTTYPE_STRING,
50 .flags = XTOPT_INVERT},
51 {.name = "localtz", .id = O_LOCAL_TZ, .type = XTTYPE_NONE,
52 .excl = F_UTC},
53 {.name = "utc", .id = O_UTC, .type = XTTYPE_NONE,
54 .excl = F_LOCAL_TZ | F_KERNEL_TZ},
55 {.name = "kerneltz", .id = O_KERNEL_TZ, .type = XTTYPE_NONE,
56 .excl = F_UTC},
57 XTOPT_TABLEEND,
58 };
59
time_help(void)60 static void time_help(void)
61 {
62 printf(
63 "time match options:\n"
64 " --datestart time Start and stop time, to be given in ISO 8601\n"
65 " --datestop time (YYYY[-MM[-DD[Thh[:mm[:ss]]]]])\n"
66 " --timestart time Start and stop daytime (hh:mm[:ss])\n"
67 " --timestop time (between 00:00:00 and 23:59:59)\n"
68 "[!] --monthdays value List of days on which to match, separated by comma\n"
69 " (Possible days: 1 to 31; defaults to all)\n"
70 "[!] --weekdays value List of weekdays on which to match, sep. by comma\n"
71 " (Possible days: Mon,Tue,Wed,Thu,Fri,Sat,Sun or 1 to 7\n"
72 " Defaults to all weekdays.)\n"
73 " --kerneltz Work with the kernel timezone instead of UTC\n");
74 }
75
time_init(struct xt_entry_match * m)76 static void time_init(struct xt_entry_match *m)
77 {
78 struct xt_time_info *info = (void *)m->data;
79
80 /* By default, we match on every day, every daytime */
81 info->monthdays_match = XT_TIME_ALL_MONTHDAYS;
82 info->weekdays_match = XT_TIME_ALL_WEEKDAYS;
83 info->daytime_start = XT_TIME_MIN_DAYTIME;
84 info->daytime_stop = XT_TIME_MAX_DAYTIME;
85
86 /* ...and have no date-begin or date-end boundary */
87 info->date_start = 0;
88 info->date_stop = INT_MAX;
89 }
90
time_parse_date(const char * s,bool end)91 static time_t time_parse_date(const char *s, bool end)
92 {
93 unsigned int month = 1, day = 1, hour = 0, minute = 0, second = 0;
94 unsigned int year = end ? 2038 : 1970;
95 const char *os = s;
96 struct tm tm;
97 time_t ret;
98 char *e;
99
100 year = strtoul(s, &e, 10);
101 if ((*e != '-' && *e != '\0') || year < 1970 || year > 2038)
102 goto out;
103 if (*e == '\0')
104 goto eval;
105
106 s = e + 1;
107 month = strtoul(s, &e, 10);
108 if ((*e != '-' && *e != '\0') || month > 12)
109 goto out;
110 if (*e == '\0')
111 goto eval;
112
113 s = e + 1;
114 day = strtoul(s, &e, 10);
115 if ((*e != 'T' && *e != '\0') || day > 31)
116 goto out;
117 if (*e == '\0')
118 goto eval;
119
120 s = e + 1;
121 hour = strtoul(s, &e, 10);
122 if ((*e != ':' && *e != '\0') || hour > 23)
123 goto out;
124 if (*e == '\0')
125 goto eval;
126
127 s = e + 1;
128 minute = strtoul(s, &e, 10);
129 if ((*e != ':' && *e != '\0') || minute > 59)
130 goto out;
131 if (*e == '\0')
132 goto eval;
133
134 s = e + 1;
135 second = strtoul(s, &e, 10);
136 if (*e != '\0' || second > 59)
137 goto out;
138
139 eval:
140 tm.tm_year = year - 1900;
141 tm.tm_mon = month - 1;
142 tm.tm_mday = day;
143 tm.tm_hour = hour;
144 tm.tm_min = minute;
145 tm.tm_sec = second;
146 tm.tm_isdst = 0;
147 /*
148 * Offsetting, if any, is done by xt_time.ko,
149 * so we have to disable it here in userspace.
150 */
151 setenv("TZ", "UTC", true);
152 tzset();
153 ret = mktime(&tm);
154 if (ret >= 0)
155 return ret;
156 perror("mktime");
157 xtables_error(OTHER_PROBLEM, "mktime returned an error");
158
159 out:
160 xtables_error(PARAMETER_PROBLEM, "Invalid date \"%s\" specified. Should "
161 "be YYYY[-MM[-DD[Thh[:mm[:ss]]]]]", os);
162 return -1;
163 }
164
time_parse_minutes(const char * s)165 static unsigned int time_parse_minutes(const char *s)
166 {
167 unsigned int hour, minute, second = 0;
168 char *e;
169
170 hour = strtoul(s, &e, 10);
171 if (*e != ':' || hour > 23)
172 goto out;
173
174 s = e + 1;
175 minute = strtoul(s, &e, 10);
176 if ((*e != ':' && *e != '\0') || minute > 59)
177 goto out;
178 if (*e == '\0')
179 goto eval;
180
181 s = e + 1;
182 second = strtoul(s, &e, 10);
183 if (*e != '\0' || second > 59)
184 goto out;
185
186 eval:
187 return 60 * 60 * hour + 60 * minute + second;
188
189 out:
190 xtables_error(PARAMETER_PROBLEM, "invalid time \"%s\" specified, "
191 "should be hh:mm[:ss] format and within the boundaries", s);
192 return -1;
193 }
194
my_strseg(char * buf,unsigned int buflen,const char ** arg,char delim)195 static const char *my_strseg(char *buf, unsigned int buflen,
196 const char **arg, char delim)
197 {
198 const char *sep;
199
200 if (*arg == NULL || **arg == '\0')
201 return NULL;
202 sep = strchr(*arg, delim);
203 if (sep == NULL) {
204 snprintf(buf, buflen, "%s", *arg);
205 *arg = NULL;
206 return buf;
207 }
208 snprintf(buf, buflen, "%.*s", (unsigned int)(sep - *arg), *arg);
209 *arg = sep + 1;
210 return buf;
211 }
212
time_parse_monthdays(const char * arg)213 static uint32_t time_parse_monthdays(const char *arg)
214 {
215 char day[3], *err = NULL;
216 uint32_t ret = 0;
217 unsigned int i;
218
219 while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
220 i = strtoul(day, &err, 0);
221 if ((*err != ',' && *err != '\0') || i > 31)
222 xtables_error(PARAMETER_PROBLEM,
223 "%s is not a valid day for --monthdays", day);
224 ret |= 1 << i;
225 }
226
227 return ret;
228 }
229
time_parse_weekdays(const char * arg)230 static unsigned int time_parse_weekdays(const char *arg)
231 {
232 char day[4], *err = NULL;
233 unsigned int i, ret = 0;
234 bool valid;
235
236 while (my_strseg(day, sizeof(day), &arg, ',') != NULL) {
237 i = strtoul(day, &err, 0);
238 if (*err == '\0') {
239 if (i == 0)
240 xtables_error(PARAMETER_PROBLEM,
241 "No, the week does NOT begin with Sunday.");
242 ret |= 1 << i;
243 continue;
244 }
245
246 valid = false;
247 for (i = 1; i < ARRAY_SIZE(week_days); ++i)
248 if (strncmp(day, week_days[i], 2) == 0) {
249 ret |= 1 << i;
250 valid = true;
251 }
252
253 if (!valid)
254 xtables_error(PARAMETER_PROBLEM,
255 "%s is not a valid day specifier", day);
256 }
257
258 return ret;
259 }
260
time_parse(struct xt_option_call * cb)261 static void time_parse(struct xt_option_call *cb)
262 {
263 struct xt_time_info *info = cb->data;
264
265 xtables_option_parse(cb);
266 switch (cb->entry->id) {
267 case O_DATE_START:
268 info->date_start = time_parse_date(cb->arg, false);
269 break;
270 case O_DATE_STOP:
271 info->date_stop = time_parse_date(cb->arg, true);
272 break;
273 case O_TIME_START:
274 info->daytime_start = time_parse_minutes(cb->arg);
275 break;
276 case O_TIME_STOP:
277 info->daytime_stop = time_parse_minutes(cb->arg);
278 break;
279 case O_TIME_CONTIGUOUS:
280 info->flags |= XT_TIME_CONTIGUOUS;
281 break;
282 case O_LOCAL_TZ:
283 fprintf(stderr, "WARNING: --localtz is being replaced by "
284 "--kerneltz, since \"local\" is ambiguous. Note the "
285 "kernel timezone has caveats - "
286 "see manpage for details.\n");
287 /* fallthrough */
288 case O_KERNEL_TZ:
289 info->flags |= XT_TIME_LOCAL_TZ;
290 break;
291 case O_MONTHDAYS:
292 info->monthdays_match = time_parse_monthdays(cb->arg);
293 if (cb->invert)
294 info->monthdays_match ^= XT_TIME_ALL_MONTHDAYS;
295 break;
296 case O_WEEKDAYS:
297 info->weekdays_match = time_parse_weekdays(cb->arg);
298 if (cb->invert)
299 info->weekdays_match ^= XT_TIME_ALL_WEEKDAYS;
300 break;
301 }
302 }
303
time_print_date(time_t date,const char * command)304 static void time_print_date(time_t date, const char *command)
305 {
306 struct tm *t;
307
308 /* If it is the default value, do not print it. */
309 if (date == 0 || date == LONG_MAX)
310 return;
311
312 t = gmtime(&date);
313 if (command != NULL)
314 /*
315 * Need a contiguous string (no whitespaces), hence using
316 * the ISO 8601 "T" variant.
317 */
318 printf(" %s %04u-%02u-%02uT%02u:%02u:%02u",
319 command, t->tm_year + 1900, t->tm_mon + 1,
320 t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
321 else
322 printf(" %04u-%02u-%02u %02u:%02u:%02u",
323 t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
324 t->tm_hour, t->tm_min, t->tm_sec);
325 }
326
time_print_monthdays(uint32_t mask,bool human_readable)327 static void time_print_monthdays(uint32_t mask, bool human_readable)
328 {
329 unsigned int i, nbdays = 0;
330
331 printf(" ");
332 for (i = 1; i <= 31; ++i)
333 if (mask & (1 << i)) {
334 if (nbdays++ > 0)
335 printf(",");
336 printf("%u", i);
337 if (human_readable)
338 switch (i % 10) {
339 case 1:
340 printf("st");
341 break;
342 case 2:
343 printf("nd");
344 break;
345 case 3:
346 printf("rd");
347 break;
348 default:
349 printf("th");
350 break;
351 }
352 }
353 }
354
time_print_weekdays(unsigned int mask)355 static void time_print_weekdays(unsigned int mask)
356 {
357 unsigned int i, nbdays = 0;
358
359 printf(" ");
360 for (i = 1; i <= 7; ++i)
361 if (mask & (1 << i)) {
362 if (nbdays > 0)
363 printf(",%s", week_days[i]);
364 else
365 printf("%s", week_days[i]);
366 ++nbdays;
367 }
368 }
369
divide_time(unsigned int fulltime,unsigned int * hours,unsigned int * minutes,unsigned int * seconds)370 static inline void divide_time(unsigned int fulltime, unsigned int *hours,
371 unsigned int *minutes, unsigned int *seconds)
372 {
373 *seconds = fulltime % 60;
374 fulltime /= 60;
375 *minutes = fulltime % 60;
376 *hours = fulltime / 60;
377 }
378
time_print(const void * ip,const struct xt_entry_match * match,int numeric)379 static void time_print(const void *ip, const struct xt_entry_match *match,
380 int numeric)
381 {
382 const struct xt_time_info *info = (const void *)match->data;
383 unsigned int h, m, s;
384
385 printf(" TIME");
386
387 if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
388 info->daytime_stop != XT_TIME_MAX_DAYTIME) {
389 divide_time(info->daytime_start, &h, &m, &s);
390 printf(" from %02u:%02u:%02u", h, m, s);
391 divide_time(info->daytime_stop, &h, &m, &s);
392 printf(" to %02u:%02u:%02u", h, m, s);
393 }
394 if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
395 printf(" on");
396 time_print_weekdays(info->weekdays_match);
397 }
398 if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
399 printf(" on");
400 time_print_monthdays(info->monthdays_match, true);
401 }
402 if (info->date_start != 0) {
403 printf(" starting from");
404 time_print_date(info->date_start, NULL);
405 }
406 if (info->date_stop != INT_MAX) {
407 printf(" until date");
408 time_print_date(info->date_stop, NULL);
409 }
410 if (!(info->flags & XT_TIME_LOCAL_TZ))
411 printf(" UTC");
412 if (info->flags & XT_TIME_CONTIGUOUS)
413 printf(" contiguous");
414 }
415
time_save(const void * ip,const struct xt_entry_match * match)416 static void time_save(const void *ip, const struct xt_entry_match *match)
417 {
418 const struct xt_time_info *info = (const void *)match->data;
419 unsigned int h, m, s;
420
421 if (info->daytime_start != XT_TIME_MIN_DAYTIME ||
422 info->daytime_stop != XT_TIME_MAX_DAYTIME) {
423 divide_time(info->daytime_start, &h, &m, &s);
424 printf(" --timestart %02u:%02u:%02u", h, m, s);
425 divide_time(info->daytime_stop, &h, &m, &s);
426 printf(" --timestop %02u:%02u:%02u", h, m, s);
427 }
428 if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) {
429 printf(" --monthdays");
430 time_print_monthdays(info->monthdays_match, false);
431 }
432 if (info->weekdays_match != XT_TIME_ALL_WEEKDAYS) {
433 printf(" --weekdays");
434 time_print_weekdays(info->weekdays_match);
435 }
436 time_print_date(info->date_start, "--datestart");
437 time_print_date(info->date_stop, "--datestop");
438 if (info->flags & XT_TIME_LOCAL_TZ)
439 printf(" --kerneltz");
440 if (info->flags & XT_TIME_CONTIGUOUS)
441 printf(" --contiguous");
442 }
443
time_check(struct xt_fcheck_call * cb)444 static void time_check(struct xt_fcheck_call *cb)
445 {
446 const struct xt_time_info *info = (const void *) cb->data;
447 if ((cb->xflags & F_TIME_CONTIGUOUS) &&
448 info->daytime_start < info->daytime_stop)
449 xtables_error(PARAMETER_PROBLEM,
450 "time: --contiguous only makes sense when stoptime is smaller than starttime");
451 }
452
453 static struct xtables_match time_match = {
454 .name = "time",
455 .family = NFPROTO_UNSPEC,
456 .version = XTABLES_VERSION,
457 .size = XT_ALIGN(sizeof(struct xt_time_info)),
458 .userspacesize = XT_ALIGN(sizeof(struct xt_time_info)),
459 .help = time_help,
460 .init = time_init,
461 .print = time_print,
462 .save = time_save,
463 .x6_parse = time_parse,
464 .x6_fcheck = time_check,
465 .x6_options = time_opts,
466 };
467
_init(void)468 void _init(void)
469 {
470 xtables_register_match(&time_match);
471 }
472