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cipso: unsigned buf_len cannot be negative
[linux-2.6/next.git] / net / netfilter / xt_recent.c
blob280c471bcdf444fdc2228a46895c2b44baf8d549
1 /*
2 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
3 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This is a replacement of the old ipt_recent module, which carried the
10 * following copyright notice:
11 *
12 * Author: Stephen Frost <sfrost@snowman.net>
13 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
14 */
15 #include <linux/init.h>
16 #include <linux/ip.h>
17 #include <linux/ipv6.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/proc_fs.h>
21 #include <linux/seq_file.h>
22 #include <linux/string.h>
23 #include <linux/ctype.h>
24 #include <linux/list.h>
25 #include <linux/random.h>
26 #include <linux/jhash.h>
27 #include <linux/bitops.h>
28 #include <linux/skbuff.h>
29 #include <linux/inet.h>
30 #include <net/net_namespace.h>
31
32 #include <linux/netfilter/x_tables.h>
33 #include <linux/netfilter/xt_recent.h>
34
35 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
36 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
37 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
38 MODULE_LICENSE("GPL");
39 MODULE_ALIAS("ipt_recent");
40 MODULE_ALIAS("ip6t_recent");
41
42 static unsigned int ip_list_tot = 100;
43 static unsigned int ip_pkt_list_tot = 20;
44 static unsigned int ip_list_hash_size = 0;
45 static unsigned int ip_list_perms = 0644;
46 static unsigned int ip_list_uid = 0;
47 static unsigned int ip_list_gid = 0;
48 module_param(ip_list_tot, uint, 0400);
49 module_param(ip_pkt_list_tot, uint, 0400);
50 module_param(ip_list_hash_size, uint, 0400);
51 module_param(ip_list_perms, uint, 0400);
52 module_param(ip_list_uid, uint, 0400);
53 module_param(ip_list_gid, uint, 0400);
54 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
55 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
56 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
57 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
58 MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/xt_recent/* files");
59 MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/xt_recent/* files");
60
61 struct recent_entry {
62 struct list_head list;
63 struct list_head lru_list;
64 union nf_inet_addr addr;
65 u_int16_t family;
66 u_int8_t ttl;
67 u_int8_t index;
68 u_int16_t nstamps;
69 unsigned long stamps[0];
70 };
71
72 struct recent_table {
73 struct list_head list;
74 char name[XT_RECENT_NAME_LEN];
75 #ifdef CONFIG_PROC_FS
76 struct proc_dir_entry *proc_old, *proc;
77 #endif
78 unsigned int refcnt;
79 unsigned int entries;
80 struct list_head lru_list;
81 struct list_head iphash[0];
82 };
83
84 static LIST_HEAD(tables);
85 static DEFINE_SPINLOCK(recent_lock);
86 static DEFINE_MUTEX(recent_mutex);
87
88 #ifdef CONFIG_PROC_FS
89 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
90 static struct proc_dir_entry *proc_old_dir;
91 #endif
92 static struct proc_dir_entry *recent_proc_dir;
93 static const struct file_operations recent_old_fops, recent_mt_fops;
94 #endif
95
96 static u_int32_t hash_rnd;
97 static bool hash_rnd_initted;
98
99 static unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
100 {
101 if (!hash_rnd_initted) {
102 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
103 hash_rnd_initted = true;
104 }
105 return jhash_1word((__force u32)addr->ip, hash_rnd) &
106 (ip_list_hash_size - 1);
107 }
108
109 static unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
110 {
111 if (!hash_rnd_initted) {
112 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
113 hash_rnd_initted = true;
114 }
115 return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
116 (ip_list_hash_size - 1);
117 }
118
119 static struct recent_entry *
120 recent_entry_lookup(const struct recent_table *table,
121 const union nf_inet_addr *addrp, u_int16_t family,
122 u_int8_t ttl)
123 {
124 struct recent_entry *e;
125 unsigned int h;
126
127 if (family == NFPROTO_IPV4)
128 h = recent_entry_hash4(addrp);
129 else
130 h = recent_entry_hash6(addrp);
131
132 list_for_each_entry(e, &table->iphash[h], list)
133 if (e->family == family &&
134 memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
135 (ttl == e->ttl || ttl == 0 || e->ttl == 0))
136 return e;
137 return NULL;
138 }
139
140 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
141 {
142 list_del(&e->list);
143 list_del(&e->lru_list);
144 kfree(e);
145 t->entries--;
146 }
147
148 static struct recent_entry *
149 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
150 u_int16_t family, u_int8_t ttl)
151 {
152 struct recent_entry *e;
153
154 if (t->entries >= ip_list_tot) {
155 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
156 recent_entry_remove(t, e);
157 }
158 e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
159 GFP_ATOMIC);
160 if (e == NULL)
161 return NULL;
162 memcpy(&e->addr, addr, sizeof(e->addr));
163 e->ttl = ttl;
164 e->stamps[0] = jiffies;
165 e->nstamps = 1;
166 e->index = 1;
167 e->family = family;
168 if (family == NFPROTO_IPV4)
169 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
170 else
171 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
172 list_add_tail(&e->lru_list, &t->lru_list);
173 t->entries++;
174 return e;
175 }
176
177 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
178 {
179 e->stamps[e->index++] = jiffies;
180 if (e->index > e->nstamps)
181 e->nstamps = e->index;
182 e->index %= ip_pkt_list_tot;
183 list_move_tail(&e->lru_list, &t->lru_list);
184 }
185
186 static struct recent_table *recent_table_lookup(const char *name)
187 {
188 struct recent_table *t;
189
190 list_for_each_entry(t, &tables, list)
191 if (!strcmp(t->name, name))
192 return t;
193 return NULL;
194 }
195
196 static void recent_table_flush(struct recent_table *t)
197 {
198 struct recent_entry *e, *next;
199 unsigned int i;
200
201 for (i = 0; i < ip_list_hash_size; i++)
202 list_for_each_entry_safe(e, next, &t->iphash[i], list)
203 recent_entry_remove(t, e);
204 }
205
206 static bool
207 recent_mt(const struct sk_buff *skb, const struct xt_match_param *par)
208 {
209 const struct xt_recent_mtinfo *info = par->matchinfo;
210 struct recent_table *t;
211 struct recent_entry *e;
212 union nf_inet_addr addr = {};
213 u_int8_t ttl;
214 bool ret = info->invert;
215
216 if (par->match->family == NFPROTO_IPV4) {
217 const struct iphdr *iph = ip_hdr(skb);
218
219 if (info->side == XT_RECENT_DEST)
220 addr.ip = iph->daddr;
221 else
222 addr.ip = iph->saddr;
223
224 ttl = iph->ttl;
225 } else {
226 const struct ipv6hdr *iph = ipv6_hdr(skb);
227
228 if (info->side == XT_RECENT_DEST)
229 memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
230 else
231 memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
232
233 ttl = iph->hop_limit;
234 }
235
236 /* use TTL as seen before forwarding */
237 if (par->out != NULL && skb->sk == NULL)
238 ttl++;
239
240 spin_lock_bh(&recent_lock);
241 t = recent_table_lookup(info->name);
242 e = recent_entry_lookup(t, &addr, par->match->family,
243 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
244 if (e == NULL) {
245 if (!(info->check_set & XT_RECENT_SET))
246 goto out;
247 e = recent_entry_init(t, &addr, par->match->family, ttl);
248 if (e == NULL)
249 *par->hotdrop = true;
250 ret = !ret;
251 goto out;
252 }
253
254 if (info->check_set & XT_RECENT_SET)
255 ret = !ret;
256 else if (info->check_set & XT_RECENT_REMOVE) {
257 recent_entry_remove(t, e);
258 ret = !ret;
259 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
260 unsigned long time = jiffies - info->seconds * HZ;
261 unsigned int i, hits = 0;
262
263 for (i = 0; i < e->nstamps; i++) {
264 if (info->seconds && time_after(time, e->stamps[i]))
265 continue;
266 if (++hits >= info->hit_count) {
267 ret = !ret;
268 break;
269 }
270 }
271 }
272
273 if (info->check_set & XT_RECENT_SET ||
274 (info->check_set & XT_RECENT_UPDATE && ret)) {
275 recent_entry_update(t, e);
276 e->ttl = ttl;
277 }
278 out:
279 spin_unlock_bh(&recent_lock);
280 return ret;
281 }
282
283 static bool recent_mt_check(const struct xt_mtchk_param *par)
284 {
285 const struct xt_recent_mtinfo *info = par->matchinfo;
286 struct recent_table *t;
287 unsigned i;
288 bool ret = false;
289
290 if (hweight8(info->check_set &
291 (XT_RECENT_SET | XT_RECENT_REMOVE |
292 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
293 return false;
294 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
295 (info->seconds || info->hit_count))
296 return false;
297 if (info->hit_count > ip_pkt_list_tot)
298 return false;
299 if (info->name[0] == '\0' ||
300 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
301 return false;
302
303 mutex_lock(&recent_mutex);
304 t = recent_table_lookup(info->name);
305 if (t != NULL) {
306 t->refcnt++;
307 ret = true;
308 goto out;
309 }
310
311 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
312 GFP_KERNEL);
313 if (t == NULL)
314 goto out;
315 t->refcnt = 1;
316 strcpy(t->name, info->name);
317 INIT_LIST_HEAD(&t->lru_list);
318 for (i = 0; i < ip_list_hash_size; i++)
319 INIT_LIST_HEAD(&t->iphash[i]);
320 #ifdef CONFIG_PROC_FS
321 t->proc = proc_create_data(t->name, ip_list_perms, recent_proc_dir,
322 &recent_mt_fops, t);
323 if (t->proc == NULL) {
324 kfree(t);
325 goto out;
326 }
327 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
328 t->proc_old = proc_create_data(t->name, ip_list_perms, proc_old_dir,
329 &recent_old_fops, t);
330 if (t->proc_old == NULL) {
331 remove_proc_entry(t->name, proc_old_dir);
332 kfree(t);
333 goto out;
334 }
335 t->proc_old->uid = ip_list_uid;
336 t->proc_old->gid = ip_list_gid;
337 #endif
338 t->proc->uid = ip_list_uid;
339 t->proc->gid = ip_list_gid;
340 #endif
341 spin_lock_bh(&recent_lock);
342 list_add_tail(&t->list, &tables);
343 spin_unlock_bh(&recent_lock);
344 ret = true;
345 out:
346 mutex_unlock(&recent_mutex);
347 return ret;
348 }
349
350 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
351 {
352 const struct xt_recent_mtinfo *info = par->matchinfo;
353 struct recent_table *t;
354
355 mutex_lock(&recent_mutex);
356 t = recent_table_lookup(info->name);
357 if (--t->refcnt == 0) {
358 spin_lock_bh(&recent_lock);
359 list_del(&t->list);
360 spin_unlock_bh(&recent_lock);
361 #ifdef CONFIG_PROC_FS
362 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
363 remove_proc_entry(t->name, proc_old_dir);
364 #endif
365 remove_proc_entry(t->name, recent_proc_dir);
366 #endif
367 recent_table_flush(t);
368 kfree(t);
369 }
370 mutex_unlock(&recent_mutex);
371 }
372
373 #ifdef CONFIG_PROC_FS
374 struct recent_iter_state {
375 const struct recent_table *table;
376 unsigned int bucket;
377 };
378
379 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
380 __acquires(recent_lock)
381 {
382 struct recent_iter_state *st = seq->private;
383 const struct recent_table *t = st->table;
384 struct recent_entry *e;
385 loff_t p = *pos;
386
387 spin_lock_bh(&recent_lock);
388
389 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
390 list_for_each_entry(e, &t->iphash[st->bucket], list)
391 if (p-- == 0)
392 return e;
393 return NULL;
394 }
395
396 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
397 {
398 struct recent_iter_state *st = seq->private;
399 const struct recent_table *t = st->table;
400 const struct recent_entry *e = v;
401 const struct list_head *head = e->list.next;
402
403 while (head == &t->iphash[st->bucket]) {
404 if (++st->bucket >= ip_list_hash_size)
405 return NULL;
406 head = t->iphash[st->bucket].next;
407 }
408 (*pos)++;
409 return list_entry(head, struct recent_entry, list);
410 }
411
412 static void recent_seq_stop(struct seq_file *s, void *v)
413 __releases(recent_lock)
414 {
415 spin_unlock_bh(&recent_lock);
416 }
417
418 static int recent_seq_show(struct seq_file *seq, void *v)
419 {
420 const struct recent_entry *e = v;
421 unsigned int i;
422
423 i = (e->index - 1) % ip_pkt_list_tot;
424 if (e->family == NFPROTO_IPV4)
425 seq_printf(seq, "src=" NIPQUAD_FMT " ttl: %u last_seen: %lu "
426 "oldest_pkt: %u", NIPQUAD(e->addr.ip), e->ttl,
427 e->stamps[i], e->index);
428 else
429 seq_printf(seq, "src=" NIP6_FMT " ttl: %u last_seen: %lu "
430 "oldest_pkt: %u", NIP6(e->addr.in6), e->ttl,
431 e->stamps[i], e->index);
432 for (i = 0; i < e->nstamps; i++)
433 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
434 seq_printf(seq, "\n");
435 return 0;
436 }
437
438 static const struct seq_operations recent_seq_ops = {
439 .start = recent_seq_start,
440 .next = recent_seq_next,
441 .stop = recent_seq_stop,
442 .show = recent_seq_show,
443 };
444
445 static int recent_seq_open(struct inode *inode, struct file *file)
446 {
447 struct proc_dir_entry *pde = PDE(inode);
448 struct recent_iter_state *st;
449
450 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
451 if (st == NULL)
452 return -ENOMEM;
453
454 st->table = pde->data;
455 return 0;
456 }
457
458 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
459 static int recent_old_seq_open(struct inode *inode, struct file *filp)
460 {
461 static bool warned_of_old;
462
463 if (unlikely(!warned_of_old)) {
464 printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
465 " is deprecated; use /proc/net/xt_recent.\n");
466 warned_of_old = true;
467 }
468 return recent_seq_open(inode, filp);
469 }
470
471 static ssize_t recent_old_proc_write(struct file *file,
472 const char __user *input,
473 size_t size, loff_t *loff)
474 {
475 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
476 struct recent_table *t = pde->data;
477 struct recent_entry *e;
478 char buf[sizeof("+255.255.255.255")], *c = buf;
479 __be32 addr;
480 int add;
481
482 if (size > sizeof(buf))
483 size = sizeof(buf);
484 if (copy_from_user(buf, input, size))
485 return -EFAULT;
486
487 while (isspace(*c))
488 c++;
489
490 if (size - (c - buf) < 5)
491 return c - buf;
492 if (!strncmp(c, "clear", 5)) {
493 c += 5;
494 spin_lock_bh(&recent_lock);
495 recent_table_flush(t);
496 spin_unlock_bh(&recent_lock);
497 return c - buf;
498 }
499
500 switch (*c) {
501 case '-':
502 add = 0;
503 c++;
504 break;
505 case '+':
506 c++;
507 default:
508 add = 1;
509 break;
510 }
511 addr = in_aton(c);
512
513 spin_lock_bh(&recent_lock);
514 e = recent_entry_lookup(t, (const void *)&addr, NFPROTO_IPV4, 0);
515 if (e == NULL) {
516 if (add)
517 recent_entry_init(t, (const void *)&addr,
518 NFPROTO_IPV4, 0);
519 } else {
520 if (add)
521 recent_entry_update(t, e);
522 else
523 recent_entry_remove(t, e);
524 }
525 spin_unlock_bh(&recent_lock);
526 return size;
527 }
528
529 static const struct file_operations recent_old_fops = {
530 .open = recent_old_seq_open,
531 .read = seq_read,
532 .write = recent_old_proc_write,
533 .release = seq_release_private,
534 .owner = THIS_MODULE,
535 };
536 #endif
537
538 static ssize_t
539 recent_mt_proc_write(struct file *file, const char __user *input,
540 size_t size, loff_t *loff)
541 {
542 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
543 struct recent_table *t = pde->data;
544 struct recent_entry *e;
545 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
546 const char *c = buf;
547 union nf_inet_addr addr;
548 u_int16_t family;
549 bool add, succ;
550
551 if (size == 0)
552 return 0;
553 if (size > sizeof(buf))
554 size = sizeof(buf);
555 if (copy_from_user(buf, input, size) != 0)
556 return -EFAULT;
557
558 /* Strict protocol! */
559 if (*loff != 0)
560 return -ESPIPE;
561 switch (*c) {
562 case '/': /* flush table */
563 spin_lock_bh(&recent_lock);
564 recent_table_flush(t);
565 spin_unlock_bh(&recent_lock);
566 return size;
567 case '-': /* remove address */
568 add = false;
569 break;
570 case '+': /* add address */
571 add = true;
572 break;
573 default:
574 printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
575 return -EINVAL;
576 }
577
578 ++c;
579 --size;
580 if (strnchr(c, size, ':') != NULL) {
581 family = NFPROTO_IPV6;
582 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
583 } else {
584 family = NFPROTO_IPV4;
585 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
586 }
587
588 if (!succ) {
589 printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
590 "to procfs\n");
591 return -EINVAL;
592 }
593
594 spin_lock_bh(&recent_lock);
595 e = recent_entry_lookup(t, &addr, family, 0);
596 if (e == NULL) {
597 if (add)
598 recent_entry_init(t, &addr, family, 0);
599 } else {
600 if (add)
601 recent_entry_update(t, e);
602 else
603 recent_entry_remove(t, e);
604 }
605 spin_unlock_bh(&recent_lock);
606 /* Note we removed one above */
607 *loff += size + 1;
608 return size + 1;
609 }
610
611 static const struct file_operations recent_mt_fops = {
612 .open = recent_seq_open,
613 .read = seq_read,
614 .write = recent_mt_proc_write,
615 .release = seq_release_private,
616 .owner = THIS_MODULE,
617 };
618 #endif /* CONFIG_PROC_FS */
619
620 static struct xt_match recent_mt_reg[] __read_mostly = {
621 {
622 .name = "recent",
623 .revision = 0,
624 .family = NFPROTO_IPV4,
625 .match = recent_mt,
626 .matchsize = sizeof(struct xt_recent_mtinfo),
627 .checkentry = recent_mt_check,
628 .destroy = recent_mt_destroy,
629 .me = THIS_MODULE,
630 },
631 {
632 .name = "recent",
633 .revision = 0,
634 .family = NFPROTO_IPV6,
635 .match = recent_mt,
636 .matchsize = sizeof(struct xt_recent_mtinfo),
637 .checkentry = recent_mt_check,
638 .destroy = recent_mt_destroy,
639 .me = THIS_MODULE,
640 },
641 };
642
643 static int __init recent_mt_init(void)
644 {
645 int err;
646
647 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
648 return -EINVAL;
649 ip_list_hash_size = 1 << fls(ip_list_tot);
650
651 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
652 #ifdef CONFIG_PROC_FS
653 if (err)
654 return err;
655 recent_proc_dir = proc_mkdir("xt_recent", init_net.proc_net);
656 if (recent_proc_dir == NULL) {
657 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
658 err = -ENOMEM;
659 }
660 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
661 if (err < 0)
662 return err;
663 proc_old_dir = proc_mkdir("ipt_recent", init_net.proc_net);
664 if (proc_old_dir == NULL) {
665 remove_proc_entry("xt_recent", init_net.proc_net);
666 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
667 err = -ENOMEM;
668 }
669 #endif
670 #endif
671 return err;
672 }
673
674 static void __exit recent_mt_exit(void)
675 {
676 BUG_ON(!list_empty(&tables));
677 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
678 #ifdef CONFIG_PROC_FS
679 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
680 remove_proc_entry("ipt_recent", init_net.proc_net);
681 #endif
682 remove_proc_entry("xt_recent", init_net.proc_net);
683 #endif
684 }
685
686 module_init(recent_mt_init);
687 module_exit(recent_mt_exit);
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