1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
4  * Copyright © CC Computer Consultants GmbH, 2007 - 2008
5  *
6  * This is a replacement of the old ipt_recent module, which carried the
7  * following copyright notice:
8  *
9  * Author: Stephen Frost <sfrost@snowman.net>
10  * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
11  */
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/init.h>
14 #include <linux/ip.h>
15 #include <linux/ipv6.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/string.h>
21 #include <linux/ctype.h>
22 #include <linux/list.h>
23 #include <linux/random.h>
24 #include <linux/jhash.h>
25 #include <linux/bitops.h>
26 #include <linux/skbuff.h>
27 #include <linux/inet.h>
28 #include <linux/slab.h>
29 #include <linux/vmalloc.h>
30 #include <net/net_namespace.h>
31 #include <net/netns/generic.h>
32 
33 #include <linux/netfilter/x_tables.h>
34 #include <linux/netfilter/xt_recent.h>
35 
36 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
37 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
38 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
39 MODULE_LICENSE("GPL");
40 MODULE_ALIAS("ipt_recent");
41 MODULE_ALIAS("ip6t_recent");
42 
43 static unsigned int ip_list_tot __read_mostly = 100;
44 static unsigned int ip_list_hash_size __read_mostly;
45 static unsigned int ip_list_perms __read_mostly = 0644;
46 static unsigned int ip_list_uid __read_mostly;
47 static unsigned int ip_list_gid __read_mostly;
48 module_param(ip_list_tot, uint, 0400);
49 module_param(ip_list_hash_size, uint, 0400);
50 module_param(ip_list_perms, uint, 0400);
51 module_param(ip_list_uid, uint, 0644);
52 module_param(ip_list_gid, uint, 0644);
53 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
54 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
55 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
56 MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
57 MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
58 
59 /* retained for backwards compatibility */
60 static unsigned int ip_pkt_list_tot __read_mostly;
61 module_param(ip_pkt_list_tot, uint, 0400);
62 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 65535)");
63 
64 #define XT_RECENT_MAX_NSTAMPS	65536
65 
66 struct recent_entry {
67 	struct list_head	list;
68 	struct list_head	lru_list;
69 	union nf_inet_addr	addr;
70 	u_int16_t		family;
71 	u_int8_t		ttl;
72 	u_int16_t		index;
73 	u_int16_t		nstamps;
74 	unsigned long		stamps[];
75 };
76 
77 struct recent_table {
78 	struct list_head	list;
79 	char			name[XT_RECENT_NAME_LEN];
80 	union nf_inet_addr	mask;
81 	unsigned int		refcnt;
82 	unsigned int		entries;
83 	u_int16_t		nstamps_max_mask;
84 	struct list_head	lru_list;
85 	struct list_head	iphash[];
86 };
87 
88 struct recent_net {
89 	struct list_head	tables;
90 #ifdef CONFIG_PROC_FS
91 	struct proc_dir_entry	*xt_recent;
92 #endif
93 };
94 
95 static unsigned int recent_net_id __read_mostly;
96 
recent_pernet(struct net * net)97 static inline struct recent_net *recent_pernet(struct net *net)
98 {
99 	return net_generic(net, recent_net_id);
100 }
101 
102 static DEFINE_SPINLOCK(recent_lock);
103 static DEFINE_MUTEX(recent_mutex);
104 
105 #ifdef CONFIG_PROC_FS
106 static const struct proc_ops recent_mt_proc_ops;
107 #endif
108 
109 static u_int32_t hash_rnd __read_mostly;
110 
recent_entry_hash4(const union nf_inet_addr * addr)111 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
112 {
113 	return jhash_1word((__force u32)addr->ip, hash_rnd) &
114 	       (ip_list_hash_size - 1);
115 }
116 
recent_entry_hash6(const union nf_inet_addr * addr)117 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
118 {
119 	return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
120 	       (ip_list_hash_size - 1);
121 }
122 
123 static struct recent_entry *
recent_entry_lookup(const struct recent_table * table,const union nf_inet_addr * addrp,u_int16_t family,u_int8_t ttl)124 recent_entry_lookup(const struct recent_table *table,
125 		    const union nf_inet_addr *addrp, u_int16_t family,
126 		    u_int8_t ttl)
127 {
128 	struct recent_entry *e;
129 	unsigned int h;
130 
131 	if (family == NFPROTO_IPV4)
132 		h = recent_entry_hash4(addrp);
133 	else
134 		h = recent_entry_hash6(addrp);
135 
136 	list_for_each_entry(e, &table->iphash[h], list)
137 		if (e->family == family &&
138 		    memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
139 		    (ttl == e->ttl || ttl == 0 || e->ttl == 0))
140 			return e;
141 	return NULL;
142 }
143 
recent_entry_remove(struct recent_table * t,struct recent_entry * e)144 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
145 {
146 	list_del(&e->list);
147 	list_del(&e->lru_list);
148 	kfree(e);
149 	t->entries--;
150 }
151 
152 /*
153  * Drop entries with timestamps older then 'time'.
154  */
recent_entry_reap(struct recent_table * t,unsigned long time,struct recent_entry * working,bool update)155 static void recent_entry_reap(struct recent_table *t, unsigned long time,
156 			      struct recent_entry *working, bool update)
157 {
158 	struct recent_entry *e;
159 
160 	/*
161 	 * The head of the LRU list is always the oldest entry.
162 	 */
163 	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
164 
165 	/*
166 	 * Do not reap the entry which are going to be updated.
167 	 */
168 	if (e == working && update)
169 		return;
170 
171 	/*
172 	 * The last time stamp is the most recent.
173 	 */
174 	if (time_after(time, e->stamps[e->index-1]))
175 		recent_entry_remove(t, e);
176 }
177 
178 static struct recent_entry *
recent_entry_init(struct recent_table * t,const union nf_inet_addr * addr,u_int16_t family,u_int8_t ttl)179 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
180 		  u_int16_t family, u_int8_t ttl)
181 {
182 	struct recent_entry *e;
183 	unsigned int nstamps_max = t->nstamps_max_mask;
184 
185 	if (t->entries >= ip_list_tot) {
186 		e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
187 		recent_entry_remove(t, e);
188 	}
189 
190 	nstamps_max += 1;
191 	e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC);
192 	if (e == NULL)
193 		return NULL;
194 	memcpy(&e->addr, addr, sizeof(e->addr));
195 	e->ttl       = ttl;
196 	e->stamps[0] = jiffies;
197 	e->nstamps   = 1;
198 	e->index     = 1;
199 	e->family    = family;
200 	if (family == NFPROTO_IPV4)
201 		list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
202 	else
203 		list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
204 	list_add_tail(&e->lru_list, &t->lru_list);
205 	t->entries++;
206 	return e;
207 }
208 
recent_entry_update(struct recent_table * t,struct recent_entry * e)209 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
210 {
211 	e->index &= t->nstamps_max_mask;
212 	e->stamps[e->index++] = jiffies;
213 	if (e->index > e->nstamps)
214 		e->nstamps = e->index;
215 	list_move_tail(&e->lru_list, &t->lru_list);
216 }
217 
recent_table_lookup(struct recent_net * recent_net,const char * name)218 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
219 						const char *name)
220 {
221 	struct recent_table *t;
222 
223 	list_for_each_entry(t, &recent_net->tables, list)
224 		if (!strcmp(t->name, name))
225 			return t;
226 	return NULL;
227 }
228 
recent_table_flush(struct recent_table * t)229 static void recent_table_flush(struct recent_table *t)
230 {
231 	struct recent_entry *e, *next;
232 	unsigned int i;
233 
234 	for (i = 0; i < ip_list_hash_size; i++)
235 		list_for_each_entry_safe(e, next, &t->iphash[i], list)
236 			recent_entry_remove(t, e);
237 }
238 
239 static bool
recent_mt(const struct sk_buff * skb,struct xt_action_param * par)240 recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
241 {
242 	struct net *net = xt_net(par);
243 	struct recent_net *recent_net = recent_pernet(net);
244 	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
245 	struct recent_table *t;
246 	struct recent_entry *e;
247 	union nf_inet_addr addr = {}, addr_mask;
248 	u_int8_t ttl;
249 	bool ret = info->invert;
250 
251 	if (xt_family(par) == NFPROTO_IPV4) {
252 		const struct iphdr *iph = ip_hdr(skb);
253 
254 		if (info->side == XT_RECENT_DEST)
255 			addr.ip = iph->daddr;
256 		else
257 			addr.ip = iph->saddr;
258 
259 		ttl = iph->ttl;
260 	} else {
261 		const struct ipv6hdr *iph = ipv6_hdr(skb);
262 
263 		if (info->side == XT_RECENT_DEST)
264 			memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
265 		else
266 			memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
267 
268 		ttl = iph->hop_limit;
269 	}
270 
271 	/* use TTL as seen before forwarding */
272 	if (xt_out(par) != NULL &&
273 	    (!skb->sk || !net_eq(net, sock_net(skb->sk))))
274 		ttl++;
275 
276 	spin_lock_bh(&recent_lock);
277 	t = recent_table_lookup(recent_net, info->name);
278 
279 	nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
280 
281 	e = recent_entry_lookup(t, &addr_mask, xt_family(par),
282 				(info->check_set & XT_RECENT_TTL) ? ttl : 0);
283 	if (e == NULL) {
284 		if (!(info->check_set & XT_RECENT_SET))
285 			goto out;
286 		e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
287 		if (e == NULL)
288 			par->hotdrop = true;
289 		ret = !ret;
290 		goto out;
291 	}
292 
293 	if (info->check_set & XT_RECENT_SET)
294 		ret = !ret;
295 	else if (info->check_set & XT_RECENT_REMOVE) {
296 		recent_entry_remove(t, e);
297 		ret = !ret;
298 	} else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
299 		unsigned long time = jiffies - info->seconds * HZ;
300 		unsigned int i, hits = 0;
301 
302 		for (i = 0; i < e->nstamps; i++) {
303 			if (info->seconds && time_after(time, e->stamps[i]))
304 				continue;
305 			if (!info->hit_count || ++hits >= info->hit_count) {
306 				ret = !ret;
307 				break;
308 			}
309 		}
310 
311 		/* info->seconds must be non-zero */
312 		if (info->check_set & XT_RECENT_REAP)
313 			recent_entry_reap(t, time, e,
314 				info->check_set & XT_RECENT_UPDATE && ret);
315 	}
316 
317 	if (info->check_set & XT_RECENT_SET ||
318 	    (info->check_set & XT_RECENT_UPDATE && ret)) {
319 		recent_entry_update(t, e);
320 		e->ttl = ttl;
321 	}
322 out:
323 	spin_unlock_bh(&recent_lock);
324 	return ret;
325 }
326 
recent_table_free(void * addr)327 static void recent_table_free(void *addr)
328 {
329 	kvfree(addr);
330 }
331 
recent_mt_check(const struct xt_mtchk_param * par,const struct xt_recent_mtinfo_v1 * info)332 static int recent_mt_check(const struct xt_mtchk_param *par,
333 			   const struct xt_recent_mtinfo_v1 *info)
334 {
335 	struct recent_net *recent_net = recent_pernet(par->net);
336 	struct recent_table *t;
337 #ifdef CONFIG_PROC_FS
338 	struct proc_dir_entry *pde;
339 	kuid_t uid;
340 	kgid_t gid;
341 #endif
342 	unsigned int nstamp_mask;
343 	unsigned int i;
344 	int ret = -EINVAL;
345 
346 	net_get_random_once(&hash_rnd, sizeof(hash_rnd));
347 
348 	if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
349 		pr_info_ratelimited("Unsupported userspace flags (%08x)\n",
350 				    info->check_set);
351 		return -EINVAL;
352 	}
353 	if (hweight8(info->check_set &
354 		     (XT_RECENT_SET | XT_RECENT_REMOVE |
355 		      XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
356 		return -EINVAL;
357 	if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
358 	    (info->seconds || info->hit_count ||
359 	    (info->check_set & XT_RECENT_MODIFIERS)))
360 		return -EINVAL;
361 	if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
362 		return -EINVAL;
363 	if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
364 		pr_info_ratelimited("hitcount (%u) is larger than allowed maximum (%u)\n",
365 				    info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
366 		return -EINVAL;
367 	}
368 	ret = xt_check_proc_name(info->name, sizeof(info->name));
369 	if (ret)
370 		return ret;
371 
372 	if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
373 		nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
374 	else if (info->hit_count)
375 		nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
376 	else
377 		nstamp_mask = 32 - 1;
378 
379 	mutex_lock(&recent_mutex);
380 	t = recent_table_lookup(recent_net, info->name);
381 	if (t != NULL) {
382 		if (nstamp_mask > t->nstamps_max_mask) {
383 			spin_lock_bh(&recent_lock);
384 			recent_table_flush(t);
385 			t->nstamps_max_mask = nstamp_mask;
386 			spin_unlock_bh(&recent_lock);
387 		}
388 
389 		t->refcnt++;
390 		ret = 0;
391 		goto out;
392 	}
393 
394 	t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL);
395 	if (t == NULL) {
396 		ret = -ENOMEM;
397 		goto out;
398 	}
399 	t->refcnt = 1;
400 	t->nstamps_max_mask = nstamp_mask;
401 
402 	memcpy(&t->mask, &info->mask, sizeof(t->mask));
403 	strcpy(t->name, info->name);
404 	INIT_LIST_HEAD(&t->lru_list);
405 	for (i = 0; i < ip_list_hash_size; i++)
406 		INIT_LIST_HEAD(&t->iphash[i]);
407 #ifdef CONFIG_PROC_FS
408 	uid = make_kuid(&init_user_ns, ip_list_uid);
409 	gid = make_kgid(&init_user_ns, ip_list_gid);
410 	if (!uid_valid(uid) || !gid_valid(gid)) {
411 		recent_table_free(t);
412 		ret = -EINVAL;
413 		goto out;
414 	}
415 	pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
416 			       &recent_mt_proc_ops, t);
417 	if (pde == NULL) {
418 		recent_table_free(t);
419 		ret = -ENOMEM;
420 		goto out;
421 	}
422 	proc_set_user(pde, uid, gid);
423 #endif
424 	spin_lock_bh(&recent_lock);
425 	list_add_tail(&t->list, &recent_net->tables);
426 	spin_unlock_bh(&recent_lock);
427 	ret = 0;
428 out:
429 	mutex_unlock(&recent_mutex);
430 	return ret;
431 }
432 
recent_mt_check_v0(const struct xt_mtchk_param * par)433 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
434 {
435 	const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
436 	struct xt_recent_mtinfo_v1 info_v1;
437 
438 	/* Copy revision 0 structure to revision 1 */
439 	memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
440 	/* Set default mask to ensure backward compatible behaviour */
441 	memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
442 
443 	return recent_mt_check(par, &info_v1);
444 }
445 
recent_mt_check_v1(const struct xt_mtchk_param * par)446 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
447 {
448 	return recent_mt_check(par, par->matchinfo);
449 }
450 
recent_mt_destroy(const struct xt_mtdtor_param * par)451 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
452 {
453 	struct recent_net *recent_net = recent_pernet(par->net);
454 	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
455 	struct recent_table *t;
456 
457 	mutex_lock(&recent_mutex);
458 	t = recent_table_lookup(recent_net, info->name);
459 	if (--t->refcnt == 0) {
460 		spin_lock_bh(&recent_lock);
461 		list_del(&t->list);
462 		spin_unlock_bh(&recent_lock);
463 #ifdef CONFIG_PROC_FS
464 		if (recent_net->xt_recent != NULL)
465 			remove_proc_entry(t->name, recent_net->xt_recent);
466 #endif
467 		recent_table_flush(t);
468 		recent_table_free(t);
469 	}
470 	mutex_unlock(&recent_mutex);
471 }
472 
473 #ifdef CONFIG_PROC_FS
474 struct recent_iter_state {
475 	const struct recent_table *table;
476 	unsigned int		bucket;
477 };
478 
recent_seq_start(struct seq_file * seq,loff_t * pos)479 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
480 	__acquires(recent_lock)
481 {
482 	struct recent_iter_state *st = seq->private;
483 	const struct recent_table *t = st->table;
484 	struct recent_entry *e;
485 	loff_t p = *pos;
486 
487 	spin_lock_bh(&recent_lock);
488 
489 	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
490 		list_for_each_entry(e, &t->iphash[st->bucket], list)
491 			if (p-- == 0)
492 				return e;
493 	return NULL;
494 }
495 
recent_seq_next(struct seq_file * seq,void * v,loff_t * pos)496 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
497 {
498 	struct recent_iter_state *st = seq->private;
499 	const struct recent_table *t = st->table;
500 	const struct recent_entry *e = v;
501 	const struct list_head *head = e->list.next;
502 
503 	(*pos)++;
504 	while (head == &t->iphash[st->bucket]) {
505 		if (++st->bucket >= ip_list_hash_size)
506 			return NULL;
507 		head = t->iphash[st->bucket].next;
508 	}
509 	return list_entry(head, struct recent_entry, list);
510 }
511 
recent_seq_stop(struct seq_file * s,void * v)512 static void recent_seq_stop(struct seq_file *s, void *v)
513 	__releases(recent_lock)
514 {
515 	spin_unlock_bh(&recent_lock);
516 }
517 
recent_seq_show(struct seq_file * seq,void * v)518 static int recent_seq_show(struct seq_file *seq, void *v)
519 {
520 	const struct recent_entry *e = v;
521 	struct recent_iter_state *st = seq->private;
522 	const struct recent_table *t = st->table;
523 	unsigned int i;
524 
525 	i = (e->index - 1) & t->nstamps_max_mask;
526 
527 	if (e->family == NFPROTO_IPV4)
528 		seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
529 			   &e->addr.ip, e->ttl, e->stamps[i], e->index);
530 	else
531 		seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
532 			   &e->addr.in6, e->ttl, e->stamps[i], e->index);
533 	for (i = 0; i < e->nstamps; i++)
534 		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
535 	seq_putc(seq, '\n');
536 	return 0;
537 }
538 
539 static const struct seq_operations recent_seq_ops = {
540 	.start		= recent_seq_start,
541 	.next		= recent_seq_next,
542 	.stop		= recent_seq_stop,
543 	.show		= recent_seq_show,
544 };
545 
recent_seq_open(struct inode * inode,struct file * file)546 static int recent_seq_open(struct inode *inode, struct file *file)
547 {
548 	struct recent_iter_state *st;
549 
550 	st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
551 	if (st == NULL)
552 		return -ENOMEM;
553 
554 	st->table    = pde_data(inode);
555 	return 0;
556 }
557 
558 static ssize_t
recent_mt_proc_write(struct file * file,const char __user * input,size_t size,loff_t * loff)559 recent_mt_proc_write(struct file *file, const char __user *input,
560 		     size_t size, loff_t *loff)
561 {
562 	struct recent_table *t = pde_data(file_inode(file));
563 	struct recent_entry *e;
564 	char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:255.255.255.255")];
565 	const char *c = buf;
566 	union nf_inet_addr addr = {};
567 	u_int16_t family;
568 	bool add, succ;
569 
570 	if (size == 0)
571 		return 0;
572 	if (size > sizeof(buf))
573 		size = sizeof(buf);
574 	if (copy_from_user(buf, input, size) != 0)
575 		return -EFAULT;
576 
577 	/* Strict protocol! */
578 	if (*loff != 0)
579 		return -ESPIPE;
580 	switch (*c) {
581 	case '/': /* flush table */
582 		spin_lock_bh(&recent_lock);
583 		recent_table_flush(t);
584 		spin_unlock_bh(&recent_lock);
585 		return size;
586 	case '-': /* remove address */
587 		add = false;
588 		break;
589 	case '+': /* add address */
590 		add = true;
591 		break;
592 	default:
593 		pr_info_ratelimited("Need \"+ip\", \"-ip\" or \"/\"\n");
594 		return -EINVAL;
595 	}
596 
597 	++c;
598 	--size;
599 	if (strnchr(c, size, ':') != NULL) {
600 		family = NFPROTO_IPV6;
601 		succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
602 	} else {
603 		family = NFPROTO_IPV4;
604 		succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
605 	}
606 
607 	if (!succ)
608 		return -EINVAL;
609 
610 	spin_lock_bh(&recent_lock);
611 	e = recent_entry_lookup(t, &addr, family, 0);
612 	if (e == NULL) {
613 		if (add)
614 			recent_entry_init(t, &addr, family, 0);
615 	} else {
616 		if (add)
617 			recent_entry_update(t, e);
618 		else
619 			recent_entry_remove(t, e);
620 	}
621 	spin_unlock_bh(&recent_lock);
622 	/* Note we removed one above */
623 	*loff += size + 1;
624 	return size + 1;
625 }
626 
627 static const struct proc_ops recent_mt_proc_ops = {
628 	.proc_open	= recent_seq_open,
629 	.proc_read	= seq_read,
630 	.proc_write	= recent_mt_proc_write,
631 	.proc_release	= seq_release_private,
632 	.proc_lseek	= seq_lseek,
633 };
634 
recent_proc_net_init(struct net * net)635 static int __net_init recent_proc_net_init(struct net *net)
636 {
637 	struct recent_net *recent_net = recent_pernet(net);
638 
639 	recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
640 	if (!recent_net->xt_recent)
641 		return -ENOMEM;
642 	return 0;
643 }
644 
recent_proc_net_exit(struct net * net)645 static void __net_exit recent_proc_net_exit(struct net *net)
646 {
647 	struct recent_net *recent_net = recent_pernet(net);
648 	struct recent_table *t;
649 
650 	/* recent_net_exit() is called before recent_mt_destroy(). Make sure
651 	 * that the parent xt_recent proc entry is empty before trying to
652 	 * remove it.
653 	 */
654 	spin_lock_bh(&recent_lock);
655 	list_for_each_entry(t, &recent_net->tables, list)
656 	        remove_proc_entry(t->name, recent_net->xt_recent);
657 
658 	recent_net->xt_recent = NULL;
659 	spin_unlock_bh(&recent_lock);
660 
661 	remove_proc_entry("xt_recent", net->proc_net);
662 }
663 #else
recent_proc_net_init(struct net * net)664 static inline int recent_proc_net_init(struct net *net)
665 {
666 	return 0;
667 }
668 
recent_proc_net_exit(struct net * net)669 static inline void recent_proc_net_exit(struct net *net)
670 {
671 }
672 #endif /* CONFIG_PROC_FS */
673 
recent_net_init(struct net * net)674 static int __net_init recent_net_init(struct net *net)
675 {
676 	struct recent_net *recent_net = recent_pernet(net);
677 
678 	INIT_LIST_HEAD(&recent_net->tables);
679 	return recent_proc_net_init(net);
680 }
681 
recent_net_exit(struct net * net)682 static void __net_exit recent_net_exit(struct net *net)
683 {
684 	recent_proc_net_exit(net);
685 }
686 
687 static struct pernet_operations recent_net_ops = {
688 	.init	= recent_net_init,
689 	.exit	= recent_net_exit,
690 	.id	= &recent_net_id,
691 	.size	= sizeof(struct recent_net),
692 };
693 
694 static struct xt_match recent_mt_reg[] __read_mostly = {
695 	{
696 		.name       = "recent",
697 		.revision   = 0,
698 		.family     = NFPROTO_IPV4,
699 		.match      = recent_mt,
700 		.matchsize  = sizeof(struct xt_recent_mtinfo),
701 		.checkentry = recent_mt_check_v0,
702 		.destroy    = recent_mt_destroy,
703 		.me         = THIS_MODULE,
704 	},
705 	{
706 		.name       = "recent",
707 		.revision   = 0,
708 		.family     = NFPROTO_IPV6,
709 		.match      = recent_mt,
710 		.matchsize  = sizeof(struct xt_recent_mtinfo),
711 		.checkentry = recent_mt_check_v0,
712 		.destroy    = recent_mt_destroy,
713 		.me         = THIS_MODULE,
714 	},
715 	{
716 		.name       = "recent",
717 		.revision   = 1,
718 		.family     = NFPROTO_IPV4,
719 		.match      = recent_mt,
720 		.matchsize  = sizeof(struct xt_recent_mtinfo_v1),
721 		.checkentry = recent_mt_check_v1,
722 		.destroy    = recent_mt_destroy,
723 		.me         = THIS_MODULE,
724 	},
725 	{
726 		.name       = "recent",
727 		.revision   = 1,
728 		.family     = NFPROTO_IPV6,
729 		.match      = recent_mt,
730 		.matchsize  = sizeof(struct xt_recent_mtinfo_v1),
731 		.checkentry = recent_mt_check_v1,
732 		.destroy    = recent_mt_destroy,
733 		.me         = THIS_MODULE,
734 	}
735 };
736 
recent_mt_init(void)737 static int __init recent_mt_init(void)
738 {
739 	int err;
740 
741 	BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
742 
743 	if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
744 		return -EINVAL;
745 	ip_list_hash_size = 1 << fls(ip_list_tot);
746 
747 	err = register_pernet_subsys(&recent_net_ops);
748 	if (err)
749 		return err;
750 	err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
751 	if (err)
752 		unregister_pernet_subsys(&recent_net_ops);
753 	return err;
754 }
755 
recent_mt_exit(void)756 static void __exit recent_mt_exit(void)
757 {
758 	xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
759 	unregister_pernet_subsys(&recent_net_ops);
760 }
761 
762 module_init(recent_mt_init);
763 module_exit(recent_mt_exit);
764