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Merge tag 'please-pull-misc-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git...
[deliverable/linux.git] / net / ipv4 / netfilter / ip_tables.c
1 /*
2 * Packet matching code.
3 *
4 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
5 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
6 * Copyright (C) 2006-2010 Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/cache.h>
14 #include <linux/capability.h>
15 #include <linux/skbuff.h>
16 #include <linux/kmod.h>
17 #include <linux/vmalloc.h>
18 #include <linux/netdevice.h>
19 #include <linux/module.h>
20 #include <linux/icmp.h>
21 #include <net/ip.h>
22 #include <net/compat.h>
23 #include <asm/uaccess.h>
24 #include <linux/mutex.h>
25 #include <linux/proc_fs.h>
26 #include <linux/err.h>
27 #include <linux/cpumask.h>
28
29 #include <linux/netfilter/x_tables.h>
30 #include <linux/netfilter_ipv4/ip_tables.h>
31 #include <net/netfilter/nf_log.h>
32 #include "../../netfilter/xt_repldata.h"
33
34 MODULE_LICENSE("GPL");
35 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
36 MODULE_DESCRIPTION("IPv4 packet filter");
37
38 #ifdef CONFIG_NETFILTER_DEBUG
39 #define IP_NF_ASSERT(x) WARN_ON(!(x))
40 #else
41 #define IP_NF_ASSERT(x)
42 #endif
43
44 void *ipt_alloc_initial_table(const struct xt_table *info)
45 {
46 return xt_alloc_initial_table(ipt, IPT);
47 }
48 EXPORT_SYMBOL_GPL(ipt_alloc_initial_table);
49
50 /* Returns whether matches rule or not. */
51 /* Performance critical - called for every packet */
52 static inline bool
53 ip_packet_match(const struct iphdr *ip,
54 const char *indev,
55 const char *outdev,
56 const struct ipt_ip *ipinfo,
57 int isfrag)
58 {
59 unsigned long ret;
60
61 #define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg)))
62
63 if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
64 IPT_INV_SRCIP) ||
65 FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
66 IPT_INV_DSTIP))
67 return false;
68
69 ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask);
70
71 if (FWINV(ret != 0, IPT_INV_VIA_IN))
72 return false;
73
74 ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask);
75
76 if (FWINV(ret != 0, IPT_INV_VIA_OUT))
77 return false;
78
79 /* Check specific protocol */
80 if (ipinfo->proto &&
81 FWINV(ip->protocol != ipinfo->proto, IPT_INV_PROTO))
82 return false;
83
84 /* If we have a fragment rule but the packet is not a fragment
85 * then we return zero */
86 if (FWINV((ipinfo->flags&IPT_F_FRAG) && !isfrag, IPT_INV_FRAG))
87 return false;
88
89 return true;
90 }
91
92 static bool
93 ip_checkentry(const struct ipt_ip *ip)
94 {
95 if (ip->flags & ~IPT_F_MASK)
96 return false;
97 if (ip->invflags & ~IPT_INV_MASK)
98 return false;
99 return true;
100 }
101
102 static unsigned int
103 ipt_error(struct sk_buff *skb, const struct xt_action_param *par)
104 {
105 net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo);
106
107 return NF_DROP;
108 }
109
110 /* Performance critical */
111 static inline struct ipt_entry *
112 get_entry(const void *base, unsigned int offset)
113 {
114 return (struct ipt_entry *)(base + offset);
115 }
116
117 /* All zeroes == unconditional rule. */
118 /* Mildly perf critical (only if packet tracing is on) */
119 static inline bool unconditional(const struct ipt_entry *e)
120 {
121 static const struct ipt_ip uncond;
122
123 return e->target_offset == sizeof(struct ipt_entry) &&
124 memcmp(&e->ip, &uncond, sizeof(uncond)) == 0;
125 #undef FWINV
126 }
127
128 /* for const-correctness */
129 static inline const struct xt_entry_target *
130 ipt_get_target_c(const struct ipt_entry *e)
131 {
132 return ipt_get_target((struct ipt_entry *)e);
133 }
134
135 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
136 static const char *const hooknames[] = {
137 [NF_INET_PRE_ROUTING] = "PREROUTING",
138 [NF_INET_LOCAL_IN] = "INPUT",
139 [NF_INET_FORWARD] = "FORWARD",
140 [NF_INET_LOCAL_OUT] = "OUTPUT",
141 [NF_INET_POST_ROUTING] = "POSTROUTING",
142 };
143
144 enum nf_ip_trace_comments {
145 NF_IP_TRACE_COMMENT_RULE,
146 NF_IP_TRACE_COMMENT_RETURN,
147 NF_IP_TRACE_COMMENT_POLICY,
148 };
149
150 static const char *const comments[] = {
151 [NF_IP_TRACE_COMMENT_RULE] = "rule",
152 [NF_IP_TRACE_COMMENT_RETURN] = "return",
153 [NF_IP_TRACE_COMMENT_POLICY] = "policy",
154 };
155
156 static struct nf_loginfo trace_loginfo = {
157 .type = NF_LOG_TYPE_LOG,
158 .u = {
159 .log = {
160 .level = 4,
161 .logflags = NF_LOG_MASK,
162 },
163 },
164 };
165
166 /* Mildly perf critical (only if packet tracing is on) */
167 static inline int
168 get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e,
169 const char *hookname, const char **chainname,
170 const char **comment, unsigned int *rulenum)
171 {
172 const struct xt_standard_target *t = (void *)ipt_get_target_c(s);
173
174 if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) {
175 /* Head of user chain: ERROR target with chainname */
176 *chainname = t->target.data;
177 (*rulenum) = 0;
178 } else if (s == e) {
179 (*rulenum)++;
180
181 if (unconditional(s) &&
182 strcmp(t->target.u.kernel.target->name,
183 XT_STANDARD_TARGET) == 0 &&
184 t->verdict < 0) {
185 /* Tail of chains: STANDARD target (return/policy) */
186 *comment = *chainname == hookname
187 ? comments[NF_IP_TRACE_COMMENT_POLICY]
188 : comments[NF_IP_TRACE_COMMENT_RETURN];
189 }
190 return 1;
191 } else
192 (*rulenum)++;
193
194 return 0;
195 }
196
197 static void trace_packet(struct net *net,
198 const struct sk_buff *skb,
199 unsigned int hook,
200 const struct net_device *in,
201 const struct net_device *out,
202 const char *tablename,
203 const struct xt_table_info *private,
204 const struct ipt_entry *e)
205 {
206 const struct ipt_entry *root;
207 const char *hookname, *chainname, *comment;
208 const struct ipt_entry *iter;
209 unsigned int rulenum = 0;
210
211 root = get_entry(private->entries, private->hook_entry[hook]);
212
213 hookname = chainname = hooknames[hook];
214 comment = comments[NF_IP_TRACE_COMMENT_RULE];
215
216 xt_entry_foreach(iter, root, private->size - private->hook_entry[hook])
217 if (get_chainname_rulenum(iter, e, hookname,
218 &chainname, &comment, &rulenum) != 0)
219 break;
220
221 nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo,
222 "TRACE: %s:%s:%s:%u ",
223 tablename, chainname, comment, rulenum);
224 }
225 #endif
226
227 static inline
228 struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
229 {
230 return (void *)entry + entry->next_offset;
231 }
232
233 /* Returns one of the generic firewall policies, like NF_ACCEPT. */
234 unsigned int
235 ipt_do_table(struct sk_buff *skb,
236 const struct nf_hook_state *state,
237 struct xt_table *table)
238 {
239 unsigned int hook = state->hook;
240 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
241 const struct iphdr *ip;
242 /* Initializing verdict to NF_DROP keeps gcc happy. */
243 unsigned int verdict = NF_DROP;
244 const char *indev, *outdev;
245 const void *table_base;
246 struct ipt_entry *e, **jumpstack;
247 unsigned int stackidx, cpu;
248 const struct xt_table_info *private;
249 struct xt_action_param acpar;
250 unsigned int addend;
251
252 /* Initialization */
253 stackidx = 0;
254 ip = ip_hdr(skb);
255 indev = state->in ? state->in->name : nulldevname;
256 outdev = state->out ? state->out->name : nulldevname;
257 /* We handle fragments by dealing with the first fragment as
258 * if it was a normal packet. All other fragments are treated
259 * normally, except that they will NEVER match rules that ask
260 * things we don't know, ie. tcp syn flag or ports). If the
261 * rule is also a fragment-specific rule, non-fragments won't
262 * match it. */
263 acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
264 acpar.thoff = ip_hdrlen(skb);
265 acpar.hotdrop = false;
266 acpar.net = state->net;
267 acpar.in = state->in;
268 acpar.out = state->out;
269 acpar.family = NFPROTO_IPV4;
270 acpar.hooknum = hook;
271
272 IP_NF_ASSERT(table->valid_hooks & (1 << hook));
273 local_bh_disable();
274 addend = xt_write_recseq_begin();
275 private = table->private;
276 cpu = smp_processor_id();
277 /*
278 * Ensure we load private-> members after we've fetched the base
279 * pointer.
280 */
281 smp_read_barrier_depends();
282 table_base = private->entries;
283 jumpstack = (struct ipt_entry **)private->jumpstack[cpu];
284
285 /* Switch to alternate jumpstack if we're being invoked via TEE.
286 * TEE issues XT_CONTINUE verdict on original skb so we must not
287 * clobber the jumpstack.
288 *
289 * For recursion via REJECT or SYNPROXY the stack will be clobbered
290 * but it is no problem since absolute verdict is issued by these.
291 */
292 if (static_key_false(&xt_tee_enabled))
293 jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
294
295 e = get_entry(table_base, private->hook_entry[hook]);
296
297 do {
298 const struct xt_entry_target *t;
299 const struct xt_entry_match *ematch;
300 struct xt_counters *counter;
301
302 IP_NF_ASSERT(e);
303 if (!ip_packet_match(ip, indev, outdev,
304 &e->ip, acpar.fragoff)) {
305 no_match:
306 e = ipt_next_entry(e);
307 continue;
308 }
309
310 xt_ematch_foreach(ematch, e) {
311 acpar.match = ematch->u.kernel.match;
312 acpar.matchinfo = ematch->data;
313 if (!acpar.match->match(skb, &acpar))
314 goto no_match;
315 }
316
317 counter = xt_get_this_cpu_counter(&e->counters);
318 ADD_COUNTER(*counter, skb->len, 1);
319
320 t = ipt_get_target(e);
321 IP_NF_ASSERT(t->u.kernel.target);
322
323 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
324 /* The packet is traced: log it */
325 if (unlikely(skb->nf_trace))
326 trace_packet(state->net, skb, hook, state->in,
327 state->out, table->name, private, e);
328 #endif
329 /* Standard target? */
330 if (!t->u.kernel.target->target) {
331 int v;
332
333 v = ((struct xt_standard_target *)t)->verdict;
334 if (v < 0) {
335 /* Pop from stack? */
336 if (v != XT_RETURN) {
337 verdict = (unsigned int)(-v) - 1;
338 break;
339 }
340 if (stackidx == 0) {
341 e = get_entry(table_base,
342 private->underflow[hook]);
343 } else {
344 e = jumpstack[--stackidx];
345 e = ipt_next_entry(e);
346 }
347 continue;
348 }
349 if (table_base + v != ipt_next_entry(e) &&
350 !(e->ip.flags & IPT_F_GOTO))
351 jumpstack[stackidx++] = e;
352
353 e = get_entry(table_base, v);
354 continue;
355 }
356
357 acpar.target = t->u.kernel.target;
358 acpar.targinfo = t->data;
359
360 verdict = t->u.kernel.target->target(skb, &acpar);
361 /* Target might have changed stuff. */
362 ip = ip_hdr(skb);
363 if (verdict == XT_CONTINUE)
364 e = ipt_next_entry(e);
365 else
366 /* Verdict */
367 break;
368 } while (!acpar.hotdrop);
369
370 xt_write_recseq_end(addend);
371 local_bh_enable();
372
373 if (acpar.hotdrop)
374 return NF_DROP;
375 else return verdict;
376 }
377
378 static bool find_jump_target(const struct xt_table_info *t,
379 const struct ipt_entry *target)
380 {
381 struct ipt_entry *iter;
382
383 xt_entry_foreach(iter, t->entries, t->size) {
384 if (iter == target)
385 return true;
386 }
387 return false;
388 }
389
390 /* Figures out from what hook each rule can be called: returns 0 if
391 there are loops. Puts hook bitmask in comefrom. */
392 static int
393 mark_source_chains(const struct xt_table_info *newinfo,
394 unsigned int valid_hooks, void *entry0)
395 {
396 unsigned int hook;
397
398 /* No recursion; use packet counter to save back ptrs (reset
399 to 0 as we leave), and comefrom to save source hook bitmask */
400 for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) {
401 unsigned int pos = newinfo->hook_entry[hook];
402 struct ipt_entry *e = (struct ipt_entry *)(entry0 + pos);
403
404 if (!(valid_hooks & (1 << hook)))
405 continue;
406
407 /* Set initial back pointer. */
408 e->counters.pcnt = pos;
409
410 for (;;) {
411 const struct xt_standard_target *t
412 = (void *)ipt_get_target_c(e);
413 int visited = e->comefrom & (1 << hook);
414
415 if (e->comefrom & (1 << NF_INET_NUMHOOKS))
416 return 0;
417
418 e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS));
419
420 /* Unconditional return/END. */
421 if ((unconditional(e) &&
422 (strcmp(t->target.u.user.name,
423 XT_STANDARD_TARGET) == 0) &&
424 t->verdict < 0) || visited) {
425 unsigned int oldpos, size;
426
427 if ((strcmp(t->target.u.user.name,
428 XT_STANDARD_TARGET) == 0) &&
429 t->verdict < -NF_MAX_VERDICT - 1)
430 return 0;
431
432 /* Return: backtrack through the last
433 big jump. */
434 do {
435 e->comefrom ^= (1<<NF_INET_NUMHOOKS);
436 oldpos = pos;
437 pos = e->counters.pcnt;
438 e->counters.pcnt = 0;
439
440 /* We're at the start. */
441 if (pos == oldpos)
442 goto next;
443
444 e = (struct ipt_entry *)
445 (entry0 + pos);
446 } while (oldpos == pos + e->next_offset);
447
448 /* Move along one */
449 size = e->next_offset;
450 e = (struct ipt_entry *)
451 (entry0 + pos + size);
452 if (pos + size >= newinfo->size)
453 return 0;
454 e->counters.pcnt = pos;
455 pos += size;
456 } else {
457 int newpos = t->verdict;
458
459 if (strcmp(t->target.u.user.name,
460 XT_STANDARD_TARGET) == 0 &&
461 newpos >= 0) {
462 /* This a jump; chase it. */
463 e = (struct ipt_entry *)
464 (entry0 + newpos);
465 if (!find_jump_target(newinfo, e))
466 return 0;
467 } else {
468 /* ... this is a fallthru */
469 newpos = pos + e->next_offset;
470 if (newpos >= newinfo->size)
471 return 0;
472 }
473 e = (struct ipt_entry *)
474 (entry0 + newpos);
475 e->counters.pcnt = pos;
476 pos = newpos;
477 }
478 }
479 next: ;
480 }
481 return 1;
482 }
483
484 static void cleanup_match(struct xt_entry_match *m, struct net *net)
485 {
486 struct xt_mtdtor_param par;
487
488 par.net = net;
489 par.match = m->u.kernel.match;
490 par.matchinfo = m->data;
491 par.family = NFPROTO_IPV4;
492 if (par.match->destroy != NULL)
493 par.match->destroy(&par);
494 module_put(par.match->me);
495 }
496
497 static int
498 check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
499 {
500 const struct ipt_ip *ip = par->entryinfo;
501
502 par->match = m->u.kernel.match;
503 par->matchinfo = m->data;
504
505 return xt_check_match(par, m->u.match_size - sizeof(*m),
506 ip->proto, ip->invflags & IPT_INV_PROTO);
507 }
508
509 static int
510 find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
511 {
512 struct xt_match *match;
513 int ret;
514
515 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
516 m->u.user.revision);
517 if (IS_ERR(match))
518 return PTR_ERR(match);
519 m->u.kernel.match = match;
520
521 ret = check_match(m, par);
522 if (ret)
523 goto err;
524
525 return 0;
526 err:
527 module_put(m->u.kernel.match->me);
528 return ret;
529 }
530
531 static int check_target(struct ipt_entry *e, struct net *net, const char *name)
532 {
533 struct xt_entry_target *t = ipt_get_target(e);
534 struct xt_tgchk_param par = {
535 .net = net,
536 .table = name,
537 .entryinfo = e,
538 .target = t->u.kernel.target,
539 .targinfo = t->data,
540 .hook_mask = e->comefrom,
541 .family = NFPROTO_IPV4,
542 };
543
544 return xt_check_target(&par, t->u.target_size - sizeof(*t),
545 e->ip.proto, e->ip.invflags & IPT_INV_PROTO);
546 }
547
548 static int
549 find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
550 unsigned int size)
551 {
552 struct xt_entry_target *t;
553 struct xt_target *target;
554 int ret;
555 unsigned int j;
556 struct xt_mtchk_param mtpar;
557 struct xt_entry_match *ematch;
558 unsigned long pcnt;
559
560 pcnt = xt_percpu_counter_alloc();
561 if (IS_ERR_VALUE(pcnt))
562 return -ENOMEM;
563 e->counters.pcnt = pcnt;
564
565 j = 0;
566 mtpar.net = net;
567 mtpar.table = name;
568 mtpar.entryinfo = &e->ip;
569 mtpar.hook_mask = e->comefrom;
570 mtpar.family = NFPROTO_IPV4;
571 xt_ematch_foreach(ematch, e) {
572 ret = find_check_match(ematch, &mtpar);
573 if (ret != 0)
574 goto cleanup_matches;
575 ++j;
576 }
577
578 t = ipt_get_target(e);
579 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
580 t->u.user.revision);
581 if (IS_ERR(target)) {
582 ret = PTR_ERR(target);
583 goto cleanup_matches;
584 }
585 t->u.kernel.target = target;
586
587 ret = check_target(e, net, name);
588 if (ret)
589 goto err;
590
591 return 0;
592 err:
593 module_put(t->u.kernel.target->me);
594 cleanup_matches:
595 xt_ematch_foreach(ematch, e) {
596 if (j-- == 0)
597 break;
598 cleanup_match(ematch, net);
599 }
600
601 xt_percpu_counter_free(e->counters.pcnt);
602
603 return ret;
604 }
605
606 static bool check_underflow(const struct ipt_entry *e)
607 {
608 const struct xt_entry_target *t;
609 unsigned int verdict;
610
611 if (!unconditional(e))
612 return false;
613 t = ipt_get_target_c(e);
614 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
615 return false;
616 verdict = ((struct xt_standard_target *)t)->verdict;
617 verdict = -verdict - 1;
618 return verdict == NF_DROP || verdict == NF_ACCEPT;
619 }
620
621 static int
622 check_entry_size_and_hooks(struct ipt_entry *e,
623 struct xt_table_info *newinfo,
624 const unsigned char *base,
625 const unsigned char *limit,
626 const unsigned int *hook_entries,
627 const unsigned int *underflows,
628 unsigned int valid_hooks)
629 {
630 unsigned int h;
631 int err;
632
633 if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
634 (unsigned char *)e + sizeof(struct ipt_entry) >= limit ||
635 (unsigned char *)e + e->next_offset > limit)
636 return -EINVAL;
637
638 if (e->next_offset
639 < sizeof(struct ipt_entry) + sizeof(struct xt_entry_target))
640 return -EINVAL;
641
642 if (!ip_checkentry(&e->ip))
643 return -EINVAL;
644
645 err = xt_check_entry_offsets(e, e->elems, e->target_offset,
646 e->next_offset);
647 if (err)
648 return err;
649
650 /* Check hooks & underflows */
651 for (h = 0; h < NF_INET_NUMHOOKS; h++) {
652 if (!(valid_hooks & (1 << h)))
653 continue;
654 if ((unsigned char *)e - base == hook_entries[h])
655 newinfo->hook_entry[h] = hook_entries[h];
656 if ((unsigned char *)e - base == underflows[h]) {
657 if (!check_underflow(e))
658 return -EINVAL;
659
660 newinfo->underflow[h] = underflows[h];
661 }
662 }
663
664 /* Clear counters and comefrom */
665 e->counters = ((struct xt_counters) { 0, 0 });
666 e->comefrom = 0;
667 return 0;
668 }
669
670 static void
671 cleanup_entry(struct ipt_entry *e, struct net *net)
672 {
673 struct xt_tgdtor_param par;
674 struct xt_entry_target *t;
675 struct xt_entry_match *ematch;
676
677 /* Cleanup all matches */
678 xt_ematch_foreach(ematch, e)
679 cleanup_match(ematch, net);
680 t = ipt_get_target(e);
681
682 par.net = net;
683 par.target = t->u.kernel.target;
684 par.targinfo = t->data;
685 par.family = NFPROTO_IPV4;
686 if (par.target->destroy != NULL)
687 par.target->destroy(&par);
688 module_put(par.target->me);
689 xt_percpu_counter_free(e->counters.pcnt);
690 }
691
692 /* Checks and translates the user-supplied table segment (held in
693 newinfo) */
694 static int
695 translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0,
696 const struct ipt_replace *repl)
697 {
698 struct ipt_entry *iter;
699 unsigned int i;
700 int ret = 0;
701
702 newinfo->size = repl->size;
703 newinfo->number = repl->num_entries;
704
705 /* Init all hooks to impossible value. */
706 for (i = 0; i < NF_INET_NUMHOOKS; i++) {
707 newinfo->hook_entry[i] = 0xFFFFFFFF;
708 newinfo->underflow[i] = 0xFFFFFFFF;
709 }
710
711 i = 0;
712 /* Walk through entries, checking offsets. */
713 xt_entry_foreach(iter, entry0, newinfo->size) {
714 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
715 entry0 + repl->size,
716 repl->hook_entry,
717 repl->underflow,
718 repl->valid_hooks);
719 if (ret != 0)
720 return ret;
721 ++i;
722 if (strcmp(ipt_get_target(iter)->u.user.name,
723 XT_ERROR_TARGET) == 0)
724 ++newinfo->stacksize;
725 }
726
727 if (i != repl->num_entries)
728 return -EINVAL;
729
730 /* Check hooks all assigned */
731 for (i = 0; i < NF_INET_NUMHOOKS; i++) {
732 /* Only hooks which are valid */
733 if (!(repl->valid_hooks & (1 << i)))
734 continue;
735 if (newinfo->hook_entry[i] == 0xFFFFFFFF)
736 return -EINVAL;
737 if (newinfo->underflow[i] == 0xFFFFFFFF)
738 return -EINVAL;
739 }
740
741 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
742 return -ELOOP;
743
744 /* Finally, each sanity check must pass */
745 i = 0;
746 xt_entry_foreach(iter, entry0, newinfo->size) {
747 ret = find_check_entry(iter, net, repl->name, repl->size);
748 if (ret != 0)
749 break;
750 ++i;
751 }
752
753 if (ret != 0) {
754 xt_entry_foreach(iter, entry0, newinfo->size) {
755 if (i-- == 0)
756 break;
757 cleanup_entry(iter, net);
758 }
759 return ret;
760 }
761
762 return ret;
763 }
764
765 static void
766 get_counters(const struct xt_table_info *t,
767 struct xt_counters counters[])
768 {
769 struct ipt_entry *iter;
770 unsigned int cpu;
771 unsigned int i;
772
773 for_each_possible_cpu(cpu) {
774 seqcount_t *s = &per_cpu(xt_recseq, cpu);
775
776 i = 0;
777 xt_entry_foreach(iter, t->entries, t->size) {
778 struct xt_counters *tmp;
779 u64 bcnt, pcnt;
780 unsigned int start;
781
782 tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
783 do {
784 start = read_seqcount_begin(s);
785 bcnt = tmp->bcnt;
786 pcnt = tmp->pcnt;
787 } while (read_seqcount_retry(s, start));
788
789 ADD_COUNTER(counters[i], bcnt, pcnt);
790 ++i; /* macro does multi eval of i */
791 }
792 }
793 }
794
795 static struct xt_counters *alloc_counters(const struct xt_table *table)
796 {
797 unsigned int countersize;
798 struct xt_counters *counters;
799 const struct xt_table_info *private = table->private;
800
801 /* We need atomic snapshot of counters: rest doesn't change
802 (other than comefrom, which userspace doesn't care
803 about). */
804 countersize = sizeof(struct xt_counters) * private->number;
805 counters = vzalloc(countersize);
806
807 if (counters == NULL)
808 return ERR_PTR(-ENOMEM);
809
810 get_counters(private, counters);
811
812 return counters;
813 }
814
815 static int
816 copy_entries_to_user(unsigned int total_size,
817 const struct xt_table *table,
818 void __user *userptr)
819 {
820 unsigned int off, num;
821 const struct ipt_entry *e;
822 struct xt_counters *counters;
823 const struct xt_table_info *private = table->private;
824 int ret = 0;
825 const void *loc_cpu_entry;
826
827 counters = alloc_counters(table);
828 if (IS_ERR(counters))
829 return PTR_ERR(counters);
830
831 loc_cpu_entry = private->entries;
832 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
833 ret = -EFAULT;
834 goto free_counters;
835 }
836
837 /* FIXME: use iterator macros --RR */
838 /* ... then go back and fix counters and names */
839 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
840 unsigned int i;
841 const struct xt_entry_match *m;
842 const struct xt_entry_target *t;
843
844 e = (struct ipt_entry *)(loc_cpu_entry + off);
845 if (copy_to_user(userptr + off
846 + offsetof(struct ipt_entry, counters),
847 &counters[num],
848 sizeof(counters[num])) != 0) {
849 ret = -EFAULT;
850 goto free_counters;
851 }
852
853 for (i = sizeof(struct ipt_entry);
854 i < e->target_offset;
855 i += m->u.match_size) {
856 m = (void *)e + i;
857
858 if (copy_to_user(userptr + off + i
859 + offsetof(struct xt_entry_match,
860 u.user.name),
861 m->u.kernel.match->name,
862 strlen(m->u.kernel.match->name)+1)
863 != 0) {
864 ret = -EFAULT;
865 goto free_counters;
866 }
867 }
868
869 t = ipt_get_target_c(e);
870 if (copy_to_user(userptr + off + e->target_offset
871 + offsetof(struct xt_entry_target,
872 u.user.name),
873 t->u.kernel.target->name,
874 strlen(t->u.kernel.target->name)+1) != 0) {
875 ret = -EFAULT;
876 goto free_counters;
877 }
878 }
879
880 free_counters:
881 vfree(counters);
882 return ret;
883 }
884
885 #ifdef CONFIG_COMPAT
886 static void compat_standard_from_user(void *dst, const void *src)
887 {
888 int v = *(compat_int_t *)src;
889
890 if (v > 0)
891 v += xt_compat_calc_jump(AF_INET, v);
892 memcpy(dst, &v, sizeof(v));
893 }
894
895 static int compat_standard_to_user(void __user *dst, const void *src)
896 {
897 compat_int_t cv = *(int *)src;
898
899 if (cv > 0)
900 cv -= xt_compat_calc_jump(AF_INET, cv);
901 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
902 }
903
904 static int compat_calc_entry(const struct ipt_entry *e,
905 const struct xt_table_info *info,
906 const void *base, struct xt_table_info *newinfo)
907 {
908 const struct xt_entry_match *ematch;
909 const struct xt_entry_target *t;
910 unsigned int entry_offset;
911 int off, i, ret;
912
913 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
914 entry_offset = (void *)e - base;
915 xt_ematch_foreach(ematch, e)
916 off += xt_compat_match_offset(ematch->u.kernel.match);
917 t = ipt_get_target_c(e);
918 off += xt_compat_target_offset(t->u.kernel.target);
919 newinfo->size -= off;
920 ret = xt_compat_add_offset(AF_INET, entry_offset, off);
921 if (ret)
922 return ret;
923
924 for (i = 0; i < NF_INET_NUMHOOKS; i++) {
925 if (info->hook_entry[i] &&
926 (e < (struct ipt_entry *)(base + info->hook_entry[i])))
927 newinfo->hook_entry[i] -= off;
928 if (info->underflow[i] &&
929 (e < (struct ipt_entry *)(base + info->underflow[i])))
930 newinfo->underflow[i] -= off;
931 }
932 return 0;
933 }
934
935 static int compat_table_info(const struct xt_table_info *info,
936 struct xt_table_info *newinfo)
937 {
938 struct ipt_entry *iter;
939 const void *loc_cpu_entry;
940 int ret;
941
942 if (!newinfo || !info)
943 return -EINVAL;
944
945 /* we dont care about newinfo->entries */
946 memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
947 newinfo->initial_entries = 0;
948 loc_cpu_entry = info->entries;
949 xt_compat_init_offsets(AF_INET, info->number);
950 xt_entry_foreach(iter, loc_cpu_entry, info->size) {
951 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
952 if (ret != 0)
953 return ret;
954 }
955 return 0;
956 }
957 #endif
958
959 static int get_info(struct net *net, void __user *user,
960 const int *len, int compat)
961 {
962 char name[XT_TABLE_MAXNAMELEN];
963 struct xt_table *t;
964 int ret;
965
966 if (*len != sizeof(struct ipt_getinfo))
967 return -EINVAL;
968
969 if (copy_from_user(name, user, sizeof(name)) != 0)
970 return -EFAULT;
971
972 name[XT_TABLE_MAXNAMELEN-1] = '\0';
973 #ifdef CONFIG_COMPAT
974 if (compat)
975 xt_compat_lock(AF_INET);
976 #endif
977 t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
978 "iptable_%s", name);
979 if (!IS_ERR_OR_NULL(t)) {
980 struct ipt_getinfo info;
981 const struct xt_table_info *private = t->private;
982 #ifdef CONFIG_COMPAT
983 struct xt_table_info tmp;
984
985 if (compat) {
986 ret = compat_table_info(private, &tmp);
987 xt_compat_flush_offsets(AF_INET);
988 private = &tmp;
989 }
990 #endif
991 memset(&info, 0, sizeof(info));
992 info.valid_hooks = t->valid_hooks;
993 memcpy(info.hook_entry, private->hook_entry,
994 sizeof(info.hook_entry));
995 memcpy(info.underflow, private->underflow,
996 sizeof(info.underflow));
997 info.num_entries = private->number;
998 info.size = private->size;
999 strcpy(info.name, name);
1000
1001 if (copy_to_user(user, &info, *len) != 0)
1002 ret = -EFAULT;
1003 else
1004 ret = 0;
1005
1006 xt_table_unlock(t);
1007 module_put(t->me);
1008 } else
1009 ret = t ? PTR_ERR(t) : -ENOENT;
1010 #ifdef CONFIG_COMPAT
1011 if (compat)
1012 xt_compat_unlock(AF_INET);
1013 #endif
1014 return ret;
1015 }
1016
1017 static int
1018 get_entries(struct net *net, struct ipt_get_entries __user *uptr,
1019 const int *len)
1020 {
1021 int ret;
1022 struct ipt_get_entries get;
1023 struct xt_table *t;
1024
1025 if (*len < sizeof(get))
1026 return -EINVAL;
1027 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1028 return -EFAULT;
1029 if (*len != sizeof(struct ipt_get_entries) + get.size)
1030 return -EINVAL;
1031 get.name[sizeof(get.name) - 1] = '\0';
1032
1033 t = xt_find_table_lock(net, AF_INET, get.name);
1034 if (!IS_ERR_OR_NULL(t)) {
1035 const struct xt_table_info *private = t->private;
1036 if (get.size == private->size)
1037 ret = copy_entries_to_user(private->size,
1038 t, uptr->entrytable);
1039 else
1040 ret = -EAGAIN;
1041
1042 module_put(t->me);
1043 xt_table_unlock(t);
1044 } else
1045 ret = t ? PTR_ERR(t) : -ENOENT;
1046
1047 return ret;
1048 }
1049
1050 static int
1051 __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
1052 struct xt_table_info *newinfo, unsigned int num_counters,
1053 void __user *counters_ptr)
1054 {
1055 int ret;
1056 struct xt_table *t;
1057 struct xt_table_info *oldinfo;
1058 struct xt_counters *counters;
1059 struct ipt_entry *iter;
1060
1061 ret = 0;
1062 counters = vzalloc(num_counters * sizeof(struct xt_counters));
1063 if (!counters) {
1064 ret = -ENOMEM;
1065 goto out;
1066 }
1067
1068 t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
1069 "iptable_%s", name);
1070 if (IS_ERR_OR_NULL(t)) {
1071 ret = t ? PTR_ERR(t) : -ENOENT;
1072 goto free_newinfo_counters_untrans;
1073 }
1074
1075 /* You lied! */
1076 if (valid_hooks != t->valid_hooks) {
1077 ret = -EINVAL;
1078 goto put_module;
1079 }
1080
1081 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1082 if (!oldinfo)
1083 goto put_module;
1084
1085 /* Update module usage count based on number of rules */
1086 if ((oldinfo->number > oldinfo->initial_entries) ||
1087 (newinfo->number <= oldinfo->initial_entries))
1088 module_put(t->me);
1089 if ((oldinfo->number > oldinfo->initial_entries) &&
1090 (newinfo->number <= oldinfo->initial_entries))
1091 module_put(t->me);
1092
1093 /* Get the old counters, and synchronize with replace */
1094 get_counters(oldinfo, counters);
1095
1096 /* Decrease module usage counts and free resource */
1097 xt_entry_foreach(iter, oldinfo->entries, oldinfo->size)
1098 cleanup_entry(iter, net);
1099
1100 xt_free_table_info(oldinfo);
1101 if (copy_to_user(counters_ptr, counters,
1102 sizeof(struct xt_counters) * num_counters) != 0) {
1103 /* Silent error, can't fail, new table is already in place */
1104 net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n");
1105 }
1106 vfree(counters);
1107 xt_table_unlock(t);
1108 return ret;
1109
1110 put_module:
1111 module_put(t->me);
1112 xt_table_unlock(t);
1113 free_newinfo_counters_untrans:
1114 vfree(counters);
1115 out:
1116 return ret;
1117 }
1118
1119 static int
1120 do_replace(struct net *net, const void __user *user, unsigned int len)
1121 {
1122 int ret;
1123 struct ipt_replace tmp;
1124 struct xt_table_info *newinfo;
1125 void *loc_cpu_entry;
1126 struct ipt_entry *iter;
1127
1128 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1129 return -EFAULT;
1130
1131 /* overflow check */
1132 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1133 return -ENOMEM;
1134 if (tmp.num_counters == 0)
1135 return -EINVAL;
1136
1137 tmp.name[sizeof(tmp.name)-1] = 0;
1138
1139 newinfo = xt_alloc_table_info(tmp.size);
1140 if (!newinfo)
1141 return -ENOMEM;
1142
1143 loc_cpu_entry = newinfo->entries;
1144 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1145 tmp.size) != 0) {
1146 ret = -EFAULT;
1147 goto free_newinfo;
1148 }
1149
1150 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
1151 if (ret != 0)
1152 goto free_newinfo;
1153
1154 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1155 tmp.num_counters, tmp.counters);
1156 if (ret)
1157 goto free_newinfo_untrans;
1158 return 0;
1159
1160 free_newinfo_untrans:
1161 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1162 cleanup_entry(iter, net);
1163 free_newinfo:
1164 xt_free_table_info(newinfo);
1165 return ret;
1166 }
1167
1168 static int
1169 do_add_counters(struct net *net, const void __user *user,
1170 unsigned int len, int compat)
1171 {
1172 unsigned int i;
1173 struct xt_counters_info tmp;
1174 struct xt_counters *paddc;
1175 struct xt_table *t;
1176 const struct xt_table_info *private;
1177 int ret = 0;
1178 struct ipt_entry *iter;
1179 unsigned int addend;
1180
1181 paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1182 if (IS_ERR(paddc))
1183 return PTR_ERR(paddc);
1184
1185 t = xt_find_table_lock(net, AF_INET, tmp.name);
1186 if (IS_ERR_OR_NULL(t)) {
1187 ret = t ? PTR_ERR(t) : -ENOENT;
1188 goto free;
1189 }
1190
1191 local_bh_disable();
1192 private = t->private;
1193 if (private->number != tmp.num_counters) {
1194 ret = -EINVAL;
1195 goto unlock_up_free;
1196 }
1197
1198 i = 0;
1199 addend = xt_write_recseq_begin();
1200 xt_entry_foreach(iter, private->entries, private->size) {
1201 struct xt_counters *tmp;
1202
1203 tmp = xt_get_this_cpu_counter(&iter->counters);
1204 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1205 ++i;
1206 }
1207 xt_write_recseq_end(addend);
1208 unlock_up_free:
1209 local_bh_enable();
1210 xt_table_unlock(t);
1211 module_put(t->me);
1212 free:
1213 vfree(paddc);
1214
1215 return ret;
1216 }
1217
1218 #ifdef CONFIG_COMPAT
1219 struct compat_ipt_replace {
1220 char name[XT_TABLE_MAXNAMELEN];
1221 u32 valid_hooks;
1222 u32 num_entries;
1223 u32 size;
1224 u32 hook_entry[NF_INET_NUMHOOKS];
1225 u32 underflow[NF_INET_NUMHOOKS];
1226 u32 num_counters;
1227 compat_uptr_t counters; /* struct xt_counters * */
1228 struct compat_ipt_entry entries[0];
1229 };
1230
1231 static int
1232 compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
1233 unsigned int *size, struct xt_counters *counters,
1234 unsigned int i)
1235 {
1236 struct xt_entry_target *t;
1237 struct compat_ipt_entry __user *ce;
1238 u_int16_t target_offset, next_offset;
1239 compat_uint_t origsize;
1240 const struct xt_entry_match *ematch;
1241 int ret = 0;
1242
1243 origsize = *size;
1244 ce = (struct compat_ipt_entry __user *)*dstptr;
1245 if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 ||
1246 copy_to_user(&ce->counters, &counters[i],
1247 sizeof(counters[i])) != 0)
1248 return -EFAULT;
1249
1250 *dstptr += sizeof(struct compat_ipt_entry);
1251 *size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1252
1253 xt_ematch_foreach(ematch, e) {
1254 ret = xt_compat_match_to_user(ematch, dstptr, size);
1255 if (ret != 0)
1256 return ret;
1257 }
1258 target_offset = e->target_offset - (origsize - *size);
1259 t = ipt_get_target(e);
1260 ret = xt_compat_target_to_user(t, dstptr, size);
1261 if (ret)
1262 return ret;
1263 next_offset = e->next_offset - (origsize - *size);
1264 if (put_user(target_offset, &ce->target_offset) != 0 ||
1265 put_user(next_offset, &ce->next_offset) != 0)
1266 return -EFAULT;
1267 return 0;
1268 }
1269
1270 static int
1271 compat_find_calc_match(struct xt_entry_match *m,
1272 const struct ipt_ip *ip,
1273 int *size)
1274 {
1275 struct xt_match *match;
1276
1277 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
1278 m->u.user.revision);
1279 if (IS_ERR(match))
1280 return PTR_ERR(match);
1281
1282 m->u.kernel.match = match;
1283 *size += xt_compat_match_offset(match);
1284 return 0;
1285 }
1286
1287 static void compat_release_entry(struct compat_ipt_entry *e)
1288 {
1289 struct xt_entry_target *t;
1290 struct xt_entry_match *ematch;
1291
1292 /* Cleanup all matches */
1293 xt_ematch_foreach(ematch, e)
1294 module_put(ematch->u.kernel.match->me);
1295 t = compat_ipt_get_target(e);
1296 module_put(t->u.kernel.target->me);
1297 }
1298
1299 static int
1300 check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
1301 struct xt_table_info *newinfo,
1302 unsigned int *size,
1303 const unsigned char *base,
1304 const unsigned char *limit)
1305 {
1306 struct xt_entry_match *ematch;
1307 struct xt_entry_target *t;
1308 struct xt_target *target;
1309 unsigned int entry_offset;
1310 unsigned int j;
1311 int ret, off;
1312
1313 if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 ||
1314 (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit ||
1315 (unsigned char *)e + e->next_offset > limit)
1316 return -EINVAL;
1317
1318 if (e->next_offset < sizeof(struct compat_ipt_entry) +
1319 sizeof(struct compat_xt_entry_target))
1320 return -EINVAL;
1321
1322 if (!ip_checkentry(&e->ip))
1323 return -EINVAL;
1324
1325 ret = xt_compat_check_entry_offsets(e, e->elems,
1326 e->target_offset, e->next_offset);
1327 if (ret)
1328 return ret;
1329
1330 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1331 entry_offset = (void *)e - (void *)base;
1332 j = 0;
1333 xt_ematch_foreach(ematch, e) {
1334 ret = compat_find_calc_match(ematch, &e->ip, &off);
1335 if (ret != 0)
1336 goto release_matches;
1337 ++j;
1338 }
1339
1340 t = compat_ipt_get_target(e);
1341 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
1342 t->u.user.revision);
1343 if (IS_ERR(target)) {
1344 ret = PTR_ERR(target);
1345 goto release_matches;
1346 }
1347 t->u.kernel.target = target;
1348
1349 off += xt_compat_target_offset(target);
1350 *size += off;
1351 ret = xt_compat_add_offset(AF_INET, entry_offset, off);
1352 if (ret)
1353 goto out;
1354
1355 return 0;
1356
1357 out:
1358 module_put(t->u.kernel.target->me);
1359 release_matches:
1360 xt_ematch_foreach(ematch, e) {
1361 if (j-- == 0)
1362 break;
1363 module_put(ematch->u.kernel.match->me);
1364 }
1365 return ret;
1366 }
1367
1368 static void
1369 compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr,
1370 unsigned int *size,
1371 struct xt_table_info *newinfo, unsigned char *base)
1372 {
1373 struct xt_entry_target *t;
1374 struct xt_target *target;
1375 struct ipt_entry *de;
1376 unsigned int origsize;
1377 int h;
1378 struct xt_entry_match *ematch;
1379
1380 origsize = *size;
1381 de = (struct ipt_entry *)*dstptr;
1382 memcpy(de, e, sizeof(struct ipt_entry));
1383 memcpy(&de->counters, &e->counters, sizeof(e->counters));
1384
1385 *dstptr += sizeof(struct ipt_entry);
1386 *size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1387
1388 xt_ematch_foreach(ematch, e)
1389 xt_compat_match_from_user(ematch, dstptr, size);
1390
1391 de->target_offset = e->target_offset - (origsize - *size);
1392 t = compat_ipt_get_target(e);
1393 target = t->u.kernel.target;
1394 xt_compat_target_from_user(t, dstptr, size);
1395
1396 de->next_offset = e->next_offset - (origsize - *size);
1397
1398 for (h = 0; h < NF_INET_NUMHOOKS; h++) {
1399 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1400 newinfo->hook_entry[h] -= origsize - *size;
1401 if ((unsigned char *)de - base < newinfo->underflow[h])
1402 newinfo->underflow[h] -= origsize - *size;
1403 }
1404 }
1405
1406 static int
1407 translate_compat_table(struct net *net,
1408 struct xt_table_info **pinfo,
1409 void **pentry0,
1410 const struct compat_ipt_replace *compatr)
1411 {
1412 unsigned int i, j;
1413 struct xt_table_info *newinfo, *info;
1414 void *pos, *entry0, *entry1;
1415 struct compat_ipt_entry *iter0;
1416 struct ipt_replace repl;
1417 unsigned int size;
1418 int ret;
1419
1420 info = *pinfo;
1421 entry0 = *pentry0;
1422 size = compatr->size;
1423 info->number = compatr->num_entries;
1424
1425 j = 0;
1426 xt_compat_lock(AF_INET);
1427 xt_compat_init_offsets(AF_INET, compatr->num_entries);
1428 /* Walk through entries, checking offsets. */
1429 xt_entry_foreach(iter0, entry0, compatr->size) {
1430 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1431 entry0,
1432 entry0 + compatr->size);
1433 if (ret != 0)
1434 goto out_unlock;
1435 ++j;
1436 }
1437
1438 ret = -EINVAL;
1439 if (j != compatr->num_entries)
1440 goto out_unlock;
1441
1442 ret = -ENOMEM;
1443 newinfo = xt_alloc_table_info(size);
1444 if (!newinfo)
1445 goto out_unlock;
1446
1447 newinfo->number = compatr->num_entries;
1448 for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1449 newinfo->hook_entry[i] = compatr->hook_entry[i];
1450 newinfo->underflow[i] = compatr->underflow[i];
1451 }
1452 entry1 = newinfo->entries;
1453 pos = entry1;
1454 size = compatr->size;
1455 xt_entry_foreach(iter0, entry0, compatr->size)
1456 compat_copy_entry_from_user(iter0, &pos, &size,
1457 newinfo, entry1);
1458
1459 /* all module references in entry0 are now gone.
1460 * entry1/newinfo contains a 64bit ruleset that looks exactly as
1461 * generated by 64bit userspace.
1462 *
1463 * Call standard translate_table() to validate all hook_entrys,
1464 * underflows, check for loops, etc.
1465 */
1466 xt_compat_flush_offsets(AF_INET);
1467 xt_compat_unlock(AF_INET);
1468
1469 memcpy(&repl, compatr, sizeof(*compatr));
1470
1471 for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1472 repl.hook_entry[i] = newinfo->hook_entry[i];
1473 repl.underflow[i] = newinfo->underflow[i];
1474 }
1475
1476 repl.num_counters = 0;
1477 repl.counters = NULL;
1478 repl.size = newinfo->size;
1479 ret = translate_table(net, newinfo, entry1, &repl);
1480 if (ret)
1481 goto free_newinfo;
1482
1483 *pinfo = newinfo;
1484 *pentry0 = entry1;
1485 xt_free_table_info(info);
1486 return 0;
1487
1488 free_newinfo:
1489 xt_free_table_info(newinfo);
1490 return ret;
1491 out_unlock:
1492 xt_compat_flush_offsets(AF_INET);
1493 xt_compat_unlock(AF_INET);
1494 xt_entry_foreach(iter0, entry0, compatr->size) {
1495 if (j-- == 0)
1496 break;
1497 compat_release_entry(iter0);
1498 }
1499 return ret;
1500 }
1501
1502 static int
1503 compat_do_replace(struct net *net, void __user *user, unsigned int len)
1504 {
1505 int ret;
1506 struct compat_ipt_replace tmp;
1507 struct xt_table_info *newinfo;
1508 void *loc_cpu_entry;
1509 struct ipt_entry *iter;
1510
1511 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1512 return -EFAULT;
1513
1514 /* overflow check */
1515 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1516 return -ENOMEM;
1517 if (tmp.num_counters == 0)
1518 return -EINVAL;
1519
1520 tmp.name[sizeof(tmp.name)-1] = 0;
1521
1522 newinfo = xt_alloc_table_info(tmp.size);
1523 if (!newinfo)
1524 return -ENOMEM;
1525
1526 loc_cpu_entry = newinfo->entries;
1527 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1528 tmp.size) != 0) {
1529 ret = -EFAULT;
1530 goto free_newinfo;
1531 }
1532
1533 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1534 if (ret != 0)
1535 goto free_newinfo;
1536
1537 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1538 tmp.num_counters, compat_ptr(tmp.counters));
1539 if (ret)
1540 goto free_newinfo_untrans;
1541 return 0;
1542
1543 free_newinfo_untrans:
1544 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1545 cleanup_entry(iter, net);
1546 free_newinfo:
1547 xt_free_table_info(newinfo);
1548 return ret;
1549 }
1550
1551 static int
1552 compat_do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user,
1553 unsigned int len)
1554 {
1555 int ret;
1556
1557 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1558 return -EPERM;
1559
1560 switch (cmd) {
1561 case IPT_SO_SET_REPLACE:
1562 ret = compat_do_replace(sock_net(sk), user, len);
1563 break;
1564
1565 case IPT_SO_SET_ADD_COUNTERS:
1566 ret = do_add_counters(sock_net(sk), user, len, 1);
1567 break;
1568
1569 default:
1570 ret = -EINVAL;
1571 }
1572
1573 return ret;
1574 }
1575
1576 struct compat_ipt_get_entries {
1577 char name[XT_TABLE_MAXNAMELEN];
1578 compat_uint_t size;
1579 struct compat_ipt_entry entrytable[0];
1580 };
1581
1582 static int
1583 compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table,
1584 void __user *userptr)
1585 {
1586 struct xt_counters *counters;
1587 const struct xt_table_info *private = table->private;
1588 void __user *pos;
1589 unsigned int size;
1590 int ret = 0;
1591 unsigned int i = 0;
1592 struct ipt_entry *iter;
1593
1594 counters = alloc_counters(table);
1595 if (IS_ERR(counters))
1596 return PTR_ERR(counters);
1597
1598 pos = userptr;
1599 size = total_size;
1600 xt_entry_foreach(iter, private->entries, total_size) {
1601 ret = compat_copy_entry_to_user(iter, &pos,
1602 &size, counters, i++);
1603 if (ret != 0)
1604 break;
1605 }
1606
1607 vfree(counters);
1608 return ret;
1609 }
1610
1611 static int
1612 compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,
1613 int *len)
1614 {
1615 int ret;
1616 struct compat_ipt_get_entries get;
1617 struct xt_table *t;
1618
1619 if (*len < sizeof(get))
1620 return -EINVAL;
1621
1622 if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1623 return -EFAULT;
1624
1625 if (*len != sizeof(struct compat_ipt_get_entries) + get.size)
1626 return -EINVAL;
1627
1628 get.name[sizeof(get.name) - 1] = '\0';
1629
1630 xt_compat_lock(AF_INET);
1631 t = xt_find_table_lock(net, AF_INET, get.name);
1632 if (!IS_ERR_OR_NULL(t)) {
1633 const struct xt_table_info *private = t->private;
1634 struct xt_table_info info;
1635 ret = compat_table_info(private, &info);
1636 if (!ret && get.size == info.size)
1637 ret = compat_copy_entries_to_user(private->size,
1638 t, uptr->entrytable);
1639 else if (!ret)
1640 ret = -EAGAIN;
1641
1642 xt_compat_flush_offsets(AF_INET);
1643 module_put(t->me);
1644 xt_table_unlock(t);
1645 } else
1646 ret = t ? PTR_ERR(t) : -ENOENT;
1647
1648 xt_compat_unlock(AF_INET);
1649 return ret;
1650 }
1651
1652 static int do_ipt_get_ctl(struct sock *, int, void __user *, int *);
1653
1654 static int
1655 compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1656 {
1657 int ret;
1658
1659 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1660 return -EPERM;
1661
1662 switch (cmd) {
1663 case IPT_SO_GET_INFO:
1664 ret = get_info(sock_net(sk), user, len, 1);
1665 break;
1666 case IPT_SO_GET_ENTRIES:
1667 ret = compat_get_entries(sock_net(sk), user, len);
1668 break;
1669 default:
1670 ret = do_ipt_get_ctl(sk, cmd, user, len);
1671 }
1672 return ret;
1673 }
1674 #endif
1675
1676 static int
1677 do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1678 {
1679 int ret;
1680
1681 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1682 return -EPERM;
1683
1684 switch (cmd) {
1685 case IPT_SO_SET_REPLACE:
1686 ret = do_replace(sock_net(sk), user, len);
1687 break;
1688
1689 case IPT_SO_SET_ADD_COUNTERS:
1690 ret = do_add_counters(sock_net(sk), user, len, 0);
1691 break;
1692
1693 default:
1694 ret = -EINVAL;
1695 }
1696
1697 return ret;
1698 }
1699
1700 static int
1701 do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1702 {
1703 int ret;
1704
1705 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1706 return -EPERM;
1707
1708 switch (cmd) {
1709 case IPT_SO_GET_INFO:
1710 ret = get_info(sock_net(sk), user, len, 0);
1711 break;
1712
1713 case IPT_SO_GET_ENTRIES:
1714 ret = get_entries(sock_net(sk), user, len);
1715 break;
1716
1717 case IPT_SO_GET_REVISION_MATCH:
1718 case IPT_SO_GET_REVISION_TARGET: {
1719 struct xt_get_revision rev;
1720 int target;
1721
1722 if (*len != sizeof(rev)) {
1723 ret = -EINVAL;
1724 break;
1725 }
1726 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1727 ret = -EFAULT;
1728 break;
1729 }
1730 rev.name[sizeof(rev.name)-1] = 0;
1731
1732 if (cmd == IPT_SO_GET_REVISION_TARGET)
1733 target = 1;
1734 else
1735 target = 0;
1736
1737 try_then_request_module(xt_find_revision(AF_INET, rev.name,
1738 rev.revision,
1739 target, &ret),
1740 "ipt_%s", rev.name);
1741 break;
1742 }
1743
1744 default:
1745 ret = -EINVAL;
1746 }
1747
1748 return ret;
1749 }
1750
1751 static void __ipt_unregister_table(struct net *net, struct xt_table *table)
1752 {
1753 struct xt_table_info *private;
1754 void *loc_cpu_entry;
1755 struct module *table_owner = table->me;
1756 struct ipt_entry *iter;
1757
1758 private = xt_unregister_table(table);
1759
1760 /* Decrease module usage counts and free resources */
1761 loc_cpu_entry = private->entries;
1762 xt_entry_foreach(iter, loc_cpu_entry, private->size)
1763 cleanup_entry(iter, net);
1764 if (private->number > private->initial_entries)
1765 module_put(table_owner);
1766 xt_free_table_info(private);
1767 }
1768
1769 int ipt_register_table(struct net *net, const struct xt_table *table,
1770 const struct ipt_replace *repl,
1771 const struct nf_hook_ops *ops, struct xt_table **res)
1772 {
1773 int ret;
1774 struct xt_table_info *newinfo;
1775 struct xt_table_info bootstrap = {0};
1776 void *loc_cpu_entry;
1777 struct xt_table *new_table;
1778
1779 newinfo = xt_alloc_table_info(repl->size);
1780 if (!newinfo)
1781 return -ENOMEM;
1782
1783 loc_cpu_entry = newinfo->entries;
1784 memcpy(loc_cpu_entry, repl->entries, repl->size);
1785
1786 ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1787 if (ret != 0)
1788 goto out_free;
1789
1790 new_table = xt_register_table(net, table, &bootstrap, newinfo);
1791 if (IS_ERR(new_table)) {
1792 ret = PTR_ERR(new_table);
1793 goto out_free;
1794 }
1795
1796 /* set res now, will see skbs right after nf_register_net_hooks */
1797 WRITE_ONCE(*res, new_table);
1798
1799 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1800 if (ret != 0) {
1801 __ipt_unregister_table(net, new_table);
1802 *res = NULL;
1803 }
1804
1805 return ret;
1806
1807 out_free:
1808 xt_free_table_info(newinfo);
1809 return ret;
1810 }
1811
1812 void ipt_unregister_table(struct net *net, struct xt_table *table,
1813 const struct nf_hook_ops *ops)
1814 {
1815 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1816 __ipt_unregister_table(net, table);
1817 }
1818
1819 /* Returns 1 if the type and code is matched by the range, 0 otherwise */
1820 static inline bool
1821 icmp_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
1822 u_int8_t type, u_int8_t code,
1823 bool invert)
1824 {
1825 return ((test_type == 0xFF) ||
1826 (type == test_type && code >= min_code && code <= max_code))
1827 ^ invert;
1828 }
1829
1830 static bool
1831 icmp_match(const struct sk_buff *skb, struct xt_action_param *par)
1832 {
1833 const struct icmphdr *ic;
1834 struct icmphdr _icmph;
1835 const struct ipt_icmp *icmpinfo = par->matchinfo;
1836
1837 /* Must not be a fragment. */
1838 if (par->fragoff != 0)
1839 return false;
1840
1841 ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
1842 if (ic == NULL) {
1843 /* We've been asked to examine this packet, and we
1844 * can't. Hence, no choice but to drop.
1845 */
1846 par->hotdrop = true;
1847 return false;
1848 }
1849
1850 return icmp_type_code_match(icmpinfo->type,
1851 icmpinfo->code[0],
1852 icmpinfo->code[1],
1853 ic->type, ic->code,
1854 !!(icmpinfo->invflags&IPT_ICMP_INV));
1855 }
1856
1857 static int icmp_checkentry(const struct xt_mtchk_param *par)
1858 {
1859 const struct ipt_icmp *icmpinfo = par->matchinfo;
1860
1861 /* Must specify no unknown invflags */
1862 return (icmpinfo->invflags & ~IPT_ICMP_INV) ? -EINVAL : 0;
1863 }
1864
1865 static struct xt_target ipt_builtin_tg[] __read_mostly = {
1866 {
1867 .name = XT_STANDARD_TARGET,
1868 .targetsize = sizeof(int),
1869 .family = NFPROTO_IPV4,
1870 #ifdef CONFIG_COMPAT
1871 .compatsize = sizeof(compat_int_t),
1872 .compat_from_user = compat_standard_from_user,
1873 .compat_to_user = compat_standard_to_user,
1874 #endif
1875 },
1876 {
1877 .name = XT_ERROR_TARGET,
1878 .target = ipt_error,
1879 .targetsize = XT_FUNCTION_MAXNAMELEN,
1880 .family = NFPROTO_IPV4,
1881 },
1882 };
1883
1884 static struct nf_sockopt_ops ipt_sockopts = {
1885 .pf = PF_INET,
1886 .set_optmin = IPT_BASE_CTL,
1887 .set_optmax = IPT_SO_SET_MAX+1,
1888 .set = do_ipt_set_ctl,
1889 #ifdef CONFIG_COMPAT
1890 .compat_set = compat_do_ipt_set_ctl,
1891 #endif
1892 .get_optmin = IPT_BASE_CTL,
1893 .get_optmax = IPT_SO_GET_MAX+1,
1894 .get = do_ipt_get_ctl,
1895 #ifdef CONFIG_COMPAT
1896 .compat_get = compat_do_ipt_get_ctl,
1897 #endif
1898 .owner = THIS_MODULE,
1899 };
1900
1901 static struct xt_match ipt_builtin_mt[] __read_mostly = {
1902 {
1903 .name = "icmp",
1904 .match = icmp_match,
1905 .matchsize = sizeof(struct ipt_icmp),
1906 .checkentry = icmp_checkentry,
1907 .proto = IPPROTO_ICMP,
1908 .family = NFPROTO_IPV4,
1909 },
1910 };
1911
1912 static int __net_init ip_tables_net_init(struct net *net)
1913 {
1914 return xt_proto_init(net, NFPROTO_IPV4);
1915 }
1916
1917 static void __net_exit ip_tables_net_exit(struct net *net)
1918 {
1919 xt_proto_fini(net, NFPROTO_IPV4);
1920 }
1921
1922 static struct pernet_operations ip_tables_net_ops = {
1923 .init = ip_tables_net_init,
1924 .exit = ip_tables_net_exit,
1925 };
1926
1927 static int __init ip_tables_init(void)
1928 {
1929 int ret;
1930
1931 ret = register_pernet_subsys(&ip_tables_net_ops);
1932 if (ret < 0)
1933 goto err1;
1934
1935 /* No one else will be downing sem now, so we won't sleep */
1936 ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1937 if (ret < 0)
1938 goto err2;
1939 ret = xt_register_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1940 if (ret < 0)
1941 goto err4;
1942
1943 /* Register setsockopt */
1944 ret = nf_register_sockopt(&ipt_sockopts);
1945 if (ret < 0)
1946 goto err5;
1947
1948 pr_info("(C) 2000-2006 Netfilter Core Team\n");
1949 return 0;
1950
1951 err5:
1952 xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1953 err4:
1954 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1955 err2:
1956 unregister_pernet_subsys(&ip_tables_net_ops);
1957 err1:
1958 return ret;
1959 }
1960
1961 static void __exit ip_tables_fini(void)
1962 {
1963 nf_unregister_sockopt(&ipt_sockopts);
1964
1965 xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1966 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1967 unregister_pernet_subsys(&ip_tables_net_ops);
1968 }
1969
1970 EXPORT_SYMBOL(ipt_register_table);
1971 EXPORT_SYMBOL(ipt_unregister_table);
1972 EXPORT_SYMBOL(ipt_do_table);
1973 module_init(ip_tables_init);
1974 module_exit(ip_tables_fini);
Linux kernel - Deliverables
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