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TOMOYO Linux Cross Reference
Linux/net/ipv4/netfilter/ip_tables.c

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  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 /*#define DEBUG_IP_FIREWALL*/
 39 /*#define DEBUG_ALLOW_ALL*/ /* Useful for remote debugging */
 40 /*#define DEBUG_IP_FIREWALL_USER*/
 41 
 42 #ifdef DEBUG_IP_FIREWALL
 43 #define dprintf(format, args...) pr_info(format , ## args)
 44 #else
 45 #define dprintf(format, args...)
 46 #endif
 47 
 48 #ifdef DEBUG_IP_FIREWALL_USER
 49 #define duprintf(format, args...) pr_info(format , ## args)
 50 #else
 51 #define duprintf(format, args...)
 52 #endif
 53 
 54 #ifdef CONFIG_NETFILTER_DEBUG
 55 #define IP_NF_ASSERT(x)         WARN_ON(!(x))
 56 #else
 57 #define IP_NF_ASSERT(x)
 58 #endif
 59 
 60 #if 0
 61 /* All the better to debug you with... */
 62 #define static
 63 #define inline
 64 #endif
 65 
 66 void *ipt_alloc_initial_table(const struct xt_table *info)
 67 {
 68         return xt_alloc_initial_table(ipt, IPT);
 69 }
 70 EXPORT_SYMBOL_GPL(ipt_alloc_initial_table);
 71 
 72 /* Returns whether matches rule or not. */
 73 /* Performance critical - called for every packet */
 74 static inline bool
 75 ip_packet_match(const struct iphdr *ip,
 76                 const char *indev,
 77                 const char *outdev,
 78                 const struct ipt_ip *ipinfo,
 79                 int isfrag)
 80 {
 81         unsigned long ret;
 82 
 83 #define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg)))
 84 
 85         if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
 86                   IPT_INV_SRCIP) ||
 87             FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
 88                   IPT_INV_DSTIP)) {
 89                 dprintf("Source or dest mismatch.\n");
 90 
 91                 dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 92                         &ip->saddr, &ipinfo->smsk.s_addr, &ipinfo->src.s_addr,
 93                         ipinfo->invflags & IPT_INV_SRCIP ? " (INV)" : "");
 94                 dprintf("DST: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 95                         &ip->daddr, &ipinfo->dmsk.s_addr, &ipinfo->dst.s_addr,
 96                         ipinfo->invflags & IPT_INV_DSTIP ? " (INV)" : "");
 97                 return false;
 98         }
 99 
100         ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask);
101 
102         if (FWINV(ret != 0, IPT_INV_VIA_IN)) {
103                 dprintf("VIA in mismatch (%s vs %s).%s\n",
104                         indev, ipinfo->iniface,
105                         ipinfo->invflags&IPT_INV_VIA_IN ?" (INV)":"");
106                 return false;
107         }
108 
109         ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask);
110 
111         if (FWINV(ret != 0, IPT_INV_VIA_OUT)) {
112                 dprintf("VIA out mismatch (%s vs %s).%s\n",
113                         outdev, ipinfo->outiface,
114                         ipinfo->invflags&IPT_INV_VIA_OUT ?" (INV)":"");
115                 return false;
116         }
117 
118         /* Check specific protocol */
119         if (ipinfo->proto &&
120             FWINV(ip->protocol != ipinfo->proto, IPT_INV_PROTO)) {
121                 dprintf("Packet protocol %hi does not match %hi.%s\n",
122                         ip->protocol, ipinfo->proto,
123                         ipinfo->invflags&IPT_INV_PROTO ? " (INV)":"");
124                 return false;
125         }
126 
127         /* If we have a fragment rule but the packet is not a fragment
128          * then we return zero */
129         if (FWINV((ipinfo->flags&IPT_F_FRAG) && !isfrag, IPT_INV_FRAG)) {
130                 dprintf("Fragment rule but not fragment.%s\n",
131                         ipinfo->invflags & IPT_INV_FRAG ? " (INV)" : "");
132                 return false;
133         }
134 
135         return true;
136 }
137 
138 static bool
139 ip_checkentry(const struct ipt_ip *ip)
140 {
141         if (ip->flags & ~IPT_F_MASK) {
142                 duprintf("Unknown flag bits set: %08X\n",
143                          ip->flags & ~IPT_F_MASK);
144                 return false;
145         }
146         if (ip->invflags & ~IPT_INV_MASK) {
147                 duprintf("Unknown invflag bits set: %08X\n",
148                          ip->invflags & ~IPT_INV_MASK);
149                 return false;
150         }
151         return true;
152 }
153 
154 static unsigned int
155 ipt_error(struct sk_buff *skb, const struct xt_action_param *par)
156 {
157         net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo);
158 
159         return NF_DROP;
160 }
161 
162 /* Performance critical */
163 static inline struct ipt_entry *
164 get_entry(const void *base, unsigned int offset)
165 {
166         return (struct ipt_entry *)(base + offset);
167 }
168 
169 /* All zeroes == unconditional rule. */
170 /* Mildly perf critical (only if packet tracing is on) */
171 static inline bool unconditional(const struct ipt_ip *ip)
172 {
173         static const struct ipt_ip uncond;
174 
175         return memcmp(ip, &uncond, sizeof(uncond)) == 0;
176 #undef FWINV
177 }
178 
179 /* for const-correctness */
180 static inline const struct xt_entry_target *
181 ipt_get_target_c(const struct ipt_entry *e)
182 {
183         return ipt_get_target((struct ipt_entry *)e);
184 }
185 
186 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
187 static const char *const hooknames[] = {
188         [NF_INET_PRE_ROUTING]           = "PREROUTING",
189         [NF_INET_LOCAL_IN]              = "INPUT",
190         [NF_INET_FORWARD]               = "FORWARD",
191         [NF_INET_LOCAL_OUT]             = "OUTPUT",
192         [NF_INET_POST_ROUTING]          = "POSTROUTING",
193 };
194 
195 enum nf_ip_trace_comments {
196         NF_IP_TRACE_COMMENT_RULE,
197         NF_IP_TRACE_COMMENT_RETURN,
198         NF_IP_TRACE_COMMENT_POLICY,
199 };
200 
201 static const char *const comments[] = {
202         [NF_IP_TRACE_COMMENT_RULE]      = "rule",
203         [NF_IP_TRACE_COMMENT_RETURN]    = "return",
204         [NF_IP_TRACE_COMMENT_POLICY]    = "policy",
205 };
206 
207 static struct nf_loginfo trace_loginfo = {
208         .type = NF_LOG_TYPE_LOG,
209         .u = {
210                 .log = {
211                         .level = 4,
212                         .logflags = NF_LOG_MASK,
213                 },
214         },
215 };
216 
217 /* Mildly perf critical (only if packet tracing is on) */
218 static inline int
219 get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e,
220                       const char *hookname, const char **chainname,
221                       const char **comment, unsigned int *rulenum)
222 {
223         const struct xt_standard_target *t = (void *)ipt_get_target_c(s);
224 
225         if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) {
226                 /* Head of user chain: ERROR target with chainname */
227                 *chainname = t->target.data;
228                 (*rulenum) = 0;
229         } else if (s == e) {
230                 (*rulenum)++;
231 
232                 if (s->target_offset == sizeof(struct ipt_entry) &&
233                     strcmp(t->target.u.kernel.target->name,
234                            XT_STANDARD_TARGET) == 0 &&
235                    t->verdict < 0 &&
236                    unconditional(&s->ip)) {
237                         /* Tail of chains: STANDARD target (return/policy) */
238                         *comment = *chainname == hookname
239                                 ? comments[NF_IP_TRACE_COMMENT_POLICY]
240                                 : comments[NF_IP_TRACE_COMMENT_RETURN];
241                 }
242                 return 1;
243         } else
244                 (*rulenum)++;
245 
246         return 0;
247 }
248 
249 static void trace_packet(const struct sk_buff *skb,
250                          unsigned int hook,
251                          const struct net_device *in,
252                          const struct net_device *out,
253                          const char *tablename,
254                          const struct xt_table_info *private,
255                          const struct ipt_entry *e)
256 {
257         const struct ipt_entry *root;
258         const char *hookname, *chainname, *comment;
259         const struct ipt_entry *iter;
260         unsigned int rulenum = 0;
261         struct net *net = dev_net(in ? in : out);
262 
263         root = get_entry(private->entries, private->hook_entry[hook]);
264 
265         hookname = chainname = hooknames[hook];
266         comment = comments[NF_IP_TRACE_COMMENT_RULE];
267 
268         xt_entry_foreach(iter, root, private->size - private->hook_entry[hook])
269                 if (get_chainname_rulenum(iter, e, hookname,
270                     &chainname, &comment, &rulenum) != 0)
271                         break;
272 
273         nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo,
274                      "TRACE: %s:%s:%s:%u ",
275                      tablename, chainname, comment, rulenum);
276 }
277 #endif
278 
279 static inline __pure
280 struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
281 {
282         return (void *)entry + entry->next_offset;
283 }
284 
285 /* Returns one of the generic firewall policies, like NF_ACCEPT. */
286 unsigned int
287 ipt_do_table(struct sk_buff *skb,
288              unsigned int hook,
289              const struct nf_hook_state *state,
290              struct xt_table *table)
291 {
292         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
293         const struct iphdr *ip;
294         /* Initializing verdict to NF_DROP keeps gcc happy. */
295         unsigned int verdict = NF_DROP;
296         const char *indev, *outdev;
297         const void *table_base;
298         struct ipt_entry *e, **jumpstack;
299         unsigned int *stackptr, origptr, cpu;
300         const struct xt_table_info *private;
301         struct xt_action_param acpar;
302         unsigned int addend;
303 
304         /* Initialization */
305         ip = ip_hdr(skb);
306         indev = state->in ? state->in->name : nulldevname;
307         outdev = state->out ? state->out->name : nulldevname;
308         /* We handle fragments by dealing with the first fragment as
309          * if it was a normal packet.  All other fragments are treated
310          * normally, except that they will NEVER match rules that ask
311          * things we don't know, ie. tcp syn flag or ports).  If the
312          * rule is also a fragment-specific rule, non-fragments won't
313          * match it. */
314         acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
315         acpar.thoff   = ip_hdrlen(skb);
316         acpar.hotdrop = false;
317         acpar.in      = state->in;
318         acpar.out     = state->out;
319         acpar.family  = NFPROTO_IPV4;
320         acpar.hooknum = hook;
321 
322         IP_NF_ASSERT(table->valid_hooks & (1 << hook));
323         local_bh_disable();
324         addend = xt_write_recseq_begin();
325         private = table->private;
326         cpu        = smp_processor_id();
327         /*
328          * Ensure we load private-> members after we've fetched the base
329          * pointer.
330          */
331         smp_read_barrier_depends();
332         table_base = private->entries;
333         jumpstack  = (struct ipt_entry **)private->jumpstack[cpu];
334         stackptr   = per_cpu_ptr(private->stackptr, cpu);
335         origptr    = *stackptr;
336 
337         e = get_entry(table_base, private->hook_entry[hook]);
338 
339         pr_debug("Entering %s(hook %u); sp at %u (UF %p)\n",
340                  table->name, hook, origptr,
341                  get_entry(table_base, private->underflow[hook]));
342 
343         do {
344                 const struct xt_entry_target *t;
345                 const struct xt_entry_match *ematch;
346                 struct xt_counters *counter;
347 
348                 IP_NF_ASSERT(e);
349                 if (!ip_packet_match(ip, indev, outdev,
350                     &e->ip, acpar.fragoff)) {
351  no_match:
352                         e = ipt_next_entry(e);
353                         continue;
354                 }
355 
356                 xt_ematch_foreach(ematch, e) {
357                         acpar.match     = ematch->u.kernel.match;
358                         acpar.matchinfo = ematch->data;
359                         if (!acpar.match->match(skb, &acpar))
360                                 goto no_match;
361                 }
362 
363                 counter = xt_get_this_cpu_counter(&e->counters);
364                 ADD_COUNTER(*counter, skb->len, 1);
365 
366                 t = ipt_get_target(e);
367                 IP_NF_ASSERT(t->u.kernel.target);
368 
369 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
370                 /* The packet is traced: log it */
371                 if (unlikely(skb->nf_trace))
372                         trace_packet(skb, hook, state->in, state->out,
373                                      table->name, private, e);
374 #endif
375                 /* Standard target? */
376                 if (!t->u.kernel.target->target) {
377                         int v;
378 
379                         v = ((struct xt_standard_target *)t)->verdict;
380                         if (v < 0) {
381                                 /* Pop from stack? */
382                                 if (v != XT_RETURN) {
383                                         verdict = (unsigned int)(-v) - 1;
384                                         break;
385                                 }
386                                 if (*stackptr <= origptr) {
387                                         e = get_entry(table_base,
388                                             private->underflow[hook]);
389                                         pr_debug("Underflow (this is normal) "
390                                                  "to %p\n", e);
391                                 } else {
392                                         e = jumpstack[--*stackptr];
393                                         pr_debug("Pulled %p out from pos %u\n",
394                                                  e, *stackptr);
395                                         e = ipt_next_entry(e);
396                                 }
397                                 continue;
398                         }
399                         if (table_base + v != ipt_next_entry(e) &&
400                             !(e->ip.flags & IPT_F_GOTO)) {
401                                 if (*stackptr >= private->stacksize) {
402                                         verdict = NF_DROP;
403                                         break;
404                                 }
405                                 jumpstack[(*stackptr)++] = e;
406                                 pr_debug("Pushed %p into pos %u\n",
407                                          e, *stackptr - 1);
408                         }
409 
410                         e = get_entry(table_base, v);
411                         continue;
412                 }
413 
414                 acpar.target   = t->u.kernel.target;
415                 acpar.targinfo = t->data;
416 
417                 verdict = t->u.kernel.target->target(skb, &acpar);
418                 /* Target might have changed stuff. */
419                 ip = ip_hdr(skb);
420                 if (verdict == XT_CONTINUE)
421                         e = ipt_next_entry(e);
422                 else
423                         /* Verdict */
424                         break;
425         } while (!acpar.hotdrop);
426         pr_debug("Exiting %s; resetting sp from %u to %u\n",
427                  __func__, *stackptr, origptr);
428         *stackptr = origptr;
429         xt_write_recseq_end(addend);
430         local_bh_enable();
431 
432 #ifdef DEBUG_ALLOW_ALL
433         return NF_ACCEPT;
434 #else
435         if (acpar.hotdrop)
436                 return NF_DROP;
437         else return verdict;
438 #endif
439 }
440 
441 /* Figures out from what hook each rule can be called: returns 0 if
442    there are loops.  Puts hook bitmask in comefrom. */
443 static int
444 mark_source_chains(const struct xt_table_info *newinfo,
445                    unsigned int valid_hooks, void *entry0)
446 {
447         unsigned int hook;
448 
449         /* No recursion; use packet counter to save back ptrs (reset
450            to 0 as we leave), and comefrom to save source hook bitmask */
451         for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) {
452                 unsigned int pos = newinfo->hook_entry[hook];
453                 struct ipt_entry *e = (struct ipt_entry *)(entry0 + pos);
454 
455                 if (!(valid_hooks & (1 << hook)))
456                         continue;
457 
458                 /* Set initial back pointer. */
459                 e->counters.pcnt = pos;
460 
461                 for (;;) {
462                         const struct xt_standard_target *t
463                                 = (void *)ipt_get_target_c(e);
464                         int visited = e->comefrom & (1 << hook);
465 
466                         if (e->comefrom & (1 << NF_INET_NUMHOOKS)) {
467                                 pr_err("iptables: loop hook %u pos %u %08X.\n",
468                                        hook, pos, e->comefrom);
469                                 return 0;
470                         }
471                         e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS));
472 
473                         /* Unconditional return/END. */
474                         if ((e->target_offset == sizeof(struct ipt_entry) &&
475                              (strcmp(t->target.u.user.name,
476                                      XT_STANDARD_TARGET) == 0) &&
477                              t->verdict < 0 && unconditional(&e->ip)) ||
478                             visited) {
479                                 unsigned int oldpos, size;
480 
481                                 if ((strcmp(t->target.u.user.name,
482                                             XT_STANDARD_TARGET) == 0) &&
483                                     t->verdict < -NF_MAX_VERDICT - 1) {
484                                         duprintf("mark_source_chains: bad "
485                                                 "negative verdict (%i)\n",
486                                                                 t->verdict);
487                                         return 0;
488                                 }
489 
490                                 /* Return: backtrack through the last
491                                    big jump. */
492                                 do {
493                                         e->comefrom ^= (1<<NF_INET_NUMHOOKS);
494 #ifdef DEBUG_IP_FIREWALL_USER
495                                         if (e->comefrom
496                                             & (1 << NF_INET_NUMHOOKS)) {
497                                                 duprintf("Back unset "
498                                                          "on hook %u "
499                                                          "rule %u\n",
500                                                          hook, pos);
501                                         }
502 #endif
503                                         oldpos = pos;
504                                         pos = e->counters.pcnt;
505                                         e->counters.pcnt = 0;
506 
507                                         /* We're at the start. */
508                                         if (pos == oldpos)
509                                                 goto next;
510 
511                                         e = (struct ipt_entry *)
512                                                 (entry0 + pos);
513                                 } while (oldpos == pos + e->next_offset);
514 
515                                 /* Move along one */
516                                 size = e->next_offset;
517                                 e = (struct ipt_entry *)
518                                         (entry0 + pos + size);
519                                 e->counters.pcnt = pos;
520                                 pos += size;
521                         } else {
522                                 int newpos = t->verdict;
523 
524                                 if (strcmp(t->target.u.user.name,
525                                            XT_STANDARD_TARGET) == 0 &&
526                                     newpos >= 0) {
527                                         if (newpos > newinfo->size -
528                                                 sizeof(struct ipt_entry)) {
529                                                 duprintf("mark_source_chains: "
530                                                         "bad verdict (%i)\n",
531                                                                 newpos);
532                                                 return 0;
533                                         }
534                                         /* This a jump; chase it. */
535                                         duprintf("Jump rule %u -> %u\n",
536                                                  pos, newpos);
537                                 } else {
538                                         /* ... this is a fallthru */
539                                         newpos = pos + e->next_offset;
540                                 }
541                                 e = (struct ipt_entry *)
542                                         (entry0 + newpos);
543                                 e->counters.pcnt = pos;
544                                 pos = newpos;
545                         }
546                 }
547                 next:
548                 duprintf("Finished chain %u\n", hook);
549         }
550         return 1;
551 }
552 
553 static void cleanup_match(struct xt_entry_match *m, struct net *net)
554 {
555         struct xt_mtdtor_param par;
556 
557         par.net       = net;
558         par.match     = m->u.kernel.match;
559         par.matchinfo = m->data;
560         par.family    = NFPROTO_IPV4;
561         if (par.match->destroy != NULL)
562                 par.match->destroy(&par);
563         module_put(par.match->me);
564 }
565 
566 static int
567 check_entry(const struct ipt_entry *e, const char *name)
568 {
569         const struct xt_entry_target *t;
570 
571         if (!ip_checkentry(&e->ip)) {
572                 duprintf("ip check failed %p %s.\n", e, name);
573                 return -EINVAL;
574         }
575 
576         if (e->target_offset + sizeof(struct xt_entry_target) >
577             e->next_offset)
578                 return -EINVAL;
579 
580         t = ipt_get_target_c(e);
581         if (e->target_offset + t->u.target_size > e->next_offset)
582                 return -EINVAL;
583 
584         return 0;
585 }
586 
587 static int
588 check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
589 {
590         const struct ipt_ip *ip = par->entryinfo;
591         int ret;
592 
593         par->match     = m->u.kernel.match;
594         par->matchinfo = m->data;
595 
596         ret = xt_check_match(par, m->u.match_size - sizeof(*m),
597               ip->proto, ip->invflags & IPT_INV_PROTO);
598         if (ret < 0) {
599                 duprintf("check failed for `%s'.\n", par->match->name);
600                 return ret;
601         }
602         return 0;
603 }
604 
605 static int
606 find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
607 {
608         struct xt_match *match;
609         int ret;
610 
611         match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
612                                       m->u.user.revision);
613         if (IS_ERR(match)) {
614                 duprintf("find_check_match: `%s' not found\n", m->u.user.name);
615                 return PTR_ERR(match);
616         }
617         m->u.kernel.match = match;
618 
619         ret = check_match(m, par);
620         if (ret)
621                 goto err;
622 
623         return 0;
624 err:
625         module_put(m->u.kernel.match->me);
626         return ret;
627 }
628 
629 static int check_target(struct ipt_entry *e, struct net *net, const char *name)
630 {
631         struct xt_entry_target *t = ipt_get_target(e);
632         struct xt_tgchk_param par = {
633                 .net       = net,
634                 .table     = name,
635                 .entryinfo = e,
636                 .target    = t->u.kernel.target,
637                 .targinfo  = t->data,
638                 .hook_mask = e->comefrom,
639                 .family    = NFPROTO_IPV4,
640         };
641         int ret;
642 
643         ret = xt_check_target(&par, t->u.target_size - sizeof(*t),
644               e->ip.proto, e->ip.invflags & IPT_INV_PROTO);
645         if (ret < 0) {
646                 duprintf("check failed for `%s'.\n",
647                          t->u.kernel.target->name);
648                 return ret;
649         }
650         return 0;
651 }
652 
653 static int
654 find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
655                  unsigned int size)
656 {
657         struct xt_entry_target *t;
658         struct xt_target *target;
659         int ret;
660         unsigned int j;
661         struct xt_mtchk_param mtpar;
662         struct xt_entry_match *ematch;
663 
664         ret = check_entry(e, name);
665         if (ret)
666                 return ret;
667 
668         e->counters.pcnt = xt_percpu_counter_alloc();
669         if (IS_ERR_VALUE(e->counters.pcnt))
670                 return -ENOMEM;
671 
672         j = 0;
673         mtpar.net       = net;
674         mtpar.table     = name;
675         mtpar.entryinfo = &e->ip;
676         mtpar.hook_mask = e->comefrom;
677         mtpar.family    = NFPROTO_IPV4;
678         xt_ematch_foreach(ematch, e) {
679                 ret = find_check_match(ematch, &mtpar);
680                 if (ret != 0)
681                         goto cleanup_matches;
682                 ++j;
683         }
684 
685         t = ipt_get_target(e);
686         target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
687                                         t->u.user.revision);
688         if (IS_ERR(target)) {
689                 duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
690                 ret = PTR_ERR(target);
691                 goto cleanup_matches;
692         }
693         t->u.kernel.target = target;
694 
695         ret = check_target(e, net, name);
696         if (ret)
697                 goto err;
698 
699         return 0;
700  err:
701         module_put(t->u.kernel.target->me);
702  cleanup_matches:
703         xt_ematch_foreach(ematch, e) {
704                 if (j-- == 0)
705                         break;
706                 cleanup_match(ematch, net);
707         }
708 
709         xt_percpu_counter_free(e->counters.pcnt);
710 
711         return ret;
712 }
713 
714 static bool check_underflow(const struct ipt_entry *e)
715 {
716         const struct xt_entry_target *t;
717         unsigned int verdict;
718 
719         if (!unconditional(&e->ip))
720                 return false;
721         t = ipt_get_target_c(e);
722         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
723                 return false;
724         verdict = ((struct xt_standard_target *)t)->verdict;
725         verdict = -verdict - 1;
726         return verdict == NF_DROP || verdict == NF_ACCEPT;
727 }
728 
729 static int
730 check_entry_size_and_hooks(struct ipt_entry *e,
731                            struct xt_table_info *newinfo,
732                            const unsigned char *base,
733                            const unsigned char *limit,
734                            const unsigned int *hook_entries,
735                            const unsigned int *underflows,
736                            unsigned int valid_hooks)
737 {
738         unsigned int h;
739 
740         if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
741             (unsigned char *)e + sizeof(struct ipt_entry) >= limit) {
742                 duprintf("Bad offset %p\n", e);
743                 return -EINVAL;
744         }
745 
746         if (e->next_offset
747             < sizeof(struct ipt_entry) + sizeof(struct xt_entry_target)) {
748                 duprintf("checking: element %p size %u\n",
749                          e, e->next_offset);
750                 return -EINVAL;
751         }
752 
753         /* Check hooks & underflows */
754         for (h = 0; h < NF_INET_NUMHOOKS; h++) {
755                 if (!(valid_hooks & (1 << h)))
756                         continue;
757                 if ((unsigned char *)e - base == hook_entries[h])
758                         newinfo->hook_entry[h] = hook_entries[h];
759                 if ((unsigned char *)e - base == underflows[h]) {
760                         if (!check_underflow(e)) {
761                                 pr_err("Underflows must be unconditional and "
762                                        "use the STANDARD target with "
763                                        "ACCEPT/DROP\n");
764                                 return -EINVAL;
765                         }
766                         newinfo->underflow[h] = underflows[h];
767                 }
768         }
769 
770         /* Clear counters and comefrom */
771         e->counters = ((struct xt_counters) { 0, 0 });
772         e->comefrom = 0;
773         return 0;
774 }
775 
776 static void
777 cleanup_entry(struct ipt_entry *e, struct net *net)
778 {
779         struct xt_tgdtor_param par;
780         struct xt_entry_target *t;
781         struct xt_entry_match *ematch;
782 
783         /* Cleanup all matches */
784         xt_ematch_foreach(ematch, e)
785                 cleanup_match(ematch, net);
786         t = ipt_get_target(e);
787 
788         par.net      = net;
789         par.target   = t->u.kernel.target;
790         par.targinfo = t->data;
791         par.family   = NFPROTO_IPV4;
792         if (par.target->destroy != NULL)
793                 par.target->destroy(&par);
794         module_put(par.target->me);
795         xt_percpu_counter_free(e->counters.pcnt);
796 }
797 
798 /* Checks and translates the user-supplied table segment (held in
799    newinfo) */
800 static int
801 translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0,
802                 const struct ipt_replace *repl)
803 {
804         struct ipt_entry *iter;
805         unsigned int i;
806         int ret = 0;
807 
808         newinfo->size = repl->size;
809         newinfo->number = repl->num_entries;
810 
811         /* Init all hooks to impossible value. */
812         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
813                 newinfo->hook_entry[i] = 0xFFFFFFFF;
814                 newinfo->underflow[i] = 0xFFFFFFFF;
815         }
816 
817         duprintf("translate_table: size %u\n", newinfo->size);
818         i = 0;
819         /* Walk through entries, checking offsets. */
820         xt_entry_foreach(iter, entry0, newinfo->size) {
821                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
822                                                  entry0 + repl->size,
823                                                  repl->hook_entry,
824                                                  repl->underflow,
825                                                  repl->valid_hooks);
826                 if (ret != 0)
827                         return ret;
828                 ++i;
829                 if (strcmp(ipt_get_target(iter)->u.user.name,
830                     XT_ERROR_TARGET) == 0)
831                         ++newinfo->stacksize;
832         }
833 
834         if (i != repl->num_entries) {
835                 duprintf("translate_table: %u not %u entries\n",
836                          i, repl->num_entries);
837                 return -EINVAL;
838         }
839 
840         /* Check hooks all assigned */
841         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
842                 /* Only hooks which are valid */
843                 if (!(repl->valid_hooks & (1 << i)))
844                         continue;
845                 if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
846                         duprintf("Invalid hook entry %u %u\n",
847                                  i, repl->hook_entry[i]);
848                         return -EINVAL;
849                 }
850                 if (newinfo->underflow[i] == 0xFFFFFFFF) {
851                         duprintf("Invalid underflow %u %u\n",
852                                  i, repl->underflow[i]);
853                         return -EINVAL;
854                 }
855         }
856 
857         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
858                 return -ELOOP;
859 
860         /* Finally, each sanity check must pass */
861         i = 0;
862         xt_entry_foreach(iter, entry0, newinfo->size) {
863                 ret = find_check_entry(iter, net, repl->name, repl->size);
864                 if (ret != 0)
865                         break;
866                 ++i;
867         }
868 
869         if (ret != 0) {
870                 xt_entry_foreach(iter, entry0, newinfo->size) {
871                         if (i-- == 0)
872                                 break;
873                         cleanup_entry(iter, net);
874                 }
875                 return ret;
876         }
877 
878         return ret;
879 }
880 
881 static void
882 get_counters(const struct xt_table_info *t,
883              struct xt_counters counters[])
884 {
885         struct ipt_entry *iter;
886         unsigned int cpu;
887         unsigned int i;
888 
889         for_each_possible_cpu(cpu) {
890                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
891 
892                 i = 0;
893                 xt_entry_foreach(iter, t->entries, t->size) {
894                         struct xt_counters *tmp;
895                         u64 bcnt, pcnt;
896                         unsigned int start;
897 
898                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
899                         do {
900                                 start = read_seqcount_begin(s);
901                                 bcnt = tmp->bcnt;
902                                 pcnt = tmp->pcnt;
903                         } while (read_seqcount_retry(s, start));
904 
905                         ADD_COUNTER(counters[i], bcnt, pcnt);
906                         ++i; /* macro does multi eval of i */
907                 }
908         }
909 }
910 
911 static struct xt_counters *alloc_counters(const struct xt_table *table)
912 {
913         unsigned int countersize;
914         struct xt_counters *counters;
915         const struct xt_table_info *private = table->private;
916 
917         /* We need atomic snapshot of counters: rest doesn't change
918            (other than comefrom, which userspace doesn't care
919            about). */
920         countersize = sizeof(struct xt_counters) * private->number;
921         counters = vzalloc(countersize);
922 
923         if (counters == NULL)
924                 return ERR_PTR(-ENOMEM);
925 
926         get_counters(private, counters);
927 
928         return counters;
929 }
930 
931 static int
932 copy_entries_to_user(unsigned int total_size,
933                      const struct xt_table *table,
934                      void __user *userptr)
935 {
936         unsigned int off, num;
937         const struct ipt_entry *e;
938         struct xt_counters *counters;
939         const struct xt_table_info *private = table->private;
940         int ret = 0;
941         const void *loc_cpu_entry;
942 
943         counters = alloc_counters(table);
944         if (IS_ERR(counters))
945                 return PTR_ERR(counters);
946 
947         loc_cpu_entry = private->entries;
948         if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
949                 ret = -EFAULT;
950                 goto free_counters;
951         }
952 
953         /* FIXME: use iterator macros --RR */
954         /* ... then go back and fix counters and names */
955         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
956                 unsigned int i;
957                 const struct xt_entry_match *m;
958                 const struct xt_entry_target *t;
959 
960                 e = (struct ipt_entry *)(loc_cpu_entry + off);
961                 if (copy_to_user(userptr + off
962                                  + offsetof(struct ipt_entry, counters),
963                                  &counters[num],
964                                  sizeof(counters[num])) != 0) {
965                         ret = -EFAULT;
966                         goto free_counters;
967                 }
968 
969                 for (i = sizeof(struct ipt_entry);
970                      i < e->target_offset;
971                      i += m->u.match_size) {
972                         m = (void *)e + i;
973 
974                         if (copy_to_user(userptr + off + i
975                                          + offsetof(struct xt_entry_match,
976                                                     u.user.name),
977                                          m->u.kernel.match->name,
978                                          strlen(m->u.kernel.match->name)+1)
979                             != 0) {
980                                 ret = -EFAULT;
981                                 goto free_counters;
982                         }
983                 }
984 
985                 t = ipt_get_target_c(e);
986                 if (copy_to_user(userptr + off + e->target_offset
987                                  + offsetof(struct xt_entry_target,
988                                             u.user.name),
989                                  t->u.kernel.target->name,
990                                  strlen(t->u.kernel.target->name)+1) != 0) {
991                         ret = -EFAULT;
992                         goto free_counters;
993                 }
994         }
995 
996  free_counters:
997         vfree(counters);
998         return ret;
999 }
1000 
1001 #ifdef CONFIG_COMPAT
1002 static void compat_standard_from_user(void *dst, const void *src)
1003 {
1004         int v = *(compat_int_t *)src;
1005 
1006         if (v > 0)
1007                 v += xt_compat_calc_jump(AF_INET, v);
1008         memcpy(dst, &v, sizeof(v));
1009 }
1010 
1011 static int compat_standard_to_user(void __user *dst, const void *src)
1012 {
1013         compat_int_t cv = *(int *)src;
1014 
1015         if (cv > 0)
1016                 cv -= xt_compat_calc_jump(AF_INET, cv);
1017         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
1018 }
1019 
1020 static int compat_calc_entry(const struct ipt_entry *e,
1021                              const struct xt_table_info *info,
1022                              const void *base, struct xt_table_info *newinfo)
1023 {
1024         const struct xt_entry_match *ematch;
1025         const struct xt_entry_target *t;
1026         unsigned int entry_offset;
1027         int off, i, ret;
1028 
1029         off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1030         entry_offset = (void *)e - base;
1031         xt_ematch_foreach(ematch, e)
1032                 off += xt_compat_match_offset(ematch->u.kernel.match);
1033         t = ipt_get_target_c(e);
1034         off += xt_compat_target_offset(t->u.kernel.target);
1035         newinfo->size -= off;
1036         ret = xt_compat_add_offset(AF_INET, entry_offset, off);
1037         if (ret)
1038                 return ret;
1039 
1040         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1041                 if (info->hook_entry[i] &&
1042                     (e < (struct ipt_entry *)(base + info->hook_entry[i])))
1043                         newinfo->hook_entry[i] -= off;
1044                 if (info->underflow[i] &&
1045                     (e < (struct ipt_entry *)(base + info->underflow[i])))
1046                         newinfo->underflow[i] -= off;
1047         }
1048         return 0;
1049 }
1050 
1051 static int compat_table_info(const struct xt_table_info *info,
1052                              struct xt_table_info *newinfo)
1053 {
1054         struct ipt_entry *iter;
1055         const void *loc_cpu_entry;
1056         int ret;
1057 
1058         if (!newinfo || !info)
1059                 return -EINVAL;
1060 
1061         /* we dont care about newinfo->entries */
1062         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
1063         newinfo->initial_entries = 0;
1064         loc_cpu_entry = info->entries;
1065         xt_compat_init_offsets(AF_INET, info->number);
1066         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
1067                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
1068                 if (ret != 0)
1069                         return ret;
1070         }
1071         return 0;
1072 }
1073 #endif
1074 
1075 static int get_info(struct net *net, void __user *user,
1076                     const int *len, int compat)
1077 {
1078         char name[XT_TABLE_MAXNAMELEN];
1079         struct xt_table *t;
1080         int ret;
1081 
1082         if (*len != sizeof(struct ipt_getinfo)) {
1083                 duprintf("length %u != %zu\n", *len,
1084                          sizeof(struct ipt_getinfo));
1085                 return -EINVAL;
1086         }
1087 
1088         if (copy_from_user(name, user, sizeof(name)) != 0)
1089                 return -EFAULT;
1090 
1091         name[XT_TABLE_MAXNAMELEN-1] = '\0';
1092 #ifdef CONFIG_COMPAT
1093         if (compat)
1094                 xt_compat_lock(AF_INET);
1095 #endif
1096         t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
1097                                     "iptable_%s", name);
1098         if (!IS_ERR_OR_NULL(t)) {
1099                 struct ipt_getinfo info;
1100                 const struct xt_table_info *private = t->private;
1101 #ifdef CONFIG_COMPAT
1102                 struct xt_table_info tmp;
1103 
1104                 if (compat) {
1105                         ret = compat_table_info(private, &tmp);
1106                         xt_compat_flush_offsets(AF_INET);
1107                         private = &tmp;
1108                 }
1109 #endif
1110                 memset(&info, 0, sizeof(info));
1111                 info.valid_hooks = t->valid_hooks;
1112                 memcpy(info.hook_entry, private->hook_entry,
1113                        sizeof(info.hook_entry));
1114                 memcpy(info.underflow, private->underflow,
1115                        sizeof(info.underflow));
1116                 info.num_entries = private->number;
1117                 info.size = private->size;
1118                 strcpy(info.name, name);
1119 
1120                 if (copy_to_user(user, &info, *len) != 0)
1121                         ret = -EFAULT;
1122                 else
1123                         ret = 0;
1124 
1125                 xt_table_unlock(t);
1126                 module_put(t->me);
1127         } else
1128                 ret = t ? PTR_ERR(t) : -ENOENT;
1129 #ifdef CONFIG_COMPAT
1130         if (compat)
1131                 xt_compat_unlock(AF_INET);
1132 #endif
1133         return ret;
1134 }
1135 
1136 static int
1137 get_entries(struct net *net, struct ipt_get_entries __user *uptr,
1138             const int *len)
1139 {
1140         int ret;
1141         struct ipt_get_entries get;
1142         struct xt_table *t;
1143 
1144         if (*len < sizeof(get)) {
1145                 duprintf("get_entries: %u < %zu\n", *len, sizeof(get));
1146                 return -EINVAL;
1147         }
1148         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1149                 return -EFAULT;
1150         if (*len != sizeof(struct ipt_get_entries) + get.size) {
1151                 duprintf("get_entries: %u != %zu\n",
1152                          *len, sizeof(get) + get.size);
1153                 return -EINVAL;
1154         }
1155 
1156         t = xt_find_table_lock(net, AF_INET, get.name);
1157         if (!IS_ERR_OR_NULL(t)) {
1158                 const struct xt_table_info *private = t->private;
1159                 duprintf("t->private->number = %u\n", private->number);
1160                 if (get.size == private->size)
1161                         ret = copy_entries_to_user(private->size,
1162                                                    t, uptr->entrytable);
1163                 else {
1164                         duprintf("get_entries: I've got %u not %u!\n",
1165                                  private->size, get.size);
1166                         ret = -EAGAIN;
1167                 }
1168                 module_put(t->me);
1169                 xt_table_unlock(t);
1170         } else
1171                 ret = t ? PTR_ERR(t) : -ENOENT;
1172 
1173         return ret;
1174 }
1175 
1176 static int
1177 __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
1178              struct xt_table_info *newinfo, unsigned int num_counters,
1179              void __user *counters_ptr)
1180 {
1181         int ret;
1182         struct xt_table *t;
1183         struct xt_table_info *oldinfo;
1184         struct xt_counters *counters;
1185         struct ipt_entry *iter;
1186 
1187         ret = 0;
1188         counters = vzalloc(num_counters * sizeof(struct xt_counters));
1189         if (!counters) {
1190                 ret = -ENOMEM;
1191                 goto out;
1192         }
1193 
1194         t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
1195                                     "iptable_%s", name);
1196         if (IS_ERR_OR_NULL(t)) {
1197                 ret = t ? PTR_ERR(t) : -ENOENT;
1198                 goto free_newinfo_counters_untrans;
1199         }
1200 
1201         /* You lied! */
1202         if (valid_hooks != t->valid_hooks) {
1203                 duprintf("Valid hook crap: %08X vs %08X\n",
1204                          valid_hooks, t->valid_hooks);
1205                 ret = -EINVAL;
1206                 goto put_module;
1207         }
1208 
1209         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1210         if (!oldinfo)
1211                 goto put_module;
1212 
1213         /* Update module usage count based on number of rules */
1214         duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1215                 oldinfo->number, oldinfo->initial_entries, newinfo->number);
1216         if ((oldinfo->number > oldinfo->initial_entries) ||
1217             (newinfo->number <= oldinfo->initial_entries))
1218                 module_put(t->me);
1219         if ((oldinfo->number > oldinfo->initial_entries) &&
1220             (newinfo->number <= oldinfo->initial_entries))
1221                 module_put(t->me);
1222 
1223         /* Get the old counters, and synchronize with replace */
1224         get_counters(oldinfo, counters);
1225 
1226         /* Decrease module usage counts and free resource */
1227         xt_entry_foreach(iter, oldinfo->entries, oldinfo->size)
1228                 cleanup_entry(iter, net);
1229 
1230         xt_free_table_info(oldinfo);
1231         if (copy_to_user(counters_ptr, counters,
1232                          sizeof(struct xt_counters) * num_counters) != 0) {
1233                 /* Silent error, can't fail, new table is already in place */
1234                 net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n");
1235         }
1236         vfree(counters);
1237         xt_table_unlock(t);
1238         return ret;
1239 
1240  put_module:
1241         module_put(t->me);
1242         xt_table_unlock(t);
1243  free_newinfo_counters_untrans:
1244         vfree(counters);
1245  out:
1246         return ret;
1247 }
1248 
1249 static int
1250 do_replace(struct net *net, const void __user *user, unsigned int len)
1251 {
1252         int ret;
1253         struct ipt_replace tmp;
1254         struct xt_table_info *newinfo;
1255         void *loc_cpu_entry;
1256         struct ipt_entry *iter;
1257 
1258         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1259                 return -EFAULT;
1260 
1261         /* overflow check */
1262         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1263                 return -ENOMEM;
1264         if (tmp.num_counters == 0)
1265                 return -EINVAL;
1266 
1267         tmp.name[sizeof(tmp.name)-1] = 0;
1268 
1269         newinfo = xt_alloc_table_info(tmp.size);
1270         if (!newinfo)
1271                 return -ENOMEM;
1272 
1273         loc_cpu_entry = newinfo->entries;
1274         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1275                            tmp.size) != 0) {
1276                 ret = -EFAULT;
1277                 goto free_newinfo;
1278         }
1279 
1280         ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
1281         if (ret != 0)
1282                 goto free_newinfo;
1283 
1284         duprintf("Translated table\n");
1285 
1286         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1287                            tmp.num_counters, tmp.counters);
1288         if (ret)
1289                 goto free_newinfo_untrans;
1290         return 0;
1291 
1292  free_newinfo_untrans:
1293         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1294                 cleanup_entry(iter, net);
1295  free_newinfo:
1296         xt_free_table_info(newinfo);
1297         return ret;
1298 }
1299 
1300 static int
1301 do_add_counters(struct net *net, const void __user *user,
1302                 unsigned int len, int compat)
1303 {
1304         unsigned int i;
1305         struct xt_counters_info tmp;
1306         struct xt_counters *paddc;
1307         unsigned int num_counters;
1308         const char *name;
1309         int size;
1310         void *ptmp;
1311         struct xt_table *t;
1312         const struct xt_table_info *private;
1313         int ret = 0;
1314         struct ipt_entry *iter;
1315         unsigned int addend;
1316 #ifdef CONFIG_COMPAT
1317         struct compat_xt_counters_info compat_tmp;
1318 
1319         if (compat) {
1320                 ptmp = &compat_tmp;
1321                 size = sizeof(struct compat_xt_counters_info);
1322         } else
1323 #endif
1324         {
1325                 ptmp = &tmp;
1326                 size = sizeof(struct xt_counters_info);
1327         }
1328 
1329         if (copy_from_user(ptmp, user, size) != 0)
1330                 return -EFAULT;
1331 
1332 #ifdef CONFIG_COMPAT
1333         if (compat) {
1334                 num_counters = compat_tmp.num_counters;
1335                 name = compat_tmp.name;
1336         } else
1337 #endif
1338         {
1339                 num_counters = tmp.num_counters;
1340                 name = tmp.name;
1341         }
1342 
1343         if (len != size + num_counters * sizeof(struct xt_counters))
1344                 return -EINVAL;
1345 
1346         paddc = vmalloc(len - size);
1347         if (!paddc)
1348                 return -ENOMEM;
1349 
1350         if (copy_from_user(paddc, user + size, len - size) != 0) {
1351                 ret = -EFAULT;
1352                 goto free;
1353         }
1354 
1355         t = xt_find_table_lock(net, AF_INET, name);
1356         if (IS_ERR_OR_NULL(t)) {
1357                 ret = t ? PTR_ERR(t) : -ENOENT;
1358                 goto free;
1359         }
1360 
1361         local_bh_disable();
1362         private = t->private;
1363         if (private->number != num_counters) {
1364                 ret = -EINVAL;
1365                 goto unlock_up_free;
1366         }
1367 
1368         i = 0;
1369         addend = xt_write_recseq_begin();
1370         xt_entry_foreach(iter, private->entries, private->size) {
1371                 struct xt_counters *tmp;
1372 
1373                 tmp = xt_get_this_cpu_counter(&iter->counters);
1374                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1375                 ++i;
1376         }
1377         xt_write_recseq_end(addend);
1378  unlock_up_free:
1379         local_bh_enable();
1380         xt_table_unlock(t);
1381         module_put(t->me);
1382  free:
1383         vfree(paddc);
1384 
1385         return ret;
1386 }
1387 
1388 #ifdef CONFIG_COMPAT
1389 struct compat_ipt_replace {
1390         char                    name[XT_TABLE_MAXNAMELEN];
1391         u32                     valid_hooks;
1392         u32                     num_entries;
1393         u32                     size;
1394         u32                     hook_entry[NF_INET_NUMHOOKS];
1395         u32                     underflow[NF_INET_NUMHOOKS];
1396         u32                     num_counters;
1397         compat_uptr_t           counters;       /* struct xt_counters * */
1398         struct compat_ipt_entry entries[0];
1399 };
1400 
1401 static int
1402 compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
1403                           unsigned int *size, struct xt_counters *counters,
1404                           unsigned int i)
1405 {
1406         struct xt_entry_target *t;
1407         struct compat_ipt_entry __user *ce;
1408         u_int16_t target_offset, next_offset;
1409         compat_uint_t origsize;
1410         const struct xt_entry_match *ematch;
1411         int ret = 0;
1412 
1413         origsize = *size;
1414         ce = (struct compat_ipt_entry __user *)*dstptr;
1415         if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 ||
1416             copy_to_user(&ce->counters, &counters[i],
1417             sizeof(counters[i])) != 0)
1418                 return -EFAULT;
1419 
1420         *dstptr += sizeof(struct compat_ipt_entry);
1421         *size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1422 
1423         xt_ematch_foreach(ematch, e) {
1424                 ret = xt_compat_match_to_user(ematch, dstptr, size);
1425                 if (ret != 0)
1426                         return ret;
1427         }
1428         target_offset = e->target_offset - (origsize - *size);
1429         t = ipt_get_target(e);
1430         ret = xt_compat_target_to_user(t, dstptr, size);
1431         if (ret)
1432                 return ret;
1433         next_offset = e->next_offset - (origsize - *size);
1434         if (put_user(target_offset, &ce->target_offset) != 0 ||
1435             put_user(next_offset, &ce->next_offset) != 0)
1436                 return -EFAULT;
1437         return 0;
1438 }
1439 
1440 static int
1441 compat_find_calc_match(struct xt_entry_match *m,
1442                        const char *name,
1443                        const struct ipt_ip *ip,
1444                        int *size)
1445 {
1446         struct xt_match *match;
1447 
1448         match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
1449                                       m->u.user.revision);
1450         if (IS_ERR(match)) {
1451                 duprintf("compat_check_calc_match: `%s' not found\n",
1452                          m->u.user.name);
1453                 return PTR_ERR(match);
1454         }
1455         m->u.kernel.match = match;
1456         *size += xt_compat_match_offset(match);
1457         return 0;
1458 }
1459 
1460 static void compat_release_entry(struct compat_ipt_entry *e)
1461 {
1462         struct xt_entry_target *t;
1463         struct xt_entry_match *ematch;
1464 
1465         /* Cleanup all matches */
1466         xt_ematch_foreach(ematch, e)
1467                 module_put(ematch->u.kernel.match->me);
1468         t = compat_ipt_get_target(e);
1469         module_put(t->u.kernel.target->me);
1470 }
1471 
1472 static int
1473 check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
1474                                   struct xt_table_info *newinfo,
1475                                   unsigned int *size,
1476                                   const unsigned char *base,
1477                                   const unsigned char *limit,
1478                                   const unsigned int *hook_entries,
1479                                   const unsigned int *underflows,
1480                                   const char *name)
1481 {
1482         struct xt_entry_match *ematch;
1483         struct xt_entry_target *t;
1484         struct xt_target *target;
1485         unsigned int entry_offset;
1486         unsigned int j;
1487         int ret, off, h;
1488 
1489         duprintf("check_compat_entry_size_and_hooks %p\n", e);
1490         if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 ||
1491             (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit) {
1492                 duprintf("Bad offset %p, limit = %p\n", e, limit);
1493                 return -EINVAL;
1494         }
1495 
1496         if (e->next_offset < sizeof(struct compat_ipt_entry) +
1497                              sizeof(struct compat_xt_entry_target)) {
1498                 duprintf("checking: element %p size %u\n",
1499                          e, e->next_offset);
1500                 return -EINVAL;
1501         }
1502 
1503         /* For purposes of check_entry casting the compat entry is fine */
1504         ret = check_entry((struct ipt_entry *)e, name);
1505         if (ret)
1506                 return ret;
1507 
1508         off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1509         entry_offset = (void *)e - (void *)base;
1510         j = 0;
1511         xt_ematch_foreach(ematch, e) {
1512                 ret = compat_find_calc_match(ematch, name, &e->ip, &off);
1513                 if (ret != 0)
1514                         goto release_matches;
1515                 ++j;
1516         }
1517 
1518         t = compat_ipt_get_target(e);
1519         target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
1520                                         t->u.user.revision);
1521         if (IS_ERR(target)) {
1522                 duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1523                          t->u.user.name);
1524                 ret = PTR_ERR(target);
1525                 goto release_matches;
1526         }
1527         t->u.kernel.target = target;
1528 
1529         off += xt_compat_target_offset(target);
1530         *size += off;
1531         ret = xt_compat_add_offset(AF_INET, entry_offset, off);
1532         if (ret)
1533                 goto out;
1534 
1535         /* Check hooks & underflows */
1536         for (h = 0; h < NF_INET_NUMHOOKS; h++) {
1537                 if ((unsigned char *)e - base == hook_entries[h])
1538                         newinfo->hook_entry[h] = hook_entries[h];
1539                 if ((unsigned char *)e - base == underflows[h])
1540                         newinfo->underflow[h] = underflows[h];
1541         }
1542 
1543         /* Clear counters and comefrom */
1544         memset(&e->counters, 0, sizeof(e->counters));
1545         e->comefrom = 0;
1546         return 0;
1547 
1548 out:
1549         module_put(t->u.kernel.target->me);
1550 release_matches:
1551         xt_ematch_foreach(ematch, e) {
1552                 if (j-- == 0)
1553                         break;
1554                 module_put(ematch->u.kernel.match->me);
1555         }
1556         return ret;
1557 }
1558 
1559 static int
1560 compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr,
1561                             unsigned int *size, const char *name,
1562                             struct xt_table_info *newinfo, unsigned char *base)
1563 {
1564         struct xt_entry_target *t;
1565         struct xt_target *target;
1566         struct ipt_entry *de;
1567         unsigned int origsize;
1568         int ret, h;
1569         struct xt_entry_match *ematch;
1570 
1571         ret = 0;
1572         origsize = *size;
1573         de = (struct ipt_entry *)*dstptr;
1574         memcpy(de, e, sizeof(struct ipt_entry));
1575         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1576 
1577         *dstptr += sizeof(struct ipt_entry);
1578         *size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1579 
1580         xt_ematch_foreach(ematch, e) {
1581                 ret = xt_compat_match_from_user(ematch, dstptr, size);
1582                 if (ret != 0)
1583                         return ret;
1584         }
1585         de->target_offset = e->target_offset - (origsize - *size);
1586         t = compat_ipt_get_target(e);
1587         target = t->u.kernel.target;
1588         xt_compat_target_from_user(t, dstptr, size);
1589 
1590         de->next_offset = e->next_offset - (origsize - *size);
1591         for (h = 0; h < NF_INET_NUMHOOKS; h++) {
1592                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1593                         newinfo->hook_entry[h] -= origsize - *size;
1594                 if ((unsigned char *)de - base < newinfo->underflow[h])
1595                         newinfo->underflow[h] -= origsize - *size;
1596         }
1597         return ret;
1598 }
1599 
1600 static int
1601 compat_check_entry(struct ipt_entry *e, struct net *net, const char *name)
1602 {
1603         struct xt_entry_match *ematch;
1604         struct xt_mtchk_param mtpar;
1605         unsigned int j;
1606         int ret = 0;
1607 
1608         e->counters.pcnt = xt_percpu_counter_alloc();
1609         if (IS_ERR_VALUE(e->counters.pcnt))
1610                 return -ENOMEM;
1611 
1612         j = 0;
1613         mtpar.net       = net;
1614         mtpar.table     = name;
1615         mtpar.entryinfo = &e->ip;
1616         mtpar.hook_mask = e->comefrom;
1617         mtpar.family    = NFPROTO_IPV4;
1618         xt_ematch_foreach(ematch, e) {
1619                 ret = check_match(ematch, &mtpar);
1620                 if (ret != 0)
1621                         goto cleanup_matches;
1622                 ++j;
1623         }
1624 
1625         ret = check_target(e, net, name);
1626         if (ret)
1627                 goto cleanup_matches;
1628         return 0;
1629 
1630  cleanup_matches:
1631         xt_ematch_foreach(ematch, e) {
1632                 if (j-- == 0)
1633                         break;
1634                 cleanup_match(ematch, net);
1635         }
1636 
1637         xt_percpu_counter_free(e->counters.pcnt);
1638 
1639         return ret;
1640 }
1641 
1642 static int
1643 translate_compat_table(struct net *net,
1644                        const char *name,
1645                        unsigned int valid_hooks,
1646                        struct xt_table_info **pinfo,
1647                        void **pentry0,
1648                        unsigned int total_size,
1649                        unsigned int number,
1650                        unsigned int *hook_entries,
1651                        unsigned int *underflows)
1652 {
1653         unsigned int i, j;
1654         struct xt_table_info *newinfo, *info;
1655         void *pos, *entry0, *entry1;
1656         struct compat_ipt_entry *iter0;
1657         struct ipt_entry *iter1;
1658         unsigned int size;
1659         int ret;
1660 
1661         info = *pinfo;
1662         entry0 = *pentry0;
1663         size = total_size;
1664         info->number = number;
1665 
1666         /* Init all hooks to impossible value. */
1667         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1668                 info->hook_entry[i] = 0xFFFFFFFF;
1669                 info->underflow[i] = 0xFFFFFFFF;
1670         }
1671 
1672         duprintf("translate_compat_table: size %u\n", info->size);
1673         j = 0;
1674         xt_compat_lock(AF_INET);
1675         xt_compat_init_offsets(AF_INET, number);
1676         /* Walk through entries, checking offsets. */
1677         xt_entry_foreach(iter0, entry0, total_size) {
1678                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1679                                                         entry0,
1680                                                         entry0 + total_size,
1681                                                         hook_entries,
1682                                                         underflows,
1683                                                         name);
1684                 if (ret != 0)
1685                         goto out_unlock;
1686                 ++j;
1687         }
1688 
1689         ret = -EINVAL;
1690         if (j != number) {
1691                 duprintf("translate_compat_table: %u not %u entries\n",
1692                          j, number);
1693                 goto out_unlock;
1694         }
1695 
1696         /* Check hooks all assigned */
1697         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1698                 /* Only hooks which are valid */
1699                 if (!(valid_hooks & (1 << i)))
1700                         continue;
1701                 if (info->hook_entry[i] == 0xFFFFFFFF) {
1702                         duprintf("Invalid hook entry %u %u\n",
1703                                  i, hook_entries[i]);
1704                         goto out_unlock;
1705                 }
1706                 if (info->underflow[i] == 0xFFFFFFFF) {
1707                         duprintf("Invalid underflow %u %u\n",
1708                                  i, underflows[i]);
1709                         goto out_unlock;
1710                 }
1711         }
1712 
1713         ret = -ENOMEM;
1714         newinfo = xt_alloc_table_info(size);
1715         if (!newinfo)
1716                 goto out_unlock;
1717 
1718         newinfo->number = number;
1719         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1720                 newinfo->hook_entry[i] = info->hook_entry[i];
1721                 newinfo->underflow[i] = info->underflow[i];
1722         }
1723         entry1 = newinfo->entries;
1724         pos = entry1;
1725         size = total_size;
1726         xt_entry_foreach(iter0, entry0, total_size) {
1727                 ret = compat_copy_entry_from_user(iter0, &pos, &size,
1728                                                   name, newinfo, entry1);
1729                 if (ret != 0)
1730                         break;
1731         }
1732         xt_compat_flush_offsets(AF_INET);
1733         xt_compat_unlock(AF_INET);
1734         if (ret)
1735                 goto free_newinfo;
1736 
1737         ret = -ELOOP;
1738         if (!mark_source_chains(newinfo, valid_hooks, entry1))
1739                 goto free_newinfo;
1740 
1741         i = 0;
1742         xt_entry_foreach(iter1, entry1, newinfo->size) {
1743                 ret = compat_check_entry(iter1, net, name);
1744                 if (ret != 0)
1745                         break;
1746                 ++i;
1747                 if (strcmp(ipt_get_target(iter1)->u.user.name,
1748                     XT_ERROR_TARGET) == 0)
1749                         ++newinfo->stacksize;
1750         }
1751         if (ret) {
1752                 /*
1753                  * The first i matches need cleanup_entry (calls ->destroy)
1754                  * because they had called ->check already. The other j-i
1755                  * entries need only release.
1756                  */
1757                 int skip = i;
1758                 j -= i;
1759                 xt_entry_foreach(iter0, entry0, newinfo->size) {
1760                         if (skip-- > 0)
1761                                 continue;
1762                         if (j-- == 0)
1763                                 break;
1764                         compat_release_entry(iter0);
1765                 }
1766                 xt_entry_foreach(iter1, entry1, newinfo->size) {
1767                         if (i-- == 0)
1768                                 break;
1769                         cleanup_entry(iter1, net);
1770                 }
1771                 xt_free_table_info(newinfo);
1772                 return ret;
1773         }
1774 
1775         *pinfo = newinfo;
1776         *pentry0 = entry1;
1777         xt_free_table_info(info);
1778         return 0;
1779 
1780 free_newinfo:
1781         xt_free_table_info(newinfo);
1782 out:
1783         xt_entry_foreach(iter0, entry0, total_size) {
1784                 if (j-- == 0)
1785                         break;
1786                 compat_release_entry(iter0);
1787         }
1788         return ret;
1789 out_unlock:
1790         xt_compat_flush_offsets(AF_INET);
1791         xt_compat_unlock(AF_INET);
1792         goto out;
1793 }
1794 
1795 static int
1796 compat_do_replace(struct net *net, void __user *user, unsigned int len)
1797 {
1798         int ret;
1799         struct compat_ipt_replace tmp;
1800         struct xt_table_info *newinfo;
1801         void *loc_cpu_entry;
1802         struct ipt_entry *iter;
1803 
1804         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1805                 return -EFAULT;
1806 
1807         /* overflow check */
1808         if (tmp.size >= INT_MAX / num_possible_cpus())
1809                 return -ENOMEM;
1810         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1811                 return -ENOMEM;
1812         if (tmp.num_counters == 0)
1813                 return -EINVAL;
1814 
1815         tmp.name[sizeof(tmp.name)-1] = 0;
1816 
1817         newinfo = xt_alloc_table_info(tmp.size);
1818         if (!newinfo)
1819                 return -ENOMEM;
1820 
1821         loc_cpu_entry = newinfo->entries;
1822         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1823                            tmp.size) != 0) {
1824                 ret = -EFAULT;
1825                 goto free_newinfo;
1826         }
1827 
1828         ret = translate_compat_table(net, tmp.name, tmp.valid_hooks,
1829                                      &newinfo, &loc_cpu_entry, tmp.size,
1830                                      tmp.num_entries, tmp.hook_entry,
1831                                      tmp.underflow);
1832         if (ret != 0)
1833                 goto free_newinfo;
1834 
1835         duprintf("compat_do_replace: Translated table\n");
1836 
1837         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1838                            tmp.num_counters, compat_ptr(tmp.counters));
1839         if (ret)
1840                 goto free_newinfo_untrans;
1841         return 0;
1842 
1843  free_newinfo_untrans:
1844         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1845                 cleanup_entry(iter, net);
1846  free_newinfo:
1847         xt_free_table_info(newinfo);
1848         return ret;
1849 }
1850 
1851 static int
1852 compat_do_ipt_set_ctl(struct sock *sk,  int cmd, void __user *user,
1853                       unsigned int len)
1854 {
1855         int ret;
1856 
1857         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1858                 return -EPERM;
1859 
1860         switch (cmd) {
1861         case IPT_SO_SET_REPLACE:
1862                 ret = compat_do_replace(sock_net(sk), user, len);
1863                 break;
1864 
1865         case IPT_SO_SET_ADD_COUNTERS:
1866                 ret = do_add_counters(sock_net(sk), user, len, 1);
1867                 break;
1868 
1869         default:
1870                 duprintf("do_ipt_set_ctl:  unknown request %i\n", cmd);
1871                 ret = -EINVAL;
1872         }
1873 
1874         return ret;
1875 }
1876 
1877 struct compat_ipt_get_entries {
1878         char name[XT_TABLE_MAXNAMELEN];
1879         compat_uint_t size;
1880         struct compat_ipt_entry entrytable[0];
1881 };
1882 
1883 static int
1884 compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table,
1885                             void __user *userptr)
1886 {
1887         struct xt_counters *counters;
1888         const struct xt_table_info *private = table->private;
1889         void __user *pos;
1890         unsigned int size;
1891         int ret = 0;
1892         unsigned int i = 0;
1893         struct ipt_entry *iter;
1894 
1895         counters = alloc_counters(table);
1896         if (IS_ERR(counters))
1897                 return PTR_ERR(counters);
1898 
1899         pos = userptr;
1900         size = total_size;
1901         xt_entry_foreach(iter, private->entries, total_size) {
1902                 ret = compat_copy_entry_to_user(iter, &pos,
1903                                                 &size, counters, i++);
1904                 if (ret != 0)
1905                         break;
1906         }
1907 
1908         vfree(counters);
1909         return ret;
1910 }
1911 
1912 static int
1913 compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,
1914                    int *len)
1915 {
1916         int ret;
1917         struct compat_ipt_get_entries get;
1918         struct xt_table *t;
1919 
1920         if (*len < sizeof(get)) {
1921                 duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1922                 return -EINVAL;
1923         }
1924 
1925         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1926                 return -EFAULT;
1927 
1928         if (*len != sizeof(struct compat_ipt_get_entries) + get.size) {
1929                 duprintf("compat_get_entries: %u != %zu\n",
1930                          *len, sizeof(get) + get.size);
1931                 return -EINVAL;
1932         }
1933 
1934         xt_compat_lock(AF_INET);
1935         t = xt_find_table_lock(net, AF_INET, get.name);
1936         if (!IS_ERR_OR_NULL(t)) {
1937                 const struct xt_table_info *private = t->private;
1938                 struct xt_table_info info;
1939                 duprintf("t->private->number = %u\n", private->number);
1940                 ret = compat_table_info(private, &info);
1941                 if (!ret && get.size == info.size) {
1942                         ret = compat_copy_entries_to_user(private->size,
1943                                                           t, uptr->entrytable);
1944                 } else if (!ret) {
1945                         duprintf("compat_get_entries: I've got %u not %u!\n",
1946                                  private->size, get.size);
1947                         ret = -EAGAIN;
1948                 }
1949                 xt_compat_flush_offsets(AF_INET);
1950                 module_put(t->me);
1951                 xt_table_unlock(t);
1952         } else
1953                 ret = t ? PTR_ERR(t) : -ENOENT;
1954 
1955         xt_compat_unlock(AF_INET);
1956         return ret;
1957 }
1958 
1959 static int do_ipt_get_ctl(struct sock *, int, void __user *, int *);
1960 
1961 static int
1962 compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1963 {
1964         int ret;
1965 
1966         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1967                 return -EPERM;
1968 
1969         switch (cmd) {
1970         case IPT_SO_GET_INFO:
1971                 ret = get_info(sock_net(sk), user, len, 1);
1972                 break;
1973         case IPT_SO_GET_ENTRIES:
1974                 ret = compat_get_entries(sock_net(sk), user, len);
1975                 break;
1976         default:
1977                 ret = do_ipt_get_ctl(sk, cmd, user, len);
1978         }
1979         return ret;
1980 }
1981 #endif
1982 
1983 static int
1984 do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1985 {
1986         int ret;
1987 
1988         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1989                 return -EPERM;
1990 
1991         switch (cmd) {
1992         case IPT_SO_SET_REPLACE:
1993                 ret = do_replace(sock_net(sk), user, len);
1994                 break;
1995 
1996         case IPT_SO_SET_ADD_COUNTERS:
1997                 ret = do_add_counters(sock_net(sk), user, len, 0);
1998                 break;
1999 
2000         default:
2001                 duprintf("do_ipt_set_ctl:  unknown request %i\n", cmd);
2002                 ret = -EINVAL;
2003         }
2004 
2005         return ret;
2006 }
2007 
2008 static int
2009 do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2010 {
2011         int ret;
2012 
2013         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2014                 return -EPERM;
2015 
2016         switch (cmd) {
2017         case IPT_SO_GET_INFO:
2018                 ret = get_info(sock_net(sk), user, len, 0);
2019                 break;
2020 
2021         case IPT_SO_GET_ENTRIES:
2022                 ret = get_entries(sock_net(sk), user, len);
2023                 break;
2024 
2025         case IPT_SO_GET_REVISION_MATCH:
2026         case IPT_SO_GET_REVISION_TARGET: {
2027                 struct xt_get_revision rev;
2028                 int target;
2029 
2030                 if (*len != sizeof(rev)) {
2031                         ret = -EINVAL;
2032                         break;
2033                 }
2034                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
2035                         ret = -EFAULT;
2036                         break;
2037                 }
2038                 rev.name[sizeof(rev.name)-1] = 0;
2039 
2040                 if (cmd == IPT_SO_GET_REVISION_TARGET)
2041                         target = 1;
2042                 else
2043                         target = 0;
2044 
2045                 try_then_request_module(xt_find_revision(AF_INET, rev.name,
2046                                                          rev.revision,
2047                                                          target, &ret),
2048                                         "ipt_%s", rev.name);
2049                 break;
2050         }
2051 
2052         default:
2053                 duprintf("do_ipt_get_ctl: unknown request %i\n", cmd);
2054                 ret = -EINVAL;
2055         }
2056 
2057         return ret;
2058 }
2059 
2060 struct xt_table *ipt_register_table(struct net *net,
2061                                     const struct xt_table *table,
2062                                     const struct ipt_replace *repl)
2063 {
2064         int ret;
2065         struct xt_table_info *newinfo;
2066         struct xt_table_info bootstrap = {0};
2067         void *loc_cpu_entry;
2068         struct xt_table *new_table;
2069 
2070         newinfo = xt_alloc_table_info(repl->size);
2071         if (!newinfo) {
2072                 ret = -ENOMEM;
2073                 goto out;
2074         }
2075 
2076         loc_cpu_entry = newinfo->entries;
2077         memcpy(loc_cpu_entry, repl->entries, repl->size);
2078 
2079         ret = translate_table(net, newinfo, loc_cpu_entry, repl);
2080         if (ret != 0)
2081                 goto out_free;
2082 
2083         new_table = xt_register_table(net, table, &bootstrap, newinfo);
2084         if (IS_ERR(new_table)) {
2085                 ret = PTR_ERR(new_table);
2086                 goto out_free;
2087         }
2088 
2089         return new_table;
2090 
2091 out_free:
2092         xt_free_table_info(newinfo);
2093 out:
2094         return ERR_PTR(ret);
2095 }
2096 
2097 void ipt_unregister_table(struct net *net, struct xt_table *table)
2098 {
2099         struct xt_table_info *private;
2100         void *loc_cpu_entry;
2101         struct module *table_owner = table->me;
2102         struct ipt_entry *iter;
2103 
2104         private = xt_unregister_table(table);
2105 
2106         /* Decrease module usage counts and free resources */
2107         loc_cpu_entry = private->entries;
2108         xt_entry_foreach(iter, loc_cpu_entry, private->size)
2109                 cleanup_entry(iter, net);
2110         if (private->number > private->initial_entries)
2111                 module_put(table_owner);
2112         xt_free_table_info(private);
2113 }
2114 
2115 /* Returns 1 if the type and code is matched by the range, 0 otherwise */
2116 static inline bool
2117 icmp_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
2118                      u_int8_t type, u_int8_t code,
2119                      bool invert)
2120 {
2121         return ((test_type == 0xFF) ||
2122                 (type == test_type && code >= min_code && code <= max_code))
2123                 ^ invert;
2124 }
2125 
2126 static bool
2127 icmp_match(const struct sk_buff *skb, struct xt_action_param *par)
2128 {
2129         const struct icmphdr *ic;
2130         struct icmphdr _icmph;
2131         const struct ipt_icmp *icmpinfo = par->matchinfo;
2132 
2133         /* Must not be a fragment. */
2134         if (par->fragoff != 0)
2135                 return false;
2136 
2137         ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
2138         if (ic == NULL) {
2139                 /* We've been asked to examine this packet, and we
2140                  * can't.  Hence, no choice but to drop.
2141                  */
2142                 duprintf("Dropping evil ICMP tinygram.\n");
2143                 par->hotdrop = true;
2144                 return false;
2145         }
2146 
2147         return icmp_type_code_match(icmpinfo->type,
2148                                     icmpinfo->code[0],
2149                                     icmpinfo->code[1],
2150                                     ic->type, ic->code,
2151                                     !!(icmpinfo->invflags&IPT_ICMP_INV));
2152 }
2153 
2154 static int icmp_checkentry(const struct xt_mtchk_param *par)
2155 {
2156         const struct ipt_icmp *icmpinfo = par->matchinfo;
2157 
2158         /* Must specify no unknown invflags */
2159         return (icmpinfo->invflags & ~IPT_ICMP_INV) ? -EINVAL : 0;
2160 }
2161 
2162 static struct xt_target ipt_builtin_tg[] __read_mostly = {
2163         {
2164                 .name             = XT_STANDARD_TARGET,
2165                 .targetsize       = sizeof(int),
2166                 .family           = NFPROTO_IPV4,
2167 #ifdef CONFIG_COMPAT
2168                 .compatsize       = sizeof(compat_int_t),
2169                 .compat_from_user = compat_standard_from_user,
2170                 .compat_to_user   = compat_standard_to_user,
2171 #endif
2172         },
2173         {
2174                 .name             = XT_ERROR_TARGET,
2175                 .target           = ipt_error,
2176                 .targetsize       = XT_FUNCTION_MAXNAMELEN,
2177                 .family           = NFPROTO_IPV4,
2178         },
2179 };
2180 
2181 static struct nf_sockopt_ops ipt_sockopts = {
2182         .pf             = PF_INET,
2183         .set_optmin     = IPT_BASE_CTL,
2184         .set_optmax     = IPT_SO_SET_MAX+1,
2185         .set            = do_ipt_set_ctl,
2186 #ifdef CONFIG_COMPAT
2187         .compat_set     = compat_do_ipt_set_ctl,
2188 #endif
2189         .get_optmin     = IPT_BASE_CTL,
2190         .get_optmax     = IPT_SO_GET_MAX+1,
2191         .get            = do_ipt_get_ctl,
2192 #ifdef CONFIG_COMPAT
2193         .compat_get     = compat_do_ipt_get_ctl,
2194 #endif
2195         .owner          = THIS_MODULE,
2196 };
2197 
2198 static struct xt_match ipt_builtin_mt[] __read_mostly = {
2199         {
2200                 .name       = "icmp",
2201                 .match      = icmp_match,
2202                 .matchsize  = sizeof(struct ipt_icmp),
2203                 .checkentry = icmp_checkentry,
2204                 .proto      = IPPROTO_ICMP,
2205                 .family     = NFPROTO_IPV4,
2206         },
2207 };
2208 
2209 static int __net_init ip_tables_net_init(struct net *net)
2210 {
2211         return xt_proto_init(net, NFPROTO_IPV4);
2212 }
2213 
2214 static void __net_exit ip_tables_net_exit(struct net *net)
2215 {
2216         xt_proto_fini(net, NFPROTO_IPV4);
2217 }
2218 
2219 static struct pernet_operations ip_tables_net_ops = {
2220         .init = ip_tables_net_init,
2221         .exit = ip_tables_net_exit,
2222 };
2223 
2224 static int __init ip_tables_init(void)
2225 {
2226         int ret;
2227 
2228         ret = register_pernet_subsys(&ip_tables_net_ops);
2229         if (ret < 0)
2230                 goto err1;
2231 
2232         /* No one else will be downing sem now, so we won't sleep */
2233         ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
2234         if (ret < 0)
2235                 goto err2;
2236         ret = xt_register_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
2237         if (ret < 0)
2238                 goto err4;
2239 
2240         /* Register setsockopt */
2241         ret = nf_register_sockopt(&ipt_sockopts);
2242         if (ret < 0)
2243                 goto err5;
2244 
2245         pr_info("(C) 2000-2006 Netfilter Core Team\n");
2246         return 0;
2247 
2248 err5:
2249         xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
2250 err4:
2251         xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
2252 err2:
2253         unregister_pernet_subsys(&ip_tables_net_ops);
2254 err1:
2255         return ret;
2256 }
2257 
2258 static void __exit ip_tables_fini(void)
2259 {
2260         nf_unregister_sockopt(&ipt_sockopts);
2261 
2262         xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
2263         xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
2264         unregister_pernet_subsys(&ip_tables_net_ops);
2265 }
2266 
2267 EXPORT_SYMBOL(ipt_register_table);
2268 EXPORT_SYMBOL(ipt_unregister_table);
2269 EXPORT_SYMBOL(ipt_do_table);
2270 module_init(ip_tables_init);
2271 module_exit(ip_tables_fini);
2272 

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