bridge/netfilter/ebtables.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  ebtables
0004  *
0005  *  Author:
0006  *  Bart De Schuymer        <bdschuym@pandora.be>
0007  *
0008  *  ebtables.c,v 2.0, July, 2002
0009  *
0010  *  This code is strongly inspired by the iptables code which is
0011  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
0012  */
0013 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0014 #include <linux/kmod.h>
0015 #include <linux/module.h>
0016 #include <linux/vmalloc.h>
0017 #include <linux/netfilter/x_tables.h>
0018 #include <linux/netfilter_bridge/ebtables.h>
0019 #include <linux/spinlock.h>
0020 #include <linux/mutex.h>
0021 #include <linux/slab.h>
0022 #include <linux/uaccess.h>
0023 #include <linux/smp.h>
0024 #include <linux/cpumask.h>
0025 #include <linux/audit.h>
0026 #include <net/sock.h>
0027 #include <net/netns/generic.h>
0028 /* needed for logical [in,out]-dev filtering */
0029 #include "../br_private.h"
0030
0031 /* Each cpu has its own set of counters, so there is no need for write_lock in
0032  * the softirq
0033  * For reading or updating the counters, the user context needs to
0034  * get a write_lock
0035  */
0036
0037 /* The size of each set of counters is altered to get cache alignment */
0038 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
0039 #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter)))
0040 #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \
0041                  COUNTER_OFFSET(n) * cpu))
0042
0043 struct ebt_pernet {
0044     struct list_head tables;
0045 };
0046
0047 struct ebt_template {
0048     struct list_head list;
0049     char name[EBT_TABLE_MAXNAMELEN];
0050     struct module *owner;
0051     /* called when table is needed in the given netns */
0052     int (*table_init)(struct net *net);
0053 };
0054
0055 static unsigned int ebt_pernet_id __read_mostly;
0056 static LIST_HEAD(template_tables);
0057 static DEFINE_MUTEX(ebt_mutex);
0058
0059 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
0060 static void ebt_standard_compat_from_user(void *dst, const void *src)
0061 {
0062     int v = *(compat_int_t *)src;
0063
0064     if (v >= 0)
0065         v += xt_compat_calc_jump(NFPROTO_BRIDGE, v);
0066     memcpy(dst, &v, sizeof(v));
0067 }
0068
0069 static int ebt_standard_compat_to_user(void __user *dst, const void *src)
0070 {
0071     compat_int_t cv = *(int *)src;
0072
0073     if (cv >= 0)
0074         cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv);
0075     return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
0076 }
0077 #endif
0078
0079
0080 static struct xt_target ebt_standard_target = {
0081     .name       = "standard",
0082     .revision   = 0,
0083     .family     = NFPROTO_BRIDGE,
0084     .targetsize = sizeof(int),
0085 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
0086     .compatsize = sizeof(compat_int_t),
0087     .compat_from_user = ebt_standard_compat_from_user,
0088     .compat_to_user =  ebt_standard_compat_to_user,
0089 #endif
0090 };
0091
0092 static inline int
0093 ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb,
0094            struct xt_action_param *par)
0095 {
0096     par->target   = w->u.watcher;
0097     par->targinfo = w->data;
0098     w->u.watcher->target(skb, par);
0099     /* watchers don't give a verdict */
0100     return 0;
0101 }
0102
0103 static inline int
0104 ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb,
0105          struct xt_action_param *par)
0106 {
0107     par->match     = m->u.match;
0108     par->matchinfo = m->data;
0109     return !m->u.match->match(skb, par);
0110 }
0111
0112 static inline int
0113 ebt_dev_check(const char *entry, const struct net_device *device)
0114 {
0115     int i = 0;
0116     const char *devname;
0117
0118     if (*entry == '\0')
0119         return 0;
0120     if (!device)
0121         return 1;
0122     devname = device->name;
0123     /* 1 is the wildcard token */
0124     while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i])
0125         i++;
0126     return devname[i] != entry[i] && entry[i] != 1;
0127 }
0128
0129 /* process standard matches */
0130 static inline int
0131 ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
0132         const struct net_device *in, const struct net_device *out)
0133 {
0134     const struct ethhdr *h = eth_hdr(skb);
0135     const struct net_bridge_port *p;
0136     __be16 ethproto;
0137
0138     if (skb_vlan_tag_present(skb))
0139         ethproto = htons(ETH_P_8021Q);
0140     else
0141         ethproto = h->h_proto;
0142
0143     if (e->bitmask & EBT_802_3) {
0144         if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto)))
0145             return 1;
0146     } else if (!(e->bitmask & EBT_NOPROTO) &&
0147            NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto))
0148         return 1;
0149
0150     if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in)))
0151         return 1;
0152     if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
0153         return 1;
0154     /* rcu_read_lock()ed by nf_hook_thresh */
0155     if (in && (p = br_port_get_rcu(in)) != NULL &&
0156         NF_INVF(e, EBT_ILOGICALIN,
0157             ebt_dev_check(e->logical_in, p->br->dev)))
0158         return 1;
0159     if (out && (p = br_port_get_rcu(out)) != NULL &&
0160         NF_INVF(e, EBT_ILOGICALOUT,
0161             ebt_dev_check(e->logical_out, p->br->dev)))
0162         return 1;
0163
0164     if (e->bitmask & EBT_SOURCEMAC) {
0165         if (NF_INVF(e, EBT_ISOURCE,
0166                 !ether_addr_equal_masked(h->h_source, e->sourcemac,
0167                              e->sourcemsk)))
0168             return 1;
0169     }
0170     if (e->bitmask & EBT_DESTMAC) {
0171         if (NF_INVF(e, EBT_IDEST,
0172                 !ether_addr_equal_masked(h->h_dest, e->destmac,
0173                              e->destmsk)))
0174             return 1;
0175     }
0176     return 0;
0177 }
0178
0179 static inline
0180 struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry)
0181 {
0182     return (void *)entry + entry->next_offset;
0183 }
0184
0185 static inline const struct ebt_entry_target *
0186 ebt_get_target_c(const struct ebt_entry *e)
0187 {
0188     return ebt_get_target((struct ebt_entry *)e);
0189 }
0190
0191 /* Do some firewalling */
0192 unsigned int ebt_do_table(void *priv, struct sk_buff *skb,
0193               const struct nf_hook_state *state)
0194 {
0195     struct ebt_table *table = priv;
0196     unsigned int hook = state->hook;
0197     int i, nentries;
0198     struct ebt_entry *point;
0199     struct ebt_counter *counter_base, *cb_base;
0200     const struct ebt_entry_target *t;
0201     int verdict, sp = 0;
0202     struct ebt_chainstack *cs;
0203     struct ebt_entries *chaininfo;
0204     const char *base;
0205     const struct ebt_table_info *private;
0206     struct xt_action_param acpar;
0207
0208     acpar.state   = state;
0209     acpar.hotdrop = false;
0210
0211     read_lock_bh(&table->lock);
0212     private = table->private;
0213     cb_base = COUNTER_BASE(private->counters, private->nentries,
0214        smp_processor_id());
0215     if (private->chainstack)
0216         cs = private->chainstack[smp_processor_id()];
0217     else
0218         cs = NULL;
0219     chaininfo = private->hook_entry[hook];
0220     nentries = private->hook_entry[hook]->nentries;
0221     point = (struct ebt_entry *)(private->hook_entry[hook]->data);
0222     counter_base = cb_base + private->hook_entry[hook]->counter_offset;
0223     /* base for chain jumps */
0224     base = private->entries;
0225     i = 0;
0226     while (i < nentries) {
0227         if (ebt_basic_match(point, skb, state->in, state->out))
0228             goto letscontinue;
0229
0230         if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0)
0231             goto letscontinue;
0232         if (acpar.hotdrop) {
0233             read_unlock_bh(&table->lock);
0234             return NF_DROP;
0235         }
0236
0237         ADD_COUNTER(*(counter_base + i), skb->len, 1);
0238
0239         /* these should only watch: not modify, nor tell us
0240          * what to do with the packet
0241          */
0242         EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar);
0243
0244         t = ebt_get_target_c(point);
0245         /* standard target */
0246         if (!t->u.target->target)
0247             verdict = ((struct ebt_standard_target *)t)->verdict;
0248         else {
0249             acpar.target   = t->u.target;
0250             acpar.targinfo = t->data;
0251             verdict = t->u.target->target(skb, &acpar);
0252         }
0253         if (verdict == EBT_ACCEPT) {
0254             read_unlock_bh(&table->lock);
0255             return NF_ACCEPT;
0256         }
0257         if (verdict == EBT_DROP) {
0258             read_unlock_bh(&table->lock);
0259             return NF_DROP;
0260         }
0261         if (verdict == EBT_RETURN) {
0262 letsreturn:
0263             if (WARN(sp == 0, "RETURN on base chain")) {
0264                 /* act like this is EBT_CONTINUE */
0265                 goto letscontinue;
0266             }
0267
0268             sp--;
0269             /* put all the local variables right */
0270             i = cs[sp].n;
0271             chaininfo = cs[sp].chaininfo;
0272             nentries = chaininfo->nentries;
0273             point = cs[sp].e;
0274             counter_base = cb_base +
0275                chaininfo->counter_offset;
0276             continue;
0277         }
0278         if (verdict == EBT_CONTINUE)
0279             goto letscontinue;
0280
0281         if (WARN(verdict < 0, "bogus standard verdict\n")) {
0282             read_unlock_bh(&table->lock);
0283             return NF_DROP;
0284         }
0285
0286         /* jump to a udc */
0287         cs[sp].n = i + 1;
0288         cs[sp].chaininfo = chaininfo;
0289         cs[sp].e = ebt_next_entry(point);
0290         i = 0;
0291         chaininfo = (struct ebt_entries *) (base + verdict);
0292
0293         if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) {
0294             read_unlock_bh(&table->lock);
0295             return NF_DROP;
0296         }
0297
0298         nentries = chaininfo->nentries;
0299         point = (struct ebt_entry *)chaininfo->data;
0300         counter_base = cb_base + chaininfo->counter_offset;
0301         sp++;
0302         continue;
0303 letscontinue:
0304         point = ebt_next_entry(point);
0305         i++;
0306     }
0307
0308     /* I actually like this :) */
0309     if (chaininfo->policy == EBT_RETURN)
0310         goto letsreturn;
0311     if (chaininfo->policy == EBT_ACCEPT) {
0312         read_unlock_bh(&table->lock);
0313         return NF_ACCEPT;
0314     }
0315     read_unlock_bh(&table->lock);
0316     return NF_DROP;
0317 }
0318
0319 /* If it succeeds, returns element and locks mutex */
0320 static inline void *
0321 find_inlist_lock_noload(struct net *net, const char *name, int *error,
0322             struct mutex *mutex)
0323 {
0324     struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
0325     struct ebt_template *tmpl;
0326     struct ebt_table *table;
0327
0328     mutex_lock(mutex);
0329     list_for_each_entry(table, &ebt_net->tables, list) {
0330         if (strcmp(table->name, name) == 0)
0331             return table;
0332     }
0333
0334     list_for_each_entry(tmpl, &template_tables, list) {
0335         if (strcmp(name, tmpl->name) == 0) {
0336             struct module *owner = tmpl->owner;
0337
0338             if (!try_module_get(owner))
0339                 goto out;
0340
0341             mutex_unlock(mutex);
0342
0343             *error = tmpl->table_init(net);
0344             if (*error) {
0345                 module_put(owner);
0346                 return NULL;
0347             }
0348
0349             mutex_lock(mutex);
0350             module_put(owner);
0351             break;
0352         }
0353     }
0354
0355     list_for_each_entry(table, &ebt_net->tables, list) {
0356         if (strcmp(table->name, name) == 0)
0357             return table;
0358     }
0359
0360 out:
0361     *error = -ENOENT;
0362     mutex_unlock(mutex);
0363     return NULL;
0364 }
0365
0366 static void *
0367 find_inlist_lock(struct net *net, const char *name, const char *prefix,
0368          int *error, struct mutex *mutex)
0369 {
0370     return try_then_request_module(
0371             find_inlist_lock_noload(net, name, error, mutex),
0372             "%s%s", prefix, name);
0373 }
0374
0375 static inline struct ebt_table *
0376 find_table_lock(struct net *net, const char *name, int *error,
0377         struct mutex *mutex)
0378 {
0379     return find_inlist_lock(net, name, "ebtable_", error, mutex);
0380 }
0381
0382 static inline void ebt_free_table_info(struct ebt_table_info *info)
0383 {
0384     int i;
0385
0386     if (info->chainstack) {
0387         for_each_possible_cpu(i)
0388             vfree(info->chainstack[i]);
0389         vfree(info->chainstack);
0390     }
0391 }
0392 static inline int
0393 ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par,
0394         unsigned int *cnt)
0395 {
0396     const struct ebt_entry *e = par->entryinfo;
0397     struct xt_match *match;
0398     size_t left = ((char *)e + e->watchers_offset) - (char *)m;
0399     int ret;
0400
0401     if (left < sizeof(struct ebt_entry_match) ||
0402         left - sizeof(struct ebt_entry_match) < m->match_size)
0403         return -EINVAL;
0404
0405     match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
0406     if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
0407         if (!IS_ERR(match))
0408             module_put(match->me);
0409         request_module("ebt_%s", m->u.name);
0410         match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision);
0411     }
0412     if (IS_ERR(match))
0413         return PTR_ERR(match);
0414     m->u.match = match;
0415
0416     par->match     = match;
0417     par->matchinfo = m->data;
0418     ret = xt_check_match(par, m->match_size,
0419           ntohs(e->ethproto), e->invflags & EBT_IPROTO);
0420     if (ret < 0) {
0421         module_put(match->me);
0422         return ret;
0423     }
0424
0425     (*cnt)++;
0426     return 0;
0427 }
0428
0429 static inline int
0430 ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par,
0431           unsigned int *cnt)
0432 {
0433     const struct ebt_entry *e = par->entryinfo;
0434     struct xt_target *watcher;
0435     size_t left = ((char *)e + e->target_offset) - (char *)w;
0436     int ret;
0437
0438     if (left < sizeof(struct ebt_entry_watcher) ||
0439        left - sizeof(struct ebt_entry_watcher) < w->watcher_size)
0440         return -EINVAL;
0441
0442     watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0);
0443     if (IS_ERR(watcher))
0444         return PTR_ERR(watcher);
0445
0446     if (watcher->family != NFPROTO_BRIDGE) {
0447         module_put(watcher->me);
0448         return -ENOENT;
0449     }
0450
0451     w->u.watcher = watcher;
0452
0453     par->target   = watcher;
0454     par->targinfo = w->data;
0455     ret = xt_check_target(par, w->watcher_size,
0456           ntohs(e->ethproto), e->invflags & EBT_IPROTO);
0457     if (ret < 0) {
0458         module_put(watcher->me);
0459         return ret;
0460     }
0461
0462     (*cnt)++;
0463     return 0;
0464 }
0465
0466 static int ebt_verify_pointers(const struct ebt_replace *repl,
0467                    struct ebt_table_info *newinfo)
0468 {
0469     unsigned int limit = repl->entries_size;
0470     unsigned int valid_hooks = repl->valid_hooks;
0471     unsigned int offset = 0;
0472     int i;
0473
0474     for (i = 0; i < NF_BR_NUMHOOKS; i++)
0475         newinfo->hook_entry[i] = NULL;
0476
0477     newinfo->entries_size = repl->entries_size;
0478     newinfo->nentries = repl->nentries;
0479
0480     while (offset < limit) {
0481         size_t left = limit - offset;
0482         struct ebt_entry *e = (void *)newinfo->entries + offset;
0483
0484         if (left < sizeof(unsigned int))
0485             break;
0486
0487         for (i = 0; i < NF_BR_NUMHOOKS; i++) {
0488             if ((valid_hooks & (1 << i)) == 0)
0489                 continue;
0490             if ((char __user *)repl->hook_entry[i] ==
0491                  repl->entries + offset)
0492                 break;
0493         }
0494
0495         if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) {
0496             if (e->bitmask != 0) {
0497                 /* we make userspace set this right,
0498                  * so there is no misunderstanding
0499                  */
0500                 return -EINVAL;
0501             }
0502             if (i != NF_BR_NUMHOOKS)
0503                 newinfo->hook_entry[i] = (struct ebt_entries *)e;
0504             if (left < sizeof(struct ebt_entries))
0505                 break;
0506             offset += sizeof(struct ebt_entries);
0507         } else {
0508             if (left < sizeof(struct ebt_entry))
0509                 break;
0510             if (left < e->next_offset)
0511                 break;
0512             if (e->next_offset < sizeof(struct ebt_entry))
0513                 return -EINVAL;
0514             offset += e->next_offset;
0515         }
0516     }
0517     if (offset != limit)
0518         return -EINVAL;
0519
0520     /* check if all valid hooks have a chain */
0521     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
0522         if (!newinfo->hook_entry[i] &&
0523            (valid_hooks & (1 << i)))
0524             return -EINVAL;
0525     }
0526     return 0;
0527 }
0528
0529 /* this one is very careful, as it is the first function
0530  * to parse the userspace data
0531  */
0532 static inline int
0533 ebt_check_entry_size_and_hooks(const struct ebt_entry *e,
0534                    const struct ebt_table_info *newinfo,
0535                    unsigned int *n, unsigned int *cnt,
0536                    unsigned int *totalcnt, unsigned int *udc_cnt)
0537 {
0538     int i;
0539
0540     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
0541         if ((void *)e == (void *)newinfo->hook_entry[i])
0542             break;
0543     }
0544     /* beginning of a new chain
0545      * if i == NF_BR_NUMHOOKS it must be a user defined chain
0546      */
0547     if (i != NF_BR_NUMHOOKS || !e->bitmask) {
0548         /* this checks if the previous chain has as many entries
0549          * as it said it has
0550          */
0551         if (*n != *cnt)
0552             return -EINVAL;
0553
0554         if (((struct ebt_entries *)e)->policy != EBT_DROP &&
0555            ((struct ebt_entries *)e)->policy != EBT_ACCEPT) {
0556             /* only RETURN from udc */
0557             if (i != NF_BR_NUMHOOKS ||
0558                ((struct ebt_entries *)e)->policy != EBT_RETURN)
0559                 return -EINVAL;
0560         }
0561         if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */
0562             (*udc_cnt)++;
0563         if (((struct ebt_entries *)e)->counter_offset != *totalcnt)
0564             return -EINVAL;
0565         *n = ((struct ebt_entries *)e)->nentries;
0566         *cnt = 0;
0567         return 0;
0568     }
0569     /* a plain old entry, heh */
0570     if (sizeof(struct ebt_entry) > e->watchers_offset ||
0571        e->watchers_offset > e->target_offset ||
0572        e->target_offset >= e->next_offset)
0573         return -EINVAL;
0574
0575     /* this is not checked anywhere else */
0576     if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target))
0577         return -EINVAL;
0578
0579     (*cnt)++;
0580     (*totalcnt)++;
0581     return 0;
0582 }
0583
0584 struct ebt_cl_stack {
0585     struct ebt_chainstack cs;
0586     int from;
0587     unsigned int hookmask;
0588 };
0589
0590 /* We need these positions to check that the jumps to a different part of the
0591  * entries is a jump to the beginning of a new chain.
0592  */
0593 static inline int
0594 ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo,
0595               unsigned int *n, struct ebt_cl_stack *udc)
0596 {
0597     int i;
0598
0599     /* we're only interested in chain starts */
0600     if (e->bitmask)
0601         return 0;
0602     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
0603         if (newinfo->hook_entry[i] == (struct ebt_entries *)e)
0604             break;
0605     }
0606     /* only care about udc */
0607     if (i != NF_BR_NUMHOOKS)
0608         return 0;
0609
0610     udc[*n].cs.chaininfo = (struct ebt_entries *)e;
0611     /* these initialisations are depended on later in check_chainloops() */
0612     udc[*n].cs.n = 0;
0613     udc[*n].hookmask = 0;
0614
0615     (*n)++;
0616     return 0;
0617 }
0618
0619 static inline int
0620 ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i)
0621 {
0622     struct xt_mtdtor_param par;
0623
0624     if (i && (*i)-- == 0)
0625         return 1;
0626
0627     par.net       = net;
0628     par.match     = m->u.match;
0629     par.matchinfo = m->data;
0630     par.family    = NFPROTO_BRIDGE;
0631     if (par.match->destroy != NULL)
0632         par.match->destroy(&par);
0633     module_put(par.match->me);
0634     return 0;
0635 }
0636
0637 static inline int
0638 ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i)
0639 {
0640     struct xt_tgdtor_param par;
0641
0642     if (i && (*i)-- == 0)
0643         return 1;
0644
0645     par.net      = net;
0646     par.target   = w->u.watcher;
0647     par.targinfo = w->data;
0648     par.family   = NFPROTO_BRIDGE;
0649     if (par.target->destroy != NULL)
0650         par.target->destroy(&par);
0651     module_put(par.target->me);
0652     return 0;
0653 }
0654
0655 static inline int
0656 ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt)
0657 {
0658     struct xt_tgdtor_param par;
0659     struct ebt_entry_target *t;
0660
0661     if (e->bitmask == 0)
0662         return 0;
0663     /* we're done */
0664     if (cnt && (*cnt)-- == 0)
0665         return 1;
0666     EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL);
0667     EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL);
0668     t = ebt_get_target(e);
0669
0670     par.net      = net;
0671     par.target   = t->u.target;
0672     par.targinfo = t->data;
0673     par.family   = NFPROTO_BRIDGE;
0674     if (par.target->destroy != NULL)
0675         par.target->destroy(&par);
0676     module_put(par.target->me);
0677     return 0;
0678 }
0679
0680 static inline int
0681 ebt_check_entry(struct ebt_entry *e, struct net *net,
0682         const struct ebt_table_info *newinfo,
0683         const char *name, unsigned int *cnt,
0684         struct ebt_cl_stack *cl_s, unsigned int udc_cnt)
0685 {
0686     struct ebt_entry_target *t;
0687     struct xt_target *target;
0688     unsigned int i, j, hook = 0, hookmask = 0;
0689     size_t gap;
0690     int ret;
0691     struct xt_mtchk_param mtpar;
0692     struct xt_tgchk_param tgpar;
0693
0694     /* don't mess with the struct ebt_entries */
0695     if (e->bitmask == 0)
0696         return 0;
0697
0698     if (e->bitmask & ~EBT_F_MASK)
0699         return -EINVAL;
0700
0701     if (e->invflags & ~EBT_INV_MASK)
0702         return -EINVAL;
0703
0704     if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3))
0705         return -EINVAL;
0706
0707     /* what hook do we belong to? */
0708     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
0709         if (!newinfo->hook_entry[i])
0710             continue;
0711         if ((char *)newinfo->hook_entry[i] < (char *)e)
0712             hook = i;
0713         else
0714             break;
0715     }
0716     /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on
0717      * a base chain
0718      */
0719     if (i < NF_BR_NUMHOOKS)
0720         hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
0721     else {
0722         for (i = 0; i < udc_cnt; i++)
0723             if ((char *)(cl_s[i].cs.chaininfo) > (char *)e)
0724                 break;
0725         if (i == 0)
0726             hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS);
0727         else
0728             hookmask = cl_s[i - 1].hookmask;
0729     }
0730     i = 0;
0731
0732     memset(&mtpar, 0, sizeof(mtpar));
0733     memset(&tgpar, 0, sizeof(tgpar));
0734     mtpar.net   = tgpar.net       = net;
0735     mtpar.table     = tgpar.table     = name;
0736     mtpar.entryinfo = tgpar.entryinfo = e;
0737     mtpar.hook_mask = tgpar.hook_mask = hookmask;
0738     mtpar.family    = tgpar.family    = NFPROTO_BRIDGE;
0739     ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i);
0740     if (ret != 0)
0741         goto cleanup_matches;
0742     j = 0;
0743     ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j);
0744     if (ret != 0)
0745         goto cleanup_watchers;
0746     t = ebt_get_target(e);
0747     gap = e->next_offset - e->target_offset;
0748
0749     target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0);
0750     if (IS_ERR(target)) {
0751         ret = PTR_ERR(target);
0752         goto cleanup_watchers;
0753     }
0754
0755     /* Reject UNSPEC, xtables verdicts/return values are incompatible */
0756     if (target->family != NFPROTO_BRIDGE) {
0757         module_put(target->me);
0758         ret = -ENOENT;
0759         goto cleanup_watchers;
0760     }
0761
0762     t->u.target = target;
0763     if (t->u.target == &ebt_standard_target) {
0764         if (gap < sizeof(struct ebt_standard_target)) {
0765             ret = -EFAULT;
0766             goto cleanup_watchers;
0767         }
0768         if (((struct ebt_standard_target *)t)->verdict <
0769            -NUM_STANDARD_TARGETS) {
0770             ret = -EFAULT;
0771             goto cleanup_watchers;
0772         }
0773     } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) {
0774         module_put(t->u.target->me);
0775         ret = -EFAULT;
0776         goto cleanup_watchers;
0777     }
0778
0779     tgpar.target   = target;
0780     tgpar.targinfo = t->data;
0781     ret = xt_check_target(&tgpar, t->target_size,
0782           ntohs(e->ethproto), e->invflags & EBT_IPROTO);
0783     if (ret < 0) {
0784         module_put(target->me);
0785         goto cleanup_watchers;
0786     }
0787     (*cnt)++;
0788     return 0;
0789 cleanup_watchers:
0790     EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j);
0791 cleanup_matches:
0792     EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i);
0793     return ret;
0794 }
0795
0796 /* checks for loops and sets the hook mask for udc
0797  * the hook mask for udc tells us from which base chains the udc can be
0798  * accessed. This mask is a parameter to the check() functions of the extensions
0799  */
0800 static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s,
0801                 unsigned int udc_cnt, unsigned int hooknr, char *base)
0802 {
0803     int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict;
0804     const struct ebt_entry *e = (struct ebt_entry *)chain->data;
0805     const struct ebt_entry_target *t;
0806
0807     while (pos < nentries || chain_nr != -1) {
0808         /* end of udc, go back one 'recursion' step */
0809         if (pos == nentries) {
0810             /* put back values of the time when this chain was called */
0811             e = cl_s[chain_nr].cs.e;
0812             if (cl_s[chain_nr].from != -1)
0813                 nentries =
0814                 cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries;
0815             else
0816                 nentries = chain->nentries;
0817             pos = cl_s[chain_nr].cs.n;
0818             /* make sure we won't see a loop that isn't one */
0819             cl_s[chain_nr].cs.n = 0;
0820             chain_nr = cl_s[chain_nr].from;
0821             if (pos == nentries)
0822                 continue;
0823         }
0824         t = ebt_get_target_c(e);
0825         if (strcmp(t->u.name, EBT_STANDARD_TARGET))
0826             goto letscontinue;
0827         if (e->target_offset + sizeof(struct ebt_standard_target) >
0828            e->next_offset)
0829             return -1;
0830
0831         verdict = ((struct ebt_standard_target *)t)->verdict;
0832         if (verdict >= 0) { /* jump to another chain */
0833             struct ebt_entries *hlp2 =
0834                (struct ebt_entries *)(base + verdict);
0835             for (i = 0; i < udc_cnt; i++)
0836                 if (hlp2 == cl_s[i].cs.chaininfo)
0837                     break;
0838             /* bad destination or loop */
0839             if (i == udc_cnt)
0840                 return -1;
0841
0842             if (cl_s[i].cs.n)
0843                 return -1;
0844
0845             if (cl_s[i].hookmask & (1 << hooknr))
0846                 goto letscontinue;
0847             /* this can't be 0, so the loop test is correct */
0848             cl_s[i].cs.n = pos + 1;
0849             pos = 0;
0850             cl_s[i].cs.e = ebt_next_entry(e);
0851             e = (struct ebt_entry *)(hlp2->data);
0852             nentries = hlp2->nentries;
0853             cl_s[i].from = chain_nr;
0854             chain_nr = i;
0855             /* this udc is accessible from the base chain for hooknr */
0856             cl_s[i].hookmask |= (1 << hooknr);
0857             continue;
0858         }
0859 letscontinue:
0860         e = ebt_next_entry(e);
0861         pos++;
0862     }
0863     return 0;
0864 }
0865
0866 /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */
0867 static int translate_table(struct net *net, const char *name,
0868                struct ebt_table_info *newinfo)
0869 {
0870     unsigned int i, j, k, udc_cnt;
0871     int ret;
0872     struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */
0873
0874     i = 0;
0875     while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i])
0876         i++;
0877     if (i == NF_BR_NUMHOOKS)
0878         return -EINVAL;
0879
0880     if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries)
0881         return -EINVAL;
0882
0883     /* make sure chains are ordered after each other in same order
0884      * as their corresponding hooks
0885      */
0886     for (j = i + 1; j < NF_BR_NUMHOOKS; j++) {
0887         if (!newinfo->hook_entry[j])
0888             continue;
0889         if (newinfo->hook_entry[j] <= newinfo->hook_entry[i])
0890             return -EINVAL;
0891
0892         i = j;
0893     }
0894
0895     /* do some early checkings and initialize some things */
0896     i = 0; /* holds the expected nr. of entries for the chain */
0897     j = 0; /* holds the up to now counted entries for the chain */
0898     k = 0; /* holds the total nr. of entries, should equal
0899         * newinfo->nentries afterwards
0900         */
0901     udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */
0902     ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
0903        ebt_check_entry_size_and_hooks, newinfo,
0904        &i, &j, &k, &udc_cnt);
0905
0906     if (ret != 0)
0907         return ret;
0908
0909     if (i != j)
0910         return -EINVAL;
0911
0912     if (k != newinfo->nentries)
0913         return -EINVAL;
0914
0915     /* get the location of the udc, put them in an array
0916      * while we're at it, allocate the chainstack
0917      */
0918     if (udc_cnt) {
0919         /* this will get free'd in do_replace()/ebt_register_table()
0920          * if an error occurs
0921          */
0922         newinfo->chainstack =
0923             vmalloc(array_size(nr_cpu_ids,
0924                        sizeof(*(newinfo->chainstack))));
0925         if (!newinfo->chainstack)
0926             return -ENOMEM;
0927         for_each_possible_cpu(i) {
0928             newinfo->chainstack[i] =
0929               vmalloc_node(array_size(udc_cnt,
0930                       sizeof(*(newinfo->chainstack[0]))),
0931                        cpu_to_node(i));
0932             if (!newinfo->chainstack[i]) {
0933                 while (i)
0934                     vfree(newinfo->chainstack[--i]);
0935                 vfree(newinfo->chainstack);
0936                 newinfo->chainstack = NULL;
0937                 return -ENOMEM;
0938             }
0939         }
0940
0941         cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s)));
0942         if (!cl_s)
0943             return -ENOMEM;
0944         i = 0; /* the i'th udc */
0945         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
0946            ebt_get_udc_positions, newinfo, &i, cl_s);
0947         /* sanity check */
0948         if (i != udc_cnt) {
0949             vfree(cl_s);
0950             return -EFAULT;
0951         }
0952     }
0953
0954     /* Check for loops */
0955     for (i = 0; i < NF_BR_NUMHOOKS; i++)
0956         if (newinfo->hook_entry[i])
0957             if (check_chainloops(newinfo->hook_entry[i],
0958                cl_s, udc_cnt, i, newinfo->entries)) {
0959                 vfree(cl_s);
0960                 return -EINVAL;
0961             }
0962
0963     /* we now know the following (along with E=mc²):
0964      *  - the nr of entries in each chain is right
0965      *  - the size of the allocated space is right
0966      *  - all valid hooks have a corresponding chain
0967      *  - there are no loops
0968      *  - wrong data can still be on the level of a single entry
0969      *  - could be there are jumps to places that are not the
0970      *    beginning of a chain. This can only occur in chains that
0971      *    are not accessible from any base chains, so we don't care.
0972      */
0973
0974     /* used to know what we need to clean up if something goes wrong */
0975     i = 0;
0976     ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
0977        ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt);
0978     if (ret != 0) {
0979         EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
0980                   ebt_cleanup_entry, net, &i);
0981     }
0982     vfree(cl_s);
0983     return ret;
0984 }
0985
0986 /* called under write_lock */
0987 static void get_counters(const struct ebt_counter *oldcounters,
0988              struct ebt_counter *counters, unsigned int nentries)
0989 {
0990     int i, cpu;
0991     struct ebt_counter *counter_base;
0992
0993     /* counters of cpu 0 */
0994     memcpy(counters, oldcounters,
0995            sizeof(struct ebt_counter) * nentries);
0996
0997     /* add other counters to those of cpu 0 */
0998     for_each_possible_cpu(cpu) {
0999         if (cpu == 0)
1000             continue;
1001         counter_base = COUNTER_BASE(oldcounters, nentries, cpu);
1002         for (i = 0; i < nentries; i++)
1003             ADD_COUNTER(counters[i], counter_base[i].bcnt,
1004                     counter_base[i].pcnt);
1005     }
1006 }
1007
1008 static int do_replace_finish(struct net *net, struct ebt_replace *repl,
1009                   struct ebt_table_info *newinfo)
1010 {
1011     int ret;
1012     struct ebt_counter *counterstmp = NULL;
1013     /* used to be able to unlock earlier */
1014     struct ebt_table_info *table;
1015     struct ebt_table *t;
1016
1017     /* the user wants counters back
1018      * the check on the size is done later, when we have the lock
1019      */
1020     if (repl->num_counters) {
1021         unsigned long size = repl->num_counters * sizeof(*counterstmp);
1022         counterstmp = vmalloc(size);
1023         if (!counterstmp)
1024             return -ENOMEM;
1025     }
1026
1027     newinfo->chainstack = NULL;
1028     ret = ebt_verify_pointers(repl, newinfo);
1029     if (ret != 0)
1030         goto free_counterstmp;
1031
1032     ret = translate_table(net, repl->name, newinfo);
1033
1034     if (ret != 0)
1035         goto free_counterstmp;
1036
1037     t = find_table_lock(net, repl->name, &ret, &ebt_mutex);
1038     if (!t) {
1039         ret = -ENOENT;
1040         goto free_iterate;
1041     }
1042
1043     if (repl->valid_hooks != t->valid_hooks) {
1044         ret = -EINVAL;
1045         goto free_unlock;
1046     }
1047
1048     if (repl->num_counters && repl->num_counters != t->private->nentries) {
1049         ret = -EINVAL;
1050         goto free_unlock;
1051     }
1052
1053     /* we have the mutex lock, so no danger in reading this pointer */
1054     table = t->private;
1055     /* make sure the table can only be rmmod'ed if it contains no rules */
1056     if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) {
1057         ret = -ENOENT;
1058         goto free_unlock;
1059     } else if (table->nentries && !newinfo->nentries)
1060         module_put(t->me);
1061     /* we need an atomic snapshot of the counters */
1062     write_lock_bh(&t->lock);
1063     if (repl->num_counters)
1064         get_counters(t->private->counters, counterstmp,
1065            t->private->nentries);
1066
1067     t->private = newinfo;
1068     write_unlock_bh(&t->lock);
1069     mutex_unlock(&ebt_mutex);
1070     /* so, a user can change the chains while having messed up her counter
1071      * allocation. Only reason why this is done is because this way the lock
1072      * is held only once, while this doesn't bring the kernel into a
1073      * dangerous state.
1074      */
1075     if (repl->num_counters &&
1076        copy_to_user(repl->counters, counterstmp,
1077        array_size(repl->num_counters, sizeof(struct ebt_counter)))) {
1078         /* Silent error, can't fail, new table is already in place */
1079         net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
1080     }
1081
1082     /* decrease module count and free resources */
1083     EBT_ENTRY_ITERATE(table->entries, table->entries_size,
1084               ebt_cleanup_entry, net, NULL);
1085
1086     vfree(table->entries);
1087     ebt_free_table_info(table);
1088     vfree(table);
1089     vfree(counterstmp);
1090
1091     audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1092             AUDIT_XT_OP_REPLACE, GFP_KERNEL);
1093     return ret;
1094
1095 free_unlock:
1096     mutex_unlock(&ebt_mutex);
1097 free_iterate:
1098     EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size,
1099               ebt_cleanup_entry, net, NULL);
1100 free_counterstmp:
1101     vfree(counterstmp);
1102     /* can be initialized in translate_table() */
1103     ebt_free_table_info(newinfo);
1104     return ret;
1105 }
1106
1107 /* replace the table */
1108 static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
1109 {
1110     int ret, countersize;
1111     struct ebt_table_info *newinfo;
1112     struct ebt_replace tmp;
1113
1114     if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1115         return -EFAULT;
1116
1117     if (len != sizeof(tmp) + tmp.entries_size)
1118         return -EINVAL;
1119
1120     if (tmp.entries_size == 0)
1121         return -EINVAL;
1122
1123     /* overflow check */
1124     if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
1125             NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
1126         return -ENOMEM;
1127     if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
1128         return -ENOMEM;
1129
1130     tmp.name[sizeof(tmp.name) - 1] = 0;
1131
1132     countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
1133     newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT);
1134     if (!newinfo)
1135         return -ENOMEM;
1136
1137     if (countersize)
1138         memset(newinfo->counters, 0, countersize);
1139
1140     newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT);
1141     if (!newinfo->entries) {
1142         ret = -ENOMEM;
1143         goto free_newinfo;
1144     }
1145     if (copy_from_user(
1146        newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
1147         ret = -EFAULT;
1148         goto free_entries;
1149     }
1150
1151     ret = do_replace_finish(net, &tmp, newinfo);
1152     if (ret == 0)
1153         return ret;
1154 free_entries:
1155     vfree(newinfo->entries);
1156 free_newinfo:
1157     vfree(newinfo);
1158     return ret;
1159 }
1160
1161 static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
1162 {
1163     mutex_lock(&ebt_mutex);
1164     list_del(&table->list);
1165     mutex_unlock(&ebt_mutex);
1166     audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries,
1167             AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
1168     EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size,
1169               ebt_cleanup_entry, net, NULL);
1170     if (table->private->nentries)
1171         module_put(table->me);
1172     vfree(table->private->entries);
1173     ebt_free_table_info(table->private);
1174     vfree(table->private);
1175     kfree(table->ops);
1176     kfree(table);
1177 }
1178
1179 int ebt_register_table(struct net *net, const struct ebt_table *input_table,
1180                const struct nf_hook_ops *template_ops)
1181 {
1182     struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1183     struct ebt_table_info *newinfo;
1184     struct ebt_table *t, *table;
1185     struct nf_hook_ops *ops;
1186     unsigned int num_ops;
1187     struct ebt_replace_kernel *repl;
1188     int ret, i, countersize;
1189     void *p;
1190
1191     if (input_table == NULL || (repl = input_table->table) == NULL ||
1192         repl->entries == NULL || repl->entries_size == 0 ||
1193         repl->counters != NULL || input_table->private != NULL)
1194         return -EINVAL;
1195
1196     /* Don't add one table to multiple lists. */
1197     table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL);
1198     if (!table) {
1199         ret = -ENOMEM;
1200         goto out;
1201     }
1202
1203     countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
1204     newinfo = vmalloc(sizeof(*newinfo) + countersize);
1205     ret = -ENOMEM;
1206     if (!newinfo)
1207         goto free_table;
1208
1209     p = vmalloc(repl->entries_size);
1210     if (!p)
1211         goto free_newinfo;
1212
1213     memcpy(p, repl->entries, repl->entries_size);
1214     newinfo->entries = p;
1215
1216     newinfo->entries_size = repl->entries_size;
1217     newinfo->nentries = repl->nentries;
1218
1219     if (countersize)
1220         memset(newinfo->counters, 0, countersize);
1221
1222     /* fill in newinfo and parse the entries */
1223     newinfo->chainstack = NULL;
1224     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1225         if ((repl->valid_hooks & (1 << i)) == 0)
1226             newinfo->hook_entry[i] = NULL;
1227         else
1228             newinfo->hook_entry[i] = p +
1229                 ((char *)repl->hook_entry[i] - repl->entries);
1230     }
1231     ret = translate_table(net, repl->name, newinfo);
1232     if (ret != 0)
1233         goto free_chainstack;
1234
1235     table->private = newinfo;
1236     rwlock_init(&table->lock);
1237     mutex_lock(&ebt_mutex);
1238     list_for_each_entry(t, &ebt_net->tables, list) {
1239         if (strcmp(t->name, table->name) == 0) {
1240             ret = -EEXIST;
1241             goto free_unlock;
1242         }
1243     }
1244
1245     /* Hold a reference count if the chains aren't empty */
1246     if (newinfo->nentries && !try_module_get(table->me)) {
1247         ret = -ENOENT;
1248         goto free_unlock;
1249     }
1250
1251     num_ops = hweight32(table->valid_hooks);
1252     if (num_ops == 0) {
1253         ret = -EINVAL;
1254         goto free_unlock;
1255     }
1256
1257     ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL);
1258     if (!ops) {
1259         ret = -ENOMEM;
1260         if (newinfo->nentries)
1261             module_put(table->me);
1262         goto free_unlock;
1263     }
1264
1265     for (i = 0; i < num_ops; i++)
1266         ops[i].priv = table;
1267
1268     list_add(&table->list, &ebt_net->tables);
1269     mutex_unlock(&ebt_mutex);
1270
1271     table->ops = ops;
1272     ret = nf_register_net_hooks(net, ops, num_ops);
1273     if (ret)
1274         __ebt_unregister_table(net, table);
1275
1276     audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
1277             AUDIT_XT_OP_REGISTER, GFP_KERNEL);
1278     return ret;
1279 free_unlock:
1280     mutex_unlock(&ebt_mutex);
1281 free_chainstack:
1282     ebt_free_table_info(newinfo);
1283     vfree(newinfo->entries);
1284 free_newinfo:
1285     vfree(newinfo);
1286 free_table:
1287     kfree(table);
1288 out:
1289     return ret;
1290 }
1291
1292 int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net))
1293 {
1294     struct ebt_template *tmpl;
1295
1296     mutex_lock(&ebt_mutex);
1297     list_for_each_entry(tmpl, &template_tables, list) {
1298         if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) {
1299             mutex_unlock(&ebt_mutex);
1300             return -EEXIST;
1301         }
1302     }
1303
1304     tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL);
1305     if (!tmpl) {
1306         mutex_unlock(&ebt_mutex);
1307         return -ENOMEM;
1308     }
1309
1310     tmpl->table_init = table_init;
1311     strscpy(tmpl->name, t->name, sizeof(tmpl->name));
1312     tmpl->owner = t->me;
1313     list_add(&tmpl->list, &template_tables);
1314
1315     mutex_unlock(&ebt_mutex);
1316     return 0;
1317 }
1318 EXPORT_SYMBOL(ebt_register_template);
1319
1320 void ebt_unregister_template(const struct ebt_table *t)
1321 {
1322     struct ebt_template *tmpl;
1323
1324     mutex_lock(&ebt_mutex);
1325     list_for_each_entry(tmpl, &template_tables, list) {
1326         if (strcmp(t->name, tmpl->name))
1327             continue;
1328
1329         list_del(&tmpl->list);
1330         mutex_unlock(&ebt_mutex);
1331         kfree(tmpl);
1332         return;
1333     }
1334
1335     mutex_unlock(&ebt_mutex);
1336     WARN_ON_ONCE(1);
1337 }
1338 EXPORT_SYMBOL(ebt_unregister_template);
1339
1340 static struct ebt_table *__ebt_find_table(struct net *net, const char *name)
1341 {
1342     struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
1343     struct ebt_table *t;
1344
1345     mutex_lock(&ebt_mutex);
1346
1347     list_for_each_entry(t, &ebt_net->tables, list) {
1348         if (strcmp(t->name, name) == 0) {
1349             mutex_unlock(&ebt_mutex);
1350             return t;
1351         }
1352     }
1353
1354     mutex_unlock(&ebt_mutex);
1355     return NULL;
1356 }
1357
1358 void ebt_unregister_table_pre_exit(struct net *net, const char *name)
1359 {
1360     struct ebt_table *table = __ebt_find_table(net, name);
1361
1362     if (table)
1363         nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks));
1364 }
1365 EXPORT_SYMBOL(ebt_unregister_table_pre_exit);
1366
1367 void ebt_unregister_table(struct net *net, const char *name)
1368 {
1369     struct ebt_table *table = __ebt_find_table(net, name);
1370
1371     if (table)
1372         __ebt_unregister_table(net, table);
1373 }
1374
1375 /* userspace just supplied us with counters */
1376 static int do_update_counters(struct net *net, const char *name,
1377                   struct ebt_counter __user *counters,
1378                   unsigned int num_counters, unsigned int len)
1379 {
1380     int i, ret;
1381     struct ebt_counter *tmp;
1382     struct ebt_table *t;
1383
1384     if (num_counters == 0)
1385         return -EINVAL;
1386
1387     tmp = vmalloc(array_size(num_counters, sizeof(*tmp)));
1388     if (!tmp)
1389         return -ENOMEM;
1390
1391     t = find_table_lock(net, name, &ret, &ebt_mutex);
1392     if (!t)
1393         goto free_tmp;
1394
1395     if (num_counters != t->private->nentries) {
1396         ret = -EINVAL;
1397         goto unlock_mutex;
1398     }
1399
1400     if (copy_from_user(tmp, counters,
1401                array_size(num_counters, sizeof(*counters)))) {
1402         ret = -EFAULT;
1403         goto unlock_mutex;
1404     }
1405
1406     /* we want an atomic add of the counters */
1407     write_lock_bh(&t->lock);
1408
1409     /* we add to the counters of the first cpu */
1410     for (i = 0; i < num_counters; i++)
1411         ADD_COUNTER(t->private->counters[i], tmp[i].bcnt, tmp[i].pcnt);
1412
1413     write_unlock_bh(&t->lock);
1414     ret = 0;
1415 unlock_mutex:
1416     mutex_unlock(&ebt_mutex);
1417 free_tmp:
1418     vfree(tmp);
1419     return ret;
1420 }
1421
1422 static int update_counters(struct net *net, sockptr_t arg, unsigned int len)
1423 {
1424     struct ebt_replace hlp;
1425
1426     if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
1427         return -EFAULT;
1428
1429     if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
1430         return -EINVAL;
1431
1432     return do_update_counters(net, hlp.name, hlp.counters,
1433                   hlp.num_counters, len);
1434 }
1435
1436 static inline int ebt_obj_to_user(char __user *um, const char *_name,
1437                   const char *data, int entrysize,
1438                   int usersize, int datasize, u8 revision)
1439 {
1440     char name[EBT_EXTENSION_MAXNAMELEN] = {0};
1441
1442     /* ebtables expects 31 bytes long names but xt_match names are 29 bytes
1443      * long. Copy 29 bytes and fill remaining bytes with zeroes.
1444      */
1445     strlcpy(name, _name, sizeof(name));
1446     if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) ||
1447         put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) ||
1448         put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) ||
1449         xt_data_to_user(um + entrysize, data, usersize, datasize,
1450                 XT_ALIGN(datasize)))
1451         return -EFAULT;
1452
1453     return 0;
1454 }
1455
1456 static inline int ebt_match_to_user(const struct ebt_entry_match *m,
1457                     const char *base, char __user *ubase)
1458 {
1459     return ebt_obj_to_user(ubase + ((char *)m - base),
1460                    m->u.match->name, m->data, sizeof(*m),
1461                    m->u.match->usersize, m->match_size,
1462                    m->u.match->revision);
1463 }
1464
1465 static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w,
1466                       const char *base, char __user *ubase)
1467 {
1468     return ebt_obj_to_user(ubase + ((char *)w - base),
1469                    w->u.watcher->name, w->data, sizeof(*w),
1470                    w->u.watcher->usersize, w->watcher_size,
1471                    w->u.watcher->revision);
1472 }
1473
1474 static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base,
1475                     char __user *ubase)
1476 {
1477     int ret;
1478     char __user *hlp;
1479     const struct ebt_entry_target *t;
1480
1481     if (e->bitmask == 0) {
1482         /* special case !EBT_ENTRY_OR_ENTRIES */
1483         if (copy_to_user(ubase + ((char *)e - base), e,
1484                  sizeof(struct ebt_entries)))
1485             return -EFAULT;
1486         return 0;
1487     }
1488
1489     if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e)))
1490         return -EFAULT;
1491
1492     hlp = ubase + (((char *)e + e->target_offset) - base);
1493     t = ebt_get_target_c(e);
1494
1495     ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase);
1496     if (ret != 0)
1497         return ret;
1498     ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase);
1499     if (ret != 0)
1500         return ret;
1501     ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t),
1502                   t->u.target->usersize, t->target_size,
1503                   t->u.target->revision);
1504     if (ret != 0)
1505         return ret;
1506
1507     return 0;
1508 }
1509
1510 static int copy_counters_to_user(struct ebt_table *t,
1511                  const struct ebt_counter *oldcounters,
1512                  void __user *user, unsigned int num_counters,
1513                  unsigned int nentries)
1514 {
1515     struct ebt_counter *counterstmp;
1516     int ret = 0;
1517
1518     /* userspace might not need the counters */
1519     if (num_counters == 0)
1520         return 0;
1521
1522     if (num_counters != nentries)
1523         return -EINVAL;
1524
1525     counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp)));
1526     if (!counterstmp)
1527         return -ENOMEM;
1528
1529     write_lock_bh(&t->lock);
1530     get_counters(oldcounters, counterstmp, nentries);
1531     write_unlock_bh(&t->lock);
1532
1533     if (copy_to_user(user, counterstmp,
1534         array_size(nentries, sizeof(struct ebt_counter))))
1535         ret = -EFAULT;
1536     vfree(counterstmp);
1537     return ret;
1538 }
1539
1540 /* called with ebt_mutex locked */
1541 static int copy_everything_to_user(struct ebt_table *t, void __user *user,
1542                    const int *len, int cmd)
1543 {
1544     struct ebt_replace tmp;
1545     const struct ebt_counter *oldcounters;
1546     unsigned int entries_size, nentries;
1547     int ret;
1548     char *entries;
1549
1550     if (cmd == EBT_SO_GET_ENTRIES) {
1551         entries_size = t->private->entries_size;
1552         nentries = t->private->nentries;
1553         entries = t->private->entries;
1554         oldcounters = t->private->counters;
1555     } else {
1556         entries_size = t->table->entries_size;
1557         nentries = t->table->nentries;
1558         entries = t->table->entries;
1559         oldcounters = t->table->counters;
1560     }
1561
1562     if (copy_from_user(&tmp, user, sizeof(tmp)))
1563         return -EFAULT;
1564
1565     if (*len != sizeof(struct ebt_replace) + entries_size +
1566        (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0))
1567         return -EINVAL;
1568
1569     if (tmp.nentries != nentries)
1570         return -EINVAL;
1571
1572     if (tmp.entries_size != entries_size)
1573         return -EINVAL;
1574
1575     ret = copy_counters_to_user(t, oldcounters, tmp.counters,
1576                     tmp.num_counters, nentries);
1577     if (ret)
1578         return ret;
1579
1580     /* set the match/watcher/target names right */
1581     return EBT_ENTRY_ITERATE(entries, entries_size,
1582        ebt_entry_to_user, entries, tmp.entries);
1583 }
1584
1585 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
1586 /* 32 bit-userspace compatibility definitions. */
1587 struct compat_ebt_replace {
1588     char name[EBT_TABLE_MAXNAMELEN];
1589     compat_uint_t valid_hooks;
1590     compat_uint_t nentries;
1591     compat_uint_t entries_size;
1592     /* start of the chains */
1593     compat_uptr_t hook_entry[NF_BR_NUMHOOKS];
1594     /* nr of counters userspace expects back */
1595     compat_uint_t num_counters;
1596     /* where the kernel will put the old counters. */
1597     compat_uptr_t counters;
1598     compat_uptr_t entries;
1599 };
1600
1601 /* struct ebt_entry_match, _target and _watcher have same layout */
1602 struct compat_ebt_entry_mwt {
1603     union {
1604         struct {
1605             char name[EBT_EXTENSION_MAXNAMELEN];
1606             u8 revision;
1607         };
1608         compat_uptr_t ptr;
1609     } u;
1610     compat_uint_t match_size;
1611     compat_uint_t data[] __aligned(__alignof__(struct compat_ebt_replace));
1612 };
1613
1614 /* account for possible padding between match_size and ->data */
1615 static int ebt_compat_entry_padsize(void)
1616 {
1617     BUILD_BUG_ON(sizeof(struct ebt_entry_match) <
1618             sizeof(struct compat_ebt_entry_mwt));
1619     return (int) sizeof(struct ebt_entry_match) -
1620             sizeof(struct compat_ebt_entry_mwt);
1621 }
1622
1623 static int ebt_compat_match_offset(const struct xt_match *match,
1624                    unsigned int userlen)
1625 {
1626     /* ebt_among needs special handling. The kernel .matchsize is
1627      * set to -1 at registration time; at runtime an EBT_ALIGN()ed
1628      * value is expected.
1629      * Example: userspace sends 4500, ebt_among.c wants 4504.
1630      */
1631     if (unlikely(match->matchsize == -1))
1632         return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen);
1633     return xt_compat_match_offset(match);
1634 }
1635
1636 static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr,
1637                 unsigned int *size)
1638 {
1639     const struct xt_match *match = m->u.match;
1640     struct compat_ebt_entry_mwt __user *cm = *dstptr;
1641     int off = ebt_compat_match_offset(match, m->match_size);
1642     compat_uint_t msize = m->match_size - off;
1643
1644     if (WARN_ON(off >= m->match_size))
1645         return -EINVAL;
1646
1647     if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) ||
1648         put_user(match->revision, &cm->u.revision) ||
1649         put_user(msize, &cm->match_size))
1650         return -EFAULT;
1651
1652     if (match->compat_to_user) {
1653         if (match->compat_to_user(cm->data, m->data))
1654             return -EFAULT;
1655     } else {
1656         if (xt_data_to_user(cm->data, m->data, match->usersize, msize,
1657                     COMPAT_XT_ALIGN(msize)))
1658             return -EFAULT;
1659     }
1660
1661     *size -= ebt_compat_entry_padsize() + off;
1662     *dstptr = cm->data;
1663     *dstptr += msize;
1664     return 0;
1665 }
1666
1667 static int compat_target_to_user(struct ebt_entry_target *t,
1668                  void __user **dstptr,
1669                  unsigned int *size)
1670 {
1671     const struct xt_target *target = t->u.target;
1672     struct compat_ebt_entry_mwt __user *cm = *dstptr;
1673     int off = xt_compat_target_offset(target);
1674     compat_uint_t tsize = t->target_size - off;
1675
1676     if (WARN_ON(off >= t->target_size))
1677         return -EINVAL;
1678
1679     if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) ||
1680         put_user(target->revision, &cm->u.revision) ||
1681         put_user(tsize, &cm->match_size))
1682         return -EFAULT;
1683
1684     if (target->compat_to_user) {
1685         if (target->compat_to_user(cm->data, t->data))
1686             return -EFAULT;
1687     } else {
1688         if (xt_data_to_user(cm->data, t->data, target->usersize, tsize,
1689                     COMPAT_XT_ALIGN(tsize)))
1690             return -EFAULT;
1691     }
1692
1693     *size -= ebt_compat_entry_padsize() + off;
1694     *dstptr = cm->data;
1695     *dstptr += tsize;
1696     return 0;
1697 }
1698
1699 static int compat_watcher_to_user(struct ebt_entry_watcher *w,
1700                   void __user **dstptr,
1701                   unsigned int *size)
1702 {
1703     return compat_target_to_user((struct ebt_entry_target *)w,
1704                             dstptr, size);
1705 }
1706
1707 static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr,
1708                 unsigned int *size)
1709 {
1710     struct ebt_entry_target *t;
1711     struct ebt_entry __user *ce;
1712     u32 watchers_offset, target_offset, next_offset;
1713     compat_uint_t origsize;
1714     int ret;
1715
1716     if (e->bitmask == 0) {
1717         if (*size < sizeof(struct ebt_entries))
1718             return -EINVAL;
1719         if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries)))
1720             return -EFAULT;
1721
1722         *dstptr += sizeof(struct ebt_entries);
1723         *size -= sizeof(struct ebt_entries);
1724         return 0;
1725     }
1726
1727     if (*size < sizeof(*ce))
1728         return -EINVAL;
1729
1730     ce = *dstptr;
1731     if (copy_to_user(ce, e, sizeof(*ce)))
1732         return -EFAULT;
1733
1734     origsize = *size;
1735     *dstptr += sizeof(*ce);
1736
1737     ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size);
1738     if (ret)
1739         return ret;
1740     watchers_offset = e->watchers_offset - (origsize - *size);
1741
1742     ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size);
1743     if (ret)
1744         return ret;
1745     target_offset = e->target_offset - (origsize - *size);
1746
1747     t = ebt_get_target(e);
1748
1749     ret = compat_target_to_user(t, dstptr, size);
1750     if (ret)
1751         return ret;
1752     next_offset = e->next_offset - (origsize - *size);
1753
1754     if (put_user(watchers_offset, &ce->watchers_offset) ||
1755         put_user(target_offset, &ce->target_offset) ||
1756         put_user(next_offset, &ce->next_offset))
1757         return -EFAULT;
1758
1759     *size -= sizeof(*ce);
1760     return 0;
1761 }
1762
1763 static int compat_calc_match(struct ebt_entry_match *m, int *off)
1764 {
1765     *off += ebt_compat_match_offset(m->u.match, m->match_size);
1766     *off += ebt_compat_entry_padsize();
1767     return 0;
1768 }
1769
1770 static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off)
1771 {
1772     *off += xt_compat_target_offset(w->u.watcher);
1773     *off += ebt_compat_entry_padsize();
1774     return 0;
1775 }
1776
1777 static int compat_calc_entry(const struct ebt_entry *e,
1778                  const struct ebt_table_info *info,
1779                  const void *base,
1780                  struct compat_ebt_replace *newinfo)
1781 {
1782     const struct ebt_entry_target *t;
1783     unsigned int entry_offset;
1784     int off, ret, i;
1785
1786     if (e->bitmask == 0)
1787         return 0;
1788
1789     off = 0;
1790     entry_offset = (void *)e - base;
1791
1792     EBT_MATCH_ITERATE(e, compat_calc_match, &off);
1793     EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off);
1794
1795     t = ebt_get_target_c(e);
1796
1797     off += xt_compat_target_offset(t->u.target);
1798     off += ebt_compat_entry_padsize();
1799
1800     newinfo->entries_size -= off;
1801
1802     ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off);
1803     if (ret)
1804         return ret;
1805
1806     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
1807         const void *hookptr = info->hook_entry[i];
1808         if (info->hook_entry[i] &&
1809             (e < (struct ebt_entry *)(base - hookptr))) {
1810             newinfo->hook_entry[i] -= off;
1811             pr_debug("0x%08X -> 0x%08X\n",
1812                     newinfo->hook_entry[i] + off,
1813                     newinfo->hook_entry[i]);
1814         }
1815     }
1816
1817     return 0;
1818 }
1819
1820 static int ebt_compat_init_offsets(unsigned int number)
1821 {
1822     if (number > INT_MAX)
1823         return -EINVAL;
1824
1825     /* also count the base chain policies */
1826     number += NF_BR_NUMHOOKS;
1827
1828     return xt_compat_init_offsets(NFPROTO_BRIDGE, number);
1829 }
1830
1831 static int compat_table_info(const struct ebt_table_info *info,
1832                  struct compat_ebt_replace *newinfo)
1833 {
1834     unsigned int size = info->entries_size;
1835     const void *entries = info->entries;
1836     int ret;
1837
1838     newinfo->entries_size = size;
1839     ret = ebt_compat_init_offsets(info->nentries);
1840     if (ret)
1841         return ret;
1842
1843     return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info,
1844                             entries, newinfo);
1845 }
1846
1847 static int compat_copy_everything_to_user(struct ebt_table *t,
1848                       void __user *user, int *len, int cmd)
1849 {
1850     struct compat_ebt_replace repl, tmp;
1851     struct ebt_counter *oldcounters;
1852     struct ebt_table_info tinfo;
1853     int ret;
1854     void __user *pos;
1855
1856     memset(&tinfo, 0, sizeof(tinfo));
1857
1858     if (cmd == EBT_SO_GET_ENTRIES) {
1859         tinfo.entries_size = t->private->entries_size;
1860         tinfo.nentries = t->private->nentries;
1861         tinfo.entries = t->private->entries;
1862         oldcounters = t->private->counters;
1863     } else {
1864         tinfo.entries_size = t->table->entries_size;
1865         tinfo.nentries = t->table->nentries;
1866         tinfo.entries = t->table->entries;
1867         oldcounters = t->table->counters;
1868     }
1869
1870     if (copy_from_user(&tmp, user, sizeof(tmp)))
1871         return -EFAULT;
1872
1873     if (tmp.nentries != tinfo.nentries ||
1874        (tmp.num_counters && tmp.num_counters != tinfo.nentries))
1875         return -EINVAL;
1876
1877     memcpy(&repl, &tmp, sizeof(repl));
1878     if (cmd == EBT_SO_GET_ENTRIES)
1879         ret = compat_table_info(t->private, &repl);
1880     else
1881         ret = compat_table_info(&tinfo, &repl);
1882     if (ret)
1883         return ret;
1884
1885     if (*len != sizeof(tmp) + repl.entries_size +
1886        (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) {
1887         pr_err("wrong size: *len %d, entries_size %u, replsz %d\n",
1888                 *len, tinfo.entries_size, repl.entries_size);
1889         return -EINVAL;
1890     }
1891
1892     /* userspace might not need the counters */
1893     ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters),
1894                     tmp.num_counters, tinfo.nentries);
1895     if (ret)
1896         return ret;
1897
1898     pos = compat_ptr(tmp.entries);
1899     return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size,
1900             compat_copy_entry_to_user, &pos, &tmp.entries_size);
1901 }
1902
1903 struct ebt_entries_buf_state {
1904     char *buf_kern_start;   /* kernel buffer to copy (translated) data to */
1905     u32 buf_kern_len;   /* total size of kernel buffer */
1906     u32 buf_kern_offset;    /* amount of data copied so far */
1907     u32 buf_user_offset;    /* read position in userspace buffer */
1908 };
1909
1910 static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz)
1911 {
1912     state->buf_kern_offset += sz;
1913     return state->buf_kern_offset >= sz ? 0 : -EINVAL;
1914 }
1915
1916 static int ebt_buf_add(struct ebt_entries_buf_state *state,
1917                const void *data, unsigned int sz)
1918 {
1919     if (state->buf_kern_start == NULL)
1920         goto count_only;
1921
1922     if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len))
1923         return -EINVAL;
1924
1925     memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz);
1926
1927  count_only:
1928     state->buf_user_offset += sz;
1929     return ebt_buf_count(state, sz);
1930 }
1931
1932 static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz)
1933 {
1934     char *b = state->buf_kern_start;
1935
1936     if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len))
1937         return -EINVAL;
1938
1939     if (b != NULL && sz > 0)
1940         memset(b + state->buf_kern_offset, 0, sz);
1941     /* do not adjust ->buf_user_offset here, we added kernel-side padding */
1942     return ebt_buf_count(state, sz);
1943 }
1944
1945 enum compat_mwt {
1946     EBT_COMPAT_MATCH,
1947     EBT_COMPAT_WATCHER,
1948     EBT_COMPAT_TARGET,
1949 };
1950
1951 static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt,
1952                 enum compat_mwt compat_mwt,
1953                 struct ebt_entries_buf_state *state,
1954                 const unsigned char *base)
1955 {
1956     char name[EBT_EXTENSION_MAXNAMELEN];
1957     struct xt_match *match;
1958     struct xt_target *wt;
1959     void *dst = NULL;
1960     int off, pad = 0;
1961     unsigned int size_kern, match_size = mwt->match_size;
1962
1963     if (strscpy(name, mwt->u.name, sizeof(name)) < 0)
1964         return -EINVAL;
1965
1966     if (state->buf_kern_start)
1967         dst = state->buf_kern_start + state->buf_kern_offset;
1968
1969     switch (compat_mwt) {
1970     case EBT_COMPAT_MATCH:
1971         match = xt_request_find_match(NFPROTO_BRIDGE, name,
1972                           mwt->u.revision);
1973         if (IS_ERR(match))
1974             return PTR_ERR(match);
1975
1976         off = ebt_compat_match_offset(match, match_size);
1977         if (dst) {
1978             if (match->compat_from_user)
1979                 match->compat_from_user(dst, mwt->data);
1980             else
1981                 memcpy(dst, mwt->data, match_size);
1982         }
1983
1984         size_kern = match->matchsize;
1985         if (unlikely(size_kern == -1))
1986             size_kern = match_size;
1987         module_put(match->me);
1988         break;
1989     case EBT_COMPAT_WATCHER:
1990     case EBT_COMPAT_TARGET:
1991         wt = xt_request_find_target(NFPROTO_BRIDGE, name,
1992                         mwt->u.revision);
1993         if (IS_ERR(wt))
1994             return PTR_ERR(wt);
1995         off = xt_compat_target_offset(wt);
1996
1997         if (dst) {
1998             if (wt->compat_from_user)
1999                 wt->compat_from_user(dst, mwt->data);
2000             else
2001                 memcpy(dst, mwt->data, match_size);
2002         }
2003
2004         size_kern = wt->targetsize;
2005         module_put(wt->me);
2006         break;
2007
2008     default:
2009         return -EINVAL;
2010     }
2011
2012     state->buf_kern_offset += match_size + off;
2013     state->buf_user_offset += match_size;
2014     pad = XT_ALIGN(size_kern) - size_kern;
2015
2016     if (pad > 0 && dst) {
2017         if (WARN_ON(state->buf_kern_len <= pad))
2018             return -EINVAL;
2019         if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad))
2020             return -EINVAL;
2021         memset(dst + size_kern, 0, pad);
2022     }
2023     return off + match_size;
2024 }
2025
2026 /* return size of all matches, watchers or target, including necessary
2027  * alignment and padding.
2028  */
2029 static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32,
2030             unsigned int size_left, enum compat_mwt type,
2031             struct ebt_entries_buf_state *state, const void *base)
2032 {
2033     const char *buf = (const char *)match32;
2034     int growth = 0;
2035
2036     if (size_left == 0)
2037         return 0;
2038
2039     do {
2040         struct ebt_entry_match *match_kern;
2041         int ret;
2042
2043         if (size_left < sizeof(*match32))
2044             return -EINVAL;
2045
2046         match_kern = (struct ebt_entry_match *) state->buf_kern_start;
2047         if (match_kern) {
2048             char *tmp;
2049             tmp = state->buf_kern_start + state->buf_kern_offset;
2050             match_kern = (struct ebt_entry_match *) tmp;
2051         }
2052         ret = ebt_buf_add(state, buf, sizeof(*match32));
2053         if (ret < 0)
2054             return ret;
2055         size_left -= sizeof(*match32);
2056
2057         /* add padding before match->data (if any) */
2058         ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize());
2059         if (ret < 0)
2060             return ret;
2061
2062         if (match32->match_size > size_left)
2063             return -EINVAL;
2064
2065         size_left -= match32->match_size;
2066
2067         ret = compat_mtw_from_user(match32, type, state, base);
2068         if (ret < 0)
2069             return ret;
2070
2071         if (WARN_ON(ret < match32->match_size))
2072             return -EINVAL;
2073         growth += ret - match32->match_size;
2074         growth += ebt_compat_entry_padsize();
2075
2076         buf += sizeof(*match32);
2077         buf += match32->match_size;
2078
2079         if (match_kern)
2080             match_kern->match_size = ret;
2081
2082         match32 = (struct compat_ebt_entry_mwt *) buf;
2083     } while (size_left);
2084
2085     return growth;
2086 }
2087
2088 /* called for all ebt_entry structures. */
2089 static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base,
2090               unsigned int *total,
2091               struct ebt_entries_buf_state *state)
2092 {
2093     unsigned int i, j, startoff, next_expected_off, new_offset = 0;
2094     /* stores match/watchers/targets & offset of next struct ebt_entry: */
2095     unsigned int offsets[4];
2096     unsigned int *offsets_update = NULL;
2097     int ret;
2098     char *buf_start;
2099
2100     if (*total < sizeof(struct ebt_entries))
2101         return -EINVAL;
2102
2103     if (!entry->bitmask) {
2104         *total -= sizeof(struct ebt_entries);
2105         return ebt_buf_add(state, entry, sizeof(struct ebt_entries));
2106     }
2107     if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry))
2108         return -EINVAL;
2109
2110     startoff = state->buf_user_offset;
2111     /* pull in most part of ebt_entry, it does not need to be changed. */
2112     ret = ebt_buf_add(state, entry,
2113             offsetof(struct ebt_entry, watchers_offset));
2114     if (ret < 0)
2115         return ret;
2116
2117     offsets[0] = sizeof(struct ebt_entry); /* matches come first */
2118     memcpy(&offsets[1], &entry->watchers_offset,
2119             sizeof(offsets) - sizeof(offsets[0]));
2120
2121     if (state->buf_kern_start) {
2122         buf_start = state->buf_kern_start + state->buf_kern_offset;
2123         offsets_update = (unsigned int *) buf_start;
2124     }
2125     ret = ebt_buf_add(state, &offsets[1],
2126             sizeof(offsets) - sizeof(offsets[0]));
2127     if (ret < 0)
2128         return ret;
2129     buf_start = (char *) entry;
2130     /* 0: matches offset, always follows ebt_entry.
2131      * 1: watchers offset, from ebt_entry structure
2132      * 2: target offset, from ebt_entry structure
2133      * 3: next ebt_entry offset, from ebt_entry structure
2134      *
2135      * offsets are relative to beginning of struct ebt_entry (i.e., 0).
2136      */
2137     for (i = 0; i < 4 ; ++i) {
2138         if (offsets[i] > *total)
2139             return -EINVAL;
2140
2141         if (i < 3 && offsets[i] == *total)
2142             return -EINVAL;
2143
2144         if (i == 0)
2145             continue;
2146         if (offsets[i-1] > offsets[i])
2147             return -EINVAL;
2148     }
2149
2150     for (i = 0, j = 1 ; j < 4 ; j++, i++) {
2151         struct compat_ebt_entry_mwt *match32;
2152         unsigned int size;
2153         char *buf = buf_start + offsets[i];
2154
2155         if (offsets[i] > offsets[j])
2156             return -EINVAL;
2157
2158         match32 = (struct compat_ebt_entry_mwt *) buf;
2159         size = offsets[j] - offsets[i];
2160         ret = ebt_size_mwt(match32, size, i, state, base);
2161         if (ret < 0)
2162             return ret;
2163         new_offset += ret;
2164         if (offsets_update && new_offset) {
2165             pr_debug("change offset %d to %d\n",
2166                 offsets_update[i], offsets[j] + new_offset);
2167             offsets_update[i] = offsets[j] + new_offset;
2168         }
2169     }
2170
2171     if (state->buf_kern_start == NULL) {
2172         unsigned int offset = buf_start - (char *) base;
2173
2174         ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset);
2175         if (ret < 0)
2176             return ret;
2177     }
2178
2179     next_expected_off = state->buf_user_offset - startoff;
2180     if (next_expected_off != entry->next_offset)
2181         return -EINVAL;
2182
2183     if (*total < entry->next_offset)
2184         return -EINVAL;
2185     *total -= entry->next_offset;
2186     return 0;
2187 }
2188
2189 /* repl->entries_size is the size of the ebt_entry blob in userspace.
2190  * It might need more memory when copied to a 64 bit kernel in case
2191  * userspace is 32-bit. So, first task: find out how much memory is needed.
2192  *
2193  * Called before validation is performed.
2194  */
2195 static int compat_copy_entries(unsigned char *data, unsigned int size_user,
2196                 struct ebt_entries_buf_state *state)
2197 {
2198     unsigned int size_remaining = size_user;
2199     int ret;
2200
2201     ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data,
2202                     &size_remaining, state);
2203     if (ret < 0)
2204         return ret;
2205
2206     if (size_remaining)
2207         return -EINVAL;
2208
2209     return state->buf_kern_offset;
2210 }
2211
2212
2213 static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl,
2214                          sockptr_t arg, unsigned int len)
2215 {
2216     struct compat_ebt_replace tmp;
2217     int i;
2218
2219     if (len < sizeof(tmp))
2220         return -EINVAL;
2221
2222     if (copy_from_sockptr(&tmp, arg, sizeof(tmp)))
2223         return -EFAULT;
2224
2225     if (len != sizeof(tmp) + tmp.entries_size)
2226         return -EINVAL;
2227
2228     if (tmp.entries_size == 0)
2229         return -EINVAL;
2230
2231     if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) /
2232             NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter))
2233         return -ENOMEM;
2234     if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
2235         return -ENOMEM;
2236
2237     memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
2238
2239     /* starting with hook_entry, 32 vs. 64 bit structures are different */
2240     for (i = 0; i < NF_BR_NUMHOOKS; i++)
2241         repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]);
2242
2243     repl->num_counters = tmp.num_counters;
2244     repl->counters = compat_ptr(tmp.counters);
2245     repl->entries = compat_ptr(tmp.entries);
2246     return 0;
2247 }
2248
2249 static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
2250 {
2251     int ret, i, countersize, size64;
2252     struct ebt_table_info *newinfo;
2253     struct ebt_replace tmp;
2254     struct ebt_entries_buf_state state;
2255     void *entries_tmp;
2256
2257     ret = compat_copy_ebt_replace_from_user(&tmp, arg, len);
2258     if (ret) {
2259         /* try real handler in case userland supplied needed padding */
2260         if (ret == -EINVAL && do_replace(net, arg, len) == 0)
2261             ret = 0;
2262         return ret;
2263     }
2264
2265     countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
2266     newinfo = vmalloc(sizeof(*newinfo) + countersize);
2267     if (!newinfo)
2268         return -ENOMEM;
2269
2270     if (countersize)
2271         memset(newinfo->counters, 0, countersize);
2272
2273     memset(&state, 0, sizeof(state));
2274
2275     newinfo->entries = vmalloc(tmp.entries_size);
2276     if (!newinfo->entries) {
2277         ret = -ENOMEM;
2278         goto free_newinfo;
2279     }
2280     if (copy_from_user(
2281        newinfo->entries, tmp.entries, tmp.entries_size) != 0) {
2282         ret = -EFAULT;
2283         goto free_entries;
2284     }
2285
2286     entries_tmp = newinfo->entries;
2287
2288     xt_compat_lock(NFPROTO_BRIDGE);
2289
2290     ret = ebt_compat_init_offsets(tmp.nentries);
2291     if (ret < 0)
2292         goto out_unlock;
2293
2294     ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2295     if (ret < 0)
2296         goto out_unlock;
2297
2298     pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n",
2299         tmp.entries_size, state.buf_kern_offset, state.buf_user_offset,
2300         xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size));
2301
2302     size64 = ret;
2303     newinfo->entries = vmalloc(size64);
2304     if (!newinfo->entries) {
2305         vfree(entries_tmp);
2306         ret = -ENOMEM;
2307         goto out_unlock;
2308     }
2309
2310     memset(&state, 0, sizeof(state));
2311     state.buf_kern_start = newinfo->entries;
2312     state.buf_kern_len = size64;
2313
2314     ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
2315     if (WARN_ON(ret < 0)) {
2316         vfree(entries_tmp);
2317         goto out_unlock;
2318     }
2319
2320     vfree(entries_tmp);
2321     tmp.entries_size = size64;
2322
2323     for (i = 0; i < NF_BR_NUMHOOKS; i++) {
2324         char __user *usrptr;
2325         if (tmp.hook_entry[i]) {
2326             unsigned int delta;
2327             usrptr = (char __user *) tmp.hook_entry[i];
2328             delta = usrptr - tmp.entries;
2329             usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta);
2330             tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr;
2331         }
2332     }
2333
2334     xt_compat_flush_offsets(NFPROTO_BRIDGE);
2335     xt_compat_unlock(NFPROTO_BRIDGE);
2336
2337     ret = do_replace_finish(net, &tmp, newinfo);
2338     if (ret == 0)
2339         return ret;
2340 free_entries:
2341     vfree(newinfo->entries);
2342 free_newinfo:
2343     vfree(newinfo);
2344     return ret;
2345 out_unlock:
2346     xt_compat_flush_offsets(NFPROTO_BRIDGE);
2347     xt_compat_unlock(NFPROTO_BRIDGE);
2348     goto free_entries;
2349 }
2350
2351 static int compat_update_counters(struct net *net, sockptr_t arg,
2352                   unsigned int len)
2353 {
2354     struct compat_ebt_replace hlp;
2355
2356     if (copy_from_sockptr(&hlp, arg, sizeof(hlp)))
2357         return -EFAULT;
2358
2359     /* try real handler in case userland supplied needed padding */
2360     if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter))
2361         return update_counters(net, arg, len);
2362
2363     return do_update_counters(net, hlp.name, compat_ptr(hlp.counters),
2364                   hlp.num_counters, len);
2365 }
2366
2367 static int compat_do_ebt_get_ctl(struct sock *sk, int cmd,
2368         void __user *user, int *len)
2369 {
2370     int ret;
2371     struct compat_ebt_replace tmp;
2372     struct ebt_table *t;
2373     struct net *net = sock_net(sk);
2374
2375     if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) &&
2376         *len != sizeof(struct compat_ebt_replace))
2377         return -EINVAL;
2378
2379     if (copy_from_user(&tmp, user, sizeof(tmp)))
2380         return -EFAULT;
2381
2382     tmp.name[sizeof(tmp.name) - 1] = '\0';
2383
2384     t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2385     if (!t)
2386         return ret;
2387
2388     xt_compat_lock(NFPROTO_BRIDGE);
2389     switch (cmd) {
2390     case EBT_SO_GET_INFO:
2391         tmp.nentries = t->private->nentries;
2392         ret = compat_table_info(t->private, &tmp);
2393         if (ret)
2394             goto out;
2395         tmp.valid_hooks = t->valid_hooks;
2396
2397         if (copy_to_user(user, &tmp, *len) != 0) {
2398             ret = -EFAULT;
2399             break;
2400         }
2401         ret = 0;
2402         break;
2403     case EBT_SO_GET_INIT_INFO:
2404         tmp.nentries = t->table->nentries;
2405         tmp.entries_size = t->table->entries_size;
2406         tmp.valid_hooks = t->table->valid_hooks;
2407
2408         if (copy_to_user(user, &tmp, *len) != 0) {
2409             ret = -EFAULT;
2410             break;
2411         }
2412         ret = 0;
2413         break;
2414     case EBT_SO_GET_ENTRIES:
2415     case EBT_SO_GET_INIT_ENTRIES:
2416         /* try real handler first in case of userland-side padding.
2417          * in case we are dealing with an 'ordinary' 32 bit binary
2418          * without 64bit compatibility padding, this will fail right
2419          * after copy_from_user when the *len argument is validated.
2420          *
2421          * the compat_ variant needs to do one pass over the kernel
2422          * data set to adjust for size differences before it the check.
2423          */
2424         if (copy_everything_to_user(t, user, len, cmd) == 0)
2425             ret = 0;
2426         else
2427             ret = compat_copy_everything_to_user(t, user, len, cmd);
2428         break;
2429     default:
2430         ret = -EINVAL;
2431     }
2432  out:
2433     xt_compat_flush_offsets(NFPROTO_BRIDGE);
2434     xt_compat_unlock(NFPROTO_BRIDGE);
2435     mutex_unlock(&ebt_mutex);
2436     return ret;
2437 }
2438 #endif
2439
2440 static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
2441 {
2442     struct net *net = sock_net(sk);
2443     struct ebt_replace tmp;
2444     struct ebt_table *t;
2445     int ret;
2446
2447     if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2448         return -EPERM;
2449
2450 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2451     /* try real handler in case userland supplied needed padding */
2452     if (in_compat_syscall() &&
2453         ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) ||
2454          *len != sizeof(tmp)))
2455         return compat_do_ebt_get_ctl(sk, cmd, user, len);
2456 #endif
2457
2458     if (copy_from_user(&tmp, user, sizeof(tmp)))
2459         return -EFAULT;
2460
2461     tmp.name[sizeof(tmp.name) - 1] = '\0';
2462
2463     t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
2464     if (!t)
2465         return ret;
2466
2467     switch (cmd) {
2468     case EBT_SO_GET_INFO:
2469     case EBT_SO_GET_INIT_INFO:
2470         if (*len != sizeof(struct ebt_replace)) {
2471             ret = -EINVAL;
2472             mutex_unlock(&ebt_mutex);
2473             break;
2474         }
2475         if (cmd == EBT_SO_GET_INFO) {
2476             tmp.nentries = t->private->nentries;
2477             tmp.entries_size = t->private->entries_size;
2478             tmp.valid_hooks = t->valid_hooks;
2479         } else {
2480             tmp.nentries = t->table->nentries;
2481             tmp.entries_size = t->table->entries_size;
2482             tmp.valid_hooks = t->table->valid_hooks;
2483         }
2484         mutex_unlock(&ebt_mutex);
2485         if (copy_to_user(user, &tmp, *len) != 0) {
2486             ret = -EFAULT;
2487             break;
2488         }
2489         ret = 0;
2490         break;
2491
2492     case EBT_SO_GET_ENTRIES:
2493     case EBT_SO_GET_INIT_ENTRIES:
2494         ret = copy_everything_to_user(t, user, len, cmd);
2495         mutex_unlock(&ebt_mutex);
2496         break;
2497
2498     default:
2499         mutex_unlock(&ebt_mutex);
2500         ret = -EINVAL;
2501     }
2502
2503     return ret;
2504 }
2505
2506 static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg,
2507         unsigned int len)
2508 {
2509     struct net *net = sock_net(sk);
2510     int ret;
2511
2512     if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2513         return -EPERM;
2514
2515     switch (cmd) {
2516     case EBT_SO_SET_ENTRIES:
2517 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2518         if (in_compat_syscall())
2519             ret = compat_do_replace(net, arg, len);
2520         else
2521 #endif
2522             ret = do_replace(net, arg, len);
2523         break;
2524     case EBT_SO_SET_COUNTERS:
2525 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT
2526         if (in_compat_syscall())
2527             ret = compat_update_counters(net, arg, len);
2528         else
2529 #endif
2530             ret = update_counters(net, arg, len);
2531         break;
2532     default:
2533         ret = -EINVAL;
2534     }
2535     return ret;
2536 }
2537
2538 static struct nf_sockopt_ops ebt_sockopts = {
2539     .pf     = PF_INET,
2540     .set_optmin = EBT_BASE_CTL,
2541     .set_optmax = EBT_SO_SET_MAX + 1,
2542     .set        = do_ebt_set_ctl,
2543     .get_optmin = EBT_BASE_CTL,
2544     .get_optmax = EBT_SO_GET_MAX + 1,
2545     .get        = do_ebt_get_ctl,
2546     .owner      = THIS_MODULE,
2547 };
2548
2549 static int __net_init ebt_pernet_init(struct net *net)
2550 {
2551     struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id);
2552
2553     INIT_LIST_HEAD(&ebt_net->tables);
2554     return 0;
2555 }
2556
2557 static struct pernet_operations ebt_net_ops = {
2558     .init = ebt_pernet_init,
2559     .id   = &ebt_pernet_id,
2560     .size = sizeof(struct ebt_pernet),
2561 };
2562
2563 static int __init ebtables_init(void)
2564 {
2565     int ret;
2566
2567     ret = xt_register_target(&ebt_standard_target);
2568     if (ret < 0)
2569         return ret;
2570     ret = nf_register_sockopt(&ebt_sockopts);
2571     if (ret < 0) {
2572         xt_unregister_target(&ebt_standard_target);
2573         return ret;
2574     }
2575
2576     ret = register_pernet_subsys(&ebt_net_ops);
2577     if (ret < 0) {
2578         nf_unregister_sockopt(&ebt_sockopts);
2579         xt_unregister_target(&ebt_standard_target);
2580         return ret;
2581     }
2582
2583     return 0;
2584 }
2585
2586 static void ebtables_fini(void)
2587 {
2588     nf_unregister_sockopt(&ebt_sockopts);
2589     xt_unregister_target(&ebt_standard_target);
2590     unregister_pernet_subsys(&ebt_net_ops);
2591 }
2592
2593 EXPORT_SYMBOL(ebt_register_table);
2594 EXPORT_SYMBOL(ebt_unregister_table);
2595 EXPORT_SYMBOL(ebt_do_table);
2596 module_init(ebtables_init);
2597 module_exit(ebtables_fini);
2598 MODULE_LICENSE("GPL");