/* * ebtables * * Author: * Bart De Schuymer * * ebtables.c,v 2.0, July, 2002 * * This code is strongly inspired by the iptables code which is * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include /* needed for logical [in,out]-dev filtering */ #include "../br_private.h" #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\ "report to author: "format, ## args) /* #define BUGPRINT(format, args...) */ /* Each cpu has its own set of counters, so there is no need for write_lock in * the softirq * For reading or updating the counters, the user context needs to * get a write_lock */ /* The size of each set of counters is altered to get cache alignment */ #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter))) #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \ COUNTER_OFFSET(n) * cpu)) static DEFINE_MUTEX(ebt_mutex); #ifdef CONFIG_COMPAT static void ebt_standard_compat_from_user(void *dst, const void *src) { int v = *(compat_int_t *)src; if (v >= 0) v += xt_compat_calc_jump(NFPROTO_BRIDGE, v); memcpy(dst, &v, sizeof(v)); } static int ebt_standard_compat_to_user(void __user *dst, const void *src) { compat_int_t cv = *(int *)src; if (cv >= 0) cv -= xt_compat_calc_jump(NFPROTO_BRIDGE, cv); return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; } #endif static struct xt_target ebt_standard_target = { .name = "standard", .revision = 0, .family = NFPROTO_BRIDGE, .targetsize = sizeof(int), #ifdef CONFIG_COMPAT .compatsize = sizeof(compat_int_t), .compat_from_user = ebt_standard_compat_from_user, .compat_to_user = ebt_standard_compat_to_user, #endif }; static inline int ebt_do_watcher(const struct ebt_entry_watcher *w, struct sk_buff *skb, struct xt_action_param *par) { par->target = w->u.watcher; par->targinfo = w->data; w->u.watcher->target(skb, par); /* watchers don't give a verdict */ return 0; } static inline int ebt_do_match(struct ebt_entry_match *m, const struct sk_buff *skb, struct xt_action_param *par) { par->match = m->u.match; par->matchinfo = m->data; return !m->u.match->match(skb, par); } static inline int ebt_dev_check(const char *entry, const struct net_device *device) { int i = 0; const char *devname; if (*entry == '\0') return 0; if (!device) return 1; devname = device->name; /* 1 is the wildcard token */ while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i]) i++; return devname[i] != entry[i] && entry[i] != 1; } /* process standard matches */ static inline int ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb, const struct net_device *in, const struct net_device *out) { const struct ethhdr *h = eth_hdr(skb); const struct net_bridge_port *p; __be16 ethproto; if (skb_vlan_tag_present(skb)) ethproto = htons(ETH_P_8021Q); else ethproto = h->h_proto; if (e->bitmask & EBT_802_3) { if (NF_INVF(e, EBT_IPROTO, eth_proto_is_802_3(ethproto))) return 1; } else if (!(e->bitmask & EBT_NOPROTO) && NF_INVF(e, EBT_IPROTO, e->ethproto != ethproto)) return 1; if (NF_INVF(e, EBT_IIN, ebt_dev_check(e->in, in))) return 1; if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out))) return 1; /* rcu_read_lock()ed by nf_hook_thresh */ if (in && (p = br_port_get_rcu(in)) != NULL && NF_INVF(e, EBT_ILOGICALIN, ebt_dev_check(e->logical_in, p->br->dev))) return 1; if (out && (p = br_port_get_rcu(out)) != NULL && NF_INVF(e, EBT_ILOGICALOUT, ebt_dev_check(e->logical_out, p->br->dev))) return 1; if (e->bitmask & EBT_SOURCEMAC) { if (NF_INVF(e, EBT_ISOURCE, !ether_addr_equal_masked(h->h_source, e->sourcemac, e->sourcemsk))) return 1; } if (e->bitmask & EBT_DESTMAC) { if (NF_INVF(e, EBT_IDEST, !ether_addr_equal_masked(h->h_dest, e->destmac, e->destmsk))) return 1; } return 0; } static inline struct ebt_entry *ebt_next_entry(const struct ebt_entry *entry) { return (void *)entry + entry->next_offset; } static inline const struct ebt_entry_target * ebt_get_target_c(const struct ebt_entry *e) { return ebt_get_target((struct ebt_entry *)e); } /* Do some firewalling */ unsigned int ebt_do_table(struct sk_buff *skb, const struct nf_hook_state *state, struct ebt_table *table) { unsigned int hook = state->hook; int i, nentries; struct ebt_entry *point; struct ebt_counter *counter_base, *cb_base; const struct ebt_entry_target *t; int verdict, sp = 0; struct ebt_chainstack *cs; struct ebt_entries *chaininfo; const char *base; const struct ebt_table_info *private; struct xt_action_param acpar; acpar.state = state; acpar.hotdrop = false; read_lock_bh(&table->lock); private = table->private; cb_base = COUNTER_BASE(private->counters, private->nentries, smp_processor_id()); if (private->chainstack) cs = private->chainstack[smp_processor_id()]; else cs = NULL; chaininfo = private->hook_entry[hook]; nentries = private->hook_entry[hook]->nentries; point = (struct ebt_entry *)(private->hook_entry[hook]->data); counter_base = cb_base + private->hook_entry[hook]->counter_offset; /* base for chain jumps */ base = private->entries; i = 0; while (i < nentries) { if (ebt_basic_match(point, skb, state->in, state->out)) goto letscontinue; if (EBT_MATCH_ITERATE(point, ebt_do_match, skb, &acpar) != 0) goto letscontinue; if (acpar.hotdrop) { read_unlock_bh(&table->lock); return NF_DROP; } ADD_COUNTER(*(counter_base + i), 1, skb->len); /* these should only watch: not modify, nor tell us * what to do with the packet */ EBT_WATCHER_ITERATE(point, ebt_do_watcher, skb, &acpar); t = ebt_get_target_c(point); /* standard target */ if (!t->u.target->target) verdict = ((struct ebt_standard_target *)t)->verdict; else { acpar.target = t->u.target; acpar.targinfo = t->data; verdict = t->u.target->target(skb, &acpar); } if (verdict == EBT_ACCEPT) { read_unlock_bh(&table->lock); return NF_ACCEPT; } if (verdict == EBT_DROP) { read_unlock_bh(&table->lock); return NF_DROP; } if (verdict == EBT_RETURN) { letsreturn: if (WARN(sp == 0, "RETURN on base chain")) { /* act like this is EBT_CONTINUE */ goto letscontinue; } sp--; /* put all the local variables right */ i = cs[sp].n; chaininfo = cs[sp].chaininfo; nentries = chaininfo->nentries; point = cs[sp].e; counter_base = cb_base + chaininfo->counter_offset; continue; } if (verdict == EBT_CONTINUE) goto letscontinue; if (WARN(verdict < 0, "bogus standard verdict\n")) { read_unlock_bh(&table->lock); return NF_DROP; } /* jump to a udc */ cs[sp].n = i + 1; cs[sp].chaininfo = chaininfo; cs[sp].e = ebt_next_entry(point); i = 0; chaininfo = (struct ebt_entries *) (base + verdict); if (WARN(chaininfo->distinguisher, "jump to non-chain\n")) { read_unlock_bh(&table->lock); return NF_DROP; } nentries = chaininfo->nentries; point = (struct ebt_entry *)chaininfo->data; counter_base = cb_base + chaininfo->counter_offset; sp++; continue; letscontinue: point = ebt_next_entry(point); i++; } /* I actually like this :) */ if (chaininfo->policy == EBT_RETURN) goto letsreturn; if (chaininfo->policy == EBT_ACCEPT) { read_unlock_bh(&table->lock); return NF_ACCEPT; } read_unlock_bh(&table->lock); return NF_DROP; } /* If it succeeds, returns element and locks mutex */ static inline void * find_inlist_lock_noload(struct list_head *head, const char *name, int *error, struct mutex *mutex) { struct { struct list_head list; char name[EBT_FUNCTION_MAXNAMELEN]; } *e; mutex_lock(mutex); list_for_each_entry(e, head, list) { if (strcmp(e->name, name) == 0) return e; } *error = -ENOENT; mutex_unlock(mutex); return NULL; } static void * find_inlist_lock(struct list_head *head, const char *name, const char *prefix, int *error, struct mutex *mutex) { return try_then_request_module( find_inlist_lock_noload(head, name, error, mutex), "%s%s", prefix, name); } static inline struct ebt_table * find_table_lock(struct net *net, const char *name, int *error, struct mutex *mutex) { return find_inlist_lock(&net->xt.tables[NFPROTO_BRIDGE], name, "ebtable_", error, mutex); } static inline void ebt_free_table_info(struct ebt_table_info *info) { int i; if (info->chainstack) { for_each_possible_cpu(i) vfree(info->chainstack[i]); vfree(info->chainstack); } } static inline int ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, unsigned int *cnt) { const struct ebt_entry *e = par->entryinfo; struct xt_match *match; size_t left = ((char *)e + e->watchers_offset) - (char *)m; int ret; if (left < sizeof(struct ebt_entry_match) || left - sizeof(struct ebt_entry_match) < m->match_size) return -EINVAL; match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { if (!IS_ERR(match)) module_put(match->me); request_module("ebt_%s", m->u.name); match = xt_find_match(NFPROTO_BRIDGE, m->u.name, m->u.revision); } if (IS_ERR(match)) return PTR_ERR(match); m->u.match = match; par->match = match; par->matchinfo = m->data; ret = xt_check_match(par, m->match_size, e->ethproto, e->invflags & EBT_IPROTO); if (ret < 0) { module_put(match->me); return ret; } (*cnt)++; return 0; } static inline int ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par, unsigned int *cnt) { const struct ebt_entry *e = par->entryinfo; struct xt_target *watcher; size_t left = ((char *)e + e->target_offset) - (char *)w; int ret; if (left < sizeof(struct ebt_entry_watcher) || left - sizeof(struct ebt_entry_watcher) < w->watcher_size) return -EINVAL; watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); if (IS_ERR(watcher)) return PTR_ERR(watcher); if (watcher->family != NFPROTO_BRIDGE) { module_put(watcher->me); return -ENOENT; } w->u.watcher = watcher; par->target = watcher; par->targinfo = w->data; ret = xt_check_target(par, w->watcher_size, e->ethproto, e->invflags & EBT_IPROTO); if (ret < 0) { module_put(watcher->me); return ret; } (*cnt)++; return 0; } static int ebt_verify_pointers(const struct ebt_replace *repl, struct ebt_table_info *newinfo) { unsigned int limit = repl->entries_size; unsigned int valid_hooks = repl->valid_hooks; unsigned int offset = 0; int i; for (i = 0; i < NF_BR_NUMHOOKS; i++) newinfo->hook_entry[i] = NULL; newinfo->entries_size = repl->entries_size; newinfo->nentries = repl->nentries; while (offset < limit) { size_t left = limit - offset; struct ebt_entry *e = (void *)newinfo->entries + offset; if (left < sizeof(unsigned int)) break; for (i = 0; i < NF_BR_NUMHOOKS; i++) { if ((valid_hooks & (1 << i)) == 0) continue; if ((char __user *)repl->hook_entry[i] == repl->entries + offset) break; } if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { if (e->bitmask != 0) { /* we make userspace set this right, * so there is no misunderstanding */ BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set " "in distinguisher\n"); return -EINVAL; } if (i != NF_BR_NUMHOOKS) newinfo->hook_entry[i] = (struct ebt_entries *)e; if (left < sizeof(struct ebt_entries)) break; offset += sizeof(struct ebt_entries); } else { if (left < sizeof(struct ebt_entry)) break; if (left < e->next_offset) break; if (e->next_offset < sizeof(struct ebt_entry)) return -EINVAL; offset += e->next_offset; } } if (offset != limit) { BUGPRINT("entries_size too small\n"); return -EINVAL; } /* check if all valid hooks have a chain */ for (i = 0; i < NF_BR_NUMHOOKS; i++) { if (!newinfo->hook_entry[i] && (valid_hooks & (1 << i))) { BUGPRINT("Valid hook without chain\n"); return -EINVAL; } } return 0; } /* this one is very careful, as it is the first function * to parse the userspace data */ static inline int ebt_check_entry_size_and_hooks(const struct ebt_entry *e, const struct ebt_table_info *newinfo, unsigned int *n, unsigned int *cnt, unsigned int *totalcnt, unsigned int *udc_cnt) { int i; for (i = 0; i < NF_BR_NUMHOOKS; i++) { if ((void *)e == (void *)newinfo->hook_entry[i]) break; } /* beginning of a new chain * if i == NF_BR_NUMHOOKS it must be a user defined chain */ if (i != NF_BR_NUMHOOKS || !e->bitmask) { /* this checks if the previous chain has as many entries * as it said it has */ if (*n != *cnt) { BUGPRINT("nentries does not equal the nr of entries " "in the chain\n"); return -EINVAL; } if (((struct ebt_entries *)e)->policy != EBT_DROP && ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { /* only RETURN from udc */ if (i != NF_BR_NUMHOOKS || ((struct ebt_entries *)e)->policy != EBT_RETURN) { BUGPRINT("bad policy\n"); return -EINVAL; } } if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ (*udc_cnt)++; if (((struct ebt_entries *)e)->counter_offset != *totalcnt) { BUGPRINT("counter_offset != totalcnt"); return -EINVAL; } *n = ((struct ebt_entries *)e)->nentries; *cnt = 0; return 0; } /* a plain old entry, heh */ if (sizeof(struct ebt_entry) > e->watchers_offset || e->watchers_offset > e->target_offset || e->target_offset >= e->next_offset) { BUGPRINT("entry offsets not in right order\n"); return -EINVAL; } /* this is not checked anywhere else */ if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) { BUGPRINT("target size too small\n"); return -EINVAL; } (*cnt)++; (*totalcnt)++; return 0; } struct ebt_cl_stack { struct ebt_chainstack cs; int from; unsigned int hookmask; }; /* We need these positions to check that the jumps to a different part of the * entries is a jump to the beginning of a new chain. */ static inline int ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, unsigned int *n, struct ebt_cl_stack *udc) { int i; /* we're only interested in chain starts */ if (e->bitmask) return 0; for (i = 0; i < NF_BR_NUMHOOKS; i++) { if (newinfo->hook_entry[i] == (struct ebt_entries *)e) break; } /* only care about udc */ if (i != NF_BR_NUMHOOKS) return 0; udc[*n].cs.chaininfo = (struct ebt_entries *)e; /* these initialisations are depended on later in check_chainloops() */ udc[*n].cs.n = 0; udc[*n].hookmask = 0; (*n)++; return 0; } static inline int ebt_cleanup_match(struct ebt_entry_match *m, struct net *net, unsigned int *i) { struct xt_mtdtor_param par; if (i && (*i)-- == 0) return 1; par.net = net; par.match = m->u.match; par.matchinfo = m->data; par.family = NFPROTO_BRIDGE; if (par.match->destroy != NULL) par.match->destroy(&par); module_put(par.match->me); return 0; } static inline int ebt_cleanup_watcher(struct ebt_entry_watcher *w, struct net *net, unsigned int *i) { struct xt_tgdtor_param par; if (i && (*i)-- == 0) return 1; par.net = net; par.target = w->u.watcher; par.targinfo = w->data; par.family = NFPROTO_BRIDGE; if (par.target->destroy != NULL) par.target->destroy(&par); module_put(par.target->me); return 0; } static inline int ebt_cleanup_entry(struct ebt_entry *e, struct net *net, unsigned int *cnt) { struct xt_tgdtor_param par; struct ebt_entry_target *t; if (e->bitmask == 0) return 0; /* we're done */ if (cnt && (*cnt)-- == 0) return 1; EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, NULL); EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, NULL); t = ebt_get_target(e); par.net = net; par.target = t->u.target; par.targinfo = t->data; par.family = NFPROTO_BRIDGE; if (par.target->destroy != NULL) par.target->destroy(&par); module_put(par.target->me); return 0; } static inline int ebt_check_entry(struct ebt_entry *e, struct net *net, const struct ebt_table_info *newinfo, const char *name, unsigned int *cnt, struct ebt_cl_stack *cl_s, unsigned int udc_cnt) { struct ebt_entry_target *t; struct xt_target *target; unsigned int i, j, hook = 0, hookmask = 0; size_t gap; int ret; struct xt_mtchk_param mtpar; struct xt_tgchk_param tgpar; /* don't mess with the struct ebt_entries */ if (e->bitmask == 0) return 0; if (e->bitmask & ~EBT_F_MASK) { BUGPRINT("Unknown flag for bitmask\n"); return -EINVAL; } if (e->invflags & ~EBT_INV_MASK) { BUGPRINT("Unknown flag for inv bitmask\n"); return -EINVAL; } if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) { BUGPRINT("NOPROTO & 802_3 not allowed\n"); return -EINVAL; } /* what hook do we belong to? */ for (i = 0; i < NF_BR_NUMHOOKS; i++) { if (!newinfo->hook_entry[i]) continue; if ((char *)newinfo->hook_entry[i] < (char *)e) hook = i; else break; } /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on * a base chain */ if (i < NF_BR_NUMHOOKS) hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); else { for (i = 0; i < udc_cnt; i++) if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) break; if (i == 0) hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); else hookmask = cl_s[i - 1].hookmask; } i = 0; memset(&mtpar, 0, sizeof(mtpar)); memset(&tgpar, 0, sizeof(tgpar)); mtpar.net = tgpar.net = net; mtpar.table = tgpar.table = name; mtpar.entryinfo = tgpar.entryinfo = e; mtpar.hook_mask = tgpar.hook_mask = hookmask; mtpar.family = tgpar.family = NFPROTO_BRIDGE; ret = EBT_MATCH_ITERATE(e, ebt_check_match, &mtpar, &i); if (ret != 0) goto cleanup_matches; j = 0; ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, &tgpar, &j); if (ret != 0) goto cleanup_watchers; t = ebt_get_target(e); gap = e->next_offset - e->target_offset; target = xt_request_find_target(NFPROTO_BRIDGE, t->u.name, 0); if (IS_ERR(target)) { ret = PTR_ERR(target); goto cleanup_watchers; } /* Reject UNSPEC, xtables verdicts/return values are incompatible */ if (target->family != NFPROTO_BRIDGE) { module_put(target->me); ret = -ENOENT; goto cleanup_watchers; } t->u.target = target; if (t->u.target == &ebt_standard_target) { if (gap < sizeof(struct ebt_standard_target)) { BUGPRINT("Standard target size too big\n"); ret = -EFAULT; goto cleanup_watchers; } if (((struct ebt_standard_target *)t)->verdict < -NUM_STANDARD_TARGETS) { BUGPRINT("Invalid standard target\n"); ret = -EFAULT; goto cleanup_watchers; } } else if (t->target_size > gap - sizeof(struct ebt_entry_target)) { module_put(t->u.target->me); ret = -EFAULT; goto cleanup_watchers; } tgpar.target = target; tgpar.targinfo = t->data; ret = xt_check_target(&tgpar, t->target_size, e->ethproto, e->invflags & EBT_IPROTO); if (ret < 0) { module_put(target->me); goto cleanup_watchers; } (*cnt)++; return 0; cleanup_watchers: EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, net, &j); cleanup_matches: EBT_MATCH_ITERATE(e, ebt_cleanup_match, net, &i); return ret; } /* checks for loops and sets the hook mask for udc * the hook mask for udc tells us from which base chains the udc can be * accessed. This mask is a parameter to the check() functions of the extensions */ static int check_chainloops(const struct ebt_entries *chain, struct ebt_cl_stack *cl_s, unsigned int udc_cnt, unsigned int hooknr, char *base) { int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; const struct ebt_entry *e = (struct ebt_entry *)chain->data; const struct ebt_entry_target *t; while (pos < nentries || chain_nr != -1) { /* end of udc, go back one 'recursion' step */ if (pos == nentries) { /* put back values of the time when this chain was called */ e = cl_s[chain_nr].cs.e; if (cl_s[chain_nr].from != -1) nentries = cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; else nentries = chain->nentries; pos = cl_s[chain_nr].cs.n; /* make sure we won't see a loop that isn't one */ cl_s[chain_nr].cs.n = 0; chain_nr = cl_s[chain_nr].from; if (pos == nentries) continue; } t = ebt_get_target_c(e); if (strcmp(t->u.name, EBT_STANDARD_TARGET)) goto letscontinue; if (e->target_offset + sizeof(struct ebt_standard_target) > e->next_offset) { BUGPRINT("Standard target size too big\n"); return -1; } verdict = ((struct ebt_standard_target *)t)->verdict; if (verdict >= 0) { /* jump to another chain */ struct ebt_entries *hlp2 = (struct ebt_entries *)(base + verdict); for (i = 0; i < udc_cnt; i++) if (hlp2 == cl_s[i].cs.chaininfo) break; /* bad destination or loop */ if (i == udc_cnt) { BUGPRINT("bad destination\n"); return -1; } if (cl_s[i].cs.n) { BUGPRINT("loop\n"); return -1; } if (cl_s[i].hookmask & (1 << hooknr)) goto letscontinue; /* this can't be 0, so the loop test is correct */ cl_s[i].cs.n = pos + 1; pos = 0; cl_s[i].cs.e = ebt_next_entry(e); e = (struct ebt_entry *)(hlp2->data); nentries = hlp2->nentries; cl_s[i].from = chain_nr; chain_nr = i; /* this udc is accessible from the base chain for hooknr */ cl_s[i].hookmask |= (1 << hooknr); continue; } letscontinue: e = ebt_next_entry(e); pos++; } return 0; } /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ static int translate_table(struct net *net, const char *name, struct ebt_table_info *newinfo) { unsigned int i, j, k, udc_cnt; int ret; struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ i = 0; while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i]) i++; if (i == NF_BR_NUMHOOKS) { BUGPRINT("No valid hooks specified\n"); return -EINVAL; } if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) { BUGPRINT("Chains don't start at beginning\n"); return -EINVAL; } /* make sure chains are ordered after each other in same order * as their corresponding hooks */ for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { if (!newinfo->hook_entry[j]) continue; if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) { BUGPRINT("Hook order must be followed\n"); return -EINVAL; } i = j; } /* do some early checkings and initialize some things */ i = 0; /* holds the expected nr. of entries for the chain */ j = 0; /* holds the up to now counted entries for the chain */ k = 0; /* holds the total nr. of entries, should equal * newinfo->nentries afterwards */ udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, ebt_check_entry_size_and_hooks, newinfo, &i, &j, &k, &udc_cnt); if (ret != 0) return ret; if (i != j) { BUGPRINT("nentries does not equal the nr of entries in the " "(last) chain\n"); return -EINVAL; } if (k != newinfo->nentries) { BUGPRINT("Total nentries is wrong\n"); return -EINVAL; } /* get the location of the udc, put them in an array * while we're at it, allocate the chainstack */ if (udc_cnt) { /* this will get free'd in do_replace()/ebt_register_table() * if an error occurs */ newinfo->chainstack = vmalloc(array_size(nr_cpu_ids, sizeof(*(newinfo->chainstack)))); if (!newinfo->chainstack) return -ENOMEM; for_each_possible_cpu(i) { newinfo->chainstack[i] = vmalloc(array_size(udc_cnt, sizeof(*(newinfo->chainstack[0])))); if (!newinfo->chainstack[i]) { while (i) vfree(newinfo->chainstack[--i]); vfree(newinfo->chainstack); newinfo->chainstack = NULL; return -ENOMEM; } } cl_s = vmalloc(array_size(udc_cnt, sizeof(*cl_s))); if (!cl_s) return -ENOMEM; i = 0; /* the i'th udc */ EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, ebt_get_udc_positions, newinfo, &i, cl_s); /* sanity check */ if (i != udc_cnt) { BUGPRINT("i != udc_cnt\n"); vfree(cl_s); return -EFAULT; } } /* Check for loops */ for (i = 0; i < NF_BR_NUMHOOKS; i++) if (newinfo->hook_entry[i]) if (check_chainloops(newinfo->hook_entry[i], cl_s, udc_cnt, i, newinfo->entries)) { vfree(cl_s); return -EINVAL; } /* we now know the following (along with E=mc²): * - the nr of entries in each chain is right * - the size of the allocated space is right * - all valid hooks have a corresponding chain * - there are no loops * - wrong data can still be on the level of a single entry * - could be there are jumps to places that are not the * beginning of a chain. This can only occur in chains that * are not accessible from any base chains, so we don't care. */ /* used to know what we need to clean up if something goes wrong */ i = 0; ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, ebt_check_entry, net, newinfo, name, &i, cl_s, udc_cnt); if (ret != 0) { EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, ebt_cleanup_entry, net, &i); } vfree(cl_s); return ret; } /* called under write_lock */ static void get_counters(const struct ebt_counter *oldcounters, struct ebt_counter *counters, unsigned int nentries) { int i, cpu; struct ebt_counter *counter_base; /* counters of cpu 0 */ memcpy(counters, oldcounters, sizeof(struct ebt_counter) * nentries); /* add other counters to those of cpu 0 */ for_each_possible_cpu(cpu) { if (cpu == 0) continue; counter_base = COUNTER_BASE(oldcounters, nentries, cpu); for (i = 0; i < nentries; i++) ADD_COUNTER(counters[i], counter_base[i].pcnt, counter_base[i].bcnt); } } static int do_replace_finish(struct net *net, struct ebt_replace *repl, struct ebt_table_info *newinfo) { int ret; struct ebt_counter *counterstmp = NULL; /* used to be able to unlock earlier */ struct ebt_table_info *table; struct ebt_table *t; /* the user wants counters back * the check on the size is done later, when we have the lock */ if (repl->num_counters) { unsigned long size = repl->num_counters * sizeof(*counterstmp); counterstmp = vmalloc(size); if (!counterstmp) return -ENOMEM; } newinfo->chainstack = NULL; ret = ebt_verify_pointers(repl, newinfo); if (ret != 0) goto free_counterstmp; ret = translate_table(net, repl->name, newinfo); if (ret != 0) goto free_counterstmp; t = find_table_lock(net, repl->name, &ret, &ebt_mutex); if (!t) { ret = -ENOENT; goto free_iterate; } /* the table doesn't like it */ if (t->check && (ret = t->check(newinfo, repl->valid_hooks))) goto free_unlock; if (repl->num_counters && repl->num_counters != t->private->nentries) { BUGPRINT("Wrong nr. of counters requested\n"); ret = -EINVAL; goto free_unlock; } /* we have the mutex lock, so no danger in reading this pointer */ table = t->private; /* make sure the table can only be rmmod'ed if it contains no rules */ if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) { ret = -ENOENT; goto free_unlock; } else if (table->nentries && !newinfo->nentries) module_put(t->me); /* we need an atomic snapshot of the counters */ write_lock_bh(&t->lock); if (repl->num_counters) get_counters(t->private->counters, counterstmp, t->private->nentries); t->private = newinfo; write_unlock_bh(&t->lock); mutex_unlock(&ebt_mutex); /* so, a user can change the chains while having messed up her counter * allocation. Only reason why this is done is because this way the lock * is held only once, while this doesn't bring the kernel into a * dangerous state. */ if (repl->num_counters && copy_to_user(repl->counters, counterstmp, repl->num_counters * sizeof(struct ebt_counter))) { /* Silent error, can't fail, new table is already in place */ net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n"); } /* decrease module count and free resources */ EBT_ENTRY_ITERATE(table->entries, table->entries_size, ebt_cleanup_entry, net, NULL); vfree(table->entries); ebt_free_table_info(table); vfree(table); vfree(counterstmp); #ifdef CONFIG_AUDIT if (audit_enabled) { audit_log(audit_context(), GFP_KERNEL, AUDIT_NETFILTER_CFG, "table=%s family=%u entries=%u", repl->name, AF_BRIDGE, repl->nentries); } #endif return ret; free_unlock: mutex_unlock(&ebt_mutex); free_iterate: EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, ebt_cleanup_entry, net, NULL); free_counterstmp: vfree(counterstmp); /* can be initialized in translate_table() */ ebt_free_table_info(newinfo); return ret; } /* replace the table */ static int do_replace(struct net *net, const void __user *user, unsigned int len) { int ret, countersize; struct ebt_table_info *newinfo; struct ebt_replace tmp; if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) return -EFAULT; if (len != sizeof(tmp) + tmp.entries_size) { BUGPRINT("Wrong len argument\n"); return -EINVAL; } if (tmp.entries_size == 0) { BUGPRINT("Entries_size never zero\n"); return -EINVAL; } /* overflow check */ if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) return -ENOMEM; tmp.name[sizeof(tmp.name) - 1] = 0; countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; newinfo = __vmalloc(sizeof(*newinfo) + countersize, GFP_KERNEL_ACCOUNT, PAGE_KERNEL); if (!newinfo) return -ENOMEM; if (countersize) memset(newinfo->counters, 0, countersize); newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT, PAGE_KERNEL); if (!newinfo->entries) { ret = -ENOMEM; goto free_newinfo; } if (copy_from_user( newinfo->entries, tmp.entries, tmp.entries_size) != 0) { BUGPRINT("Couldn't copy entries from userspace\n"); ret = -EFAULT; goto free_entries; } ret = do_replace_finish(net, &tmp, newinfo); if (ret == 0) return ret; free_entries: vfree(newinfo->entries); free_newinfo: vfree(newinfo); return ret; } static void __ebt_unregister_table(struct net *net, struct ebt_table *table) { mutex_lock(&ebt_mutex); list_del(&table->list); mutex_unlock(&ebt_mutex); EBT_ENTRY_ITERATE(table->private->entries, table->private->entries_size, ebt_cleanup_entry, net, NULL); if (table->private->nentries) module_put(table->me); vfree(table->private->entries); ebt_free_table_info(table->private); vfree(table->private); kfree(table); } int ebt_register_table(struct net *net, const struct ebt_table *input_table, const struct nf_hook_ops *ops, struct ebt_table **res) { struct ebt_table_info *newinfo; struct ebt_table *t, *table; struct ebt_replace_kernel *repl; int ret, i, countersize; void *p; if (input_table == NULL || (repl = input_table->table) == NULL || repl->entries == NULL || repl->entries_size == 0 || repl->counters != NULL || input_table->private != NULL) { BUGPRINT("Bad table data for ebt_register_table!!!\n"); return -EINVAL; } /* Don't add one table to multiple lists. */ table = kmemdup(input_table, sizeof(struct ebt_table), GFP_KERNEL); if (!table) { ret = -ENOMEM; goto out; } countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids; newinfo = vmalloc(sizeof(*newinfo) + countersize); ret = -ENOMEM; if (!newinfo) goto free_table; p = vmalloc(repl->entries_size); if (!p) goto free_newinfo; memcpy(p, repl->entries, repl->entries_size); newinfo->entries = p; newinfo->entries_size = repl->entries_size; newinfo->nentries = repl->nentries; if (countersize) memset(newinfo->counters, 0, countersize); /* fill in newinfo and parse the entries */ newinfo->chainstack = NULL; for (i = 0; i < NF_BR_NUMHOOKS; i++) { if ((repl->valid_hooks & (1 << i)) == 0) newinfo->hook_entry[i] = NULL; else newinfo->hook_entry[i] = p + ((char *)repl->hook_entry[i] - repl->entries); } ret = translate_table(net, repl->name, newinfo); if (ret != 0) { BUGPRINT("Translate_table failed\n"); goto free_chainstack; } if (table->check && table->check(newinfo, table->valid_hooks)) { BUGPRINT("The table doesn't like its own initial data, lol\n"); ret = -EINVAL; goto free_chainstack; } table->private = newinfo; rwlock_init(&table->lock); mutex_lock(&ebt_mutex); list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) { if (strcmp(t->name, table->name) == 0) { ret = -EEXIST; BUGPRINT("Table name already exists\n"); goto free_unlock; } } /* Hold a reference count if the chains aren't empty */ if (newinfo->nentries && !try_module_get(table->me)) { ret = -ENOENT; goto free_unlock; } list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]); mutex_unlock(&ebt_mutex); WRITE_ONCE(*res, table); if (!ops) return 0; ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); if (ret) { __ebt_unregister_table(net, table); *res = NULL; } return ret; free_unlock: mutex_unlock(&ebt_mutex); free_chainstack: ebt_free_table_info(newinfo); vfree(newinfo->entries); free_newinfo: vfree(newinfo); free_table: kfree(table); out: return ret; } void ebt_unregister_table(struct net *net, struct ebt_table *table, const struct nf_hook_ops *ops) { if (ops) nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); __ebt_unregister_table(net, table); } /* userspace just supplied us with counters */ static int do_update_counters(struct net *net, const char *name, struct ebt_counter __user *counters, unsigned int num_counters, const void __user *user, unsigned int len) { int i, ret; struct ebt_counter *tmp; struct ebt_table *t; if (num_counters == 0) return -EINVAL; tmp = vmalloc(array_size(num_counters, sizeof(*tmp))); if (!tmp) return -ENOMEM; t = find_table_lock(net, name, &ret, &ebt_mutex); if (!t) goto free_tmp; if (num_counters != t->private->nentries) { BUGPRINT("Wrong nr of counters\n"); ret = -EINVAL; goto unlock_mutex; } if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) { ret = -EFAULT; goto unlock_mutex; } /* we want an atomic add of the counters */ write_lock_bh(&t->lock); /* we add to the counters of the first cpu */ for (i = 0; i < num_counters; i++) ADD_COUNTER(t->private->counters[i], tmp[i].pcnt, tmp[i].bcnt); write_unlock_bh(&t->lock); ret = 0; unlock_mutex: mutex_unlock(&ebt_mutex); free_tmp: vfree(tmp); return ret; } static int update_counters(struct net *net, const void __user *user, unsigned int len) { struct ebt_replace hlp; if (copy_from_user(&hlp, user, sizeof(hlp))) return -EFAULT; if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) return -EINVAL; return do_update_counters(net, hlp.name, hlp.counters, hlp.num_counters, user, len); } static inline int ebt_obj_to_user(char __user *um, const char *_name, const char *data, int entrysize, int usersize, int datasize, u8 revision) { char name[EBT_EXTENSION_MAXNAMELEN] = {0}; /* ebtables expects 31 bytes long names but xt_match names are 29 bytes * long. Copy 29 bytes and fill remaining bytes with zeroes. */ strlcpy(name, _name, sizeof(name)); if (copy_to_user(um, name, EBT_EXTENSION_MAXNAMELEN) || put_user(revision, (u8 __user *)(um + EBT_EXTENSION_MAXNAMELEN)) || put_user(datasize, (int __user *)(um + EBT_EXTENSION_MAXNAMELEN + 1)) || xt_data_to_user(um + entrysize, data, usersize, datasize, XT_ALIGN(datasize))) return -EFAULT; return 0; } static inline int ebt_match_to_user(const struct ebt_entry_match *m, const char *base, char __user *ubase) { return ebt_obj_to_user(ubase + ((char *)m - base), m->u.match->name, m->data, sizeof(*m), m->u.match->usersize, m->match_size, m->u.match->revision); } static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w, const char *base, char __user *ubase) { return ebt_obj_to_user(ubase + ((char *)w - base), w->u.watcher->name, w->data, sizeof(*w), w->u.watcher->usersize, w->watcher_size, w->u.watcher->revision); } static inline int ebt_entry_to_user(struct ebt_entry *e, const char *base, char __user *ubase) { int ret; char __user *hlp; const struct ebt_entry_target *t; if (e->bitmask == 0) { /* special case !EBT_ENTRY_OR_ENTRIES */ if (copy_to_user(ubase + ((char *)e - base), e, sizeof(struct ebt_entries))) return -EFAULT; return 0; } if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e))) return -EFAULT; hlp = ubase + (((char *)e + e->target_offset) - base); t = ebt_get_target_c(e); ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase); if (ret != 0) return ret; ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase); if (ret != 0) return ret; ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t), t->u.target->usersize, t->target_size, t->u.target->revision); if (ret != 0) return ret; return 0; } static int copy_counters_to_user(struct ebt_table *t, const struct ebt_counter *oldcounters, void __user *user, unsigned int num_counters, unsigned int nentries) { struct ebt_counter *counterstmp; int ret = 0; /* userspace might not need the counters */ if (num_counters == 0) return 0; if (num_counters != nentries) { BUGPRINT("Num_counters wrong\n"); return -EINVAL; } counterstmp = vmalloc(array_size(nentries, sizeof(*counterstmp))); if (!counterstmp) return -ENOMEM; write_lock_bh(&t->lock); get_counters(oldcounters, counterstmp, nentries); write_unlock_bh(&t->lock); if (copy_to_user(user, counterstmp, nentries * sizeof(struct ebt_counter))) ret = -EFAULT; vfree(counterstmp); return ret; } /* called with ebt_mutex locked */ static int copy_everything_to_user(struct ebt_table *t, void __user *user, const int *len, int cmd) { struct ebt_replace tmp; const struct ebt_counter *oldcounters; unsigned int entries_size, nentries; int ret; char *entries; if (cmd == EBT_SO_GET_ENTRIES) { entries_size = t->private->entries_size; nentries = t->private->nentries; entries = t->private->entries; oldcounters = t->private->counters; } else { entries_size = t->table->entries_size; nentries = t->table->nentries; entries = t->table->entries; oldcounters = t->table->counters; } if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; if (*len != sizeof(struct ebt_replace) + entries_size + (tmp.num_counters ? nentries * sizeof(struct ebt_counter) : 0)) return -EINVAL; if (tmp.nentries != nentries) { BUGPRINT("Nentries wrong\n"); return -EINVAL; } if (tmp.entries_size != entries_size) { BUGPRINT("Wrong size\n"); return -EINVAL; } ret = copy_counters_to_user(t, oldcounters, tmp.counters, tmp.num_counters, nentries); if (ret) return ret; /* set the match/watcher/target names right */ return EBT_ENTRY_ITERATE(entries, entries_size, ebt_entry_to_user, entries, tmp.entries); } static int do_ebt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) { int ret; struct net *net = sock_net(sk); if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; switch (cmd) { case EBT_SO_SET_ENTRIES: ret = do_replace(net, user, len); break; case EBT_SO_SET_COUNTERS: ret = update_counters(net, user, len); break; default: ret = -EINVAL; } return ret; } static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) { int ret; struct ebt_replace tmp; struct ebt_table *t; struct net *net = sock_net(sk); if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; tmp.name[sizeof(tmp.name) - 1] = '\0'; t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); if (!t) return ret; switch (cmd) { case EBT_SO_GET_INFO: case EBT_SO_GET_INIT_INFO: if (*len != sizeof(struct ebt_replace)) { ret = -EINVAL; mutex_unlock(&ebt_mutex); break; } if (cmd == EBT_SO_GET_INFO) { tmp.nentries = t->private->nentries; tmp.entries_size = t->private->entries_size; tmp.valid_hooks = t->valid_hooks; } else { tmp.nentries = t->table->nentries; tmp.entries_size = t->table->entries_size; tmp.valid_hooks = t->table->valid_hooks; } mutex_unlock(&ebt_mutex); if (copy_to_user(user, &tmp, *len) != 0) { BUGPRINT("c2u Didn't work\n"); ret = -EFAULT; break; } ret = 0; break; case EBT_SO_GET_ENTRIES: case EBT_SO_GET_INIT_ENTRIES: ret = copy_everything_to_user(t, user, len, cmd); mutex_unlock(&ebt_mutex); break; default: mutex_unlock(&ebt_mutex); ret = -EINVAL; } return ret; } #ifdef CONFIG_COMPAT /* 32 bit-userspace compatibility definitions. */ struct compat_ebt_replace { char name[EBT_TABLE_MAXNAMELEN]; compat_uint_t valid_hooks; compat_uint_t nentries; compat_uint_t entries_size; /* start of the chains */ compat_uptr_t hook_entry[NF_BR_NUMHOOKS]; /* nr of counters userspace expects back */ compat_uint_t num_counters; /* where the kernel will put the old counters. */ compat_uptr_t counters; compat_uptr_t entries; }; /* struct ebt_entry_match, _target and _watcher have same layout */ struct compat_ebt_entry_mwt { union { struct { char name[EBT_EXTENSION_MAXNAMELEN]; u8 revision; }; compat_uptr_t ptr; } u; compat_uint_t match_size; compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace)))); }; /* account for possible padding between match_size and ->data */ static int ebt_compat_entry_padsize(void) { BUILD_BUG_ON(sizeof(struct ebt_entry_match) < sizeof(struct compat_ebt_entry_mwt)); return (int) sizeof(struct ebt_entry_match) - sizeof(struct compat_ebt_entry_mwt); } static int ebt_compat_match_offset(const struct xt_match *match, unsigned int userlen) { /* ebt_among needs special handling. The kernel .matchsize is * set to -1 at registration time; at runtime an EBT_ALIGN()ed * value is expected. * Example: userspace sends 4500, ebt_among.c wants 4504. */ if (unlikely(match->matchsize == -1)) return XT_ALIGN(userlen) - COMPAT_XT_ALIGN(userlen); return xt_compat_match_offset(match); } static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr, unsigned int *size) { const struct xt_match *match = m->u.match; struct compat_ebt_entry_mwt __user *cm = *dstptr; int off = ebt_compat_match_offset(match, m->match_size); compat_uint_t msize = m->match_size - off; if (WARN_ON(off >= m->match_size)) return -EINVAL; if (copy_to_user(cm->u.name, match->name, strlen(match->name) + 1) || put_user(match->revision, &cm->u.revision) || put_user(msize, &cm->match_size)) return -EFAULT; if (match->compat_to_user) { if (match->compat_to_user(cm->data, m->data)) return -EFAULT; } else { if (xt_data_to_user(cm->data, m->data, match->usersize, msize, COMPAT_XT_ALIGN(msize))) return -EFAULT; } *size -= ebt_compat_entry_padsize() + off; *dstptr = cm->data; *dstptr += msize; return 0; } static int compat_target_to_user(struct ebt_entry_target *t, void __user **dstptr, unsigned int *size) { const struct xt_target *target = t->u.target; struct compat_ebt_entry_mwt __user *cm = *dstptr; int off = xt_compat_target_offset(target); compat_uint_t tsize = t->target_size - off; if (WARN_ON(off >= t->target_size)) return -EINVAL; if (copy_to_user(cm->u.name, target->name, strlen(target->name) + 1) || put_user(target->revision, &cm->u.revision) || put_user(tsize, &cm->match_size)) return -EFAULT; if (target->compat_to_user) { if (target->compat_to_user(cm->data, t->data)) return -EFAULT; } else { if (xt_data_to_user(cm->data, t->data, target->usersize, tsize, COMPAT_XT_ALIGN(tsize))) return -EFAULT; } *size -= ebt_compat_entry_padsize() + off; *dstptr = cm->data; *dstptr += tsize; return 0; } static int compat_watcher_to_user(struct ebt_entry_watcher *w, void __user **dstptr, unsigned int *size) { return compat_target_to_user((struct ebt_entry_target *)w, dstptr, size); } static int compat_copy_entry_to_user(struct ebt_entry *e, void __user **dstptr, unsigned int *size) { struct ebt_entry_target *t; struct ebt_entry __user *ce; u32 watchers_offset, target_offset, next_offset; compat_uint_t origsize; int ret; if (e->bitmask == 0) { if (*size < sizeof(struct ebt_entries)) return -EINVAL; if (copy_to_user(*dstptr, e, sizeof(struct ebt_entries))) return -EFAULT; *dstptr += sizeof(struct ebt_entries); *size -= sizeof(struct ebt_entries); return 0; } if (*size < sizeof(*ce)) return -EINVAL; ce = *dstptr; if (copy_to_user(ce, e, sizeof(*ce))) return -EFAULT; origsize = *size; *dstptr += sizeof(*ce); ret = EBT_MATCH_ITERATE(e, compat_match_to_user, dstptr, size); if (ret) return ret; watchers_offset = e->watchers_offset - (origsize - *size); ret = EBT_WATCHER_ITERATE(e, compat_watcher_to_user, dstptr, size); if (ret) return ret; target_offset = e->target_offset - (origsize - *size); t = ebt_get_target(e); ret = compat_target_to_user(t, dstptr, size); if (ret) return ret; next_offset = e->next_offset - (origsize - *size); if (put_user(watchers_offset, &ce->watchers_offset) || put_user(target_offset, &ce->target_offset) || put_user(next_offset, &ce->next_offset)) return -EFAULT; *size -= sizeof(*ce); return 0; } static int compat_calc_match(struct ebt_entry_match *m, int *off) { *off += ebt_compat_match_offset(m->u.match, m->match_size); *off += ebt_compat_entry_padsize(); return 0; } static int compat_calc_watcher(struct ebt_entry_watcher *w, int *off) { *off += xt_compat_target_offset(w->u.watcher); *off += ebt_compat_entry_padsize(); return 0; } static int compat_calc_entry(const struct ebt_entry *e, const struct ebt_table_info *info, const void *base, struct compat_ebt_replace *newinfo) { const struct ebt_entry_target *t; unsigned int entry_offset; int off, ret, i; if (e->bitmask == 0) return 0; off = 0; entry_offset = (void *)e - base; EBT_MATCH_ITERATE(e, compat_calc_match, &off); EBT_WATCHER_ITERATE(e, compat_calc_watcher, &off); t = ebt_get_target_c(e); off += xt_compat_target_offset(t->u.target); off += ebt_compat_entry_padsize(); newinfo->entries_size -= off; ret = xt_compat_add_offset(NFPROTO_BRIDGE, entry_offset, off); if (ret) return ret; for (i = 0; i < NF_BR_NUMHOOKS; i++) { const void *hookptr = info->hook_entry[i]; if (info->hook_entry[i] && (e < (struct ebt_entry *)(base - hookptr))) { newinfo->hook_entry[i] -= off; pr_debug("0x%08X -> 0x%08X\n", newinfo->hook_entry[i] + off, newinfo->hook_entry[i]); } } return 0; } static int compat_table_info(const struct ebt_table_info *info, struct compat_ebt_replace *newinfo) { unsigned int size = info->entries_size; const void *entries = info->entries; newinfo->entries_size = size; if (info->nentries) { int ret = xt_compat_init_offsets(NFPROTO_BRIDGE, info->nentries); if (ret) return ret; } return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, entries, newinfo); } static int compat_copy_everything_to_user(struct ebt_table *t, void __user *user, int *len, int cmd) { struct compat_ebt_replace repl, tmp; struct ebt_counter *oldcounters; struct ebt_table_info tinfo; int ret; void __user *pos; memset(&tinfo, 0, sizeof(tinfo)); if (cmd == EBT_SO_GET_ENTRIES) { tinfo.entries_size = t->private->entries_size; tinfo.nentries = t->private->nentries; tinfo.entries = t->private->entries; oldcounters = t->private->counters; } else { tinfo.entries_size = t->table->entries_size; tinfo.nentries = t->table->nentries; tinfo.entries = t->table->entries; oldcounters = t->table->counters; } if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; if (tmp.nentries != tinfo.nentries || (tmp.num_counters && tmp.num_counters != tinfo.nentries)) return -EINVAL; memcpy(&repl, &tmp, sizeof(repl)); if (cmd == EBT_SO_GET_ENTRIES) ret = compat_table_info(t->private, &repl); else ret = compat_table_info(&tinfo, &repl); if (ret) return ret; if (*len != sizeof(tmp) + repl.entries_size + (tmp.num_counters? tinfo.nentries * sizeof(struct ebt_counter): 0)) { pr_err("wrong size: *len %d, entries_size %u, replsz %d\n", *len, tinfo.entries_size, repl.entries_size); return -EINVAL; } /* userspace might not need the counters */ ret = copy_counters_to_user(t, oldcounters, compat_ptr(tmp.counters), tmp.num_counters, tinfo.nentries); if (ret) return ret; pos = compat_ptr(tmp.entries); return EBT_ENTRY_ITERATE(tinfo.entries, tinfo.entries_size, compat_copy_entry_to_user, &pos, &tmp.entries_size); } struct ebt_entries_buf_state { char *buf_kern_start; /* kernel buffer to copy (translated) data to */ u32 buf_kern_len; /* total size of kernel buffer */ u32 buf_kern_offset; /* amount of data copied so far */ u32 buf_user_offset; /* read position in userspace buffer */ }; static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz) { state->buf_kern_offset += sz; return state->buf_kern_offset >= sz ? 0 : -EINVAL; } static int ebt_buf_add(struct ebt_entries_buf_state *state, void *data, unsigned int sz) { if (state->buf_kern_start == NULL) goto count_only; if (WARN_ON(state->buf_kern_offset + sz > state->buf_kern_len)) return -EINVAL; memcpy(state->buf_kern_start + state->buf_kern_offset, data, sz); count_only: state->buf_user_offset += sz; return ebt_buf_count(state, sz); } static int ebt_buf_add_pad(struct ebt_entries_buf_state *state, unsigned int sz) { char *b = state->buf_kern_start; if (WARN_ON(b && state->buf_kern_offset > state->buf_kern_len)) return -EINVAL; if (b != NULL && sz > 0) memset(b + state->buf_kern_offset, 0, sz); /* do not adjust ->buf_user_offset here, we added kernel-side padding */ return ebt_buf_count(state, sz); } enum compat_mwt { EBT_COMPAT_MATCH, EBT_COMPAT_WATCHER, EBT_COMPAT_TARGET, }; static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt, enum compat_mwt compat_mwt, struct ebt_entries_buf_state *state, const unsigned char *base) { char name[EBT_EXTENSION_MAXNAMELEN]; struct xt_match *match; struct xt_target *wt; void *dst = NULL; int off, pad = 0; unsigned int size_kern, match_size = mwt->match_size; if (strscpy(name, mwt->u.name, sizeof(name)) < 0) return -EINVAL; if (state->buf_kern_start) dst = state->buf_kern_start + state->buf_kern_offset; switch (compat_mwt) { case EBT_COMPAT_MATCH: match = xt_request_find_match(NFPROTO_BRIDGE, name, mwt->u.revision); if (IS_ERR(match)) return PTR_ERR(match); off = ebt_compat_match_offset(match, match_size); if (dst) { if (match->compat_from_user) match->compat_from_user(dst, mwt->data); else memcpy(dst, mwt->data, match_size); } size_kern = match->matchsize; if (unlikely(size_kern == -1)) size_kern = match_size; module_put(match->me); break; case EBT_COMPAT_WATCHER: /* fallthrough */ case EBT_COMPAT_TARGET: wt = xt_request_find_target(NFPROTO_BRIDGE, name, mwt->u.revision); if (IS_ERR(wt)) return PTR_ERR(wt); off = xt_compat_target_offset(wt); if (dst) { if (wt->compat_from_user) wt->compat_from_user(dst, mwt->data); else memcpy(dst, mwt->data, match_size); } size_kern = wt->targetsize; module_put(wt->me); break; default: return -EINVAL; } state->buf_kern_offset += match_size + off; state->buf_user_offset += match_size; pad = XT_ALIGN(size_kern) - size_kern; if (pad > 0 && dst) { if (WARN_ON(state->buf_kern_len <= pad)) return -EINVAL; if (WARN_ON(state->buf_kern_offset - (match_size + off) + size_kern > state->buf_kern_len - pad)) return -EINVAL; memset(dst + size_kern, 0, pad); } return off + match_size; } /* return size of all matches, watchers or target, including necessary * alignment and padding. */ static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32, unsigned int size_left, enum compat_mwt type, struct ebt_entries_buf_state *state, const void *base) { int growth = 0; char *buf; if (size_left == 0) return 0; buf = (char *) match32; while (size_left >= sizeof(*match32)) { struct ebt_entry_match *match_kern; int ret; match_kern = (struct ebt_entry_match *) state->buf_kern_start; if (match_kern) { char *tmp; tmp = state->buf_kern_start + state->buf_kern_offset; match_kern = (struct ebt_entry_match *) tmp; } ret = ebt_buf_add(state, buf, sizeof(*match32)); if (ret < 0) return ret; size_left -= sizeof(*match32); /* add padding before match->data (if any) */ ret = ebt_buf_add_pad(state, ebt_compat_entry_padsize()); if (ret < 0) return ret; if (match32->match_size > size_left) return -EINVAL; size_left -= match32->match_size; ret = compat_mtw_from_user(match32, type, state, base); if (ret < 0) return ret; if (WARN_ON(ret < match32->match_size)) return -EINVAL; growth += ret - match32->match_size; growth += ebt_compat_entry_padsize(); buf += sizeof(*match32); buf += match32->match_size; if (match_kern) match_kern->match_size = ret; if (WARN_ON(type == EBT_COMPAT_TARGET && size_left)) return -EINVAL; match32 = (struct compat_ebt_entry_mwt *) buf; } return growth; } /* called for all ebt_entry structures. */ static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, unsigned int *total, struct ebt_entries_buf_state *state) { unsigned int i, j, startoff, new_offset = 0; /* stores match/watchers/targets & offset of next struct ebt_entry: */ unsigned int offsets[4]; unsigned int *offsets_update = NULL; int ret; char *buf_start; if (*total < sizeof(struct ebt_entries)) return -EINVAL; if (!entry->bitmask) { *total -= sizeof(struct ebt_entries); return ebt_buf_add(state, entry, sizeof(struct ebt_entries)); } if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry)) return -EINVAL; startoff = state->buf_user_offset; /* pull in most part of ebt_entry, it does not need to be changed. */ ret = ebt_buf_add(state, entry, offsetof(struct ebt_entry, watchers_offset)); if (ret < 0) return ret; offsets[0] = sizeof(struct ebt_entry); /* matches come first */ memcpy(&offsets[1], &entry->watchers_offset, sizeof(offsets) - sizeof(offsets[0])); if (state->buf_kern_start) { buf_start = state->buf_kern_start + state->buf_kern_offset; offsets_update = (unsigned int *) buf_start; } ret = ebt_buf_add(state, &offsets[1], sizeof(offsets) - sizeof(offsets[0])); if (ret < 0) return ret; buf_start = (char *) entry; /* 0: matches offset, always follows ebt_entry. * 1: watchers offset, from ebt_entry structure * 2: target offset, from ebt_entry structure * 3: next ebt_entry offset, from ebt_entry structure * * offsets are relative to beginning of struct ebt_entry (i.e., 0). */ for (i = 0; i < 4 ; ++i) { if (offsets[i] > *total) return -EINVAL; if (i < 3 && offsets[i] == *total) return -EINVAL; if (i == 0) continue; if (offsets[i-1] > offsets[i]) return -EINVAL; } for (i = 0, j = 1 ; j < 4 ; j++, i++) { struct compat_ebt_entry_mwt *match32; unsigned int size; char *buf = buf_start + offsets[i]; if (offsets[i] > offsets[j]) return -EINVAL; match32 = (struct compat_ebt_entry_mwt *) buf; size = offsets[j] - offsets[i]; ret = ebt_size_mwt(match32, size, i, state, base); if (ret < 0) return ret; new_offset += ret; if (offsets_update && new_offset) { pr_debug("change offset %d to %d\n", offsets_update[i], offsets[j] + new_offset); offsets_update[i] = offsets[j] + new_offset; } } if (state->buf_kern_start == NULL) { unsigned int offset = buf_start - (char *) base; ret = xt_compat_add_offset(NFPROTO_BRIDGE, offset, new_offset); if (ret < 0) return ret; } startoff = state->buf_user_offset - startoff; if (WARN_ON(*total < startoff)) return -EINVAL; *total -= startoff; return 0; } /* repl->entries_size is the size of the ebt_entry blob in userspace. * It might need more memory when copied to a 64 bit kernel in case * userspace is 32-bit. So, first task: find out how much memory is needed. * * Called before validation is performed. */ static int compat_copy_entries(unsigned char *data, unsigned int size_user, struct ebt_entries_buf_state *state) { unsigned int size_remaining = size_user; int ret; ret = EBT_ENTRY_ITERATE(data, size_user, size_entry_mwt, data, &size_remaining, state); if (ret < 0) return ret; WARN_ON(size_remaining); return state->buf_kern_offset; } static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, void __user *user, unsigned int len) { struct compat_ebt_replace tmp; int i; if (len < sizeof(tmp)) return -EINVAL; if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; if (len != sizeof(tmp) + tmp.entries_size) return -EINVAL; if (tmp.entries_size == 0) return -EINVAL; if (tmp.nentries >= ((INT_MAX - sizeof(struct ebt_table_info)) / NR_CPUS - SMP_CACHE_BYTES) / sizeof(struct ebt_counter)) return -ENOMEM; if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter)) return -ENOMEM; memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry)); /* starting with hook_entry, 32 vs. 64 bit structures are different */ for (i = 0; i < NF_BR_NUMHOOKS; i++) repl->hook_entry[i] = compat_ptr(tmp.hook_entry[i]); repl->num_counters = tmp.num_counters; repl->counters = compat_ptr(tmp.counters); repl->entries = compat_ptr(tmp.entries); return 0; } static int compat_do_replace(struct net *net, void __user *user, unsigned int len) { int ret, i, countersize, size64; struct ebt_table_info *newinfo; struct ebt_replace tmp; struct ebt_entries_buf_state state; void *entries_tmp; ret = compat_copy_ebt_replace_from_user(&tmp, user, len); if (ret) { /* try real handler in case userland supplied needed padding */ if (ret == -EINVAL && do_replace(net, user, len) == 0) ret = 0; return ret; } countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids; newinfo = vmalloc(sizeof(*newinfo) + countersize); if (!newinfo) return -ENOMEM; if (countersize) memset(newinfo->counters, 0, countersize); memset(&state, 0, sizeof(state)); newinfo->entries = vmalloc(tmp.entries_size); if (!newinfo->entries) { ret = -ENOMEM; goto free_newinfo; } if (copy_from_user( newinfo->entries, tmp.entries, tmp.entries_size) != 0) { ret = -EFAULT; goto free_entries; } entries_tmp = newinfo->entries; xt_compat_lock(NFPROTO_BRIDGE); if (tmp.nentries) { ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries); if (ret < 0) goto out_unlock; } ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); if (ret < 0) goto out_unlock; pr_debug("tmp.entries_size %d, kern off %d, user off %d delta %d\n", tmp.entries_size, state.buf_kern_offset, state.buf_user_offset, xt_compat_calc_jump(NFPROTO_BRIDGE, tmp.entries_size)); size64 = ret; newinfo->entries = vmalloc(size64); if (!newinfo->entries) { vfree(entries_tmp); ret = -ENOMEM; goto out_unlock; } memset(&state, 0, sizeof(state)); state.buf_kern_start = newinfo->entries; state.buf_kern_len = size64; ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); if (WARN_ON(ret < 0)) goto out_unlock; vfree(entries_tmp); tmp.entries_size = size64; for (i = 0; i < NF_BR_NUMHOOKS; i++) { char __user *usrptr; if (tmp.hook_entry[i]) { unsigned int delta; usrptr = (char __user *) tmp.hook_entry[i]; delta = usrptr - tmp.entries; usrptr += xt_compat_calc_jump(NFPROTO_BRIDGE, delta); tmp.hook_entry[i] = (struct ebt_entries __user *)usrptr; } } xt_compat_flush_offsets(NFPROTO_BRIDGE); xt_compat_unlock(NFPROTO_BRIDGE); ret = do_replace_finish(net, &tmp, newinfo); if (ret == 0) return ret; free_entries: vfree(newinfo->entries); free_newinfo: vfree(newinfo); return ret; out_unlock: xt_compat_flush_offsets(NFPROTO_BRIDGE); xt_compat_unlock(NFPROTO_BRIDGE); goto free_entries; } static int compat_update_counters(struct net *net, void __user *user, unsigned int len) { struct compat_ebt_replace hlp; if (copy_from_user(&hlp, user, sizeof(hlp))) return -EFAULT; /* try real handler in case userland supplied needed padding */ if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) return update_counters(net, user, len); return do_update_counters(net, hlp.name, compat_ptr(hlp.counters), hlp.num_counters, user, len); } static int compat_do_ebt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) { int ret; struct net *net = sock_net(sk); if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; switch (cmd) { case EBT_SO_SET_ENTRIES: ret = compat_do_replace(net, user, len); break; case EBT_SO_SET_COUNTERS: ret = compat_update_counters(net, user, len); break; default: ret = -EINVAL; } return ret; } static int compat_do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) { int ret; struct compat_ebt_replace tmp; struct ebt_table *t; struct net *net = sock_net(sk); if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; /* try real handler in case userland supplied needed padding */ if ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) && *len != sizeof(tmp)) return do_ebt_get_ctl(sk, cmd, user, len); if (copy_from_user(&tmp, user, sizeof(tmp))) return -EFAULT; tmp.name[sizeof(tmp.name) - 1] = '\0'; t = find_table_lock(net, tmp.name, &ret, &ebt_mutex); if (!t) return ret; xt_compat_lock(NFPROTO_BRIDGE); switch (cmd) { case EBT_SO_GET_INFO: tmp.nentries = t->private->nentries; ret = compat_table_info(t->private, &tmp); if (ret) goto out; tmp.valid_hooks = t->valid_hooks; if (copy_to_user(user, &tmp, *len) != 0) { ret = -EFAULT; break; } ret = 0; break; case EBT_SO_GET_INIT_INFO: tmp.nentries = t->table->nentries; tmp.entries_size = t->table->entries_size; tmp.valid_hooks = t->table->valid_hooks; if (copy_to_user(user, &tmp, *len) != 0) { ret = -EFAULT; break; } ret = 0; break; case EBT_SO_GET_ENTRIES: case EBT_SO_GET_INIT_ENTRIES: /* try real handler first in case of userland-side padding. * in case we are dealing with an 'ordinary' 32 bit binary * without 64bit compatibility padding, this will fail right * after copy_from_user when the *len argument is validated. * * the compat_ variant needs to do one pass over the kernel * data set to adjust for size differences before it the check. */ if (copy_everything_to_user(t, user, len, cmd) == 0) ret = 0; else ret = compat_copy_everything_to_user(t, user, len, cmd); break; default: ret = -EINVAL; } out: xt_compat_flush_offsets(NFPROTO_BRIDGE); xt_compat_unlock(NFPROTO_BRIDGE); mutex_unlock(&ebt_mutex); return ret; } #endif static struct nf_sockopt_ops ebt_sockopts = { .pf = PF_INET, .set_optmin = EBT_BASE_CTL, .set_optmax = EBT_SO_SET_MAX + 1, .set = do_ebt_set_ctl, #ifdef CONFIG_COMPAT .compat_set = compat_do_ebt_set_ctl, #endif .get_optmin = EBT_BASE_CTL, .get_optmax = EBT_SO_GET_MAX + 1, .get = do_ebt_get_ctl, #ifdef CONFIG_COMPAT .compat_get = compat_do_ebt_get_ctl, #endif .owner = THIS_MODULE, }; static int __init ebtables_init(void) { int ret; ret = xt_register_target(&ebt_standard_target); if (ret < 0) return ret; ret = nf_register_sockopt(&ebt_sockopts); if (ret < 0) { xt_unregister_target(&ebt_standard_target); return ret; } return 0; } static void __exit ebtables_fini(void) { nf_unregister_sockopt(&ebt_sockopts); xt_unregister_target(&ebt_standard_target); } EXPORT_SYMBOL(ebt_register_table); EXPORT_SYMBOL(ebt_unregister_table); EXPORT_SYMBOL(ebt_do_table); module_init(ebtables_init); module_exit(ebtables_fini); MODULE_LICENSE("GPL");