diff options
Diffstat (limited to 'net/bridge/netfilter/ebtables.c')
| -rw-r--r-- | net/bridge/netfilter/ebtables.c | 2597 |
1 files changed, 2597 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c new file mode 100644 index 000000000..aa23479b2 --- /dev/null +++ b/net/bridge/netfilter/ebtables.c @@ -0,0 +1,2597 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * ebtables + * + * Author: + * Bart De Schuymer <bdschuym@pandora.be> + * + * 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 + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/kmod.h> +#include <linux/module.h> +#include <linux/vmalloc.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter_bridge/ebtables.h> +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/smp.h> +#include <linux/cpumask.h> +#include <linux/audit.h> +#include <net/sock.h> +#include <net/netns/generic.h> +/* needed for logical [in,out]-dev filtering */ +#include "../br_private.h" + +/* 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)) + +struct ebt_pernet { + struct list_head tables; +}; + +struct ebt_template { + struct list_head list; + char name[EBT_TABLE_MAXNAMELEN]; + struct module *owner; + /* called when table is needed in the given netns */ + int (*table_init)(struct net *net); +}; + +static unsigned int ebt_pernet_id __read_mostly; +static LIST_HEAD(template_tables); +static DEFINE_MUTEX(ebt_mutex); + +#ifdef CONFIG_NETFILTER_XTABLES_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_NETFILTER_XTABLES_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(void *priv, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct ebt_table *table = priv; + 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), skb->len, 1); + + /* 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 net *net, const char *name, int *error, + struct mutex *mutex) +{ + struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); + struct ebt_template *tmpl; + struct ebt_table *table; + + mutex_lock(mutex); + list_for_each_entry(table, &ebt_net->tables, list) { + if (strcmp(table->name, name) == 0) + return table; + } + + list_for_each_entry(tmpl, &template_tables, list) { + if (strcmp(name, tmpl->name) == 0) { + struct module *owner = tmpl->owner; + + if (!try_module_get(owner)) + goto out; + + mutex_unlock(mutex); + + *error = tmpl->table_init(net); + if (*error) { + module_put(owner); + return NULL; + } + + mutex_lock(mutex); + module_put(owner); + break; + } + } + + list_for_each_entry(table, &ebt_net->tables, list) { + if (strcmp(table->name, name) == 0) + return table; + } + +out: + *error = -ENOENT; + mutex_unlock(mutex); + return NULL; +} + +static void * +find_inlist_lock(struct net *net, const char *name, const char *prefix, + int *error, struct mutex *mutex) +{ + return try_then_request_module( + find_inlist_lock_noload(net, 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, 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, + ntohs(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, + ntohs(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 + */ + 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) + 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))) + 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) + 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) + return -EINVAL; + } + if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ + (*udc_cnt)++; + if (((struct ebt_entries *)e)->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) + return -EINVAL; + + /* this is not checked anywhere else */ + if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) + 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) + return -EINVAL; + + if (e->invflags & ~EBT_INV_MASK) + return -EINVAL; + + if ((e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3)) + 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)) { + ret = -EFAULT; + goto cleanup_watchers; + } + if (((struct ebt_standard_target *)t)->verdict < + -NUM_STANDARD_TARGETS) { + 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, + ntohs(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) + 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) + return -1; + + if (cl_s[i].cs.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) + return -EINVAL; + + if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) + 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]) + 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) + return -EINVAL; + + if (k != newinfo->nentries) + 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_node(array_size(udc_cnt, + sizeof(*(newinfo->chainstack[0]))), + cpu_to_node(i)); + 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) { + 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].bcnt, + counter_base[i].pcnt); + } +} + +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; + } + + if (repl->valid_hooks != t->valid_hooks) { + ret = -EINVAL; + goto free_unlock; + } + + if (repl->num_counters && repl->num_counters != t->private->nentries) { + 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, + array_size(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); + + audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries, + AUDIT_XT_OP_REPLACE, GFP_KERNEL); + return 0; + +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, sockptr_t arg, unsigned int len) +{ + int ret, countersize; + struct ebt_table_info *newinfo; + struct ebt_replace tmp; + + if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) + return -EFAULT; + + if (len != sizeof(tmp) + tmp.entries_size) + return -EINVAL; + + if (tmp.entries_size == 0) + 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); + if (!newinfo) + return -ENOMEM; + + if (countersize) + memset(newinfo->counters, 0, countersize); + + newinfo->entries = __vmalloc(tmp.entries_size, GFP_KERNEL_ACCOUNT); + 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; + } + + 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); + audit_log_nfcfg(table->name, AF_BRIDGE, table->private->nentries, + AUDIT_XT_OP_UNREGISTER, GFP_KERNEL); + 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->ops); + kfree(table); +} + +int ebt_register_table(struct net *net, const struct ebt_table *input_table, + const struct nf_hook_ops *template_ops) +{ + struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); + struct ebt_table_info *newinfo; + struct ebt_table *t, *table; + struct nf_hook_ops *ops; + unsigned int num_ops; + 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) + 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) + goto free_chainstack; + + table->private = newinfo; + rwlock_init(&table->lock); + mutex_lock(&ebt_mutex); + list_for_each_entry(t, &ebt_net->tables, list) { + if (strcmp(t->name, table->name) == 0) { + ret = -EEXIST; + 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; + } + + num_ops = hweight32(table->valid_hooks); + if (num_ops == 0) { + ret = -EINVAL; + goto free_unlock; + } + + ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL); + if (!ops) { + ret = -ENOMEM; + if (newinfo->nentries) + module_put(table->me); + goto free_unlock; + } + + for (i = 0; i < num_ops; i++) + ops[i].priv = table; + + list_add(&table->list, &ebt_net->tables); + mutex_unlock(&ebt_mutex); + + table->ops = ops; + ret = nf_register_net_hooks(net, ops, num_ops); + if (ret) + __ebt_unregister_table(net, table); + + audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries, + AUDIT_XT_OP_REGISTER, GFP_KERNEL); + 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; +} + +int ebt_register_template(const struct ebt_table *t, int (*table_init)(struct net *net)) +{ + struct ebt_template *tmpl; + + mutex_lock(&ebt_mutex); + list_for_each_entry(tmpl, &template_tables, list) { + if (WARN_ON_ONCE(strcmp(t->name, tmpl->name) == 0)) { + mutex_unlock(&ebt_mutex); + return -EEXIST; + } + } + + tmpl = kzalloc(sizeof(*tmpl), GFP_KERNEL); + if (!tmpl) { + mutex_unlock(&ebt_mutex); + return -ENOMEM; + } + + tmpl->table_init = table_init; + strscpy(tmpl->name, t->name, sizeof(tmpl->name)); + tmpl->owner = t->me; + list_add(&tmpl->list, &template_tables); + + mutex_unlock(&ebt_mutex); + return 0; +} +EXPORT_SYMBOL(ebt_register_template); + +void ebt_unregister_template(const struct ebt_table *t) +{ + struct ebt_template *tmpl; + + mutex_lock(&ebt_mutex); + list_for_each_entry(tmpl, &template_tables, list) { + if (strcmp(t->name, tmpl->name)) + continue; + + list_del(&tmpl->list); + mutex_unlock(&ebt_mutex); + kfree(tmpl); + return; + } + + mutex_unlock(&ebt_mutex); + WARN_ON_ONCE(1); +} +EXPORT_SYMBOL(ebt_unregister_template); + +static struct ebt_table *__ebt_find_table(struct net *net, const char *name) +{ + struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); + struct ebt_table *t; + + mutex_lock(&ebt_mutex); + + list_for_each_entry(t, &ebt_net->tables, list) { + if (strcmp(t->name, name) == 0) { + mutex_unlock(&ebt_mutex); + return t; + } + } + + mutex_unlock(&ebt_mutex); + return NULL; +} + +void ebt_unregister_table_pre_exit(struct net *net, const char *name) +{ + struct ebt_table *table = __ebt_find_table(net, name); + + if (table) + nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks)); +} +EXPORT_SYMBOL(ebt_unregister_table_pre_exit); + +void ebt_unregister_table(struct net *net, const char *name) +{ + struct ebt_table *table = __ebt_find_table(net, name); + + if (table) + __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, 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) { + ret = -EINVAL; + goto unlock_mutex; + } + + if (copy_from_user(tmp, counters, + array_size(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].bcnt, tmp[i].pcnt); + + 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, sockptr_t arg, unsigned int len) +{ + struct ebt_replace hlp; + + if (copy_from_sockptr(&hlp, arg, 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, 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. + */ + strscpy(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) + 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, + array_size(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) + return -EINVAL; + + if (tmp.entries_size != entries_size) + 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); +} + +#ifdef CONFIG_NETFILTER_XTABLES_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[] __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 ebt_compat_init_offsets(unsigned int number) +{ + if (number > INT_MAX) + return -EINVAL; + + /* also count the base chain policies */ + number += NF_BR_NUMHOOKS; + + return xt_compat_init_offsets(NFPROTO_BRIDGE, number); +} + +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; + int ret; + + newinfo->entries_size = size; + ret = ebt_compat_init_offsets(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, + const 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(const 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: + 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(const struct compat_ebt_entry_mwt *match32, + unsigned int size_left, enum compat_mwt type, + struct ebt_entries_buf_state *state, const void *base) +{ + const char *buf = (const char *)match32; + int growth = 0; + + if (size_left == 0) + return 0; + + do { + struct ebt_entry_match *match_kern; + int ret; + + if (size_left < sizeof(*match32)) + return -EINVAL; + + 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; + + match32 = (struct compat_ebt_entry_mwt *) buf; + } while (size_left); + + return growth; +} + +/* called for all ebt_entry structures. */ +static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base, + unsigned int *total, + struct ebt_entries_buf_state *state) +{ + unsigned int i, j, startoff, next_expected_off, 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->offsets, sizeof(entry->offsets)); + + 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; + } + + next_expected_off = state->buf_user_offset - startoff; + if (next_expected_off != entry->next_offset) + return -EINVAL; + + if (*total < entry->next_offset) + return -EINVAL; + *total -= entry->next_offset; + 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; + + if (size_remaining) + return -EINVAL; + + return state->buf_kern_offset; +} + + +static int compat_copy_ebt_replace_from_user(struct ebt_replace *repl, + sockptr_t arg, unsigned int len) +{ + struct compat_ebt_replace tmp; + int i; + + if (len < sizeof(tmp)) + return -EINVAL; + + if (copy_from_sockptr(&tmp, arg, 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, sockptr_t arg, 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, arg, len); + if (ret) { + /* try real handler in case userland supplied needed padding */ + if (ret == -EINVAL && do_replace(net, arg, 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); + + ret = ebt_compat_init_offsets(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)) { + vfree(entries_tmp); + 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, sockptr_t arg, + unsigned int len) +{ + struct compat_ebt_replace hlp; + + if (copy_from_sockptr(&hlp, arg, 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, arg, len); + + return do_update_counters(net, hlp.name, compat_ptr(hlp.counters), + hlp.num_counters, len); +} + +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 ((cmd == EBT_SO_GET_INFO || cmd == EBT_SO_GET_INIT_INFO) && + *len != sizeof(struct compat_ebt_replace)) + return -EINVAL; + + 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 int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) +{ + struct net *net = sock_net(sk); + struct ebt_replace tmp; + struct ebt_table *t; + int ret; + + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + return -EPERM; + +#ifdef CONFIG_NETFILTER_XTABLES_COMPAT + /* try real handler in case userland supplied needed padding */ + if (in_compat_syscall() && + ((cmd != EBT_SO_GET_INFO && cmd != EBT_SO_GET_INIT_INFO) || + *len != sizeof(tmp))) + return compat_do_ebt_get_ctl(sk, cmd, user, len); +#endif + + 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) { + 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; +} + +static int do_ebt_set_ctl(struct sock *sk, int cmd, sockptr_t arg, + unsigned int len) +{ + struct net *net = sock_net(sk); + int ret; + + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + return -EPERM; + + switch (cmd) { + case EBT_SO_SET_ENTRIES: +#ifdef CONFIG_NETFILTER_XTABLES_COMPAT + if (in_compat_syscall()) + ret = compat_do_replace(net, arg, len); + else +#endif + ret = do_replace(net, arg, len); + break; + case EBT_SO_SET_COUNTERS: +#ifdef CONFIG_NETFILTER_XTABLES_COMPAT + if (in_compat_syscall()) + ret = compat_update_counters(net, arg, len); + else +#endif + ret = update_counters(net, arg, len); + break; + default: + ret = -EINVAL; + } + return ret; +} + +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, + .get_optmin = EBT_BASE_CTL, + .get_optmax = EBT_SO_GET_MAX + 1, + .get = do_ebt_get_ctl, + .owner = THIS_MODULE, +}; + +static int __net_init ebt_pernet_init(struct net *net) +{ + struct ebt_pernet *ebt_net = net_generic(net, ebt_pernet_id); + + INIT_LIST_HEAD(&ebt_net->tables); + return 0; +} + +static struct pernet_operations ebt_net_ops = { + .init = ebt_pernet_init, + .id = &ebt_pernet_id, + .size = sizeof(struct ebt_pernet), +}; + +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; + } + + ret = register_pernet_subsys(&ebt_net_ops); + if (ret < 0) { + nf_unregister_sockopt(&ebt_sockopts); + xt_unregister_target(&ebt_standard_target); + return ret; + } + + return 0; +} + +static void ebtables_fini(void) +{ + nf_unregister_sockopt(&ebt_sockopts); + xt_unregister_target(&ebt_standard_target); + unregister_pernet_subsys(&ebt_net_ops); +} + +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"); |