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ebtables.c
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ebtables.c
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/*
* 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
*
* 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 <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 <asm/uaccess.h>
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/audit.h>
#include <net/sock.h>
/* 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) ? EBT_MATCH : EBT_NOMATCH;
}
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_slow */
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;
}
/* 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.family = NFPROTO_BRIDGE;
acpar.net = state->net;
acpar.in = state->in;
acpar.out = state->out;
acpar.hotdrop = false;
acpar.hooknum = hook;
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;
}
/* increase counter */
(*(counter_base + i)).pcnt++;
(*(counter_base + i)).bcnt += 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 = (struct ebt_entry_target *)
(((char *)point) + point->target_offset);
/* 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:
#ifdef CONFIG_NETFILTER_DEBUG
if (sp == 0) {
BUGPRINT("RETURN on base chain");
/* act like this is EBT_CONTINUE */
goto letscontinue;
}
#endif
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;
#ifdef CONFIG_NETFILTER_DEBUG
if (verdict < 0) {
BUGPRINT("bogus standard verdict\n");
read_unlock_bh(&table->lock);
return NF_DROP;
}
#endif
/* 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);
#ifdef CONFIG_NETFILTER_DEBUG
if (chaininfo->distinguisher) {
BUGPRINT("jump to non-chain\n");
read_unlock_bh(&table->lock);
return NF_DROP;
}
#endif
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 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, 0);
if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) {
request_module("ebt_%s", m->u.name);
match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0);
}
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);
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 = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
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;
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 = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
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;
}
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 = (struct ebt_entry_target *)
(((char *)e) + e->target_offset);
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(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
if (!newinfo->chainstack)
return -ENOMEM;
for_each_possible_cpu(i) {
newinfo->chainstack[i] =
vmalloc(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(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++) {
counters[i].pcnt += counter_base[i].pcnt;
counters[i].bcnt += counter_base[i].bcnt;
}
}
}
static int do_replace_finish(struct net *net, struct ebt_replace *repl,
struct ebt_table_info *newinfo)
{
int ret, i;
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;