// SPDX-License-Identifier: GPL-2.0-only
/*
* x_tables core - Backend for {ip,ip6,arp}_tables
*
* Copyright (C) 2006-2006 Harald Welte <[email protected]>
* Copyright (C) 2006-2012 Patrick McHardy <[email protected]>
*
* Based on existing ip_tables code which is
* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
* Copyright (C) 2000-2005 Netfilter Core Team <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/audit.h>
#include <linux/user_namespace.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_arp.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_arp/arp_tables.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <[email protected]>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
#define XT_PCPU_BLOCK_SIZE 4096
#define XT_MAX_TABLE_SIZE (512 * 1024 * 1024)
struct xt_template {
struct list_head list;
/* called when table is needed in the given netns */
int (*table_init)(struct net *net);
struct module *me;
/* A unique name... */
char name[XT_TABLE_MAXNAMELEN];
};
static struct list_head xt_templates[NFPROTO_NUMPROTO];
struct xt_pernet {
struct list_head tables[NFPROTO_NUMPROTO];
};
struct compat_delta {
unsigned int offset; /* offset in kernel */
int delta; /* delta in 32bit user land */
};
struct xt_af {
struct mutex mutex;
struct list_head match;
struct list_head target;
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
struct mutex compat_mutex;
struct compat_delta *compat_tab;
unsigned int number; /* number of slots in compat_tab[] */
unsigned int cur; /* number of used slots in compat_tab[] */
#endif
};
static unsigned int xt_pernet_id __read_mostly;
static struct xt_af *xt __read_mostly;
static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
[NFPROTO_UNSPEC] = "x",
[NFPROTO_IPV4] = "ip",
[NFPROTO_ARP] = "arp",
[NFPROTO_BRIDGE] = "eb",
[NFPROTO_IPV6] = "ip6",
};
/* Registration hooks for targets. */
int xt_register_target(struct xt_target *target)
{
u_int8_t af = target->family;
mutex_lock(&xt[af].mutex);
list_add(&target->list, &xt[af].target);
mutex_unlock(&xt[af].mutex);
return 0;
}
EXPORT_SYMBOL(xt_register_target);
void
xt_unregister_target(struct xt_target *target)
{
u_int8_t af = target->family;
mutex_lock(&xt[af].mutex);
list_del(&target->list);
mutex_unlock(&xt[af].mutex);
}
EXPORT_SYMBOL(xt_unregister_target);
int
xt_register_targets(struct xt_target *target, unsigned int n)
{
unsigned int i;
int err = 0;
for (i = 0; i < n; i++) {
err = xt_register_target(&target[i]);
if (err)
goto err;
}
return err;
err:
if (i > 0)
xt_unregister_targets(target, i);
return err;
}
EXPORT_SYMBOL(xt_register_targets);
void
xt_unregister_targets(struct xt_target *target, unsigned int n)
{
while (n-- > 0)
xt_unregister_target(&target[n]);
}
EXPORT_SYMBOL(xt_unregister_targets);
int xt_register_match(struct xt_match *match)
{
u_int8_t af = match->family;
mutex_lock(&xt[af].mutex);
list_add(&match->list, &xt[af].match);
mutex_unlock(&xt[af].mutex);
return 0;
}
EXPORT_SYMBOL(xt_register_match);
void
xt_unregister_match(struct xt_match *match)
{
u_int8_t af = match->family;
mutex_lock(&xt[af].mutex);
list_del(&match->list);
mutex_unlock(&xt[af].mutex);
}
EXPORT_SYMBOL(xt_unregister_match);
int
xt_register_matches(struct xt_match *match, unsigned int n)
{
unsigned int i;
int err = 0;
for (i = 0; i < n; i++) {
err = xt_register_match(&match[i]);
if (err)
goto err;
}
return err;
err:
if (i > 0)
xt_unregister_matches(match, i);
return err;
}
EXPORT_SYMBOL(xt_register_matches);
void
xt_unregister_matches(struct xt_match *match, unsigned int n)
{
while (n-- > 0)
xt_unregister_match(&match[n]);
}
EXPORT_SYMBOL(xt_unregister_matches);
/*
* These are weird, but module loading must not be done with mutex
* held (since they will register), and we have to have a single
* function to use.
*/
/* Find match, grabs ref. Returns ERR_PTR() on error. */
struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
{
struct xt_match *m;
int err = -ENOENT;
if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
return ERR_PTR(-EINVAL);
mutex_lock(&xt[af].mutex);
list_for_each_entry(m, &xt[af].match, list) {
if (strcmp(m->name, name) == 0) {
if (m->revision == revision) {
if (try_module_get(m->me)) {
mutex_unlock(&xt[af].mutex);
return m;
}
} else
err = -EPROTOTYPE; /* Found something. */
}
}
mutex_unlock(&xt[af].mutex);
if (af != NFPROTO_UNSPEC)
/* Try searching again in the family-independent list */
return xt_find_match(NFPROTO_UNSPEC, name, revision);
return ERR_PTR(err);
}
EXPORT_SYMBOL(xt_find_match);
struct xt_match *
xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
{
struct xt_match *match;
if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
return ERR_PTR(-EINVAL);
match = xt_find_match(nfproto, name, revision);
if (IS_ERR(match)) {
request_module("%st_%s", xt_prefix[nfproto], name);
match = xt_find_match(nfproto, name, revision);
}
return match;
}
EXPORT_SYMBOL_GPL(xt_request_find_match);
/* Find target, grabs ref. Returns ERR_PTR() on error. */
static struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
{
struct xt_target *t;
int err = -ENOENT;
if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
return ERR_PTR(-EINVAL);
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt[af].target, list) {
if (strcmp(t->name, name) == 0) {
if (t->revision == revision) {
if (try_module_get(t->me)) {
mutex_unlock(&xt[af].mutex);
return t;
}
} else
err = -EPROTOTYPE; /* Found something. */
}
}
mutex_unlock(&xt[af].mutex);
if (af != NFPROTO_UNSPEC)
/* Try searching again in the family-independent list */
return xt_find_target(NFPROTO_UNSPEC, name, revision);
return ERR_PTR(err);
}
struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
{
struct xt_target *target;
if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
return ERR_PTR(-EINVAL);
target = xt_find_target(af, name, revision);
if (IS_ERR(target)) {
request_module("%st_%s", xt_prefix[af], name);
target = xt_find_target(af, name, revision);
}
return target;
}
EXPORT_SYMBOL_GPL(xt_request_find_target);
static int xt_obj_to_user(u16 __user *psize, u16 size,
void __user *pname, const char *name,
u8 __user *prev, u8 rev)
{
if (put_user(size, psize))
return -EFAULT;
if (copy_to_user(pname, name, strlen(name) + 1))
return -EFAULT;
if (put_user(rev, prev))
return -EFAULT;
return 0;
}
#define XT_OBJ_TO_USER(U, K, TYPE, C_SIZE) \
xt_obj_to_user(&U->u.TYPE##_size, C_SIZE ? : K->u.TYPE##_size, \
U->u.user.name, K->u.kernel.TYPE->name, \
&U->u.user.revision, K->u.kernel.TYPE->revision)
int xt_data_to_user(void __user *dst, const void *src,
int usersize, int size, int aligned_size)
{
usersize = usersize ? : size;
if (copy_to_user(dst, src, usersize))
return -EFAULT;
if (usersize != aligned_size &&
clear_user(dst + usersize, aligned_size - usersize))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(xt_data_to_user);
#define XT_DATA_TO_USER(U, K, TYPE) \
xt_data_to_user(U->data, K->data, \
K->u.kernel.TYPE->usersize, \
K->u.kernel.TYPE->TYPE##size, \
XT_ALIGN(K->u.kernel.TYPE->TYPE##size))
int xt_match_to_user(const struct xt_entry_match *m,
struct xt_entry_match __user *u)
{
return XT_OBJ_TO_USER(u, m, match, 0) ||
XT_DATA_TO_USER(u, m, match);
}
EXPORT_SYMBOL_GPL(xt_match_to_user);
int xt_target_to_user(const struct xt_entry_target *t,
struct xt_entry_target __user *u)
{
return XT_OBJ_TO_USER(u, t, target, 0) ||
XT_DATA_TO_USER(u, t, target);
}
EXPORT_SYMBOL_GPL(xt_target_to_user);
static int match_revfn(u8 af, const char *name, u8 revision, int *bestp)
{
const struct xt_match *m;
int have_rev = 0;
mutex_lock(&xt[af].mutex);
list_for_each_entry(m, &xt[af].match, list) {
if (strcmp(m->name, name) == 0) {
if (m->revision > *bestp)
*bestp = m->revision;
if (m->revision == revision)
have_rev = 1;
}
}
mutex_unlock(&xt[af].mutex);
if (af != NFPROTO_UNSPEC && !have_rev)
return match_revfn(NFPROTO_UNSPEC, name, revision, bestp);
return have_rev;
}
static int target_revfn(u8 af, const char *name, u8 revision, int *bestp)
{
const struct xt_target *t;
int have_rev = 0;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt[af].target, list) {
if (strcmp(t->name, name) == 0) {
if (t->revision > *bestp)
*bestp = t->revision;
if (t->revision == revision)
have_rev = 1;
}
}
mutex_unlock(&xt[af].mutex);
if (af != NFPROTO_UNSPEC && !have_rev)
return target_revfn(NFPROTO_UNSPEC, name, revision, bestp);
return have_rev;
}
/* Returns true or false (if no such extension at all) */
int xt_find_revision(u8 af, const char *name, u8 revision, int target,
int *err)
{
int have_rev, best = -1;
if (target == 1)
have_rev = target_revfn(af, name, revision, &best);
else
have_rev = match_revfn(af, name, revision, &best);
/* Nothing at all? Return 0 to try loading module. */
if (best == -1) {
*err = -ENOENT;
return 0;
}
*err = best;
if (!have_rev)
*err = -EPROTONOSUPPORT;
return 1;
}
EXPORT_SYMBOL_GPL(xt_find_revision);
static char *
textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto)
{
static const char *const inetbr_names[] = {
"PREROUTING", "INPUT", "FORWARD",
"OUTPUT", "POSTROUTING", "BROUTING",
};
static const char *const arp_names[] = {
"INPUT", "FORWARD", "OUTPUT",
};
const char *const *names;
unsigned int i, max;
char *p = buf;
bool np = false;
int res;
names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names;
max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) :
ARRAY_SIZE(inetbr_names);
*p = '\0';
for (i = 0; i < max; ++i) {
if (!(mask & (1 << i)))
continue;
res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]);
if (res > 0) {
size -= res;
p += res;
}
np = true;
}
return buf;
}
/**
* xt_check_proc_name - check that name is suitable for /proc file creation
*
* @name: file name candidate
* @size: length of buffer
*
* some x_tables modules wish to create a file in /proc.
* This function makes sure that the name is suitable for this
* purpose, it checks that name is NUL terminated and isn't a 'special'
* name, like "..".
*
* returns negative number on error or 0 if name is useable.
*/
int xt_check_proc_name(const char *name, unsigned int size)
{
if (name[0] == '\0')
return -EINVAL;
if (strnlen(name, size) == size)
return -ENAMETOOLONG;
if (strcmp(name, ".") == 0 ||
strcmp(name, "..") == 0 ||
strchr(name, '/'))
return -EINVAL;
return 0;
}
EXPORT_SYMBOL(xt_check_proc_name);
int xt_check_match(struct xt_mtchk_param *par,
unsigned int size, u16 proto, bool inv_proto)
{
int ret;
if (XT_ALIGN(par->match->matchsize) != size &&
par->match->matchsize != -1) {
/*
* ebt_among is exempt from centralized matchsize checking
* because it uses a dynamic-size data set.
*/
pr_err_ratelimited("%s_tables: %s.%u match: invalid size %u (kernel) != (user) %u\n",
xt_prefix[par->family], par->match->name,
par->match->revision,
XT_ALIGN(par->match->matchsize), size);
return -EINVAL;
}
if (par->match->table != NULL &&
strcmp(par->match->table, par->table) != 0) {
pr_info_ratelimited("%s_tables: %s match: only valid in %s table, not %s\n",
xt_prefix[par->family], par->match->name,
par->match->table, par->table);
return -EINVAL;
}
if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
char used[64], allow[64];
pr_info_ratelimited("%s_tables: %s match: used from hooks %s, but only valid from %s\n",
xt_prefix[par->family], par->match->name,
textify_hooks(used, sizeof(used),
par->hook_mask, par->family),
textify_hooks(allow, sizeof(allow),
par->match->hooks,
par->family));
return -EINVAL;
}
if (par->match->proto && (par->match->proto != proto || inv_proto)) {
pr_info_ratelimited("%s_tables: %s match: only valid for protocol %u\n",
xt_prefix[par->family], par->match->name,
par->match->proto);
return -EINVAL;
}
if (par->match->checkentry != NULL) {
ret = par->match->checkentry(par);
if (ret < 0)
return ret;
else if (ret > 0)
/* Flag up potential errors. */
return -EIO;
}
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_match);
/** xt_check_entry_match - check that matches end before start of target
*
* @match: beginning of xt_entry_match
* @target: beginning of this rules target (alleged end of matches)
* @alignment: alignment requirement of match structures
*
* Validates that all matches add up to the beginning of the target,
* and that each match covers at least the base structure size.
*
* Return: 0 on success, negative errno on failure.
*/
static int xt_check_entry_match(const char *match, const char *target,
const size_t alignment)
{
const struct xt_entry_match *pos;
int length = target - match;
if (length == 0) /* no matches */
return 0;
pos = (struct xt_entry_match *)match;
do {
if ((unsigned long)pos % alignment)
return -EINVAL;
if (length < (int)sizeof(struct xt_entry_match))
return -EINVAL;
if (pos->u.match_size < sizeof(struct xt_entry_match))
return -EINVAL;
if (pos->u.match_size > length)
return -EINVAL;
length -= pos->u.match_size;
pos = ((void *)((char *)(pos) + (pos)->u.match_size));
} while (length > 0);
return 0;
}
/** xt_check_table_hooks - check hook entry points are sane
*
* @info xt_table_info to check
* @valid_hooks - hook entry points that we can enter from
*
* Validates that the hook entry and underflows points are set up.
*
* Return: 0 on success, negative errno on failure.
*/
int xt_check_table_hooks(const struct xt_table_info *info, unsigned int valid_hooks)
{
const char *err = "unsorted underflow";
unsigned int i, max_uflow, max_entry;
bool check_hooks = false;
BUILD_BUG_ON(ARRAY_SIZE(info->hook_entry) != ARRAY_SIZE(info->underflow));
max_entry = 0;
max_uflow = 0;
for (i = 0; i < ARRAY_SIZE(info->hook_entry); i++) {
if (!(valid_hooks & (1 << i)))
continue;
if (info->hook_entry[i] == 0xFFFFFFFF)
return -EINVAL;
if (info->underflow[i] == 0xFFFFFFFF)
return -EINVAL;
if (check_hooks) {
if (max_uflow > info->underflow[i])
goto error;
if (max_uflow == info->underflow[i]) {
err = "duplicate underflow";
goto error;
}
if (max_entry > info->hook_entry[i]) {
err = "unsorted entry";
goto error;
}
if (max_entry == info->hook_entry[i]) {
err = "duplicate entry";
goto error;
}
}
max_entry = info->hook_entry[i];
max_uflow = info->underflow[i];
check_hooks = true;
}
return 0;
error:
pr_err_ratelimited("%s at hook %d\n", err, i);
return -EINVAL;
}
EXPORT_SYMBOL(xt_check_table_hooks);
static bool verdict_ok(int verdict)
{
if (verdict > 0)
return true;
if (verdict < 0) {
int v = -verdict - 1;
if (verdict == XT_RETURN)
return true;
switch (v) {
case NF_ACCEPT: return true;
case NF_DROP: return true;
case NF_QUEUE: return true;
default:
break;
}
return false;
}
return false;
}
static bool error_tg_ok(unsigned int usersize, unsigned int kernsize,
const char *msg, unsigned int msglen)
{
return usersize == kernsize && strnlen(msg, msglen) < msglen;
}
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
{
struct xt_af *xp = &xt[af];
WARN_ON(!mutex_is_locked(&xt[af].compat_mutex));
if (WARN_ON(!xp->compat_tab))
return -ENOMEM;
if (xp->cur >= xp->number)
return -EINVAL;
if (xp->cur)
delta += xp->compat_tab[xp->cur - 1].delta;
xp->compat_tab[xp->cur].offset = offset;
xp->compat_tab[xp->cur].delta = delta;
xp->cur++;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_add_offset);
void xt_compat_flush_offsets(u_int8_t af)
{
WARN_ON(!mutex_is_locked(&xt[af].compat_mutex));
if (xt[af].compat_tab) {
vfree(xt[af].compat_tab);
xt[af].compat_tab = NULL;
xt[af].number = 0;
xt[af].cur = 0;
}
}
EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
{
struct compat_delta *tmp = xt[af].compat_tab;
int mid, left = 0, right = xt[af].cur - 1;
while (left <= right) {
mid = (left + right) >> 1;
if (offset > tmp[mid].offset)
left = mid + 1;
else if (offset < tmp[mid].offset)
right = mid - 1;
else
return mid ? tmp[mid - 1].delta : 0;
}
return left ? tmp[left - 1].delta : 0;
}
EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
int xt_compat_init_offsets(u8 af, unsigned int number)
{
size_t mem;
WARN_ON(!mutex_is_locked(&xt[af].compat_mutex));
if (!number || number > (INT_MAX / sizeof(struct compat_delta)))
return -EINVAL;
if (WARN_ON(xt[af].compat_tab))
return -EINVAL;
mem = sizeof(struct compat_delta) * number;
if (mem > XT_MAX_TABLE_SIZE)
return -ENOMEM;
xt[af].compat_tab = vmalloc(mem);
if (!xt[af].compat_tab)
return -ENOMEM;
xt[af].number = number;
xt[af].cur = 0;
return 0;
}
EXPORT_SYMBOL(xt_compat_init_offsets);
int xt_compat_match_offset(const struct xt_match *match)
{
u_int16_t csize = match->compatsize ? : match->matchsize;
return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
}
EXPORT_SYMBOL_GPL(xt_compat_match_offset);
void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
unsigned int *size)
{
const struct xt_match *match = m->u.kernel.match;
struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
int off = xt_compat_match_offset(match);
u_int16_t msize = cm->u.user.match_size;
char name[sizeof(m->u.user.name)];
m = *dstptr;
memcpy(m, cm, sizeof(*cm));
if (match->compat_from_user)
match->compat_from_user(m->data, cm->data);
else
memcpy(m->data, cm->data, msize - sizeof(*cm));
msize += off;
m->u.user.match_size = msize;
strscpy(name, match->name, sizeof(name));
module_put(match->me);
strscpy_pad(m->u.user.name, name, sizeof(m->u.user.name));
*size += off;
*dstptr += msize;
}
EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
#define COMPAT_XT_DATA_TO_USER(U, K, TYPE, C_SIZE) \
xt_data_to_user(U->data, K->data, \
K->u.kernel.TYPE->usersize, \
C_SIZE, \
COMPAT_XT_ALIGN(C_SIZE))
int xt_compat_match_to_user(const struct xt_entry_match *m,
void __user **dstptr, unsigned int *size)
{
const struct xt_match *match = m->u.kernel.match;
struct compat_xt_entry_match __user *cm = *dstptr;
int off = xt_compat_match_offset(match);
u_int16_t msize = m->u.user.match_size - off;
if (XT_OBJ_TO_USER(cm, m, match, msize))
return -EFAULT;
if (match->compat_to_user) {
if (match->compat_to_user((void __user *)cm->data, m->data))
return -EFAULT;
} else {
if (COMPAT_XT_DATA_TO_USER(cm, m, match, msize - sizeof(*cm)))
return -EFAULT;
}
*size -= off;
*dstptr += msize;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
/* non-compat version may have padding after verdict */
struct compat_xt_standard_target {
struct compat_xt_entry_target t;
compat_uint_t verdict;
};
struct compat_xt_error_target {
struct compat_xt_entry_target t;
char errorname[XT_FUNCTION_MAXNAMELEN];
};
int xt_compat_check_entry_offsets(const void *base, const char *elems,
unsigned int target_offset,
unsigned int next_offset)
{
long size_of_base_struct = elems - (const char *)base;
const struct compat_xt_entry_target *t;
const char *e = base;
if (target_offset < size_of_base_struct)
return -EINVAL;
if (target_offset + sizeof(*t) > next_offset)
return -EINVAL;
t = (void *)(e + target_offset);
if (t->u.target_size < sizeof(*t))
return -EINVAL;
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0) {
const struct compat_xt_standard_target *st = (const void *)t;
if (COMPAT_XT_ALIGN(target_offset + sizeof(*st)) != next_offset)
return -EINVAL;
if (!verdict_ok(st->verdict))
return -EINVAL;
} else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0) {
const struct compat_xt_error_target *et = (const void *)t;
if (!error_tg_ok(t->u.target_size, sizeof(*et),
et->errorname, sizeof(et->errorname)))
return -EINVAL;
}
/* compat_xt_entry match has less strict alignment requirements,
* otherwise they are identical. In case of padding differences
* we need to add compat version of xt_check_entry_match.
*/
BUILD_BUG_ON(sizeof(struct compat_xt_entry_match) != sizeof(struct xt_entry_match));
return xt_check_entry_match(elems, base + target_offset,
__alignof__(struct compat_xt_entry_match));
}
EXPORT_SYMBOL(xt_compat_check_entry_offsets);
#endif /* CONFIG_NETFILTER_XTABLES_COMPAT */
/**
* xt_check_entry_offsets - validate arp/ip/ip6t_entry
*
* @base: pointer to arp/ip/ip6t_entry
* @elems: pointer to first xt_entry_match, i.e. ip(6)t_entry->elems
* @target_offset: the arp/ip/ip6_t->target_offset
* @next_offset: the arp/ip/ip6_t->next_offset
*
* validates that target_offset and next_offset are sane and that all
* match sizes (if any) align with the target offset.
*
* This function does not validate the targets or matches themselves, it
* only tests that all the offsets and sizes are correct, that all
* match structures are aligned, and that the last structure ends where
* the target structure begins.
*
* Also see xt_compat_check_entry_offsets for CONFIG_NETFILTER_XTABLES_COMPAT version.
*
* The arp/ip/ip6t_entry structure @base must have passed following tests:
* - it must point to a valid memory location
* - base to base + next_offset must be accessible, i.e. not exceed allocated
* length.
*
* A well-formed entry looks like this:
*
* ip(6)t_entry match [mtdata] match [mtdata] target [tgdata] ip(6)t_entry
* e->elems[]-----' | |
* matchsize | |
* matchsize | |
* | |
* target_offset---------------------------------' |
* next_offset---------------------------------------------------'
*
* elems[]: flexible array member at end of ip(6)/arpt_entry struct.
* This is where matches (if any) and the target reside.
* target_offset: beginning of target.
* next_offset: start of the next rule; also: size of this rule.
* Since targets have a minimum size, target_offset + minlen <= next_offset.
*
* Every match stores its size, sum of sizes must not exceed target_offset.
*
* Return: 0 on success, negative errno on failure.
*/
int xt_check_entry_offsets(const void *base,
const char *elems,
unsigned int target_offset,
unsigned int next_offset)
{
long size_of_base_struct = elems - (const char *)base;
const struct xt_entry_target *t;
const char *e = base;
/* target start is within the ip/ip6/arpt_entry struct */
if (target_offset < size_of_base_struct)
return -EINVAL;
if (target_offset + sizeof(*t) > next_offset)
return -EINVAL;
t = (void *)(e + target_offset);
if (t->u.target_size < sizeof(*t))
return -EINVAL;
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0) {
const struct xt_standard_target *st = (const void *)t;
if (XT_ALIGN(target_offset + sizeof(*st)) != next_offset)
return -EINVAL;
if (!verdict_ok(st->verdict))
return -EINVAL;
} else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0) {
const struct xt_error_target *et = (const void *)t;
if (!error_tg_ok(t->u.target_size, sizeof(*et),
et->errorname, sizeof(et->errorname)))
return -EINVAL;
}
return xt_check_entry_match(elems, base + target_offset,
__alignof__(struct xt_entry_match));
}
EXPORT_SYMBOL(xt_check_entry_offsets);
/**
* xt_alloc_entry_offsets - allocate array to store rule head offsets
*
* @size: number of entries
*
* Return: NULL or zeroed kmalloc'd or vmalloc'd array
*/
unsigned int *xt_alloc_entry_offsets(unsigned int size)
{
if (size > XT_MAX_TABLE_SIZE / sizeof(unsigned int))
return NULL;
return kvcalloc(size, sizeof(unsigned int), GFP_KERNEL);
}
EXPORT_SYMBOL(xt_alloc_entry_offsets);
/**
* xt_find_jump_offset - check if target is a valid jump offset
*
* @offsets: array containing all valid rule start offsets of a rule blob
* @target: the jump target to search for
* @size: entries in @offset
*/
bool xt_find_jump_offset(const unsigned int *offsets,
unsigned int target, unsigned int size)
{
int m, low = 0, hi = size;
while (hi > low) {
m = (low + hi) / 2u;
if (offsets[m] > target)
hi = m;
else if (offsets[m] < target)
low = m + 1;
else
return true;
}
return false;
}
EXPORT_SYMBOL(xt_find_jump_offset);
int xt_check_target(struct xt_tgchk_param *par,
unsigned int size, u16 proto, bool inv_proto)
{
int ret;
if (XT_ALIGN(par->target->targetsize) != size) {
pr_err_ratelimited("%s_tables: %s.%u target: invalid size %u (kernel) != (user) %u\n",
xt_prefix[par->family], par->target->name,
par->target->revision,
XT_ALIGN(par->target->targetsize), size);
return -EINVAL;
}
if (par->target->table != NULL &&
strcmp(par->target->table, par->table) != 0) {
pr_info_ratelimited("%s_tables: %s target: only valid in %s table, not %s\n",
xt_prefix[par->family], par->target->name,
par->target->table, par->table);
return -EINVAL;
}
if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
char used[64], allow[64];
pr_info_ratelimited("%s_tables: %s target: used from hooks %s, but only usable from %s\n",
xt_prefix[par->family], par->target->name,
textify_hooks(used, sizeof(used),
par->hook_mask, par->family),
textify_hooks(allow, sizeof(allow),
par->target->hooks,
par->family));
return -EINVAL;
}
if (par->target->proto && (par->target->proto != proto || inv_proto)) {
pr_info_ratelimited("%s_tables: %s target: only valid for protocol %u\n",
xt_prefix[par->family], par->target->name,
par->target->proto);
return -EINVAL;
}
if (par->target->checkentry != NULL) {
ret = par->target->checkentry(par);
if (ret < 0)
return ret;
else if (ret > 0)
/* Flag up potential errors. */
return -EIO;
}
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_target);
/**
* xt_copy_counters - copy counters and metadata from a sockptr_t
*
* @arg: src sockptr
* @len: alleged size of userspace memory
* @info: where to store the xt_counters_info metadata
*
* Copies counter meta data from @user and stores it in @info.
*
* vmallocs memory to hold the counters, then copies the counter data
* from @user to the new memory and returns a pointer to it.
*
* If called from a compat syscall, @info gets converted automatically to the
* 64bit representation.
*
* The metadata associated with the counters is stored in @info.
*
* Return: returns pointer that caller has to test via IS_ERR().
* If IS_ERR is false, caller has to vfree the pointer.
*/
void *xt_copy_counters(sockptr_t arg, unsigned int len,
struct xt_counters_info *info)
{
size_t offset;
void *mem;
u64 size;
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
if (in_compat_syscall()) {
/* structures only differ in size due to alignment */
struct compat_xt_counters_info compat_tmp;
if (len <= sizeof(compat_tmp))
return ERR_PTR(-EINVAL);
len -= sizeof(compat_tmp);
if (copy_from_sockptr(&compat_tmp, arg, sizeof(compat_tmp)) != 0)
return ERR_PTR(-EFAULT);
memcpy(info->name, compat_tmp.name, sizeof(info->name) - 1);
info->num_counters = compat_tmp.num_counters;
offset = sizeof(compat_tmp);
} else
#endif
{
if (len <= sizeof(*info))
return ERR_PTR(-EINVAL);
len -= sizeof(*info);
if (copy_from_sockptr(info, arg, sizeof(*info)) != 0)
return ERR_PTR(-EFAULT);
offset = sizeof(*info);
}
info->name[sizeof(info->name) - 1] = '\0';
size = sizeof(struct xt_counters);
size *= info->num_counters;
if (size != (u64)len)
return ERR_PTR(-EINVAL);
mem = vmalloc(len);
if (!mem)
return ERR_PTR(-ENOMEM);
if (copy_from_sockptr_offset(mem, arg, offset, len) == 0)
return mem;
vfree(mem);
return ERR_PTR(-EFAULT);
}
EXPORT_SYMBOL_GPL(xt_copy_counters);
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
int xt_compat_target_offset(const struct xt_target *target)
{
u_int16_t csize = target->compatsize ? : target->targetsize;
return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
}
EXPORT_SYMBOL_GPL(xt_compat_target_offset);
void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
unsigned int *size)
{
const struct xt_target *target = t->u.kernel.target;
struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
int off = xt_compat_target_offset(target);
u_int16_t tsize = ct->u.user.target_size;
char name[sizeof(t->u.user.name)];
t = *dstptr;
memcpy(t, ct, sizeof(*ct));
if (target->compat_from_user)
target->compat_from_user(t->data, ct->data);
else
unsafe_memcpy(t->data, ct->data, tsize - sizeof(*ct),
/* UAPI 0-sized destination */);
tsize += off;
t->u.user.target_size = tsize;
strscpy(name, target->name, sizeof(name));
module_put(target->me);
strscpy_pad(t->u.user.name, name, sizeof(t->u.user.name));
*size += off;
*dstptr += tsize;
}
EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
int xt_compat_target_to_user(const struct xt_entry_target *t,
void __user **dstptr, unsigned int *size)
{
const struct xt_target *target = t->u.kernel.target;
struct compat_xt_entry_target __user *ct = *dstptr;
int off = xt_compat_target_offset(target);
u_int16_t tsize = t->u.user.target_size - off;
if (XT_OBJ_TO_USER(ct, t, target, tsize))
return -EFAULT;
if (target->compat_to_user) {
if (target->compat_to_user((void __user *)ct->data, t->data))
return -EFAULT;
} else {
if (COMPAT_XT_DATA_TO_USER(ct, t, target, tsize - sizeof(*ct)))
return -EFAULT;
}
*size -= off;
*dstptr += tsize;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
#endif
struct xt_table_info *xt_alloc_table_info(unsigned int size)
{
struct xt_table_info *info = NULL;
size_t sz = sizeof(*info) + size;
if (sz < sizeof(*info) || sz >= XT_MAX_TABLE_SIZE)
return NULL;
info = kvmalloc(sz, GFP_KERNEL_ACCOUNT);
if (!info)
return NULL;
memset(info, 0, sizeof(*info));
info->size = size;
return info;
}
EXPORT_SYMBOL(xt_alloc_table_info);
void xt_free_table_info(struct xt_table_info *info)
{
int cpu;
if (info->jumpstack != NULL) {
for_each_possible_cpu(cpu)
kvfree(info->jumpstack[cpu]);
kvfree(info->jumpstack);
}
kvfree(info);
}
EXPORT_SYMBOL(xt_free_table_info);
struct xt_table *xt_find_table(struct net *net, u8 af, const char *name)
{
struct xt_pernet *xt_net = net_generic(net, xt_pernet_id);
struct xt_table *t;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt_net->tables[af], list) {
if (strcmp(t->name, name) == 0) {
mutex_unlock(&xt[af].mutex);
return t;
}
}
mutex_unlock(&xt[af].mutex);
return NULL;
}
EXPORT_SYMBOL(xt_find_table);
/* Find table by name, grabs mutex & ref. Returns ERR_PTR on error. */
struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
const char *name)
{
struct xt_pernet *xt_net = net_generic(net, xt_pernet_id);
struct module *owner = NULL;
struct xt_template *tmpl;
struct xt_table *t;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt_net->tables[af], list)
if (strcmp(t->name, name) == 0 && try_module_get(t->me))
return t;
/* Table doesn't exist in this netns, check larval list */
list_for_each_entry(tmpl, &xt_templates[af], list) {
int err;
if (strcmp(tmpl->name, name))
continue;
if (!try_module_get(tmpl->me))
goto out;
owner = tmpl->me;
mutex_unlock(&xt[af].mutex);
err = tmpl->table_init(net);
if (err < 0) {
module_put(owner);
return ERR_PTR(err);
}
mutex_lock(&xt[af].mutex);
break;
}
/* and once again: */
list_for_each_entry(t, &xt_net->tables[af], list)
if (strcmp(t->name, name) == 0)
return t;
module_put(owner);
out:
mutex_unlock(&xt[af].mutex);
return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL_GPL(xt_find_table_lock);
struct xt_table *xt_request_find_table_lock(struct net *net, u_int8_t af,
const char *name)
{
struct xt_table *t = xt_find_table_lock(net, af, name);
#ifdef CONFIG_MODULES
if (IS_ERR(t)) {
int err = request_module("%stable_%s", xt_prefix[af], name);
if (err < 0)
return ERR_PTR(err);
t = xt_find_table_lock(net, af, name);
}
#endif
return t;
}
EXPORT_SYMBOL_GPL(xt_request_find_table_lock);
void xt_table_unlock(struct xt_table *table)
{
mutex_unlock(&xt[table->af].mutex);
}
EXPORT_SYMBOL_GPL(xt_table_unlock);
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
void xt_compat_lock(u_int8_t af)
{
mutex_lock(&xt[af].compat_mutex);
}
EXPORT_SYMBOL_GPL(xt_compat_lock);
void xt_compat_unlock(u_int8_t af)
{
mutex_unlock(&xt[af].compat_mutex);
}
EXPORT_SYMBOL_GPL(xt_compat_unlock);
#endif
DEFINE_PER_CPU(seqcount_t, xt_recseq);
EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
struct static_key xt_tee_enabled __read_mostly;
EXPORT_SYMBOL_GPL(xt_tee_enabled);
static int xt_jumpstack_alloc(struct xt_table_info *i)
{
unsigned int size;
int cpu;
size = sizeof(void **) * nr_cpu_ids;
if (size > PAGE_SIZE)
i->jumpstack = kvzalloc(size, GFP_KERNEL);
else
i->jumpstack = kzalloc(size, GFP_KERNEL);
if (i->jumpstack == NULL)
return -ENOMEM;
/* ruleset without jumps -- no stack needed */
if (i->stacksize == 0)
return 0;
/* Jumpstack needs to be able to record two full callchains, one
* from the first rule set traversal, plus one table reentrancy
* via -j TEE without clobbering the callchain that brought us to
* TEE target.
*
* This is done by allocating two jumpstacks per cpu, on reentry
* the upper half of the stack is used.
*
* see the jumpstack setup in ipt_do_table() for more details.
*/
size = sizeof(void *) * i->stacksize * 2u;
for_each_possible_cpu(cpu) {
i->jumpstack[cpu] = kvmalloc_node(size, GFP_KERNEL,
cpu_to_node(cpu));
if (i->jumpstack[cpu] == NULL)
/*
* Freeing will be done later on by the callers. The
* chain is: xt_replace_table -> __do_replace ->
* do_replace -> xt_free_table_info.
*/
return -ENOMEM;
}
return 0;
}
struct xt_counters *xt_counters_alloc(unsigned int counters)
{
struct xt_counters *mem;
if (counters == 0 || counters > INT_MAX / sizeof(*mem))
return NULL;
counters *= sizeof(*mem);
if (counters > XT_MAX_TABLE_SIZE)
return NULL;
return vzalloc(counters);
}
EXPORT_SYMBOL(xt_counters_alloc);
struct xt_table_info *
xt_replace_table(struct xt_table *table,
unsigned int num_counters,
struct xt_table_info *newinfo,
int *error)
{
struct xt_table_info *private;
unsigned int cpu;
int ret;
ret = xt_jumpstack_alloc(newinfo);
if (ret < 0) {
*error = ret;
return NULL;
}
/* Do the substitution. */
local_bh_disable();
private = table->private;
/* Check inside lock: is the old number correct? */
if (num_counters != private->number) {
pr_debug("num_counters != table->private->number (%u/%u)\n",
num_counters, private->number);
local_bh_enable();
*error = -EAGAIN;
return NULL;
}
newinfo->initial_entries = private->initial_entries;
/*
* Ensure contents of newinfo are visible before assigning to
* private.
*/
smp_wmb();
table->private = newinfo;
/* make sure all cpus see new ->private value */
smp_mb();
/*
* Even though table entries have now been swapped, other CPU's
* may still be using the old entries...
*/
local_bh_enable();
/* ... so wait for even xt_recseq on all cpus */
for_each_possible_cpu(cpu) {
seqcount_t *s = &per_cpu(xt_recseq, cpu);
u32 seq = raw_read_seqcount(s);
if (seq & 1) {
do {
cond_resched();
cpu_relax();
} while (seq == raw_read_seqcount(s));
}
}
audit_log_nfcfg(table->name, table->af, private->number,
!private->number ? AUDIT_XT_OP_REGISTER :
AUDIT_XT_OP_REPLACE,
GFP_KERNEL);
return private;
}
EXPORT_SYMBOL_GPL(xt_replace_table);
struct xt_table *xt_register_table(struct net *net,
const struct xt_table *input_table,
struct xt_table_info *bootstrap,
struct xt_table_info *newinfo)
{
struct xt_pernet *xt_net = net_generic(net, xt_pernet_id);
struct xt_table_info *private;
struct xt_table *t, *table;
int ret;
/* Don't add one object to multiple lists. */
table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL);
if (!table) {
ret = -ENOMEM;
goto out;
}
mutex_lock(&xt[table->af].mutex);
/* Don't autoload: we'd eat our tail... */
list_for_each_entry(t, &xt_net->tables[table->af], list) {
if (strcmp(t->name, table->name) == 0) {
ret = -EEXIST;
goto unlock;
}
}
/* Simplifies replace_table code. */
table->private = bootstrap;
if (!xt_replace_table(table, 0, newinfo, &ret))
goto unlock;
private = table->private;
pr_debug("table->private->number = %u\n", private->number);
/* save number of initial entries */
private->initial_entries = private->number;
list_add(&table->list, &xt_net->tables[table->af]);
mutex_unlock(&xt[table->af].mutex);
return table;
unlock:
mutex_unlock(&xt[table->af].mutex);
kfree(table);
out:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(xt_register_table);
void *xt_unregister_table(struct xt_table *table)
{
struct xt_table_info *private;
mutex_lock(&xt[table->af].mutex);
private = table->private;
list_del(&table->list);
mutex_unlock(&xt[table->af].mutex);
audit_log_nfcfg(table->name, table->af, private->number,
AUDIT_XT_OP_UNREGISTER, GFP_KERNEL);
kfree(table->ops);
kfree(table);
return private;
}
EXPORT_SYMBOL_GPL(xt_unregister_table);
#ifdef CONFIG_PROC_FS
static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
{
u8 af = (unsigned long)pde_data(file_inode(seq->file));
struct net *net = seq_file_net(seq);
struct xt_pernet *xt_net;
xt_net = net_generic(net, xt_pernet_id);
mutex_lock(&xt[af].mutex);
return seq_list_start(&xt_net->tables[af], *pos);
}
static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
u8 af = (unsigned long)pde_data(file_inode(seq->file));
struct net *net = seq_file_net(seq);
struct xt_pernet *xt_net;
xt_net = net_generic(net, xt_pernet_id);
return seq_list_next(v, &xt_net->tables[af], pos);
}
static void xt_table_seq_stop(struct seq_file *seq, void *v)
{
u_int8_t af = (unsigned long)pde_data(file_inode(seq->file));
mutex_unlock(&xt[af].mutex);
}
static int xt_table_seq_show(struct seq_file *seq, void *v)
{
struct xt_table *table = list_entry(v, struct xt_table, list);
if (*table->name)
seq_printf(seq, "%s\n", table->name);
return 0;
}
static const struct seq_operations xt_table_seq_ops = {
.start = xt_table_seq_start,
.next = xt_table_seq_next,
.stop = xt_table_seq_stop,
.show = xt_table_seq_show,
};
/*
* Traverse state for ip{,6}_{tables,matches} for helping crossing
* the multi-AF mutexes.
*/
struct nf_mttg_trav {
struct list_head *head, *curr;
uint8_t class;
};
enum {
MTTG_TRAV_INIT,
MTTG_TRAV_NFP_UNSPEC,
MTTG_TRAV_NFP_SPEC,
MTTG_TRAV_DONE,
};
static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
bool is_target)
{
static const uint8_t next_class[] = {
[MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
[MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE,
};
uint8_t nfproto = (unsigned long)pde_data(file_inode(seq->file));
struct nf_mttg_trav *trav = seq->private;
if (ppos != NULL)
++(*ppos);
switch (trav->class) {
case MTTG_TRAV_INIT:
trav->class = MTTG_TRAV_NFP_UNSPEC;
mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
trav->head = trav->curr = is_target ?
&xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
break;
case MTTG_TRAV_NFP_UNSPEC:
trav->curr = trav->curr->next;
if (trav->curr != trav->head)
break;
mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
mutex_lock(&xt[nfproto].mutex);
trav->head = trav->curr = is_target ?
&xt[nfproto].target : &xt[nfproto].match;
trav->class = next_class[trav->class];
break;
case MTTG_TRAV_NFP_SPEC:
trav->curr = trav->curr->next;
if (trav->curr != trav->head)
break;
fallthrough;
default:
return NULL;
}
return trav;
}
static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
bool is_target)
{
struct nf_mttg_trav *trav = seq->private;
unsigned int j;
trav->class = MTTG_TRAV_INIT;
for (j = 0; j < *pos; ++j)
if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
return NULL;
return trav;
}
static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
{
uint8_t nfproto = (unsigned long)pde_data(file_inode(seq->file));
struct nf_mttg_trav *trav = seq->private;
switch (trav->class) {
case MTTG_TRAV_NFP_UNSPEC:
mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
break;
case MTTG_TRAV_NFP_SPEC:
mutex_unlock(&xt[nfproto].mutex);
break;
}
}
static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
{
return xt_mttg_seq_start(seq, pos, false);
}
static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
{
return xt_mttg_seq_next(seq, v, ppos, false);
}
static int xt_match_seq_show(struct seq_file *seq, void *v)
{
const struct nf_mttg_trav *trav = seq->private;
const struct xt_match *match;
switch (trav->class) {
case MTTG_TRAV_NFP_UNSPEC:
case MTTG_TRAV_NFP_SPEC:
if (trav->curr == trav->head)
return 0;
match = list_entry(trav->curr, struct xt_match, list);
if (*match->name)
seq_printf(seq, "%s\n", match->name);
}
return 0;
}
static const struct seq_operations xt_match_seq_ops = {
.start = xt_match_seq_start,
.next = xt_match_seq_next,
.stop = xt_mttg_seq_stop,
.show = xt_match_seq_show,
};
static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
{
return xt_mttg_seq_start(seq, pos, true);
}
static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
{
return xt_mttg_seq_next(seq, v, ppos, true);
}
static int xt_target_seq_show(struct seq_file *seq, void *v)
{
const struct nf_mttg_trav *trav = seq->private;
const struct xt_target *target;
switch (trav->class) {
case MTTG_TRAV_NFP_UNSPEC:
case MTTG_TRAV_NFP_SPEC:
if (trav->curr == trav->head)
return 0;
target = list_entry(trav->curr, struct xt_target, list);
if (*target->name)
seq_printf(seq, "%s\n", target->name);
}
return 0;
}
static const struct seq_operations xt_target_seq_ops = {
.start = xt_target_seq_start,
.next = xt_target_seq_next,
.stop = xt_mttg_seq_stop,
.show = xt_target_seq_show,
};
#define FORMAT_TABLES "_tables_names"
#define FORMAT_MATCHES "_tables_matches"
#define FORMAT_TARGETS "_tables_targets"
#endif /* CONFIG_PROC_FS */
/**
* xt_hook_ops_alloc - set up hooks for a new table
* @table: table with metadata needed to set up hooks
* @fn: Hook function
*
* This function will create the nf_hook_ops that the x_table needs
* to hand to xt_hook_link_net().
*/
struct nf_hook_ops *
xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn)
{
unsigned int hook_mask = table->valid_hooks;
uint8_t i, num_hooks = hweight32(hook_mask);
uint8_t hooknum;
struct nf_hook_ops *ops;
if (!num_hooks)
return ERR_PTR(-EINVAL);
ops = kcalloc(num_hooks, sizeof(*ops), GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0;
hook_mask >>= 1, ++hooknum) {
if (!(hook_mask & 1))
continue;
ops[i].hook = fn;
ops[i].pf = table->af;
ops[i].hooknum = hooknum;
ops[i].priority = table->priority;
++i;
}
return ops;
}
EXPORT_SYMBOL_GPL(xt_hook_ops_alloc);
int xt_register_template(const struct xt_table *table,
int (*table_init)(struct net *net))
{
int ret = -EEXIST, af = table->af;
struct xt_template *t;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt_templates[af], list) {
if (WARN_ON_ONCE(strcmp(table->name, t->name) == 0))
goto out_unlock;
}
ret = -ENOMEM;
t = kzalloc(sizeof(*t), GFP_KERNEL);
if (!t)
goto out_unlock;
BUILD_BUG_ON(sizeof(t->name) != sizeof(table->name));
strscpy(t->name, table->name, sizeof(t->name));
t->table_init = table_init;
t->me = table->me;
list_add(&t->list, &xt_templates[af]);
ret = 0;
out_unlock:
mutex_unlock(&xt[af].mutex);
return ret;
}
EXPORT_SYMBOL_GPL(xt_register_template);
void xt_unregister_template(const struct xt_table *table)
{
struct xt_template *t;
int af = table->af;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &xt_templates[af], list) {
if (strcmp(table->name, t->name))
continue;
list_del(&t->list);
mutex_unlock(&xt[af].mutex);
kfree(t);
return;
}
mutex_unlock(&xt[af].mutex);
WARN_ON_ONCE(1);
}
EXPORT_SYMBOL_GPL(xt_unregister_template);
int xt_proto_init(struct net *net, u_int8_t af)
{
#ifdef CONFIG_PROC_FS
char buf[XT_FUNCTION_MAXNAMELEN];
struct proc_dir_entry *proc;
kuid_t root_uid;
kgid_t root_gid;
#endif
if (af >= ARRAY_SIZE(xt_prefix))
return -EINVAL;
#ifdef CONFIG_PROC_FS
root_uid = make_kuid(net->user_ns, 0);
root_gid = make_kgid(net->user_ns, 0);
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
proc = proc_create_net_data(buf, 0440, net->proc_net, &xt_table_seq_ops,
sizeof(struct seq_net_private),
(void *)(unsigned long)af);
if (!proc)
goto out;
if (uid_valid(root_uid) && gid_valid(root_gid))
proc_set_user(proc, root_uid, root_gid);
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
proc = proc_create_seq_private(buf, 0440, net->proc_net,
&xt_match_seq_ops, sizeof(struct nf_mttg_trav),
(void *)(unsigned long)af);
if (!proc)
goto out_remove_tables;
if (uid_valid(root_uid) && gid_valid(root_gid))
proc_set_user(proc, root_uid, root_gid);
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TARGETS, sizeof(buf));
proc = proc_create_seq_private(buf, 0440, net->proc_net,
&xt_target_seq_ops, sizeof(struct nf_mttg_trav),
(void *)(unsigned long)af);
if (!proc)
goto out_remove_matches;
if (uid_valid(root_uid) && gid_valid(root_gid))
proc_set_user(proc, root_uid, root_gid);
#endif
return 0;
#ifdef CONFIG_PROC_FS
out_remove_matches:
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
remove_proc_entry(buf, net->proc_net);
out_remove_tables:
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
remove_proc_entry(buf, net->proc_net);
out:
return -1;
#endif
}
EXPORT_SYMBOL_GPL(xt_proto_init);
void xt_proto_fini(struct net *net, u_int8_t af)
{
#ifdef CONFIG_PROC_FS
char buf[XT_FUNCTION_MAXNAMELEN];
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
remove_proc_entry(buf, net->proc_net);
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TARGETS, sizeof(buf));
remove_proc_entry(buf, net->proc_net);
strscpy(buf, xt_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
remove_proc_entry(buf, net->proc_net);
#endif /*CONFIG_PROC_FS*/
}
EXPORT_SYMBOL_GPL(xt_proto_fini);
/**
* xt_percpu_counter_alloc - allocate x_tables rule counter
*
* @state: pointer to xt_percpu allocation state
* @counter: pointer to counter struct inside the ip(6)/arpt_entry struct
*
* On SMP, the packet counter [ ip(6)t_entry->counters.pcnt ] will then
* contain the address of the real (percpu) counter.
*
* Rule evaluation needs to use xt_get_this_cpu_counter() helper
* to fetch the real percpu counter.
*
* To speed up allocation and improve data locality, a 4kb block is
* allocated. Freeing any counter may free an entire block, so all
* counters allocated using the same state must be freed at the same
* time.
*
* xt_percpu_counter_alloc_state contains the base address of the
* allocated page and the current sub-offset.
*
* returns false on error.
*/
bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state,
struct xt_counters *counter)
{
BUILD_BUG_ON(XT_PCPU_BLOCK_SIZE < (sizeof(*counter) * 2));
if (nr_cpu_ids <= 1)
return true;
if (!state->mem) {
state->mem = __alloc_percpu(XT_PCPU_BLOCK_SIZE,
XT_PCPU_BLOCK_SIZE);
if (!state->mem)
return false;
}
counter->pcnt = (__force unsigned long)(state->mem + state->off);
state->off += sizeof(*counter);
if (state->off > (XT_PCPU_BLOCK_SIZE - sizeof(*counter))) {
state->mem = NULL;
state->off = 0;
}
return true;
}
EXPORT_SYMBOL_GPL(xt_percpu_counter_alloc);
void xt_percpu_counter_free(struct xt_counters *counters)
{
unsigned long pcnt = counters->pcnt;
if (nr_cpu_ids > 1 && (pcnt & (XT_PCPU_BLOCK_SIZE - 1)) == 0)
free_percpu((void __percpu *)pcnt);
}
EXPORT_SYMBOL_GPL(xt_percpu_counter_free);
static int __net_init xt_net_init(struct net *net)
{
struct xt_pernet *xt_net = net_generic(net, xt_pernet_id);
int i;
for (i = 0; i < NFPROTO_NUMPROTO; i++)
INIT_LIST_HEAD(&xt_net->tables[i]);
return 0;
}
static void __net_exit xt_net_exit(struct net *net)
{
struct xt_pernet *xt_net = net_generic(net, xt_pernet_id);
int i;
for (i = 0; i < NFPROTO_NUMPROTO; i++)
WARN_ON_ONCE(!list_empty(&xt_net->tables[i]));
}
static struct pernet_operations xt_net_ops = {
.init = xt_net_init,
.exit = xt_net_exit,
.id = &xt_pernet_id,
.size = sizeof(struct xt_pernet),
};
static int __init xt_init(void)
{
unsigned int i;
int rv;
for_each_possible_cpu(i) {
seqcount_init(&per_cpu(xt_recseq, i));
}
xt = kcalloc(NFPROTO_NUMPROTO, sizeof(struct xt_af), GFP_KERNEL);
if (!xt)
return -ENOMEM;
for (i = 0; i < NFPROTO_NUMPROTO; i++) {
mutex_init(&xt[i].mutex);
#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
mutex_init(&xt[i].compat_mutex);
xt[i].compat_tab = NULL;
#endif
INIT_LIST_HEAD(&xt[i].target);
INIT_LIST_HEAD(&xt[i].match);
INIT_LIST_HEAD(&xt_templates[i]);
}
rv = register_pernet_subsys(&xt_net_ops);
if (rv < 0)
kfree(xt);
return rv;
}
static void __exit xt_fini(void)
{
unregister_pernet_subsys(&xt_net_ops);
kfree(xt);
}
module_init(xt_init);
module_exit(xt_fini);
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