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x_tables.c
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/*
* x_tables core - Backend for {ip,ip6,arp}_tables
*
* Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
* Copyright (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*
* Based on existing ip_tables code which is
* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
* Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#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 <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 <laforge@netfilter.org>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
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_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 struct xt_af *xt;
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;
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;
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. */
struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
{
struct xt_target *t;
int err = -ENOENT;
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);
}
EXPORT_SYMBOL(xt_find_target);
struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
{
struct xt_target *target;
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 match_revfn(u8 af, const char *name, u8 revision, int *bestp)
{
const struct xt_match *m;
int have_rev = 0;
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;
}
}
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;
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;
}
}
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;
mutex_lock(&xt[af].mutex);
if (target == 1)
have_rev = target_revfn(af, name, revision, &best);
else
have_rev = match_revfn(af, name, revision, &best);
mutex_unlock(&xt[af].mutex);
/* 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;
}
int xt_check_match(struct xt_mtchk_param *par,
unsigned int size, u_int8_t 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("%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_err("%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_err("%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_err("%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;
}
#ifdef CONFIG_COMPAT
int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
{
struct xt_af *xp = &xt[af];
if (!xp->compat_tab) {
if (!xp->number)
return -EINVAL;
xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
if (!xp->compat_tab)
return -ENOMEM;
xp->cur = 0;
}
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)
{
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);
void xt_compat_init_offsets(u_int8_t af, unsigned int number)
{
xt[af].number = number;
xt[af].cur = 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 pad, 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));
pad = XT_ALIGN(match->matchsize) - match->matchsize;
if (pad > 0)
memset(m->data + match->matchsize, 0, pad);
msize += off;
m->u.user.match_size = msize;
strlcpy(name, match->name, sizeof(name));
module_put(match->me);
strncpy(m->u.user.name, name, sizeof(m->u.user.name));
*size += off;
*dstptr += msize;
}
EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
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 (copy_to_user(cm, m, sizeof(*cm)) ||
put_user(msize, &cm->u.user.match_size) ||
copy_to_user(cm->u.user.name, m->u.kernel.match->name,
strlen(m->u.kernel.match->name) + 1))
return -EFAULT;
if (match->compat_to_user) {
if (match->compat_to_user((void __user *)cm->data, m->data))
return -EFAULT;
} else {
if (copy_to_user(cm->data, m->data, 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;
};
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 &&
target_offset + sizeof(struct compat_xt_standard_target) != next_offset)
return -EINVAL;
/* compat_xt_entry match has less strict aligment 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_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_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 &&
target_offset + sizeof(struct xt_standard_target) != next_offset)
return -EINVAL;
return xt_check_entry_match(elems, base + target_offset,
__alignof__(struct xt_entry_match));
}
EXPORT_SYMBOL(xt_check_entry_offsets);
int xt_check_target(struct xt_tgchk_param *par,
unsigned int size, u_int8_t proto, bool inv_proto)
{
int ret;
if (XT_ALIGN(par->target->targetsize) != size) {
pr_err("%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_err("%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_err("%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_err("%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_from_user - copy counters and metadata from userspace
*
* @user: src pointer to userspace memory
* @len: alleged size of userspace memory
* @info: where to store the xt_counters_info metadata
* @compat: true if we setsockopt call is done by 32bit task on 64bit kernel
*
* 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 @compat is true, @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_from_user(const void __user *user, unsigned int len,
struct xt_counters_info *info, bool compat)
{
void *mem;
u64 size;
#ifdef CONFIG_COMPAT
if (compat) {
/* 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_user(&compat_tmp, user, sizeof(compat_tmp)) != 0)
return ERR_PTR(-EFAULT);
strlcpy(info->name, compat_tmp.name, sizeof(info->name));
info->num_counters = compat_tmp.num_counters;
user += sizeof(compat_tmp);
} else
#endif
{
if (len <= sizeof(*info))
return ERR_PTR(-EINVAL);
len -= sizeof(*info);
if (copy_from_user(info, user, sizeof(*info)) != 0)
return ERR_PTR(-EFAULT);
info->name[sizeof(info->name) - 1] = '\0';
user += sizeof(*info);
}
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_user(mem, user, len) == 0)
return mem;
vfree(mem);
return ERR_PTR(-EFAULT);
}
EXPORT_SYMBOL_GPL(xt_copy_counters_from_user);
#ifdef CONFIG_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 pad, 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
memcpy(t->data, ct->data, tsize - sizeof(*ct));
pad = XT_ALIGN(target->targetsize) - target->targetsize;
if (pad > 0)
memset(t->data + target->targetsize, 0, pad);
tsize += off;
t->u.user.target_size = tsize;
strlcpy(name, target->name, sizeof(name));
module_put(target->me);
strncpy(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 (copy_to_user(ct, t, sizeof(*ct)) ||
put_user(tsize, &ct->u.user.target_size) ||
copy_to_user(ct->u.user.name, t->u.kernel.target->name,
strlen(t->u.kernel.target->name) + 1))
return -EFAULT;
if (target->compat_to_user) {
if (target->compat_to_user((void __user *)ct->data, t->data))
return -EFAULT;
} else {
if (copy_to_user(ct->data, t->data, 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))
return NULL;
/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
return NULL;
if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
if (!info) {
info = vmalloc(sz);
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);
/* 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_table *t, *found = NULL;
mutex_lock(&xt[af].mutex);
list_for_each_entry(t, &net->xt.tables[af], list)
if (strcmp(t->name, name) == 0 && try_module_get(t->me))
return t;
if (net == &init_net)
goto out;
/* Table doesn't exist in this netns, re-try init */
list_for_each_entry(t, &init_net.xt.tables[af], list) {
if (strcmp(t->name, name))
continue;
if (!try_module_get(t->me))
return NULL;
mutex_unlock(&xt[af].mutex);
if (t->table_init(net) != 0) {
module_put(t->me);
return NULL;
}
found = t;
mutex_lock(&xt[af].mutex);
break;
}
if (!found)
goto out;
/* and once again: */
list_for_each_entry(t, &net->xt.tables[af], list)
if (strcmp(t->name, name) == 0)
return t;
module_put(found->me);
out:
mutex_unlock(&xt[af].mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(xt_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_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);