mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Patrick McHardy](/assets/img/avatar_default.png)
Add copyright statements to all netfilter files which have had significant changes done by myself in the past. Some notes: - nf_conntrack_ecache.c was incorrectly attributed to Rusty and Netfilter Core Team when it got split out of nf_conntrack_core.c. The copyrights even state a date which lies six years before it was written. It was written in 2005 by Harald and myself. - net/ipv{4,6}/netfilter.c, net/netfitler/nf_queue.c were missing copyright statements. I've added the copyright statement from net/netfilter/core.c, where this code originated - for nf_conntrack_proto_tcp.c I've also added Jozsef, since I didn't want it to give the wrong impression Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
491 lines
13 KiB
C
491 lines
13 KiB
C
/* Helper handling for netfilter. */
|
|
|
|
/* (C) 1999-2001 Paul `Rusty' Russell
|
|
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
|
|
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
|
|
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/random.h>
|
|
#include <linux/err.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/rtnetlink.h>
|
|
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_l3proto.h>
|
|
#include <net/netfilter/nf_conntrack_l4proto.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_core.h>
|
|
#include <net/netfilter/nf_conntrack_extend.h>
|
|
#include <net/netfilter/nf_log.h>
|
|
|
|
static DEFINE_MUTEX(nf_ct_helper_mutex);
|
|
struct hlist_head *nf_ct_helper_hash __read_mostly;
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_hash);
|
|
unsigned int nf_ct_helper_hsize __read_mostly;
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_hsize);
|
|
static unsigned int nf_ct_helper_count __read_mostly;
|
|
|
|
static bool nf_ct_auto_assign_helper __read_mostly = true;
|
|
module_param_named(nf_conntrack_helper, nf_ct_auto_assign_helper, bool, 0644);
|
|
MODULE_PARM_DESC(nf_conntrack_helper,
|
|
"Enable automatic conntrack helper assignment (default 1)");
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
static struct ctl_table helper_sysctl_table[] = {
|
|
{
|
|
.procname = "nf_conntrack_helper",
|
|
.data = &init_net.ct.sysctl_auto_assign_helper,
|
|
.maxlen = sizeof(unsigned int),
|
|
.mode = 0644,
|
|
.proc_handler = proc_dointvec,
|
|
},
|
|
{}
|
|
};
|
|
|
|
static int nf_conntrack_helper_init_sysctl(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
|
|
table = kmemdup(helper_sysctl_table, sizeof(helper_sysctl_table),
|
|
GFP_KERNEL);
|
|
if (!table)
|
|
goto out;
|
|
|
|
table[0].data = &net->ct.sysctl_auto_assign_helper;
|
|
|
|
/* Don't export sysctls to unprivileged users */
|
|
if (net->user_ns != &init_user_ns)
|
|
table[0].procname = NULL;
|
|
|
|
net->ct.helper_sysctl_header =
|
|
register_net_sysctl(net, "net/netfilter", table);
|
|
|
|
if (!net->ct.helper_sysctl_header) {
|
|
pr_err("nf_conntrack_helper: can't register to sysctl.\n");
|
|
goto out_register;
|
|
}
|
|
return 0;
|
|
|
|
out_register:
|
|
kfree(table);
|
|
out:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void nf_conntrack_helper_fini_sysctl(struct net *net)
|
|
{
|
|
struct ctl_table *table;
|
|
|
|
table = net->ct.helper_sysctl_header->ctl_table_arg;
|
|
unregister_net_sysctl_table(net->ct.helper_sysctl_header);
|
|
kfree(table);
|
|
}
|
|
#else
|
|
static int nf_conntrack_helper_init_sysctl(struct net *net)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void nf_conntrack_helper_fini_sysctl(struct net *net)
|
|
{
|
|
}
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
/* Stupid hash, but collision free for the default registrations of the
|
|
* helpers currently in the kernel. */
|
|
static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^
|
|
(__force __u16)tuple->src.u.all) % nf_ct_helper_hsize;
|
|
}
|
|
|
|
static struct nf_conntrack_helper *
|
|
__nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
struct nf_conntrack_helper *helper;
|
|
struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) };
|
|
unsigned int h;
|
|
|
|
if (!nf_ct_helper_count)
|
|
return NULL;
|
|
|
|
h = helper_hash(tuple);
|
|
hlist_for_each_entry_rcu(helper, &nf_ct_helper_hash[h], hnode) {
|
|
if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
|
|
return helper;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
struct nf_conntrack_helper *
|
|
__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < nf_ct_helper_hsize; i++) {
|
|
hlist_for_each_entry_rcu(h, &nf_ct_helper_hash[i], hnode) {
|
|
if (!strcmp(h->name, name) &&
|
|
h->tuple.src.l3num == l3num &&
|
|
h->tuple.dst.protonum == protonum)
|
|
return h;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find);
|
|
|
|
struct nf_conntrack_helper *
|
|
nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
|
|
h = __nf_conntrack_helper_find(name, l3num, protonum);
|
|
#ifdef CONFIG_MODULES
|
|
if (h == NULL) {
|
|
if (request_module("nfct-helper-%s", name) == 0)
|
|
h = __nf_conntrack_helper_find(name, l3num, protonum);
|
|
}
|
|
#endif
|
|
if (h != NULL && !try_module_get(h->me))
|
|
h = NULL;
|
|
|
|
return h;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get);
|
|
|
|
struct nf_conn_help *
|
|
nf_ct_helper_ext_add(struct nf_conn *ct,
|
|
struct nf_conntrack_helper *helper, gfp_t gfp)
|
|
{
|
|
struct nf_conn_help *help;
|
|
|
|
help = nf_ct_ext_add_length(ct, NF_CT_EXT_HELPER,
|
|
helper->data_len, gfp);
|
|
if (help)
|
|
INIT_HLIST_HEAD(&help->expectations);
|
|
else
|
|
pr_debug("failed to add helper extension area");
|
|
return help;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add);
|
|
|
|
int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
|
|
gfp_t flags)
|
|
{
|
|
struct nf_conntrack_helper *helper = NULL;
|
|
struct nf_conn_help *help;
|
|
struct net *net = nf_ct_net(ct);
|
|
int ret = 0;
|
|
|
|
/* We already got a helper explicitly attached. The function
|
|
* nf_conntrack_alter_reply - in case NAT is in use - asks for looking
|
|
* the helper up again. Since now the user is in full control of
|
|
* making consistent helper configurations, skip this automatic
|
|
* re-lookup, otherwise we'll lose the helper.
|
|
*/
|
|
if (test_bit(IPS_HELPER_BIT, &ct->status))
|
|
return 0;
|
|
|
|
if (tmpl != NULL) {
|
|
help = nfct_help(tmpl);
|
|
if (help != NULL) {
|
|
helper = help->helper;
|
|
set_bit(IPS_HELPER_BIT, &ct->status);
|
|
}
|
|
}
|
|
|
|
help = nfct_help(ct);
|
|
if (net->ct.sysctl_auto_assign_helper && helper == NULL) {
|
|
helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
|
|
if (unlikely(!net->ct.auto_assign_helper_warned && helper)) {
|
|
pr_info("nf_conntrack: automatic helper "
|
|
"assignment is deprecated and it will "
|
|
"be removed soon. Use the iptables CT target "
|
|
"to attach helpers instead.\n");
|
|
net->ct.auto_assign_helper_warned = true;
|
|
}
|
|
}
|
|
|
|
if (helper == NULL) {
|
|
if (help)
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
goto out;
|
|
}
|
|
|
|
if (help == NULL) {
|
|
help = nf_ct_helper_ext_add(ct, helper, flags);
|
|
if (help == NULL) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
} else {
|
|
/* We only allow helper re-assignment of the same sort since
|
|
* we cannot reallocate the helper extension area.
|
|
*/
|
|
struct nf_conntrack_helper *tmp = rcu_dereference(help->helper);
|
|
|
|
if (tmp && tmp->help != helper->help) {
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
rcu_assign_pointer(help->helper, helper);
|
|
out:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper);
|
|
|
|
static inline int unhelp(struct nf_conntrack_tuple_hash *i,
|
|
const struct nf_conntrack_helper *me)
|
|
{
|
|
struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i);
|
|
struct nf_conn_help *help = nfct_help(ct);
|
|
|
|
if (help && rcu_dereference_protected(
|
|
help->helper,
|
|
lockdep_is_held(&nf_conntrack_lock)
|
|
) == me) {
|
|
nf_conntrack_event(IPCT_HELPER, ct);
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void nf_ct_helper_destroy(struct nf_conn *ct)
|
|
{
|
|
struct nf_conn_help *help = nfct_help(ct);
|
|
struct nf_conntrack_helper *helper;
|
|
|
|
if (help) {
|
|
rcu_read_lock();
|
|
helper = rcu_dereference(help->helper);
|
|
if (helper && helper->destroy)
|
|
helper->destroy(ct);
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
|
|
static LIST_HEAD(nf_ct_helper_expectfn_list);
|
|
|
|
void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n)
|
|
{
|
|
spin_lock_bh(&nf_conntrack_lock);
|
|
list_add_rcu(&n->head, &nf_ct_helper_expectfn_list);
|
|
spin_unlock_bh(&nf_conntrack_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_register);
|
|
|
|
void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n)
|
|
{
|
|
spin_lock_bh(&nf_conntrack_lock);
|
|
list_del_rcu(&n->head);
|
|
spin_unlock_bh(&nf_conntrack_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister);
|
|
|
|
struct nf_ct_helper_expectfn *
|
|
nf_ct_helper_expectfn_find_by_name(const char *name)
|
|
{
|
|
struct nf_ct_helper_expectfn *cur;
|
|
bool found = false;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
|
|
if (!strcmp(cur->name, name)) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
return found ? cur : NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name);
|
|
|
|
struct nf_ct_helper_expectfn *
|
|
nf_ct_helper_expectfn_find_by_symbol(const void *symbol)
|
|
{
|
|
struct nf_ct_helper_expectfn *cur;
|
|
bool found = false;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
|
|
if (cur->expectfn == symbol) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
return found ? cur : NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol);
|
|
|
|
__printf(3, 4)
|
|
void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
|
|
const char *fmt, ...)
|
|
{
|
|
const struct nf_conn_help *help;
|
|
const struct nf_conntrack_helper *helper;
|
|
struct va_format vaf;
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
|
|
vaf.fmt = fmt;
|
|
vaf.va = &args;
|
|
|
|
/* Called from the helper function, this call never fails */
|
|
help = nfct_help(ct);
|
|
|
|
/* rcu_read_lock()ed by nf_hook_slow */
|
|
helper = rcu_dereference(help->helper);
|
|
|
|
nf_log_packet(nf_ct_net(ct), nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL,
|
|
"nf_ct_%s: dropping packet: %pV ", helper->name, &vaf);
|
|
|
|
va_end(args);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_log);
|
|
|
|
int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
|
|
{
|
|
int ret = 0;
|
|
struct nf_conntrack_helper *cur;
|
|
unsigned int h = helper_hash(&me->tuple);
|
|
|
|
BUG_ON(me->expect_policy == NULL);
|
|
BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES);
|
|
BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1);
|
|
|
|
mutex_lock(&nf_ct_helper_mutex);
|
|
hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) {
|
|
if (strncmp(cur->name, me->name, NF_CT_HELPER_NAME_LEN) == 0 &&
|
|
cur->tuple.src.l3num == me->tuple.src.l3num &&
|
|
cur->tuple.dst.protonum == me->tuple.dst.protonum) {
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
}
|
|
hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
|
|
nf_ct_helper_count++;
|
|
out:
|
|
mutex_unlock(&nf_ct_helper_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_register);
|
|
|
|
static void __nf_conntrack_helper_unregister(struct nf_conntrack_helper *me,
|
|
struct net *net)
|
|
{
|
|
struct nf_conntrack_tuple_hash *h;
|
|
struct nf_conntrack_expect *exp;
|
|
const struct hlist_node *next;
|
|
const struct hlist_nulls_node *nn;
|
|
unsigned int i;
|
|
|
|
/* Get rid of expectations */
|
|
for (i = 0; i < nf_ct_expect_hsize; i++) {
|
|
hlist_for_each_entry_safe(exp, next,
|
|
&net->ct.expect_hash[i], hnode) {
|
|
struct nf_conn_help *help = nfct_help(exp->master);
|
|
if ((rcu_dereference_protected(
|
|
help->helper,
|
|
lockdep_is_held(&nf_conntrack_lock)
|
|
) == me || exp->helper == me) &&
|
|
del_timer(&exp->timeout)) {
|
|
nf_ct_unlink_expect(exp);
|
|
nf_ct_expect_put(exp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Get rid of expecteds, set helpers to NULL. */
|
|
hlist_nulls_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode)
|
|
unhelp(h, me);
|
|
for (i = 0; i < net->ct.htable_size; i++) {
|
|
hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode)
|
|
unhelp(h, me);
|
|
}
|
|
}
|
|
|
|
void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
|
|
{
|
|
struct net *net;
|
|
|
|
mutex_lock(&nf_ct_helper_mutex);
|
|
hlist_del_rcu(&me->hnode);
|
|
nf_ct_helper_count--;
|
|
mutex_unlock(&nf_ct_helper_mutex);
|
|
|
|
/* Make sure every nothing is still using the helper unless its a
|
|
* connection in the hash.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
rtnl_lock();
|
|
spin_lock_bh(&nf_conntrack_lock);
|
|
for_each_net(net)
|
|
__nf_conntrack_helper_unregister(me, net);
|
|
spin_unlock_bh(&nf_conntrack_lock);
|
|
rtnl_unlock();
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
|
|
|
|
static struct nf_ct_ext_type helper_extend __read_mostly = {
|
|
.len = sizeof(struct nf_conn_help),
|
|
.align = __alignof__(struct nf_conn_help),
|
|
.id = NF_CT_EXT_HELPER,
|
|
};
|
|
|
|
int nf_conntrack_helper_pernet_init(struct net *net)
|
|
{
|
|
net->ct.auto_assign_helper_warned = false;
|
|
net->ct.sysctl_auto_assign_helper = nf_ct_auto_assign_helper;
|
|
return nf_conntrack_helper_init_sysctl(net);
|
|
}
|
|
|
|
void nf_conntrack_helper_pernet_fini(struct net *net)
|
|
{
|
|
nf_conntrack_helper_fini_sysctl(net);
|
|
}
|
|
|
|
int nf_conntrack_helper_init(void)
|
|
{
|
|
int ret;
|
|
nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
|
|
nf_ct_helper_hash =
|
|
nf_ct_alloc_hashtable(&nf_ct_helper_hsize, 0);
|
|
if (!nf_ct_helper_hash)
|
|
return -ENOMEM;
|
|
|
|
ret = nf_ct_extend_register(&helper_extend);
|
|
if (ret < 0) {
|
|
pr_err("nf_ct_helper: Unable to register helper extension.\n");
|
|
goto out_extend;
|
|
}
|
|
|
|
return 0;
|
|
out_extend:
|
|
nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_hsize);
|
|
return ret;
|
|
}
|
|
|
|
void nf_conntrack_helper_fini(void)
|
|
{
|
|
nf_ct_extend_unregister(&helper_extend);
|
|
nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_hsize);
|
|
}
|