netfilter: conntrack: fix boot failure with nf_conntrack.enable_hooks=1

This is a revert of
7b1957b049 ("netfilter: nf_defrag_ipv4: use net_generic infra")
and a partial revert of
8b0adbe3e3 ("netfilter: nf_defrag_ipv6: use net_generic infra").

If conntrack is builtin and kernel is booted with:
nf_conntrack.enable_hooks=1

.... kernel will fail to boot due to a NULL deref in
nf_defrag_ipv4_enable(): Its called before the ipv4 defrag initcall is
made, so net_generic() returns NULL.

To resolve this, move the user refcount back to struct net so calls
to those functions are possible even before their initcalls have run.

Fixes: 7b1957b049 ("netfilter: nf_defrag_ipv4: use net_generic infra")
Fixes: 8b0adbe3e3 ("netfilter: nf_defrag_ipv6: use net_generic infra").
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2021-09-23 16:44:34 +02:00 committed by Pablo Neira Ayuso
parent 3b1b6e82fb
commit 339031bafe
5 changed files with 25 additions and 39 deletions

View File

@ -17,7 +17,6 @@ struct inet_frags_ctl;
struct nft_ct_frag6_pernet {
struct ctl_table_header *nf_frag_frags_hdr;
struct fqdir *fqdir;
unsigned int users;
};
#endif /* _NF_DEFRAG_IPV6_H */

View File

@ -27,5 +27,11 @@ struct netns_nf {
#if IS_ENABLED(CONFIG_DECNET)
struct nf_hook_entries __rcu *hooks_decnet[NF_DN_NUMHOOKS];
#endif
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
unsigned int defrag_ipv4_users;
#endif
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
unsigned int defrag_ipv6_users;
#endif
};
#endif

View File

@ -20,13 +20,8 @@
#endif
#include <net/netfilter/nf_conntrack_zones.h>
static unsigned int defrag4_pernet_id __read_mostly;
static DEFINE_MUTEX(defrag4_mutex);
struct defrag4_pernet {
unsigned int users;
};
static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb,
u_int32_t user)
{
@ -111,19 +106,15 @@ static const struct nf_hook_ops ipv4_defrag_ops[] = {
static void __net_exit defrag4_net_exit(struct net *net)
{
struct defrag4_pernet *nf_defrag = net_generic(net, defrag4_pernet_id);
if (nf_defrag->users) {
if (net->nf.defrag_ipv4_users) {
nf_unregister_net_hooks(net, ipv4_defrag_ops,
ARRAY_SIZE(ipv4_defrag_ops));
nf_defrag->users = 0;
net->nf.defrag_ipv4_users = 0;
}
}
static struct pernet_operations defrag4_net_ops = {
.exit = defrag4_net_exit,
.id = &defrag4_pernet_id,
.size = sizeof(struct defrag4_pernet),
};
static int __init nf_defrag_init(void)
@ -138,24 +129,23 @@ static void __exit nf_defrag_fini(void)
int nf_defrag_ipv4_enable(struct net *net)
{
struct defrag4_pernet *nf_defrag = net_generic(net, defrag4_pernet_id);
int err = 0;
mutex_lock(&defrag4_mutex);
if (nf_defrag->users == UINT_MAX) {
if (net->nf.defrag_ipv4_users == UINT_MAX) {
err = -EOVERFLOW;
goto out_unlock;
}
if (nf_defrag->users) {
nf_defrag->users++;
if (net->nf.defrag_ipv4_users) {
net->nf.defrag_ipv4_users++;
goto out_unlock;
}
err = nf_register_net_hooks(net, ipv4_defrag_ops,
ARRAY_SIZE(ipv4_defrag_ops));
if (err == 0)
nf_defrag->users = 1;
net->nf.defrag_ipv4_users = 1;
out_unlock:
mutex_unlock(&defrag4_mutex);
@ -165,12 +155,10 @@ EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
void nf_defrag_ipv4_disable(struct net *net)
{
struct defrag4_pernet *nf_defrag = net_generic(net, defrag4_pernet_id);
mutex_lock(&defrag4_mutex);
if (nf_defrag->users) {
nf_defrag->users--;
if (nf_defrag->users == 0)
if (net->nf.defrag_ipv4_users) {
net->nf.defrag_ipv4_users--;
if (net->nf.defrag_ipv4_users == 0)
nf_unregister_net_hooks(net, ipv4_defrag_ops,
ARRAY_SIZE(ipv4_defrag_ops));
}

View File

@ -33,7 +33,7 @@
static const char nf_frags_cache_name[] = "nf-frags";
unsigned int nf_frag_pernet_id __read_mostly;
static unsigned int nf_frag_pernet_id __read_mostly;
static struct inet_frags nf_frags;
static struct nft_ct_frag6_pernet *nf_frag_pernet(struct net *net)

View File

@ -25,8 +25,6 @@
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
extern unsigned int nf_frag_pernet_id;
static DEFINE_MUTEX(defrag6_mutex);
static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
@ -91,12 +89,10 @@ static const struct nf_hook_ops ipv6_defrag_ops[] = {
static void __net_exit defrag6_net_exit(struct net *net)
{
struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
if (nf_frag->users) {
if (net->nf.defrag_ipv6_users) {
nf_unregister_net_hooks(net, ipv6_defrag_ops,
ARRAY_SIZE(ipv6_defrag_ops));
nf_frag->users = 0;
net->nf.defrag_ipv6_users = 0;
}
}
@ -134,24 +130,23 @@ static void __exit nf_defrag_fini(void)
int nf_defrag_ipv6_enable(struct net *net)
{
struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
int err = 0;
mutex_lock(&defrag6_mutex);
if (nf_frag->users == UINT_MAX) {
if (net->nf.defrag_ipv6_users == UINT_MAX) {
err = -EOVERFLOW;
goto out_unlock;
}
if (nf_frag->users) {
nf_frag->users++;
if (net->nf.defrag_ipv6_users) {
net->nf.defrag_ipv6_users++;
goto out_unlock;
}
err = nf_register_net_hooks(net, ipv6_defrag_ops,
ARRAY_SIZE(ipv6_defrag_ops));
if (err == 0)
nf_frag->users = 1;
net->nf.defrag_ipv6_users = 1;
out_unlock:
mutex_unlock(&defrag6_mutex);
@ -161,12 +156,10 @@ EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
void nf_defrag_ipv6_disable(struct net *net)
{
struct nft_ct_frag6_pernet *nf_frag = net_generic(net, nf_frag_pernet_id);
mutex_lock(&defrag6_mutex);
if (nf_frag->users) {
nf_frag->users--;
if (nf_frag->users == 0)
if (net->nf.defrag_ipv6_users) {
net->nf.defrag_ipv6_users--;
if (net->nf.defrag_ipv6_users == 0)
nf_unregister_net_hooks(net, ipv6_defrag_ops,
ARRAY_SIZE(ipv6_defrag_ops));
}