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netfilter: nf_tables: fix chain type module reference handling 

The chain type module reference handling makes no sense at all: we take
a reference immediately when the module is registered, preventing the
module from ever being unloaded.

Fix by taking a reference when we're actually creating a chain of the
chain type and release the reference when destroying the chain.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Patrick McHardy 2014-01-09 18:42:34 +00:00 committed by Pablo Neira Ayuso
parent 758206760c
commit baae3e62f3
2 changed files with 25 additions and 22 deletions
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2
include/net/netfilter/nf_tables.h
View File

@ -436,7 +436,7 @@ struct nft_stats {
*/
struct nft_base_chain {
struct nf_hook_ops ops[NFT_HOOK_OPS_MAX];
enum nft_chain_type type;
struct nf_chain_type *type;
u8 policy;
struct nft_stats __percpu *stats;
struct nft_chain chain;

45
net/netfilter/nf_tables_api.c
View File

@ -126,27 +126,29 @@ static inline u64 nf_tables_alloc_handle(struct nft_table *table)
static struct nf_chain_type *chain_type[AF_MAX][NFT_CHAIN_T_MAX];
static int __nf_tables_chain_type_lookup(int family, const struct nlattr *nla)
static struct nf_chain_type *
__nf_tables_chain_type_lookup(int family, const struct nlattr *nla)
{
int i;
for (i=0; i<NFT_CHAIN_T_MAX; i++) {
for (i = 0; i < NFT_CHAIN_T_MAX; i++) {
if (chain_type[family][i] != NULL &&
!nla_strcmp(nla, chain_type[family][i]->name))
return i;
return chain_type[family][i];
}
return -1;
return NULL;
}
static int nf_tables_chain_type_lookup(const struct nft_af_info *afi,
const struct nlattr *nla,
bool autoload)
static struct nf_chain_type *
nf_tables_chain_type_lookup(const struct nft_af_info *afi,
const struct nlattr *nla,
bool autoload)
{
int type;
struct nf_chain_type *type;
type = __nf_tables_chain_type_lookup(afi->family, nla);
#ifdef CONFIG_MODULES
if (type < 0 && autoload) {
if (type == NULL && autoload) {
nfnl_unlock(NFNL_SUBSYS_NFTABLES);
request_module("nft-chain-%u-%*.s", afi->family,
nla_len(nla)-1, (const char *)nla_data(nla));
@ -478,10 +480,6 @@ int nft_register_chain_type(struct nf_chain_type *ctype)
err = -EBUSY;
goto out;
}
if (!try_module_get(ctype->me))
goto out;
chain_type[ctype->family][ctype->type] = ctype;
out:
nfnl_unlock(NFNL_SUBSYS_NFTABLES);
@ -493,7 +491,6 @@ void nft_unregister_chain_type(struct nf_chain_type *ctype)
{
nfnl_lock(NFNL_SUBSYS_NFTABLES);
chain_type[ctype->family][ctype->type] = NULL;
module_put(ctype->me);
nfnl_unlock(NFNL_SUBSYS_NFTABLES);
}
EXPORT_SYMBOL_GPL(nft_unregister_chain_type);
@ -617,9 +614,8 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, u32 portid, u32 seq,
htonl(basechain->policy)))
goto nla_put_failure;
if (nla_put_string(skb, NFTA_CHAIN_TYPE,
chain_type[ops->pf][nft_base_chain(chain)->type]->name))
goto nla_put_failure;
if (nla_put_string(skb, NFTA_CHAIN_TYPE, basechain->type->name))
goto nla_put_failure;
if (nft_dump_stats(skb, nft_base_chain(chain)->stats))
goto nla_put_failure;
@ -900,16 +896,17 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
return -EOVERFLOW;
if (nla[NFTA_CHAIN_HOOK]) {
struct nf_chain_type *type;
struct nf_hook_ops *ops;
nf_hookfn *hookfn;
u32 hooknum, priority;
int type = NFT_CHAIN_T_DEFAULT;
type = chain_type[family][NFT_CHAIN_T_DEFAULT];
if (nla[NFTA_CHAIN_TYPE]) {
type = nf_tables_chain_type_lookup(afi,
nla[NFTA_CHAIN_TYPE],
create);
if (type < 0)
if (type == NULL)
return -ENOENT;
}
@ -926,9 +923,11 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
return -EINVAL;
priority = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));
if (!(chain_type[family][type]->hook_mask & (1 << hooknum)))
if (!(type->hook_mask & (1 << hooknum)))
return -EOPNOTSUPP;
hookfn = chain_type[family][type]->fn[hooknum];
if (!try_module_get(type->me))
return -ENOENT;
hookfn = type->fn[hooknum];
basechain = kzalloc(sizeof(*basechain), GFP_KERNEL);
if (basechain == NULL)
@ -938,6 +937,7 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
err = nf_tables_counters(basechain,
nla[NFTA_CHAIN_COUNTERS]);
if (err < 0) {
module_put(type->me);
kfree(basechain);
return err;
}
@ -946,6 +946,7 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
newstats = alloc_percpu(struct nft_stats);
if (newstats == NULL) {
module_put(type->me);
kfree(basechain);
return -ENOMEM;
}
@ -987,6 +988,7 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
chain->flags & NFT_BASE_CHAIN) {
err = nf_register_hooks(nft_base_chain(chain)->ops, afi->nops);
if (err < 0) {
module_put(basechain->type->me);
free_percpu(basechain->stats);
kfree(basechain);
return err;
@ -1007,6 +1009,7 @@ static void nf_tables_rcu_chain_destroy(struct rcu_head *head)
BUG_ON(chain->use > 0);
if (chain->flags & NFT_BASE_CHAIN) {
module_put(nft_base_chain(chain)->type->me);
free_percpu(nft_base_chain(chain)->stats);
kfree(nft_base_chain(chain));
} else