Commit c1ebd7df authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso

netfilter: cttimeout: fix dependency with l4protocol conntrack module

This patch introduces nf_conntrack_l4proto_find_get() and
nf_conntrack_l4proto_put() to fix module dependencies between
timeout objects and l4-protocol conntrack modules.

Thus, we make sure that the module cannot be removed if it is
used by any of the cttimeout objects.
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent a0f65a26
......@@ -118,6 +118,10 @@ extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;
extern struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto);
extern struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto);
extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);
/* Protocol registration. */
extern int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *proto);
extern void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *proto);
......
......@@ -15,7 +15,7 @@ struct ctnl_timeout {
atomic_t refcnt;
char name[CTNL_TIMEOUT_NAME_MAX];
__u16 l3num;
__u8 l4num;
struct nf_conntrack_l4proto *l4proto;
char data[0];
};
......
......@@ -127,6 +127,27 @@ void nf_ct_l3proto_module_put(unsigned short l3proto)
}
EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
{
struct nf_conntrack_l4proto *p;
rcu_read_lock();
p = __nf_ct_l4proto_find(l3num, l4num);
if (!try_module_get(p->me))
p = &nf_conntrack_l4proto_generic;
rcu_read_unlock();
return p;
}
EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
{
module_put(p->me);
}
EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
static int kill_l3proto(struct nf_conn *i, void *data)
{
return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
......
......@@ -98,11 +98,13 @@ cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
break;
}
l4proto = __nf_ct_l4proto_find(l3num, l4num);
l4proto = nf_ct_l4proto_find_get(l3num, l4num);
/* This protocol is not supportted, skip. */
if (l4proto->l4proto != l4num)
return -EOPNOTSUPP;
if (l4proto->l4proto != l4num) {
ret = -EOPNOTSUPP;
goto err_proto_put;
}
if (matching) {
if (nlh->nlmsg_flags & NLM_F_REPLACE) {
......@@ -110,20 +112,25 @@ cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
* different kind, sorry.
*/
if (matching->l3num != l3num ||
matching->l4num != l4num)
return -EINVAL;
matching->l4proto->l4proto != l4num) {
ret = -EINVAL;
goto err_proto_put;
}
ret = ctnl_timeout_parse_policy(matching, l4proto,
cda[CTA_TIMEOUT_DATA]);
return ret;
}
return -EBUSY;
ret = -EBUSY;
goto err_proto_put;
}
timeout = kzalloc(sizeof(struct ctnl_timeout) +
l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
if (timeout == NULL)
return -ENOMEM;
if (timeout == NULL) {
ret = -ENOMEM;
goto err_proto_put;
}
ret = ctnl_timeout_parse_policy(timeout, l4proto,
cda[CTA_TIMEOUT_DATA]);
......@@ -132,13 +139,15 @@ cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
timeout->l3num = l3num;
timeout->l4num = l4num;
timeout->l4proto = l4proto;
atomic_set(&timeout->refcnt, 1);
list_add_tail_rcu(&timeout->head, &cttimeout_list);
return 0;
err:
kfree(timeout);
err_proto_put:
nf_ct_l4proto_put(l4proto);
return ret;
}
......@@ -149,7 +158,7 @@ ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
unsigned int flags = pid ? NLM_F_MULTI : 0;
struct nf_conntrack_l4proto *l4proto;
struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags);
......@@ -163,20 +172,10 @@ ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
NLA_PUT_STRING(skb, CTA_TIMEOUT_NAME, timeout->name);
NLA_PUT_BE16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num));
NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4num);
NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto);
NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
htonl(atomic_read(&timeout->refcnt)));
l4proto = __nf_ct_l4proto_find(timeout->l3num, timeout->l4num);
/* If the timeout object does not match the layer 4 protocol tracker,
* then skip dumping the data part since we don't know how to
* interpret it. This may happen for UPDlite, SCTP and DCCP since
* you can unload the module.
*/
if (timeout->l4num != l4proto->l4proto)
goto out;
if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
struct nlattr *nest_parms;
int ret;
......@@ -192,7 +191,7 @@ ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
nla_nest_end(skb, nest_parms);
}
out:
nlmsg_end(skb, nlh);
return skb->len;
......@@ -293,6 +292,7 @@ static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
if (atomic_dec_and_test(&timeout->refcnt)) {
/* We are protected by nfnl mutex. */
list_del_rcu(&timeout->head);
nf_ct_l4proto_put(timeout->l4proto);
kfree_rcu(timeout, rcu_head);
} else {
/* still in use, restore reference counter. */
......@@ -417,6 +417,7 @@ static void __exit cttimeout_exit(void)
/* We are sure that our objects have no clients at this point,
* it's safe to release them all without checking refcnt.
*/
nf_ct_l4proto_put(cur->l4proto);
kfree_rcu(cur, rcu_head);
}
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
......
......@@ -16,6 +16,7 @@
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_timeout.h>
#include <net/netfilter/nf_conntrack_zones.h>
......@@ -243,11 +244,12 @@ static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
info->timeout, timeout->l3num);
goto err3;
}
if (timeout->l4num != e->ip.proto) {
if (timeout->l4proto->l4proto != e->ip.proto) {
ret = -EINVAL;
pr_info("Timeout policy `%s' can only be "
"used by L4 protocol number %d\n",
info->timeout, timeout->l4num);
info->timeout,
timeout->l4proto->l4proto);
goto err3;
}
timeout_ext = nf_ct_timeout_ext_add(ct, timeout,
......
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