netfilter 25/62: ctnetlink: only assign helpers for matching protocols

Patrick McHardy
2010-02-16T14:55:55Z

commit 794e68716bab578ae8f8912dc934496d7c7abc90
Author: Patrick McHardy <kaber@trash.net>
Date: Wed Feb 3 13:41:29 2010 +0100

netfilter: ctnetlink: only assign helpers for matching protocols

Make sure not to assign a helper for a different network or transport
layer protocol to a connection.

Additionally change expectation deletion by helper to compare the name
directly - there might be multiple helper registrations using the same
name, currently one of them is chosen in an unpredictable manner and
only those expectations are removed.

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index d015de9..86be7c4 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -40,7 +40,7 @@ struct nf_conntrack_helper {
};

extern struct nf_conntrack_helper *
-__nf_conntrack_helper_find_byname(const char *name);
+__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum);

extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 65c2a7b..c0e461f 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -65,7 +65,7 @@ __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
}

struct nf_conntrack_helper *
-__nf_conntrack_helper_find_byname(const char *name)
+__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum)
{
struct nf_conntrack_helper *h;
struct hlist_node *n;
@@ -73,13 +73,15 @@ __nf_conntrack_helper_find_byname(const char *name)

for (i = 0; i < nf_ct_helper_hsize; i++) {
hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) {
- if (!strcmp(h->name, name))
+ 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_byname);
+EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find);

struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
{
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 79478df..16f86d6 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1001,7 +1001,8 @@ ctnetlink_change_helper(struct nf_conn *ct, const struct nlattr * const cda[])
return 0;
}

- helper = __nf_conntrack_helper_find_byname(helpname);
+ helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
+ nf_ct_protonum(ct));
if (helper == NULL) {
#ifdef CONFIG_MODULES
spin_unlock_bh(&nf_conntrack_lock);
@@ -1012,7 +1013,8 @@ ctnetlink_change_helper(struct nf_conn *ct, const struct nlattr * const cda[])
}

spin_lock_bh(&nf_conntrack_lock);
- helper = __nf_conntrack_helper_find_byname(helpname);
+ helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
+ nf_ct_protonum(ct));
if (helper)
return -EAGAIN;
#endif
@@ -1211,7 +1213,8 @@ ctnetlink_create_conntrack(struct net *net,
if (err < 0)
goto err2;

- helper = __nf_conntrack_helper_find_byname(helpname);
+ helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
+ nf_ct_protonum(ct));
if (helper == NULL) {
rcu_read_unlock();
#ifdef CONFIG_MODULES
@@ -1221,7 +1224,9 @@ ctnetlink_create_conntrack(struct net *net,
}

rcu_read_lock();
- helper = __nf_conntrack_helper_find_byname(helpname);
+ helper = __nf_conntrack_helper_find(helpname,
+ nf_ct_l3num(ct),
+ nf_ct_protonum(ct));
if (helper) {
err = -EAGAIN;
goto err2;
@@ -1714,7 +1719,6 @@ ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,
struct net *net = sock_net(ctnl);
struct nf_conntrack_expect *exp;
struct nf_conntrack_tuple tuple;
- struct nf_conntrack_helper *h;
struct nfgenmsg *nfmsg = nlmsg_data(nlh);
struct hlist_node *n, *next;
u_int8_t u3 = nfmsg->nfgen_family;
@@ -1751,18 +1755,13 @@ ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,

/* delete all expectations for this helper */
spin_lock_bh(&nf_conntrack_lock);
- h = __nf_conntrack_helper_find_byname(name);
- if (!h) {
- spin_unlock_bh(&nf_conntrack_lock);
- return -EOPNOTSUPP;
- }
for (i = 0; i < nf_ct_expect_hsize; i++) {
hlist_for_each_entry_safe(exp, n, next,
&net->ct.expect_hash[i],
hnode) {
m_help = nfct_help(exp->master);
- if (m_help->helper == h
- && del_timer(&exp->timeout)) {
+ if (!strcmp(m_help->helper->name, name) &&
+ del_timer(&exp->timeout)) {
nf_ct_unlink_expect(exp);
nf_ct_expect_put(exp);
}