netfilter: ctnetlink: allow to set helper for new expectations

This patch allow you to set the helper for newly created
expectations based of the CTA_EXPECT_HELP_NAME attribute.
Before this, the helper set was NULL.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 04fb409..1b0aea6 100644 (file)
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2042,6 +2042,7 @@ ctnetlink_create_expect(struct net *net, u16 zone,
        struct nf_conntrack_expect *exp;
        struct nf_conn *ct;
        struct nf_conn_help *help;
+       struct nf_conntrack_helper *helper = NULL;
        int err = 0;
 
        /* caller guarantees that those three CTA_EXPECT_* exist */
@@ -2060,6 +2061,33 @@ ctnetlink_create_expect(struct net *net, u16 zone,
        if (!h)
                return -ENOENT;
        ct = nf_ct_tuplehash_to_ctrack(h);
+
+       /* Look for helper of this expectation */
+       if (cda[CTA_EXPECT_HELP_NAME]) {
+               const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]);
+
+               helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
+                                                   nf_ct_protonum(ct));
+               if (helper == NULL) {
+#ifdef CONFIG_MODULES
+                       if (request_module("nfct-helper-%s", helpname) < 0) {
+                               err = -EOPNOTSUPP;
+                               goto out;
+                       }
+
+                       helper = __nf_conntrack_helper_find(helpname,
+                                                           nf_ct_l3num(ct),
+                                                           nf_ct_protonum(ct));
+                       if (helper) {
+                               err = -EAGAIN;
+                               goto out;
+                       }
+#endif
+                       err = -EOPNOTSUPP;
+                       goto out;
+               }
+       }
+
        exp = nf_ct_expect_alloc(ct);
        if (!exp) {
                err = -ENOMEM;
@@ -2090,7 +2118,7 @@ ctnetlink_create_expect(struct net *net, u16 zone,
        exp->class = 0;
        exp->expectfn = NULL;
        exp->master = ct;
-       exp->helper = NULL;
+       exp->helper = helper;
        memcpy(&exp->tuple, &tuple, sizeof(struct nf_conntrack_tuple));
        memcpy(&exp->mask.src.u3, &mask.src.u3, sizeof(exp->mask.src.u3));
        exp->mask.src.u.all = mask.src.u.all;