netfilter: conntrack: helper: Replace -EEXIST by -EBUSY

The helper registration return value is passed-through by module_init
callbacks which modprobe confuses with the harmless -EEXIST returned
when trying to load an already loaded module.

Make sure modprobe fails so users notice their helper has not been
registered and won't work.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Fixes: 12f7a505331e ("netfilter: add user-space connection tracking helper infrastructure")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 4ed5878cb25b16fe90f76833fc1f9cec2f1bacfe..ceb48c3ca0a43981358f1bc61a2b47db3358e0bf 100644 (file)
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -368,7 +368,7 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
                            (cur->tuple.src.l3num == NFPROTO_UNSPEC ||
                             cur->tuple.src.l3num == me->tuple.src.l3num) &&
                            cur->tuple.dst.protonum == me->tuple.dst.protonum) {
-                               ret = -EEXIST;
+                               ret = -EBUSY;
                                goto out;
                        }
                }
@@ -379,7 +379,7 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
                hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) {
                        if (nf_ct_tuple_src_mask_cmp(&cur->tuple, &me->tuple,
                                                     &mask)) {
-                               ret = -EEXIST;
+                               ret = -EBUSY;
                                goto out;
                        }
                }