If we create a conntrack that has NAT handlings and a helper, the helper
is assigned twice. This happens because nf_nat_setup_info() - via
nf_conntrack_alter_reply() - sets the helper before ctnetlink, which
indeed does not check if the conntrack already has a helper as it thinks that
it is a brand new conntrack.
The fix moves the helper assignation before the set of the status flags.
This avoids a bogus assertion in __nf_ct_ext_add (if netfilter assertions are
enabled) which checks that the conntrack must not be confirmed.
This problem was introduced in 2.6.23 with the netfilter extension
infrastructure.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_netlink.c | 34 +++++++++++++++++++---------------
1 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index dd23339..a984b1c 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1139,16 +1139,33 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
ct->timeout.expires = jiffies + ct->timeout.expires * HZ;
ct->status |= IPS_CONFIRMED;
+ rcu_read_lock();
+ helper = __nf_ct_helper_find(rtuple);
+ if (helper) {
+ help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
+ if (help == NULL) {
+ rcu_read_unlock();
+ err = -ENOMEM;
+ goto err;
+ }
+ /* not in hash table yet so not strictly necessary */
+ rcu_assign_pointer(help->helper, helper);
+ }
+
if (cda[CTA_STATUS]) {
err = ctnetlink_change_status(ct, cda);
- if (err < 0)
+ if (err < 0) {
+ rcu_read_unlock();
goto err;
+ }
}
if (cda[CTA_PROTOINFO]) {
err = ctnetlink_change_protoinfo(ct, cda);
- if (err < 0)
+ if (err < 0) {
+ rcu_read_unlock();
goto err;
+ }
}
#if defined(CONFIG_NF_CONNTRACK_MARK)
@@ -1156,19 +1173,6 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
#endif
- rcu_read_lock();
- helper = __nf_ct_helper_find(rtuple);
- if (helper) {
- help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
- if (help == NULL) {
- rcu_read_unlock();
- err = -ENOMEM;
- goto err;
- }
- /* not in hash table yet so not strictly necessary */
- rcu_assign_pointer(help->helper, helper);
- }
-
/* setup master conntrack: this is a confirmed expectation */
if (master_ct) {
__set_bit(IPS_EXPECTED_BIT, &ct->status);
--
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