diff options
| author | Florian Westphal <fw@strlen.de> | 2022-02-02 12:00:56 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-02-04 05:39:57 +0100 |
| commit | d1ca60efc53d665cf89ed847a14a510a81770b81 (patch) | |
| tree | bfc6a9d7bf7cd19a341a9a24396607c1e11eb3f1 /net | |
| parent | 1f6339e034d5780ad7097c8d8c11b26e0762afba (diff) | |
netfilter: ctnetlink: disable helper autoassign
When userspace, e.g. conntrackd, inserts an entry with a specified helper,
its possible that the helper is lost immediately after its added:
ctnetlink_create_conntrack
-> nf_ct_helper_ext_add + assign helper
-> ctnetlink_setup_nat
-> ctnetlink_parse_nat_setup
-> parse_nat_setup -> nfnetlink_parse_nat_setup
-> nf_nat_setup_info
-> nf_conntrack_alter_reply
-> __nf_ct_try_assign_helper
... and __nf_ct_try_assign_helper will zero the helper again.
Set IPS_HELPER bit to bypass auto-assign logic, its unwanted, just like
when helper is assigned via ruleset.
Dropped old 'not strictly necessary' comment, it referred to use of
rcu_assign_pointer() before it got replaced by RCU_INIT_POINTER().
NB: Fixes tag intentionally incorrect, this extends the referenced commit,
but this change won't build without IPS_HELPER introduced there.
Fixes: 6714cf5465d280 ("netfilter: nf_conntrack: fix explicit helper attachment and NAT")
Reported-by: Pham Thanh Tuyen <phamtyn@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_conntrack_netlink.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index ac438370f94a..7032402ffd33 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -2311,7 +2311,8 @@ ctnetlink_create_conntrack(struct net *net, if (helper->from_nlattr) helper->from_nlattr(helpinfo, ct); - /* not in hash table yet so not strictly necessary */ + /* disable helper auto-assignment for this entry */ + ct->status |= IPS_HELPER; RCU_INIT_POINTER(help->helper, helper); } } else { |