github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-22 14:12:07 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

netfilter: nf_conntrack: allow early drop of offloaded UDP conns

Browse Source 
Both synchronous early drop algorithm and asynchronous gc worker completely
ignore connections with IPS_OFFLOAD_BIT status bit set. With new
functionality that enabled UDP NEW connection offload in action CT
malicious user can flood the conntrack table with offloaded UDP connections
by just sending a single packet per 5tuple because such connections can no
longer be deleted by early drop algorithm.

To mitigate the issue allow both early drop and gc to consider offloaded
UDP connections for deletion.

Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Buslov 2023-02-01 17:31:00 +01:00 committed by David S. Miller
parent 6a9bad0069
commit df25455e5a
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
net/netfilter/nf_conntrack_core.c
View File

@ -1371,9 +1371,6 @@ static unsigned int early_drop_list(struct net *net,
hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
tmp = nf_ct_tuplehash_to_ctrack(h);
if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
continue;
if (nf_ct_is_expired(tmp)) {
nf_ct_gc_expired(tmp);
continue;
@ -1443,11 +1440,14 @@ static bool gc_worker_skip_ct(const struct nf_conn *ct)
static bool gc_worker_can_early_drop(const struct nf_conn *ct)
{
const struct nf_conntrack_l4proto *l4proto;
u8 protonum = nf_ct_protonum(ct);
if (test_bit(IPS_OFFLOAD_BIT, &ct->status) && protonum != IPPROTO_UDP)
return false;
if (!test_bit(IPS_ASSURED_BIT, &ct->status))
return true;
l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
l4proto = nf_ct_l4proto_find(protonum);
if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
return true;
@ -1504,7 +1504,8 @@ static void gc_worker(struct work_struct *work)
if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
nf_ct_offload_timeout(tmp);
continue;
if (!nf_conntrack_max95)
continue;
}
if (expired_count > GC_SCAN_EXPIRED_MAX) {