[PATCH 5.14 054/151] netfilter: nf_tables: reverse order in rule replacement expansion

Greg Kroah-Hartman
2021-10-11T14:04:25Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 2c964c558641a3bddaee5719c9e6d8805f777812 ]

Deactivate old rule first, then append the new rule, so rule replacement
notification via netlink first reports the deletion of the old rule with
handle X in first place, then it adds the new rule (reusing the handle X
of the replaced old rule).

Note that the abort path releases the transaction that has been created
by nft_delrule() on error.

Fixes: ca08987885a1 ("netfilter: nf_tables: deactivate expressions in rule replecement routine")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nf_tables_api.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 085783b14075..c8acd26c7201 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3419,17 +3419,15 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
}

if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
+ err = nft_delrule(&ctx, old_rule);
+ if (err < 0)
+ goto err_destroy_flow_rule;
+
trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
if (trans == NULL) {
err = -ENOMEM;
goto err_destroy_flow_rule;
}
- err = nft_delrule(&ctx, old_rule);
- if (err < 0) {
- nft_trans_destroy(trans);
- goto err_destroy_flow_rule;
- }
-
list_add_tail_rcu(&rule->list, &old_rule->list);
} else {
trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
--
2.33.0