linux-kernel - [PATCH 5.5 140/151] netfilter: nf_tables: free flowtable hooks on hook register error

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Date:   Tue, 17 Mar 2020 11:55:50 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+a2ff6fa45162a5ed4dd3@...kaller.appspotmail.com,
        Florian Westphal <fw@...len.de>,
        Pablo Neira Ayuso <pablo@...filter.org>
Subject: [PATCH 5.5 140/151] netfilter: nf_tables: free flowtable hooks on hook register error

From: Florian Westphal <fw@...len.de>

commit 2d285f26ecd072800a29c5b71e63437f21ef830a upstream.

If hook registration fails, the hooks allocated via nft_netdev_hook_alloc
need to be freed.

We can't change the goto label to 'goto 5' -- while it does fix the memleak
it does cause a warning splat from the netfilter core (the hooks were not
registered).

Fixes: 3f0465a9ef02 ("netfilter: nf_tables: dynamically allocate hooks per net_device in flowtables")
Reported-by: syzbot+a2ff6fa45162a5ed4dd3@...kaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/netfilter/nf_tables_api.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -6172,8 +6172,13 @@ static int nf_tables_newflowtable(struct
 		goto err4;
 
 	err = nft_register_flowtable_net_hooks(ctx.net, table, flowtable);
-	if (err < 0)
+	if (err < 0) {
+		list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
+			list_del_rcu(&hook->list);
+			kfree_rcu(hook, rcu);
+		}
 		goto err4;
+	}
 
 	err = nft_trans_flowtable_add(&ctx, NFT_MSG_NEWFLOWTABLE, flowtable);
 	if (err < 0)