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Wed, 29 Apr 2026 16:19:03 -0700 (PDT) From: Tristan Madani X-Google-Original-From: Tristan Madani To: Pablo Neira Ayuso Cc: Phil Sutter , Florian Westphal , netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] netfilter: ip_tables: guard ipt_unregister_table_pre_exit against NULL ops Date: Wed, 29 Apr 2026 23:19:03 -0000 Message-ID: <177750474339.3016150.13196470704394042910@talencesecurity.com> In-Reply-To: <177750472539.3004201.15967003942391945312@talencesecurity.com> References: <20260429175613.1459342-1-tristmd@gmail.com> <177750472539.3004201.15967003942391945312@talencesecurity.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 ipt_register_table() adds the table to the per-netns list via xt_register_table() before assigning the per-net ops copy to new_table->ops. If cleanup_net runs during this window, ipt_unregister_table_pre_exit() finds the table via xt_find_table() and passes the NULL ops pointer to nf_unregister_net_hooks(), causing a general protection fault. Guard against this by checking table->ops before calling nf_unregister_net_hooks(). If ops is NULL the table is still being set up; the register path will either complete and register the hooks normally, or fail and clean up via __ipt_unregister_table(). Fixes: ae689334225f ("netfilter: xtables: Bring back xt_register_table()") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- net/ipv4/netfilter/ip_tables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index XXXXXXX..XXXXXXX 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1795,7 +1795,7 @@ void ipt_unregister_table_pre_exit(struct net *net, con= st char *name) { struct xt_table *table =3D xt_find_table(net, NFPROTO_IPV4, name); - if (table) + if (table && table->ops) nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks)); }