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Wed, 29 Apr 2026 16:18:46 -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 0/2] netfilter: fix NULL ops dereference in iptable lazy init Date: Wed, 29 Apr 2026 23:18:45 -0000 Message-ID: <177750472539.3004201.15967003942391945312@talencesecurity.com> In-Reply-To: <20260429175613.1459342-1-tristmd@gmail.com> References: <20260429175613.1459342-1-tristmd@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 v1 moved the ops allocation before xt_register_table(), but as Phil Sutter pointed out, new_table->ops is still assigned after the table becomes visible via list_add() inside xt_register_table(). The race window was reduced but not eliminated. v2 takes a different approach: guard the pre_exit path against a NULL ops pointer. If cleanup_net races against lazy table init and finds the table before ops has been assigned, it simply skips the nf_unregister_net_hooks() call. The register path will either complete normally or fail and clean up via __ipt_unregister_table(). v1: https://lore.kernel.org/netdev/20260429175613.1459342-1-tristmd@gmail.com/ Tristan Madani (2): netfilter: ip_tables: guard ipt_unregister_table_pre_exit against NULL ops netfilter: ip6_tables: guard ip6t_unregister_table_pre_exit against NULL ops net/ipv4/netfilter/ip_tables.c | 2 +- net/ipv6/netfilter/ip6_tables.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)