From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9A36F9FC; Mon, 3 Jul 2023 15:23:23 +0000 (UTC) Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8BF7E62; Mon, 3 Jul 2023 08:23:14 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qGLOC-0000cR-Qj; Mon, 03 Jul 2023 17:22:56 +0200 Date: Mon, 3 Jul 2023 17:22:56 +0200 From: Florian Westphal To: Florent Revest Cc: netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, kpsingh@kernel.org, stable@vger.kernel.org Subject: Re: [PATCH nf v2] netfilter: conntrack: Avoid nf_ct_helper_hash uses after free Message-ID: <20230703152256.GC7043@breakpoint.cc> References: <20230703145216.1096265-1-revest@chromium.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230703145216.1096265-1-revest@chromium.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_PASS,T_SCC_BODY_TEXT_LINE,T_SPF_TEMPERROR autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Florent Revest wrote: > If nf_conntrack_init_start() fails (for example due to a > register_nf_conntrack_bpf() failure), the nf_conntrack_helper_fini() > clean-up path frees the nf_ct_helper_hash map. > > When built with NF_CONNTRACK=y, further netfilter modules (e.g: > netfilter_conntrack_ftp) can still be loaded and call > nf_conntrack_helpers_register(), independently of whether nf_conntrack > initialized correctly. This accesses the nf_ct_helper_hash dangling > pointer and causes a uaf, possibly leading to random memory corruption. > > This patch guards nf_conntrack_helper_register() from accessing a freed > or uninitialized nf_ct_helper_hash pointer and fixes possible > uses-after-free when loading a conntrack module. Reviewed-by: Florian Westphal