From patchwork Wed Sep 27 02:02:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joao Moreira X-Patchwork-Id: 13399812 X-Patchwork-Delegate: kuba@kernel.org 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 DDD7A4C8F for ; Wed, 27 Sep 2023 02:02:57 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21CDE1C26C; Tue, 26 Sep 2023 19:02:56 -0700 (PDT) X-IronPort-AV: E=McAfee;i="6600,9927,10845"; a="385565355" X-IronPort-AV: E=Sophos;i="6.03,179,1694761200"; d="scan'208";a="385565355" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2023 19:02:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10845"; a="725628857" X-IronPort-AV: E=Sophos;i="6.03,179,1694761200"; d="scan'208";a="725628857" Received: from pinksteam.jf.intel.com ([10.165.239.231]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2023 19:02:41 -0700 From: joao@overdrivepizza.com To: pablo@netfilter.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, joao@overdrivepizza.com Cc: kadlec@netfilter.org, fw@strlen.de, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, rkannoth@marvell.com, wojciech.drewek@intel.com, steen.hegenlund@microhip.com, keescook@chromium.org, Joao Moreira Subject: [PATCH v2 2/2] Make num_actions unsigned Date: Tue, 26 Sep 2023 19:02:21 -0700 Message-ID: <20230927020221.85292-3-joao@overdrivepizza.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230927020221.85292-1-joao@overdrivepizza.com> References: <20230927020221.85292-1-joao@overdrivepizza.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NEUTRAL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org From: Joao Moreira Currently, in nft_flow_rule_create function, num_actions is a signed integer. Yet, it is processed within a loop which increments its value. To prevent an overflow from occurring, make it unsigned and also check if it reaches UINT_MAX when being incremented. After checking with maintainers, it was mentioned that front-end will cap the num_actions value and that it is not possible to reach such condition for an overflow. Yet, for correctness, it is still better to fix this. This issue was observed by the commit author while reviewing a write-up regarding a CVE within the same subsystem [1]. 1 - https://nickgregory.me/post/2022/03/12/cve-2022-25636/ Signed-off-by: Joao Moreira --- net/netfilter/nf_tables_offload.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c index 12ab78fa5d84..d25088791a74 100644 --- a/net/netfilter/nf_tables_offload.c +++ b/net/netfilter/nf_tables_offload.c @@ -90,7 +90,8 @@ struct nft_flow_rule *nft_flow_rule_create(struct net *net, { struct nft_offload_ctx *ctx; struct nft_flow_rule *flow; - int num_actions = 0, err; + unsigned int num_actions = 0; + int err; struct nft_expr *expr; expr = nft_expr_first(rule); @@ -99,6 +100,9 @@ struct nft_flow_rule *nft_flow_rule_create(struct net *net, expr->ops->offload_action(expr)) num_actions++; + if (num_actions == UINT_MAX) + return ERR_PTR(-ENOMEM); + expr = nft_expr_next(expr); }