From patchwork Wed Jun 23 17:03:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 466233 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AF16C4743C for ; Wed, 23 Jun 2021 17:03:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE1D7611C9 for ; Wed, 23 Jun 2021 17:03:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230212AbhFWRFg (ORCPT ); Wed, 23 Jun 2021 13:05:36 -0400 Received: from mail.netfilter.org ([217.70.188.207]:33558 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230052AbhFWRFc (ORCPT ); Wed, 23 Jun 2021 13:05:32 -0400 Received: from localhost.localdomain (unknown [90.77.255.23]) by mail.netfilter.org (Postfix) with ESMTPSA id 441D064275; Wed, 23 Jun 2021 19:01:48 +0200 (CEST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net-next 6/6] netfilter: nfnetlink_hook: fix check for snprintf() overflow Date: Wed, 23 Jun 2021 19:03:01 +0200 Message-Id: <20210623170301.59973-7-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210623170301.59973-1-pablo@netfilter.org> References: <20210623170301.59973-1-pablo@netfilter.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Dan Carpenter The kernel version of snprintf() can't return negatives. The "ret > (int)sizeof(sym)" check is off by one because and it should be >=. Finally, we need to set a negative error code. Fixes: e2cf17d3774c ("netfilter: add new hook nfnl subsystem") Signed-off-by: Dan Carpenter Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_hook.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_hook.c b/net/netfilter/nfnetlink_hook.c index 58fda6ac663b..50b4e3c9347a 100644 --- a/net/netfilter/nfnetlink_hook.c +++ b/net/netfilter/nfnetlink_hook.c @@ -126,8 +126,10 @@ static int nfnl_hook_dump_one(struct sk_buff *nlskb, #ifdef CONFIG_KALLSYMS ret = snprintf(sym, sizeof(sym), "%ps", ops->hook); - if (ret < 0 || ret > (int)sizeof(sym)) + if (ret >= sizeof(sym)) { + ret = -EINVAL; goto nla_put_failure; + } module_name = strstr(sym, " ["); if (module_name) {