From mboxrd@z Thu Jan 1 00:00:00 1970 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 6DD8AC47082 for ; Mon, 31 May 2021 14:21:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53F9B61375 for ; Mon, 31 May 2021 14:21:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231876AbhEaOWh (ORCPT ); Mon, 31 May 2021 10:22:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:46052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233478AbhEaOTH (ORCPT ); Mon, 31 May 2021 10:19:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0A00561493; Mon, 31 May 2021 13:44:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622468651; bh=3Ni3jjMcqqxbHAMZygPQBjgxXpoqPMFRowJx8DM7sN0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PhGfobfmirarNC5bKxwAGLqZV7XGiI+YLIBgWsL7Cg6ToqzvGTU2t32Ivmka/amfv zuyAdEwaTG6+X7AuIYhDD/6PkMu5jYz1z584knSe8dxYHD7qjfyCZZipvxveLSImOu Qed18FcmEU5PrPMA+6mW5LyrQECTsi+UieOE0nW8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dima Chumak , Vlad Buslov , Saeed Mahameed Subject: [PATCH 5.4 073/177] net/mlx5e: Fix nullptr in add_vlan_push_action() Date: Mon, 31 May 2021 15:13:50 +0200 Message-Id: <20210531130650.416982880@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130647.887605866@linuxfoundation.org> References: <20210531130647.887605866@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Dima Chumak commit dca59f4a791960ec73fa15803faa0abe0f92ece2 upstream. The result of dev_get_by_index_rcu() is not checked for NULL and then gets dereferenced immediately. Also, the RCU lock must be held by the caller of dev_get_by_index_rcu(), which isn't satisfied by the call stack. Fix by handling nullptr return value when iflink device is not found. Add RCU locking around dev_get_by_index_rcu() to avoid possible adverse effects while iterating over the net_device's hlist. It is safe not to increment reference count of the net_device pointer in case of a successful lookup, because it's already handled by VLAN code during VLAN device registration (see register_vlan_dev and netdev_upper_dev_link). Fixes: 278748a95aa3 ("net/mlx5e: Offload TC e-switch rules with egress VLAN device") Addresses-Coverity: ("Dereference null return value") Signed-off-by: Dima Chumak Reviewed-by: Vlad Buslov Signed-off-by: Saeed Mahameed Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -3170,8 +3170,12 @@ static int add_vlan_push_action(struct m if (err) return err; - *out_dev = dev_get_by_index_rcu(dev_net(vlan_dev), - dev_get_iflink(vlan_dev)); + rcu_read_lock(); + *out_dev = dev_get_by_index_rcu(dev_net(vlan_dev), dev_get_iflink(vlan_dev)); + rcu_read_unlock(); + if (!*out_dev) + return -ENODEV; + if (is_vlan_dev(*out_dev)) err = add_vlan_push_action(priv, attr, out_dev, action);