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=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 5B59BC47097 for ; Mon, 31 May 2021 14:34:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 404C6613AE for ; Mon, 31 May 2021 14:34:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232184AbhEaOfi (ORCPT ); Mon, 31 May 2021 10:35:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:60130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231843AbhEaNzb (ORCPT ); Mon, 31 May 2021 09:55:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3323461438; Mon, 31 May 2021 13:34:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622468059; bh=QNIFF73Sw1QWHUeB332tv0d14bDPDTq2zZcpI4cWW+E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J8cTEpTkoN3MJLOUki+cypTmjKY8TONOxHONN5XYKShweJYUkFSWCq6n4XF1gQ/C8 s4pMGq9+xNsTEYUYu6sYlivLUu91OwQ/kO3ekkw1n2dNBcKvE7+efi6pSt1KaHcwPs GUK3Tuv6rl5HlQgEzUtIrv17BEF7ZXk/i8BEU3Ks= 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 5.10 101/252] net/mlx5e: Fix nullptr in add_vlan_push_action() Date: Mon, 31 May 2021 15:12:46 +0200 Message-Id: <20210531130701.428616818@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130657.971257589@linuxfoundation.org> References: <20210531130657.971257589@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: linux-kernel@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 @@ -4025,8 +4025,12 @@ 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);