From patchwork Sat Dec 19 12:58:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 346244 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, 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 8D281C35270 for ; Sat, 19 Dec 2020 13:00:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB0AA23ACA for ; Sat, 19 Dec 2020 13:00:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726793AbgLSNAj (ORCPT ); Sat, 19 Dec 2020 08:00:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:47228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726668AbgLSM76 (ORCPT ); Sat, 19 Dec 2020 07:59:58 -0500 From: Greg Kroah-Hartman Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cengiz Can , "David S. Miller" Subject: [PATCH 5.9 32/49] net: tipc: prevent possible null deref of link Date: Sat, 19 Dec 2020 13:58:36 +0100 Message-Id: <20201219125346.242208399@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201219125344.671832095@linuxfoundation.org> References: <20201219125344.671832095@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Cengiz Can [ Upstream commit 0398ba9e5a4b5675aa571e0445689d3c2e499c2d ] `tipc_node_apply_property` does a null check on a `tipc_link_entry` pointer but also accesses the same pointer out of the null check block. This triggers a warning on Coverity Static Analyzer because we're implying that `e->link` can BE null. Move "Update MTU for node link entry" line into if block to make sure that we're not in a state that `e->link` is null. Signed-off-by: Cengiz Can Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/tipc/node.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -2170,9 +2170,11 @@ void tipc_node_apply_property(struct net &xmitq); else if (prop == TIPC_NLA_PROP_MTU) tipc_link_set_mtu(e->link, b->mtu); + + /* Update MTU for node link entry */ + e->mtu = tipc_link_mss(e->link); } - /* Update MTU for node link entry */ - e->mtu = tipc_link_mss(e->link); + tipc_node_write_unlock(n); tipc_bearer_xmit(net, bearer_id, &xmitq, &e->maddr, NULL); }