From patchwork Tue Oct 6 05:45:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Schiller X-Patchwork-Id: 288958 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 113CAC46466 for ; Tue, 6 Oct 2020 05:46:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D47702078A for ; Tue, 6 Oct 2020 05:46:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727048AbgJFFqM (ORCPT ); Tue, 6 Oct 2020 01:46:12 -0400 Received: from mxout70.expurgate.net ([91.198.224.70]:17110 "EHLO mxout70.expurgate.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726007AbgJFFqM (ORCPT ); Tue, 6 Oct 2020 01:46:12 -0400 Received: from [127.0.0.1] (helo=localhost) by relay.expurgate.net with smtp (Exim 4.92) (envelope-from ) id 1kPfnY-000SEu-CY; Tue, 06 Oct 2020 07:46:04 +0200 Received: from [195.243.126.94] (helo=securemail.tdt.de) by relay.expurgate.net with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kPfnW-000Mbe-W8; Tue, 06 Oct 2020 07:46:03 +0200 Received: from securemail.tdt.de (localhost [127.0.0.1]) by securemail.tdt.de (Postfix) with ESMTP id 1BC4824004B; Tue, 6 Oct 2020 07:46:02 +0200 (CEST) Received: from mail.dev.tdt.de (unknown [10.2.4.42]) by securemail.tdt.de (Postfix) with ESMTP id 0919E240047; Tue, 6 Oct 2020 07:46:02 +0200 (CEST) Received: from mschiller01.dev.tdt.de (unknown [10.2.3.20]) by mail.dev.tdt.de (Postfix) with ESMTPSA id 85F5420370; Tue, 6 Oct 2020 07:46:01 +0200 (CEST) From: Martin Schiller To: andrew.hendry@gmail.com, davem@davemloft.net, kuba@kernel.org, edumazet@google.com, xiyuyang19@fudan.edu.cn Cc: linux-x25@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Schiller Subject: [PATCH v2] net/x25: Fix null-ptr-deref in x25_connect Date: Tue, 6 Oct 2020 07:45:57 +0200 Message-ID: <20201006054558.19453-1-ms@dev.tdt.de> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-purgate: clean X-purgate-ID: 151534::1601963163-00014AFE-2FCB7BA5/0/0 X-purgate-type: clean Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This fixes a regression for blocking connects introduced by commit 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect"). The x25->neighbour is already set to "NULL" by x25_disconnect() now, while a blocking connect is waiting in x25_wait_for_connection_establishment(). Therefore x25->neighbour must not be accessed here again and x25->state is also already set to X25_STATE_0 by x25_disconnect(). Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect") Signed-off-by: Martin Schiller --- Change from v1: also handle interrupting signals correctly --- net/x25/af_x25.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 0bbb283f23c9..046d3fee66a9 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -825,7 +825,7 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr, sock->state = SS_CONNECTED; rc = 0; out_put_neigh: - if (rc) { + if (rc && x25->neighbour) { read_lock_bh(&x25_list_lock); x25_neigh_put(x25->neighbour); x25->neighbour = NULL;