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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 60E83C433DF for ; Thu, 28 May 2020 14:38:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 439B5207D3 for ; Thu, 28 May 2020 14:38:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728494AbgE1Oiq (ORCPT ); Thu, 28 May 2020 10:38:46 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:34590 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725768AbgE1Oim (ORCPT ); Thu, 28 May 2020 10:38:42 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 236C15584F194234AC35; Thu, 28 May 2020 22:38:35 +0800 (CST) Received: from localhost (10.166.215.154) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Thu, 28 May 2020 22:38:27 +0800 From: YueHaibing To: , , , , CC: , , , YueHaibing Subject: [PATCH net-next] tipc: Fix NULL pointer dereference in __tipc_sendstream() Date: Thu, 28 May 2020 22:34:07 +0800 Message-ID: <20200528143407.56196-1-yuehaibing@huawei.com> X-Mailer: git-send-email 2.10.2.windows.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.166.215.154] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org tipc_sendstream() may send zero length packet, then tipc_msg_append() do not alloc skb, skb_peek_tail() will get NULL, msg_set_ack_required will trigger NULL pointer dereference. Reported-by: syzbot+8eac6d030e7807c21d32@syzkaller.appspotmail.com Fixes: 0a3e060f340d ("tipc: add test for Nagle algorithm effectiveness") Signed-off-by: YueHaibing --- net/tipc/socket.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index d6b67d07d22e..2943561399f1 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1588,8 +1588,12 @@ static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dlen) tsk->pkt_cnt += skb_queue_len(txq); } else { skb = skb_peek_tail(txq); - msg_set_ack_required(buf_msg(skb)); - tsk->expect_ack = true; + if (skb) { + msg_set_ack_required(buf_msg(skb)); + tsk->expect_ack = true; + } else { + tsk->expect_ack = false; + } tsk->msg_acc = 0; tsk->pkt_cnt = 0; } -- 2.17.1