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 C52C2C47082 for ; Mon, 31 May 2021 13:23:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A95306142D for ; Mon, 31 May 2021 13:23:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232192AbhEaNYp (ORCPT ); Mon, 31 May 2021 09:24:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:54850 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232088AbhEaNT5 (ORCPT ); Mon, 31 May 2021 09:19:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 32E62613C8; Mon, 31 May 2021 13:18:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622467096; bh=xbdDosW5GMikQBppsNiOwqm+iQ2kSMsoWMhjOx1QbPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hkv0K5WXno/d5fwGKaMqMIMaftG4cQ7Chxd+h9hqcMXC15ZgfYFGiOVQHS8EjYOsD KJh9yQRt5SfUmpUZCcU/jXRCAlKZi2ZB6MRW1cVPHbIQmn8ROUaoAmKzhxVwE/maEj hIBHnBjhMrF66WIdqdP8sclREn3So2DXqwgRU6eI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Taehee Yoo , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 49/54] sch_dsmark: fix a NULL deref in qdisc_reset() Date: Mon, 31 May 2021 15:14:15 +0200 Message-Id: <20210531130636.606194088@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130635.070310929@linuxfoundation.org> References: <20210531130635.070310929@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: Taehee Yoo [ Upstream commit 9b76eade16423ef06829cccfe3e100cfce31afcd ] If Qdisc_ops->init() is failed, Qdisc_ops->reset() would be called. When dsmark_init(Qdisc_ops->init()) is failed, it possibly doesn't initialize dsmark_qdisc_data->q. But dsmark_reset(Qdisc_ops->reset()) uses dsmark_qdisc_data->q pointer wihtout any null checking. So, panic would occur. Test commands: sysctl net.core.default_qdisc=dsmark -w ip link add dummy0 type dummy ip link add vw0 link dummy0 type virt_wifi ip link set vw0 up Splat looks like: KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] CPU: 3 PID: 684 Comm: ip Not tainted 5.12.0+ #910 RIP: 0010:qdisc_reset+0x2b/0x680 Code: 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 41 57 41 56 41 55 41 54 55 48 89 fd 48 83 c7 18 53 48 89 fa 48 c1 ea 03 48 83 ec 20 <80> 3c 02 00 0f 85 09 06 00 00 4c 8b 65 18 0f 1f 44 00 00 65 8b 1d RSP: 0018:ffff88800fda6bf8 EFLAGS: 00010282 RAX: dffffc0000000000 RBX: ffff8880050ed800 RCX: 0000000000000000 RDX: 0000000000000003 RSI: ffffffff99e34100 RDI: 0000000000000018 RBP: 0000000000000000 R08: fffffbfff346b553 R09: fffffbfff346b553 R10: 0000000000000001 R11: fffffbfff346b552 R12: ffffffffc0824940 R13: ffff888109e83800 R14: 00000000ffffffff R15: ffffffffc08249e0 FS: 00007f5042287680(0000) GS:ffff888119800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ae1f4dbd90 CR3: 0000000006760002 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? rcu_read_lock_bh_held+0xa0/0xa0 dsmark_reset+0x3d/0xf0 [sch_dsmark] qdisc_reset+0xa9/0x680 qdisc_destroy+0x84/0x370 qdisc_create_dflt+0x1fe/0x380 attach_one_default_qdisc.constprop.41+0xa4/0x180 dev_activate+0x4d5/0x8c0 ? __dev_open+0x268/0x390 __dev_open+0x270/0x390 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sched/sch_dsmark.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c index 5f8f6d94336c..f5d2c32dae24 100644 --- a/net/sched/sch_dsmark.c +++ b/net/sched/sch_dsmark.c @@ -404,7 +404,8 @@ static void dsmark_reset(struct Qdisc *sch) struct dsmark_qdisc_data *p = qdisc_priv(sch); pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p); - qdisc_reset(p->q); + if (p->q) + qdisc_reset(p->q); sch->qstats.backlog = 0; sch->q.qlen = 0; } -- 2.30.2