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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 A8E90C433EF for ; Sun, 8 Sep 2019 12:59:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B3022067B for ; Sun, 8 Sep 2019 12:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567947556; bh=qVOrtOdpDjM5Dq9VnccAmG5LI4niAYI3RxO3b0EbaIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=t8e2X1pnH7ita4vmrbCOT+a6eNOkBM00OnOh/rovp+nKhj+pm9SDE8BOQqHVYvw6A qUDyG1KhO3Ejj+HO9hlGIGj7KS33LespPzI3WyUfvrRvWo0eUdoyzc8Wu2Yxz4ytSI VQuoKBOhW+0qA32sjAYAMgrsEySbJzBmA7M/XJ4o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730326AbfIHMqQ (ORCPT ); Sun, 8 Sep 2019 08:46:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:33696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730305AbfIHMqM (ORCPT ); Sun, 8 Sep 2019 08:46:12 -0400 Received: from localhost (unknown [62.28.240.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0AE2C2190F; Sun, 8 Sep 2019 12:46:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946771; bh=qVOrtOdpDjM5Dq9VnccAmG5LI4niAYI3RxO3b0EbaIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DC1bMGonTQ1l1mmyOoEXyzwHS6D3w59gpN4n27WBObeYIe4Yc69OszcmoyA2SrIjP 6rkYOTBlVu1HQ8u8+gWTFJw73sHanF3afd57zqyTfuvrzCBUu6QnDrrc2W+4S0PcV1 /AGXJ0QRVeyYmGh9liuiYHuqsRz+Po2chISq0P7I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Feng Sun , Xiaojun Zhao , "David S. Miller" Subject: [PATCH 4.14 33/40] net: fix skb use after free in netpoll Date: Sun, 8 Sep 2019 13:42:06 +0100 Message-Id: <20190908121129.116364551@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121114.260662089@linuxfoundation.org> References: <20190908121114.260662089@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Feng Sun [ Upstream commit 2c1644cf6d46a8267d79ed95cb9b563839346562 ] After commit baeababb5b85d5c4e6c917efe2a1504179438d3b ("tun: return NET_XMIT_DROP for dropped packets"), when tun_net_xmit drop packets, it will free skb and return NET_XMIT_DROP, netpoll_send_skb_on_dev will run into following use after free cases: 1. retry netpoll_start_xmit with freed skb; 2. queue freed skb in npinfo->txq. queue_process will also run into use after free case. hit netpoll_send_skb_on_dev first case with following kernel log: [ 117.864773] kernel BUG at mm/slub.c:306! [ 117.864773] invalid opcode: 0000 [#1] SMP PTI [ 117.864774] CPU: 3 PID: 2627 Comm: loop_printmsg Kdump: loaded Tainted: P OE 5.3.0-050300rc5-generic #201908182231 [ 117.864775] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 117.864775] RIP: 0010:kmem_cache_free+0x28d/0x2b0 [ 117.864781] Call Trace: [ 117.864781] ? tun_net_xmit+0x21c/0x460 [ 117.864781] kfree_skbmem+0x4e/0x60 [ 117.864782] kfree_skb+0x3a/0xa0 [ 117.864782] tun_net_xmit+0x21c/0x460 [ 117.864782] netpoll_start_xmit+0x11d/0x1b0 [ 117.864788] netpoll_send_skb_on_dev+0x1b8/0x200 [ 117.864789] __br_forward+0x1b9/0x1e0 [bridge] [ 117.864789] ? skb_clone+0x53/0xd0 [ 117.864790] ? __skb_clone+0x2e/0x120 [ 117.864790] deliver_clone+0x37/0x50 [bridge] [ 117.864790] maybe_deliver+0x89/0xc0 [bridge] [ 117.864791] br_flood+0x6c/0x130 [bridge] [ 117.864791] br_dev_xmit+0x315/0x3c0 [bridge] [ 117.864792] netpoll_start_xmit+0x11d/0x1b0 [ 117.864792] netpoll_send_skb_on_dev+0x1b8/0x200 [ 117.864792] netpoll_send_udp+0x2c6/0x3e8 [ 117.864793] write_msg+0xd9/0xf0 [netconsole] [ 117.864793] console_unlock+0x386/0x4e0 [ 117.864793] vprintk_emit+0x17e/0x280 [ 117.864794] vprintk_default+0x29/0x50 [ 117.864794] vprintk_func+0x4c/0xbc [ 117.864794] printk+0x58/0x6f [ 117.864795] loop_fun+0x24/0x41 [printmsg_loop] [ 117.864795] kthread+0x104/0x140 [ 117.864795] ? 0xffffffffc05b1000 [ 117.864796] ? kthread_park+0x80/0x80 [ 117.864796] ret_from_fork+0x35/0x40 Signed-off-by: Feng Sun Signed-off-by: Xiaojun Zhao Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/netpoll.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -122,7 +122,7 @@ static void queue_process(struct work_st txq = netdev_get_tx_queue(dev, q_index); HARD_TX_LOCK(dev, txq, smp_processor_id()); if (netif_xmit_frozen_or_stopped(txq) || - netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) { + !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) { skb_queue_head(&npinfo->txq, skb); HARD_TX_UNLOCK(dev, txq); local_irq_restore(flags); @@ -357,7 +357,7 @@ void netpoll_send_skb_on_dev(struct netp HARD_TX_UNLOCK(dev, txq); - if (status == NETDEV_TX_OK) + if (dev_xmit_complete(status)) break; } @@ -374,7 +374,7 @@ void netpoll_send_skb_on_dev(struct netp } - if (status != NETDEV_TX_OK) { + if (!dev_xmit_complete(status)) { skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); }