From patchwork Fri Aug 23 16:32:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sun Feng X-Patchwork-Id: 1152292 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="L6NTSam0"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46FRlD72FLz9sDQ for ; Sat, 24 Aug 2019 02:32:40 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436758AbfHWQci (ORCPT ); Fri, 23 Aug 2019 12:32:38 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:46054 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436736AbfHWQcf (ORCPT ); Fri, 23 Aug 2019 12:32:35 -0400 Received: by mail-pl1-f196.google.com with SMTP id y8so5854991plr.12; Fri, 23 Aug 2019 09:32:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=N2qESvJr/1pmMF3Ae2nRMhv+Yh2vmLQcSbPIwWU4XqU=; b=L6NTSam0xaVt4B1J7FbhhrgYZP5WgZ6n71bwbPTlq2kKZHhL5RuqZ8ASRxgVGcNDJO 4l6xeLN7Amq8qyJuqZ8BKsmzBSpjL0fBodG1aqg3UfhX6kRDtMkALRfnDKWE7ZtTH7JU RoRqaR659oAqLh7aS3qTx0YfSYjWqVcQisBLf5f40AGfUPg4zHD9y+BvYW210M62/e1W 7h05jsT5TrcwvoaMS3lN7XLJ+2/CPSU7xhD0XTVGn7lURuVtuAk5VFS3WSqmsxHNh93W 7XOSKSrxSSfOiGwWmK9wJy7maWwdg9vnZ9JZRC7OyTup80tmVAixLvHOureZG0T2CZLA BMZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=N2qESvJr/1pmMF3Ae2nRMhv+Yh2vmLQcSbPIwWU4XqU=; b=djy3bmJbeZOWUcQ8FIvnDgis+46EnmEUAi+E8COaVS+RiQrSo1vUkyEndC03WR2LbN 32zyq2E+92hdrDqz/KWKIc9byoNgdAU3w9uLRM669uau7ZNA2V3vkybnHkD3aBG+yKW1 oAl26Xet5QcpTqLwtLX3OsNohnIeTExCGGFj76fku+F5MudtjTAGR5a6oLkSepUVypyQ HuIWvsjd47dPHR6YpszxGB0e/vitpOYZ4YrxZPICbu2aN0/K0f8RoBWOOJ/ct6knmNu9 2Rz2SL0I1iBbyg6oGsfwBKakz1x1Rg2K1jadkdxRxMwmqeND60ttrF1Yx7XIhUt3+fF8 jRlA== X-Gm-Message-State: APjAAAUaD09s78AWFhvuwk5+H4whQNEJRrcPWeUUBjGKsC1CBqtQKLQb 1cwwi4xGRvjs70aXh6+9Hts= X-Google-Smtp-Source: APXvYqyacElY5Z9Q1CVjkdFuKXjzLiIAcvlHdRQz9qpZxIchxNE4oR4O04kSRxy29esYPVZIl+YGdg== X-Received: by 2002:a17:902:aa03:: with SMTP id be3mr5842278plb.240.1566577954950; Fri, 23 Aug 2019 09:32:34 -0700 (PDT) Received: from localhost.localdomain ([139.198.121.136]) by smtp.gmail.com with ESMTPSA id u7sm3060251pfm.96.2019.08.23.09.32.31 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 23 Aug 2019 09:32:34 -0700 (PDT) From: Feng Sun To: davem@davemloft.net Cc: edumazet@google.com, dsterba@suse.com, dbanerje@akamai.com, fw@strlen.de, davej@codemonkey.org.uk, tglx@linutronix.de, matwey@sai.msu.ru, sakari.ailus@linux.intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Feng Sun , Xiaojun Zhao Subject: [PATCH] net: fix skb use after free in netpoll_send_skb_on_dev Date: Sat, 24 Aug 2019 00:32:00 +0800 Message-Id: <1566577920-20956-1-git-send-email-loyou85@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 two use after free cases: 1. retry netpoll_start_xmit with freed skb; 2. queue freed skb in npinfo->txq. hit the 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 --- net/core/netpoll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 2cf27da..b4bffe6 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -335,7 +335,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, HARD_TX_UNLOCK(dev, txq); - if (status == NETDEV_TX_OK) + if (status == NETDEV_TX_OK || status == NET_XMIT_DROP) break; } @@ -352,7 +352,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, } - if (status != NETDEV_TX_OK) { + if (status != NETDEV_TX_OK && status != NET_XMIT_DROP) { skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); }