From patchwork Thu Mar 22 13:22:18 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 148237 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 144D7B6EF3 for ; Fri, 23 Mar 2012 00:22:36 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965020Ab2CVNWe (ORCPT ); Thu, 22 Mar 2012 09:22:34 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:41821 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751096Ab2CVNWc (ORCPT ); Thu, 22 Mar 2012 09:22:32 -0400 Received: by ghrr11 with SMTP id r11so1706876ghr.19 for ; Thu, 22 Mar 2012 06:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer; bh=fFRnuJZSI+PcBZfSvmfdjtEBerCbqtVm4OMjrP4Fdok=; b=RfFyfPTJQhvMlMY72LtnsA2bFXvSoAPqXGLHhAR4pUx6TSloOVkuBT330bMDD+eV06 COI4TrJGZQSPNRSWPQwi82/bkyTUaRPRhPm8vIRIUHAN5AlPxSeVlzHDbPXj/UrctxCp PSRVfs9PLinYqxt41/GjXN5HSPUh1/gphfIGraAEECUTMj2NxN7vOotnQY/trooPAaVP E2yWYeyzBl+/OFn7wxhrGhpAlbUDTmQH92Y5btS8Sh/2e1q0hy5v1lLOErI1iwMwlKjD Icr/xQiR4gM38FwnM9Y0OY53sDLtLhHyQc8XbPZUCaUIlKieXiw/jxUD7C8jyvefqSxK 7j+w== Received: by 10.68.236.3 with SMTP id uq3mr20765711pbc.63.1332422551828; Thu, 22 Mar 2012 06:22:31 -0700 (PDT) Received: from localhost ([113.97.238.210]) by mx.google.com with ESMTPS id r6sm3840080pbl.24.2012.03.22.06.22.24 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 22 Mar 2012 06:22:30 -0700 (PDT) From: Ming Lei To: "David S. Miller" , Greg Kroah-Hartman Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org, Ming Lei , stable@kernel.org, Sebastian Andrzej Siewior , Alan Stern , Oliver Neukum Subject: [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb Date: Thu, 22 Mar 2012 21:22:18 +0800 Message-Id: <1332422538-6597-1-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 1.7.9.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid recursive locking in usbnet_stop()) fixes the recursive locking problem by releasing the skb queue lock, but it makes usb_unlink_urb racing with defer_bh, and the URB to being unlinked may be freed before or during calling usb_unlink_urb, so use-after-free problem may be triggerd inside usb_unlink_urb. The patch fixes the use-after-free problem by increasing URB reference count with skb queue lock held before calling usb_unlink_urb, so the URB won't be freed until return from usb_unlink_urb. Cc: stable@kernel.org Cc: Sebastian Andrzej Siewior Cc: Alan Stern Cc: Oliver Neukum Reported-by: Dave Jones Signed-off-by: Ming Lei Acked-by: Greg Kroah-Hartman --- drivers/net/usb/usbnet.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 4b8b52c..febfdce 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -589,6 +589,14 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) entry = (struct skb_data *) skb->cb; urb = entry->urb; + /* + * Get reference count of the URB to avoid it to be + * freed during usb_unlink_urb, which may trigger + * use-after-free problem inside usb_unlink_urb since + * usb_unlink_urb is always racing with .complete + * handler(include defer_bh). + */ + usb_get_urb(urb); spin_unlock_irqrestore(&q->lock, flags); // during some PM-driven resume scenarios, // these (async) unlinks complete immediately @@ -597,6 +605,7 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) netdev_dbg(dev->net, "unlink urb err, %d\n", retval); else count++; + usb_put_urb(urb); spin_lock_irqsave(&q->lock, flags); } spin_unlock_irqrestore (&q->lock, flags);