From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932265AbbCaUSp (ORCPT ); Tue, 31 Mar 2015 16:18:45 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39161 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753213AbbCaTt0 (ORCPT ); Tue, 31 Mar 2015 15:49:26 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Alan Stern , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 059/143] USB: fix use-after-free bug in usb_hcd_unlink_urb() Date: Tue, 31 Mar 2015 12:47:04 -0700 Message-Id: <1427831308-1854-60-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427831308-1854-1-git-send-email-kamal@canonical.com> References: <1427831308-1854-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt18 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit c99197902da284b4b723451c1471c45b18537cde upstream. The usb_hcd_unlink_urb() routine in hcd.c contains two possible use-after-free errors. The dev_dbg() statement at the end of the routine dereferences urb and urb->dev even though both structures may have been deallocated. This patch fixes the problem by storing urb->dev in a local variable (avoiding the dereference of urb) and moving the dev_dbg() up before the usb_put_dev() call. Signed-off-by: Alan Stern Reported-by: Joe Lawrence Tested-by: Joe Lawrence Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa --- drivers/usb/core/hcd.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 4a4dae5..178696f 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1616,6 +1616,7 @@ static int unlink1(struct usb_hcd *hcd, struct urb *urb, int status) int usb_hcd_unlink_urb (struct urb *urb, int status) { struct usb_hcd *hcd; + struct usb_device *udev = urb->dev; int retval = -EIDRM; unsigned long flags; @@ -1627,20 +1628,19 @@ int usb_hcd_unlink_urb (struct urb *urb, int status) spin_lock_irqsave(&hcd_urb_unlink_lock, flags); if (atomic_read(&urb->use_count) > 0) { retval = 0; - usb_get_dev(urb->dev); + usb_get_dev(udev); } spin_unlock_irqrestore(&hcd_urb_unlink_lock, flags); if (retval == 0) { hcd = bus_to_hcd(urb->dev->bus); retval = unlink1(hcd, urb, status); - usb_put_dev(urb->dev); + if (retval == 0) + retval = -EINPROGRESS; + else if (retval != -EIDRM && retval != -EBUSY) + dev_dbg(&udev->dev, "hcd_unlink_urb %p fail %d\n", + urb, retval); + usb_put_dev(udev); } - - if (retval == 0) - retval = -EINPROGRESS; - else if (retval != -EIDRM && retval != -EBUSY) - dev_dbg(&urb->dev->dev, "hcd_unlink_urb %p fail %d\n", - urb, retval); return retval; } -- 1.9.1