Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969465AbdDTG7z (ORCPT ); Thu, 20 Apr 2017 02:59:55 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46210 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S942077AbdDTGis (ORCPT ); Thu, 20 Apr 2017 02:38:48 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Mauro Carvalho Chehab , Ben Hutchings Subject: [PATCH 3.18 053/124] [media] dvb-usb-v2: avoid use-after-free Date: Thu, 20 Apr 2017 08:35:28 +0200 Message-Id: <20170420063559.104229798@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170420063557.021306233@linuxfoundation.org> References: <20170420063557.021306233@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2285 Lines: 60 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 005145378c9ad7575a01b6ce1ba118fb427f583a upstream. I ran into a stack frame size warning because of the on-stack copy of the USB device structure: drivers/media/usb/dvb-usb-v2/dvb_usb_core.c: In function 'dvb_usbv2_disconnect': drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:1029:1: error: the frame size of 1104 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] Copying a device structure like this is wrong for a number of other reasons too aside from the possible stack overflow. One of them is that the dev_info() call will print the name of the device later, but AFAICT we have only copied a pointer to the name earlier and the actual name has been freed by the time it gets printed. This removes the on-stack copy of the device and instead copies the device name using kstrdup(). I'm ignoring the possible failure here as both printk() and kfree() are able to deal with NULL pointers. Signed-off-by: Arnd Bergmann Signed-off-by: Mauro Carvalho Chehab Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/dvb-usb-v2/dvb_usb_core.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c +++ b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c @@ -952,8 +952,9 @@ EXPORT_SYMBOL(dvb_usbv2_probe); void dvb_usbv2_disconnect(struct usb_interface *intf) { struct dvb_usb_device *d = usb_get_intfdata(intf); - const char *name = d->name; - struct device dev = d->udev->dev; + const char *devname = kstrdup(dev_name(&d->udev->dev), GFP_KERNEL); + const char *drvname = d->name; + dev_dbg(&d->udev->dev, "%s: bInterfaceNumber=%d\n", __func__, intf->cur_altsetting->desc.bInterfaceNumber); @@ -962,8 +963,9 @@ void dvb_usbv2_disconnect(struct usb_int dvb_usbv2_exit(d); - dev_info(&dev, "%s: '%s' successfully deinitialized and disconnected\n", - KBUILD_MODNAME, name); + pr_info("%s: '%s:%s' successfully deinitialized and disconnected\n", + KBUILD_MODNAME, drvname, devname); + kfree(devname); } EXPORT_SYMBOL(dvb_usbv2_disconnect);