Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932498AbaBEU1T (ORCPT ); Wed, 5 Feb 2014 15:27:19 -0500 Received: from mail1.windriver.com ([147.11.146.13]:48452 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755142AbaBEUHJ (ORCPT ); Wed, 5 Feb 2014 15:07:09 -0500 From: Paul Gortmaker To: , CC: Oliver Neukum , Oliver Neukum , Greg Kroah-Hartman , Paul Gortmaker Subject: [v2.6.34-stable 148/213] USB: cdc-wdm: fix buffer overflow Date: Wed, 5 Feb 2014 15:01:43 -0500 Message-ID: <1391630568-49251-149-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> References: <1391630568-49251-1-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver Neukum ------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. ------------------- commit c0f5ecee4e741667b2493c742b60b6218d40b3aa upstream. The buffer for responses must not overflow. If this would happen, set a flag, drop the data and return an error after user space has read all remaining data. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman [PG: minor adjustment since RESET from 880442027569 isn't in .34] Signed-off-by: Paul Gortmaker --- drivers/usb/class/cdc-wdm.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 189141ca4e05..ce1af28e54ff 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -54,6 +54,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_POLL_RUNNING 6 #define WDM_RESPONDING 7 #define WDM_SUSPENDING 8 +#define WDM_OVERFLOW 10 #define WDM_MAX 16 @@ -114,6 +115,7 @@ static void wdm_in_callback(struct urb *urb) { struct wdm_device *desc = urb->context; int status = urb->status; + int length = urb->actual_length; spin_lock(&desc->iuspin); clear_bit(WDM_RESPONDING, &desc->flags); @@ -144,9 +146,17 @@ static void wdm_in_callback(struct urb *urb) } desc->rerr = status; - desc->reslength = urb->actual_length; - memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength); - desc->length += desc->reslength; + if (length + desc->length > desc->wMaxCommand) { + /* The buffer would overflow */ + set_bit(WDM_OVERFLOW, &desc->flags); + } else { + /* we may already be in overflow */ + if (!test_bit(WDM_OVERFLOW, &desc->flags)) { + memmove(desc->ubuf + desc->length, desc->inbuf, length); + desc->length += length; + desc->reslength = length; + } + } skip_error: wake_up(&desc->wait); @@ -410,6 +420,11 @@ retry: rv = -ENODEV; goto err; } + if (test_bit(WDM_OVERFLOW, &desc->flags)) { + clear_bit(WDM_OVERFLOW, &desc->flags); + rv = -ENOBUFS; + goto err; + } i++; if (file->f_flags & O_NONBLOCK) { if (!test_bit(WDM_READ, &desc->flags)) { @@ -449,6 +464,7 @@ retry: spin_unlock_irq(&desc->iuspin); goto retry; } + if (!desc->reslength) { /* zero length read */ spin_unlock_irq(&desc->iuspin); goto retry; @@ -860,6 +876,7 @@ static int wdm_post_reset(struct usb_interface *intf) struct wdm_device *desc = usb_get_intfdata(intf); int rv; + clear_bit(WDM_OVERFLOW, &desc->flags); rv = recover_from_urb_loss(desc); mutex_unlock(&desc->lock); return 0; -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/