Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755283Ab3CRVGe (ORCPT ); Mon, 18 Mar 2013 17:06:34 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45483 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755048Ab3CRVGa (ORCPT ); Mon, 18 Mar 2013 17:06:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver Neukum Subject: [ 05/75] USB: cdc-wdm: fix buffer overflow Date: Mon, 18 Mar 2013 14:06:28 -0700 Message-Id: <20130318210510.646717843@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.2.434.g9a6c84e.dirty In-Reply-To: <20130318210510.203500214@linuxfoundation.org> References: <20130318210510.203500214@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2765 Lines: 93 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum 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 --- drivers/usb/class/cdc-wdm.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -56,6 +56,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_RESPONDING 7 #define WDM_SUSPENDING 8 #define WDM_RESETTING 9 +#define WDM_OVERFLOW 10 #define WDM_MAX 16 @@ -155,6 +156,7 @@ static void wdm_in_callback(struct 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); @@ -185,9 +187,17 @@ static void wdm_in_callback(struct 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); @@ -435,6 +445,11 @@ 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)) { @@ -478,6 +493,7 @@ retry: spin_unlock_irq(&desc->iuspin); goto retry; } + if (!desc->reslength) { /* zero length read */ dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__); clear_bit(WDM_READ, &desc->flags); @@ -1004,6 +1020,7 @@ static int wdm_post_reset(struct usb_int struct wdm_device *desc = wdm_find_device(intf); int rv; + clear_bit(WDM_OVERFLOW, &desc->flags); clear_bit(WDM_RESETTING, &desc->flags); rv = recover_from_urb_loss(desc); mutex_unlock(&desc->wlock); -- 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/