| From 126a16920a646521f9deeea090d0673cb5ca88f1 Mon Sep 17 00:00:00 2001 |
| From: Oliver Neukum <oneukum@suse.de> |
| Date: Tue, 12 Mar 2013 14:52:42 +0100 |
| Subject: [PATCH] USB: cdc-wdm: fix buffer overflow |
| |
| 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 <oliver@neukum.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| [PG: minor adjustment since RESET from 880442027569 isn't in .34] |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| 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 |
| |