Messages in this thread Patch in this message | | | From | Luis Henriques <> | Subject | [PATCH 015/150] USB: cdc-wdm: fix buffer overflow | Date | Tue, 26 Mar 2013 15:18:34 +0000 |
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3.5.7.9 -stable review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum <oneukum@suse.de>
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> Signed-off-by: Luis Henriques <luis.henriques@canonical.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 3cc771e..97c1d8e 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -81,6 +81,7 @@ 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 @@ -180,6 +181,7 @@ 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); @@ -210,9 +212,17 @@ 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); @@ -460,6 +470,11 @@ 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)) { @@ -503,6 +518,7 @@ 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); @@ -1029,6 +1045,7 @@ static int wdm_post_reset(struct usb_interface *intf) 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); -- 1.8.1.2
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