On Tue, 2013-06-04 at 19:23 +0200, Willy Tarreau wrote: > 2.6.32-longterm review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Oliver Neukum <oneukum@xxxxxxx> > > 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@xxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > [bwh: Backported to 2.6.32: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> > Signed-off-by: Willy Tarreau <w@xxxxxx> > --- > 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 37f2899..01ae519 100644 > --- a/drivers/usb/class/cdc-wdm.c > +++ b/drivers/usb/class/cdc-wdm.c > @@ -52,6 +52,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); > #define WDM_READ 4 > #define WDM_INT_STALL 5 > #define WDM_POLL_RUNNING 6 > +#define WDM_OVERFLOW 10 > > > #define WDM_MAX 16 > @@ -115,6 +116,7 @@ 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); > > @@ -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; > + } > + } > wake_up(&desc->wait); > > set_bit(WDM_READ, &desc->flags); > @@ -398,6 +408,11 @@ 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)) { > @@ -440,6 +455,7 @@ 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); > @@ -844,6 +860,7 @@ 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->plock); > return 0; -- Ben Hutchings Theory and practice are closer in theory than in practice. - John Levine, moderator of comp.compilers
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