| Message ID | 63401dc56ae64aa3a428c4bb8a84034e@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] usb:host: fix divide-by-zero in function fhci_queue_urb | expand |
On Wed, 17 Apr 2019, zhuyan (M) wrote: > On Wed, 17 Apr 2019, Alan Stern wrote: > > > On Wed, 17 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 11:07:56 -0400, Alan Stern wrote: > > > > > > > On Tue, 16 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 at 11:45:45 +0200, Greg KH wrote: > > > > > > On Tue, Apr 09, 2019 at 10:37:12PM +0800, zhuyan wrote: > > > > > > > In function fhci_queue_urb, the divisor of expression > > > > > > > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, > > > > > > > urb->pipe, > > > > > > > usb_pipeout(urb->pipe))) may be zero. > > > > > > > > > > > > How can you hit that? > > > > > > > > > > > > > When it is zero, unexpected results may occur, so it is > > > > > > > necessary to ensure that the divisor is not zero. > > > > > > > > > > > > > > Signed-off-by: zhuyan <zhuyan34@huawei.com> > > > > > > > > > > > > I need a "Full" name here, not just a single name. Whatever you use to sign documents is good. > > > > > > > > > > > > thanks, > > > > > > > > > > > > greg k-h > > > > > > > > > > In function usb_maxpacket, when ep is NULL, its return value is 0. > > > > > > > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > > > > size anyway. It should use usb_endpoint_maxp(&urb->ep->desc). > > > > > > Currently, fhci_queue_urb(), call usb_maxpacket() multiple times to > > > calculate the maxpacket size. The usb_maxpacket() will call > > > usb_endpoint_maxp() to compute the maxpacket size. > > > > I know that. What fhci_queue_urb() is doing is wrong. You should change it: > > Make it call usb_endpoint_maxp directly instead of calling usb_maxpacket. > > > > From 1996456d0cc17b5ff7746a598ff355b25d13db3e Mon Sep 17 00:00:00 2001 > From: zhuyan <zhuyan34@huawei.com> > Date: Thu, 18 Apr 2019 00:53:03 +0800 > Subject: [PATCH] usb: host: fix divide-by-zero in function fhci_queue_urb > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > size anyway.It should use usb_endpoint_maxp(&urb->ep->desc). > > In function fhci_queue_urb, the divisor of expression > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, urb->pipe, > usb_pipeout(urb->pipe))) may be zero. When it is zero, unexpected results > may occur, so it is necessary to ensure that the divisor is not zero. > > Signed-off-by: zhuyan <zhuyan34@huawei.com> > --- > drivers/usb/host/fhci-sched.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/drivers/usb/host/fhci-sched.c b/drivers/usb/host/fhci-sched.c > index 3d12cdd..7dcfe22 100644 > --- a/drivers/usb/host/fhci-sched.c > +++ b/drivers/usb/host/fhci-sched.c > @@ -704,6 +704,7 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) > struct td *td; > u8 *data; > u16 cnt = 0; > + u16 max_pkt_size = 0; > > if (ed == NULL) { > ed = fhci_get_empty_ed(fhci); > @@ -727,8 +728,7 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) > } > ed->speed = (urb->dev->speed == USB_SPEED_LOW) ? > FHCI_LOW_SPEED : FHCI_FULL_SPEED; > - ed->max_pkt_size = usb_maxpacket(urb->dev, > - urb->pipe, usb_pipeout(urb->pipe)); > + ed->max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); > urb->ep->hcpriv = ed; > fhci_dbg(fhci, "new ep speed=%d max_pkt_size=%d\n", > ed->speed, ed->max_pkt_size); > @@ -765,11 +765,12 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) > > switch (ed->mode) { > case FHCI_TF_BULK: > + max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); > if (urb->transfer_flags & URB_ZERO_PACKET && > urb->transfer_buffer_length > 0 && > + (max_pkt_size != 0) && Now you shouldn't need to add this extra test. Alan Stern > ((urb->transfer_buffer_length % > - usb_maxpacket(urb->dev, urb->pipe, > - usb_pipeout(urb->pipe))) == 0)) > + max_pkt_size) == 0)) > urb_state = US_BULK0; > while (data_len > 4096) { > td = fhci_td_fill(fhci, urb, urb_priv, ed, cnt, > @@ -807,8 +808,8 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) > break; > case FHCI_TF_CTRL: > ed->dev_addr = usb_pipedevice(urb->pipe); > - ed->max_pkt_size = usb_maxpacket(urb->dev, urb->pipe, > - usb_pipeout(urb->pipe)); > + ed->max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); > + > /* setup stage */ > td = fhci_td_fill(fhci, urb, urb_priv, ed, cnt++, FHCI_TA_SETUP, > USB_TD_TOGGLE_DATA0, urb->setup_packet, 8, 0, 0, true);
On Wed, Apr 17, 2019 at 05:05:33PM +0000, zhuyan (M) wrote: > On Wed, 17 Apr 2019, Alan Stern wrote: > > > On Wed, 17 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 11:07:56 -0400, Alan Stern wrote: > > > > > > > On Tue, 16 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 at 11:45:45 +0200, Greg KH wrote: > > > > > > On Tue, Apr 09, 2019 at 10:37:12PM +0800, zhuyan wrote: > > > > > > > In function fhci_queue_urb, the divisor of expression > > > > > > > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, > > > > > > > urb->pipe, > > > > > > > usb_pipeout(urb->pipe))) may be zero. > > > > > > > > > > > > How can you hit that? > > > > > > > > > > > > > When it is zero, unexpected results may occur, so it is > > > > > > > necessary to ensure that the divisor is not zero. > > > > > > > > > > > > > > Signed-off-by: zhuyan <zhuyan34@huawei.com> > > > > > > > > > > > > I need a "Full" name here, not just a single name. Whatever you use to sign documents is good. > > > > > > > > > > > > thanks, > > > > > > > > > > > > greg k-h > > > > > > > > > > In function usb_maxpacket, when ep is NULL, its return value is 0. > > > > > > > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > > > > size anyway. It should use usb_endpoint_maxp(&urb->ep->desc). > > > > > > Currently, fhci_queue_urb(), call usb_maxpacket() multiple times to > > > calculate the maxpacket size. The usb_maxpacket() will call > > > usb_endpoint_maxp() to compute the maxpacket size. > > > > I know that. What fhci_queue_urb() is doing is wrong. You should change it: > > Make it call usb_endpoint_maxp directly instead of calling usb_maxpacket. > > > > >From 1996456d0cc17b5ff7746a598ff355b25d13db3e Mon Sep 17 00:00:00 2001 > From: zhuyan <zhuyan34@huawei.com> > Date: Thu, 18 Apr 2019 00:53:03 +0800 > Subject: [PATCH] usb: host: fix divide-by-zero in function fhci_queue_urb > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > size anyway.It should use usb_endpoint_maxp(&urb->ep->desc). > > In function fhci_queue_urb, the divisor of expression > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, urb->pipe, > usb_pipeout(urb->pipe))) may be zero. When it is zero, unexpected results > may occur, so it is necessary to ensure that the divisor is not zero. > > Signed-off-by: zhuyan <zhuyan34@huawei.com> I still need a full name here and on the From: line :( thanks, greg k-h
diff --git a/drivers/usb/host/fhci-sched.c b/drivers/usb/host/fhci-sched.c index 3d12cdd..7dcfe22 100644 --- a/drivers/usb/host/fhci-sched.c +++ b/drivers/usb/host/fhci-sched.c @@ -704,6 +704,7 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) struct td *td; u8 *data; u16 cnt = 0; + u16 max_pkt_size = 0; if (ed == NULL) { ed = fhci_get_empty_ed(fhci); @@ -727,8 +728,7 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) } ed->speed = (urb->dev->speed == USB_SPEED_LOW) ? FHCI_LOW_SPEED : FHCI_FULL_SPEED; - ed->max_pkt_size = usb_maxpacket(urb->dev, - urb->pipe, usb_pipeout(urb->pipe)); + ed->max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); urb->ep->hcpriv = ed; fhci_dbg(fhci, "new ep speed=%d max_pkt_size=%d\n", ed->speed, ed->max_pkt_size); @@ -765,11 +765,12 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) switch (ed->mode) { case FHCI_TF_BULK: + max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); if (urb->transfer_flags & URB_ZERO_PACKET && urb->transfer_buffer_length > 0 && + (max_pkt_size != 0) && ((urb->transfer_buffer_length % - usb_maxpacket(urb->dev, urb->pipe, - usb_pipeout(urb->pipe))) == 0)) + max_pkt_size) == 0)) urb_state = US_BULK0; while (data_len > 4096) { td = fhci_td_fill(fhci, urb, urb_priv, ed, cnt, @@ -807,8 +808,8 @@ void fhci_queue_urb(struct fhci_hcd *fhci, struct urb *urb) break; case FHCI_TF_CTRL: ed->dev_addr = usb_pipedevice(urb->pipe); - ed->max_pkt_size = usb_maxpacket(urb->dev, urb->pipe, - usb_pipeout(urb->pipe)); + ed->max_pkt_size = usb_endpoint_maxp(&urb->ep->desc); + /* setup stage */ td = fhci_td_fill(fhci, urb, urb_priv, ed, cnt++, FHCI_TA_SETUP, USB_TD_TOGGLE_DATA0, urb->setup_packet, 8, 0, 0, true);