| Message ID | 20210526153244.GA1400430@rowland.harvard.edu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | USB: core: Check buffer length matches wLength for control transfers | expand |
On Wed, May 26, 2021 at 11:32:44AM -0400, Alan Stern wrote: > A type of inconsistency that can show up in control URBs is when the > setup packet's wLength value does not match the URB's > transfer_buffer_length field. The two should always be equal; > differences could lead to information leaks or undefined behavior for > OUT transfers or overruns for IN transfers. > > This patch adds a test for such mismatches during URB submission. If > the test fails, the submission is rejected with a -EBADR error code > (which is not used elsewhere in the USB core), and a debugging message > is logged for people interested in tracking down these errors. > > Signed-off-by: Alan Stern <stern@rowland.harvard.edu> > CC: Johan Hovold <johan@kernel.org> Looks good. Reviewed-by: Johan Hovold <johan@kernel.org> > --- > > > [as1961] > > > Documentation/driver-api/usb/error-codes.rst | 3 +++ > drivers/usb/core/urb.c | 6 ++++++ > 2 files changed, 9 insertions(+) > > Index: usb-devel/drivers/usb/core/urb.c > =================================================================== > --- usb-devel.orig/drivers/usb/core/urb.c > +++ usb-devel/drivers/usb/core/urb.c > @@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_ > dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out), > "BOGUS control dir, pipe %x doesn't match bRequestType %x\n", > urb->pipe, setup->bRequestType); > + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) { > + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n", > + le16_to_cpu(setup->wLength), > + urb->transfer_buffer_length); > + return -EBADR; > + } > } else { > is_out = usb_endpoint_dir_out(&ep->desc); > } > Index: usb-devel/Documentation/driver-api/usb/error-codes.rst > =================================================================== > --- usb-devel.orig/Documentation/driver-api/usb/error-codes.rst > +++ usb-devel/Documentation/driver-api/usb/error-codes.rst > @@ -61,6 +61,9 @@ USB-specific: > (c) requested data transfer length is invalid: negative > or too large for the host controller. > > +``-EBADR`` The wLength value in a control URB's setup packet does > + not match the URB's transfer_buffer_length. > + > ``-ENOSPC`` This request would overcommit the usb bandwidth reserved > for periodic transfers (interrupt, isochronous). >
On Wed, May 26, 2021 at 11:32:44AM -0400, Alan Stern wrote: > A type of inconsistency that can show up in control URBs is when the > setup packet's wLength value does not match the URB's > transfer_buffer_length field. The two should always be equal; > differences could lead to information leaks or undefined behavior for > OUT transfers or overruns for IN transfers. > > This patch adds a test for such mismatches during URB submission. If > the test fails, the submission is rejected with a -EBADR error code > (which is not used elsewhere in the USB core), and a debugging message > is logged for people interested in tracking down these errors. > > Signed-off-by: Alan Stern <stern@rowland.harvard.edu> > CC: Johan Hovold <johan@kernel.org> > > --- > > > [as1961] > > > Documentation/driver-api/usb/error-codes.rst | 3 +++ > drivers/usb/core/urb.c | 6 ++++++ > 2 files changed, 9 insertions(+) > > Index: usb-devel/drivers/usb/core/urb.c > =================================================================== > --- usb-devel.orig/drivers/usb/core/urb.c > +++ usb-devel/drivers/usb/core/urb.c > @@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_ > dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out), > "BOGUS control dir, pipe %x doesn't match bRequestType %x\n", > urb->pipe, setup->bRequestType); > + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) { > + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n", > + le16_to_cpu(setup->wLength), > + urb->transfer_buffer_length); > + return -EBADR; > + } Looks good, let's see if this catches anything :) now queued up, thanks. greg k-h
Index: usb-devel/drivers/usb/core/urb.c =================================================================== --- usb-devel.orig/drivers/usb/core/urb.c +++ usb-devel/drivers/usb/core/urb.c @@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_ dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out), "BOGUS control dir, pipe %x doesn't match bRequestType %x\n", urb->pipe, setup->bRequestType); + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) { + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n", + le16_to_cpu(setup->wLength), + urb->transfer_buffer_length); + return -EBADR; + } } else { is_out = usb_endpoint_dir_out(&ep->desc); } Index: usb-devel/Documentation/driver-api/usb/error-codes.rst =================================================================== --- usb-devel.orig/Documentation/driver-api/usb/error-codes.rst +++ usb-devel/Documentation/driver-api/usb/error-codes.rst @@ -61,6 +61,9 @@ USB-specific: (c) requested data transfer length is invalid: negative or too large for the host controller. +``-EBADR`` The wLength value in a control URB's setup packet does + not match the URB's transfer_buffer_length. + ``-ENOSPC`` This request would overcommit the usb bandwidth reserved for periodic transfers (interrupt, isochronous).
A type of inconsistency that can show up in control URBs is when the setup packet's wLength value does not match the URB's transfer_buffer_length field. The two should always be equal; differences could lead to information leaks or undefined behavior for OUT transfers or overruns for IN transfers. This patch adds a test for such mismatches during URB submission. If the test fails, the submission is rejected with a -EBADR error code (which is not used elsewhere in the USB core), and a debugging message is logged for people interested in tracking down these errors. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Johan Hovold <johan@kernel.org> --- [as1961] Documentation/driver-api/usb/error-codes.rst | 3 +++ drivers/usb/core/urb.c | 6 ++++++ 2 files changed, 9 insertions(+)