On 25/10/2021 12:45, Johan Hovold wrote:
The driver uses endpoint-sized USB transfer buffers but had no sanity checks on the sizes. This can lead to zero-size-pointer dereferences or overflowed transfer buffers in ni6501_port_command() and ni6501_counter_command() if a (malicious) device has smaller max-packet sizes than expected (or when doing descriptor fuzz testing).
Add the missing sanity checks to probe().
Fixes: a03bb00e50ab ("staging: comedi: add NI USB-6501 support") Cc: stable@vger.kernel.org # 3.18 Cc: Luca Ellero luca.ellero@brickedbrain.com Signed-off-by: Johan Hovold johan@kernel.org
drivers/comedi/drivers/ni_usb6501.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/comedi/drivers/ni_usb6501.c b/drivers/comedi/drivers/ni_usb6501.c index 5b6d9d783b2f..eb2e5c23f25d 100644 --- a/drivers/comedi/drivers/ni_usb6501.c +++ b/drivers/comedi/drivers/ni_usb6501.c @@ -144,6 +144,10 @@ static const u8 READ_COUNTER_RESPONSE[] = {0x00, 0x01, 0x00, 0x10, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00}; +/* Largest supported packets */ +static const size_t TX_MAX_SIZE = sizeof(SET_PORT_DIR_REQUEST); +static const size_t RX_MAX_SIZE = sizeof(READ_PORT_RESPONSE);
- enum commands { READ_PORT, WRITE_PORT,
@@ -486,12 +490,16 @@ static int ni6501_find_endpoints(struct comedi_device *dev) ep_desc = &iface_desc->endpoint[i].desc; if (usb_endpoint_is_bulk_in(ep_desc)) {
if (usb_endpoint_maxp(ep_desc) < RX_MAX_SIZE)continue; if (!devpriv->ep_rx) devpriv->ep_rx = ep_desc; continue;if (usb_endpoint_is_bulk_out(ep_desc)) {
if (usb_endpoint_maxp(ep_desc) < TX_MAX_SIZE)continue; if (!devpriv->ep_tx) devpriv->ep_tx = ep_desc; continue;
Perhaps it should return an error if the first encountered bulk-in endpoint has the wrong size or the first encountered bulk-out endpoint has the wrong size. Something like:
if (usb_endpoint_is_bulk_in(ep_desc)) { if (!devpriv->ep_rx) { if (usb_endpoint_maxp(ep_desc) < RX_MAX_SIZE) break; } continue;
(similar for bulk-out with TX_MAX_SIZE)