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@xxxxxxxxxxxxxxx # 3.18
Cc: Luca Ellero <luca.ellero@xxxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/comedi/drivers/ni_usb6501.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/comedi/drivers/ni_usb6501.c b/drivers/comedi/drivers/ni_usb6501.c
index 5b6d9d783b2f..c42987b74b1d 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,
@@ -501,6 +505,12 @@ static int ni6501_find_endpoints(struct comedi_device *dev)
if (!devpriv->ep_rx || !devpriv->ep_tx)
return -ENODEV;
+ if (usb_endpoint_maxp(devpriv->ep_rx) < RX_MAX_SIZE)
+ return -ENODEV;
+
+ if (usb_endpoint_maxp(devpriv->ep_tx) < TX_MAX_SIZE)
+ return -ENODEV;
+
return 0;
}
--
2.32.0
