From: Johan Hovold johan@kernel.org
commit 907767da8f3a925b060c740e0b5c92ea7dbec440 upstream.
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 Reviewed-by: Ian Abbott abbotti@mev.co.uk Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20211027093529.30896-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/comedi/drivers/ni_usb6501.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/drivers/staging/comedi/drivers/ni_usb6501.c +++ b/drivers/staging/comedi/drivers/ni_usb6501.c @@ -153,6 +153,10 @@ static const u8 READ_COUNTER_RESPONSE[] 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, @@ -510,6 +514,12 @@ static int ni6501_find_endpoints(struct 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; }