From 907767da8f3a925b060c740e0b5c92ea7dbec440 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 27 Oct 2021 11:35:28 +0200 Subject: [PATCH] comedi: ni_usb6501: fix NULL-deref in command paths 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 Reviewed-by: Ian Abbott Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20211027093529.30896-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- 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 5b6d9d7..c42987b 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; } -- 2.7.4