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comedi: ni_usb6501: fix NULL-deref in command paths

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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: a03bb00e50 ("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>
This commit is contained in:
Johan Hovold 2021-10-27 11:35:28 +02:00 committed by Greg Kroah-Hartman
parent 28eb3b363d
commit 907767da8f
1 changed files with 10 additions and 0 deletions
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10
drivers/comedi/drivers/ni_usb6501.c
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@ -144,6 +144,10 @@ static const u8 READ_COUNTER_RESPONSE[] = {0x00, 0x01, 0x00, 0x10,
0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x02,
0x00, 0x00, 0x00, 0x00}; 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 { enum commands {
READ_PORT, READ_PORT,
WRITE_PORT, WRITE_PORT,
@ -501,6 +505,12 @@ static int ni6501_find_endpoints(struct comedi_device *dev)
if (!devpriv->ep_rx || !devpriv->ep_tx) if (!devpriv->ep_rx || !devpriv->ep_tx)
return -ENODEV; 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; return 0;
} }