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Commit 063f576c authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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comedi: vmk80xx: fix bulk-buffer overflow 



commit 78cdfd62bd54af615fba9e3ca1ba35de39d3871d upstream.

The driver is using endpoint-sized buffers but must not assume that the
tx and rx buffers are of equal size or a malicious device could overflow
the slab-allocated receive buffer when doing bulk transfers.

Fixes: 985cafcc ("Staging: Comedi: vmk80xx: Add k8061 support")
Cc: stable@vger.kernel.org      # 2.6.31
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20211025114532.4599-5-johan@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7a2021b8

drivers/staging/comedi/drivers/vmk80xx.c

+7 −9
Original line number Diff line number Diff line
@@ -159,22 +159,20 @@ static void vmk80xx_do_bulk_msg(struct comedi_device *dev) 
	__u8 rx_addr;

	unsigned int tx_pipe;

	unsigned int rx_pipe;

	size_t size;

	size_t tx_size;

	size_t rx_size;



	tx_addr = devpriv->ep_tx->bEndpointAddress;

	rx_addr = devpriv->ep_rx->bEndpointAddress;

	tx_pipe = usb_sndbulkpipe(usb, tx_addr);

	rx_pipe = usb_rcvbulkpipe(usb, rx_addr);



	/*

	 * The max packet size attributes of the K8061

	 * input/output endpoints are identical

	 */

	size = usb_endpoint_maxp(devpriv->ep_tx);

	tx_size = usb_endpoint_maxp(devpriv->ep_tx);

	rx_size = usb_endpoint_maxp(devpriv->ep_rx);



	usb_bulk_msg(usb, tx_pipe, devpriv->usb_tx_buf,

		     size, NULL, devpriv->ep_tx->bInterval);

	usb_bulk_msg(usb, rx_pipe, devpriv->usb_rx_buf, size, NULL, HZ * 10);

		     tx_size, NULL, devpriv->ep_tx->bInterval);



	usb_bulk_msg(usb, rx_pipe, devpriv->usb_rx_buf, rx_size, NULL, HZ * 10);

}



static int vmk80xx_read_packet(struct comedi_device *dev)