From: Johan Hovold johan@kernel.org

stable inclusion from stable-v4.19.217 commit 063f576c43d589a4c153554b681d32b3f8317c7b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RD4V CVE: CVE-2021-47474

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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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: 985cafccbf9b ("Staging: Comedi: vmk80xx: Add k8061 support") Cc: stable@vger.kernel.org # 2.6.31 Signed-off-by: Johan Hovold johan@kernel.org Reviewed-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20211025114532.4599-5-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- drivers/staging/comedi/drivers/vmk80xx.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c index 2bbfaf54220e..ff52299c1fb0 100644 --- a/drivers/staging/comedi/drivers/vmk80xx.c +++ b/drivers/staging/comedi/drivers/vmk80xx.c @@ -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)