comedi: dt9812: fix DMA buffers on stack

stable inclusion
from stable-5.10.79
commit 786f5b03450454557ff858a8bead5d7c0cbf78d6
bugzilla: 185793 https://gitee.com/openeuler/kernel/issues/I4K65C

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=786f5b03450454557ff858a8bead5d7c0cbf78d6



--------------------------------

commit 536de747 upstream.

USB transfer buffers are typically mapped for DMA and must not be
allocated on the stack or transfers will fail.

Allocate proper transfer buffers in the various command helpers and
return an error on short transfers instead of acting on random stack
data.

Note that this also fixes a stack info leak on systems where DMA is not
used as 32 bytes are always sent to the device regardless of how short
the command is.

Fixes: 63274cd7 ("Staging: comedi: add usb dt9812 driver")
Cc: stable@vger.kernel.org      # 2.6.29
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211027093529.30896-3-johan@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Bin Li <huawei.libin@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>