char: pcmcia: error out if 'num_bytes_read' is greater than 4 in set_protocol()

Theoretically, it will cause index out of bounds error if
'num_bytes_read' is greater than 4. As we expect it(and was tested)
never to be greater than 4, error out if it happens.

Fixes: c1986ee9be ("[PATCH] New Omnikey Cardman 4000 driver")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20210521120617.138396-1-yukuai3@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yu Kuai 2021-05-21 20:06:17 +08:00 committed by Greg Kroah-Hartman
parent 7af5662826
commit 37188559c6

View File

@ -544,6 +544,10 @@ static int set_protocol(struct cm4000_dev *dev, struct ptsreq *ptsreq)
io_read_num_rec_bytes(iobase, &num_bytes_read);
if (num_bytes_read >= 4) {
DEBUGP(2, dev, "NumRecBytes = %i\n", num_bytes_read);
if (num_bytes_read > 4) {
rc = -EIO;
goto exit_setprotocol;
}
break;
}
usleep_range(10000, 11000);