From 37188559c610f1b7eec83c8e448936c361c578de Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Fri, 21 May 2021 20:06:17 +0800 Subject: [PATCH] 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: c1986ee9bea3 ("[PATCH] New Omnikey Cardman 4000 driver") Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20210521120617.138396-1-yukuai3@huawei.com Signed-off-by: Greg Kroah-Hartman --- drivers/char/pcmcia/cm4000_cs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c index 9ec25735425d..8f1bce0b4fe5 100644 --- a/drivers/char/pcmcia/cm4000_cs.c +++ b/drivers/char/pcmcia/cm4000_cs.c @@ -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);