[media] rc: divide by zero bugs in s_tx_carrier()

"carrier" comes from a get_user() in ir_lirc_ioctl().  We need to test
that it's not zero before using it as a divisor.  It might have been
nice to test for this ir_lirc_ioctl() but the mceusb driver uses zero to
disable carrier modulation.
The bug in redrat3 is a little more subtle.  The ->carrier is passed to
mod_freq_to_val() which uses it as a divisor.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/media/rc/redrat3.c b/drivers/media/rc/redrat3.c
index 49731b1a9c57..9f5a17bb5ef5 100644
--- a/drivers/media/rc/redrat3.c
+++ b/drivers/media/rc/redrat3.c
@@ -890,6 +890,9 @@ static int redrat3_set_tx_carrier(struct rc_dev *rcdev, u32 carrier)
         struct device *dev = rr3->dev;
 
         rr3_dbg(dev, "Setting modulation frequency to %u", carrier);
+        if (carrier == 0)
+                return -EINVAL;
+
         rr3->carrier = carrier;
 
         return carrier;