media: winbond-cir: buffer overrun during transmit

We're reading beyond the buffer before checking its length.

BUG: KASAN: slab-out-of-bounds in wbcir_irq_tx

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/rc/winbond-cir.c b/drivers/media/rc/winbond-cir.c
index ea7be6d35ff8140ad383d55a225a003b471b1a28..a18eb232ed810d1bd5916a685af60a829c1de47e 100644 (file)
--- a/drivers/media/rc/winbond-cir.c
+++ b/drivers/media/rc/winbond-cir.c
@@ -429,7 +429,7 @@ wbcir_irq_tx(struct wbcir_data *data)
                bytes[used] = byte;
        }
 
-       while (data->txbuf[data->txoff] == 0 && data->txoff != data->txlen)
+       while (data->txoff != data->txlen && data->txbuf[data->txoff] == 0)
                data->txoff++;
 
        if (used == 0) {