media: ttusb-dec: buffer overflow in ioctl

commit f2e323ec96077642d397bb1c355def536d489d16 upstream.

We need to add a limit check here so we don't overflow the buffer.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/ttusb-dec/ttusbdecfe.c b/drivers/media/usb/ttusb-dec/ttusbdecfe.c
index 5c45c9d0712ddf949f0ac571b5649111585046ae..9c29552aedec2e7b1a08447619671cd65c170b77 100644 (file)
--- a/drivers/media/usb/ttusb-dec/ttusbdecfe.c
+++ b/drivers/media/usb/ttusb-dec/ttusbdecfe.c
@@ -156,6 +156,9 @@ static int ttusbdecfe_dvbs_diseqc_send_master_cmd(struct dvb_frontend* fe, struc
                   0x00, 0x00, 0x00, 0x00,
                   0x00, 0x00 };
 
+       if (cmd->msg_len > sizeof(b) - 4)
+               return -EINVAL;
+
        memcpy(&b[4], cmd->msg, cmd->msg_len);
 
        state->config->send_command(fe, 0x72,