On Tue, Aug 20, 2019 at 02:19:16PM -0400, Hui Peng wrote: > In the while loop of technisat_usb2_get_ir, it scans through > a fix-sized buffer read from the device side, the termination > condition of the loop is `*b == 0xff`. If no `0xff` byte is read > from the device side, OOB access happens. > > This patch fixes the bug by adding an upper bound in the while loop. This issue was fixed in: https://git.linuxtv.org/media_tree.git/commit/drivers/media/usb/dvb-usb/technisat-usb2.c?id=0c4df39e504bf925ab666132ac3c98d6cbbe380b Note this limits the loop to the size of the buffer; using the ret return value might be better. Sean > > Reported-by: Hui Peng <benquike@xxxxxxxxx> > Reported-by: Mathias Payer <mathias.payer@xxxxxxxxxxxxx> > Signed-off-by: Hui Peng <benquike@xxxxxxxxx> > --- > drivers/media/usb/dvb-usb/technisat-usb2.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/media/usb/dvb-usb/technisat-usb2.c b/drivers/media/usb/dvb-usb/technisat-usb2.c > index c659e18b358b..181f5f97af45 100644 > --- a/drivers/media/usb/dvb-usb/technisat-usb2.c > +++ b/drivers/media/usb/dvb-usb/technisat-usb2.c > @@ -612,6 +612,7 @@ static int technisat_usb2_get_ir(struct dvb_usb_device *d) > u8 *b; > int ret; > struct ir_raw_event ev; > + int i = 0; > > buf[0] = GET_IR_DATA_VENDOR_REQUEST; > buf[1] = 0x08; > @@ -656,11 +657,15 @@ static int technisat_usb2_get_ir(struct dvb_usb_device *d) > > ev.pulse = 0; > while (1) { > + // only `ret` bytes are read from the device side > + if (i >= ret) > + break; > ev.pulse = !ev.pulse; > ev.duration = (*b * FIRMWARE_CLOCK_DIVISOR * FIRMWARE_CLOCK_TICK) / 1000; > ir_raw_event_store(d->rc_dev, &ev); > > b++; > + i++; > if (*b == 0xff) { > ev.pulse = 0; > ev.duration = 888888*2; > -- > 2.23.0
