The code attempts to check for out of range calibration. What it forgets to do is check for the 0 bitrate case. As a result the range check itself oopses the kernel. Found by Andrey Konovalov using Syzkaller. Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx> --- drivers/net/hamradio/hdlcdrv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c index 8c3633c..9f34a48 100644 --- a/drivers/net/hamradio/hdlcdrv.c +++ b/drivers/net/hamradio/hdlcdrv.c @@ -576,7 +576,7 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) case HDLCDRVCTL_CALIBRATE: if(!capable(CAP_SYS_RAWIO)) return -EPERM; - if (bi.data.calibrate > INT_MAX / s->par.bitrate) + if (!s->par.bitrate || bi.data.calibrate > INT_MAX / s->par.bitrate) return -EINVAL; s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16; return 0;
