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Message-ID: <591C493B.6060908@bfs.de>
Date: Wed, 17 May 2017 14:59:39 +0200
From: walter harms <wharms@....de>
To: Firo Yang <firogm@...il.com>
CC: t.sailer@...mni.ethz.ch, davem@...emloft.net,
gregkh@...uxfoundation.org, linux-hams@...r.kernel.org,
netdev@...r.kernel.org, dvyukov@...gle.com,
syzkaller@...glegroups.com
Subject: Re: [PATCH] hdlcdrv: fix divide error bug if bitrate is 0
Am 17.05.2017 14:35, schrieb Firo Yang:
> The divisor s->par.bitrate will always be 0 until initialized by
> ndo_open() and hdlcdrv_open().
>
> In order to fix this divide zero error, check whether the netdevice
> was opened by ndo_open() before performing divide.
>
> Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
> Signed-off-by: Firo Yang <firogm@...il.com>
> ---
> 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..3c783fd 100644
> --- a/drivers/net/hamradio/hdlcdrv.c
> +++ b/drivers/net/hamradio/hdlcdrv.c
> @@ -574,7 +574,7 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
> break;
>
> case HDLCDRVCTL_CALIBRATE:
> - if(!capable(CAP_SYS_RAWIO))
> + if (!capable(CAP_SYS_RAWIO) || !netif_running(dev))
> return -EPERM;
> if (bi.data.calibrate > INT_MAX / s->par.bitrate)
> return -EINVAL;
I would still check for s->par.bitrate > 0 later changes may affect the setting of it
and it is much more obvious.
Also perhaps !netif_running(dev) should better return ENODEV.
just my 2 cents,
re,
wh
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