Re: Re: [PATCH] net: ieee802154: fix a null pointer in nl802154_trigger_scan

[慕冬亮]

> -----原始邮件-----
> 发件人: "Miquel Raynal" <miquel.raynal@xxxxxxxxxxx>
> 发送时间: 2023-03-07 17:09:03 (星期二)
> 收件人: "Denis Kirjanov" <dkirjanov@xxxxxxx>
> 抄送: "Dongliang Mu" <dzm91@xxxxxxxxxxx>, "Alexander Aring" <alex.aring@xxxxxxxxx>, "Stefan Schmidt" <stefan@xxxxxxxxxxxxxxxxxx>, "David
>  S. Miller" <davem@xxxxxxxxxxxxx>, "Eric Dumazet" <edumazet@xxxxxxxxxx>, "Jakub
>  Kicinski" <kuba@xxxxxxxxxx>, "Paolo Abeni" <pabeni@xxxxxxxxxx>, syzbot+bd85b31816913a32e473@xxxxxxxxxxxxxxxxxxxxxxxxx, linux-wpan@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
> 主题: Re: [PATCH] net: ieee802154: fix a null pointer in nl802154_trigger_scan
> 
> Hello,
> 
> dkirjanov@xxxxxxx wrote on Tue, 7 Mar 2023 11:43:46 +0300:
> 
> > On 3/7/23 10:30, Dongliang Mu wrote:
> > > There is a null pointer dereference if NL802154_ATTR_SCAN_TYPE is
> > > not set by the user.
> > > 
> > > Fix this by adding a null pointer check.
> 
> Thanks for the patch! This has been fixed already:
> https://lore.kernel.org/linux-wpan/20230301154450.547716-1-miquel.raynal@xxxxxxxxxxx/T/#u

Oh, I see. Thanks for your reply.

A small issue: should we still check !nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])?

> 
> > > Reported-and-tested-by: syzbot+bd85b31816913a32e473@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> Just for reference, this tag shall not be used:
> 
> 	"Please do not use combined tags, e.g.
> 	``Reported-and-tested-by``"
> 	Documentation/process/maintainer-tip.rst
> 

Okay. This is suggested by Syzbot. I will use separate tags in the future.

> > > Signed-off-by: Dongliang Mu <dzm91@xxxxxxxxxxx>  
> > 
> > Please add a Fixes: tag 
> > 
> > > ---
> > >  net/ieee802154/nl802154.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
> > > index 2215f576ee37..1cf00cffd63f 100644
> > > --- a/net/ieee802154/nl802154.c
> > > +++ b/net/ieee802154/nl802154.c
> > > @@ -1412,7 +1412,8 @@ static int nl802154_trigger_scan(struct sk_buff *skb, struct genl_info *info)
> > >  		return -EOPNOTSUPP;
> > >  	}
> > >  
> > > -	if (!nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])) {
> > > +	if (!info->attrs[NL802154_ATTR_SCAN_TYPE] ||
> > > +	    !nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])) {
> > >  		NL_SET_ERR_MSG(info->extack, "Malformed request, missing scan type");
> > >  		return -EINVAL;
> > >  	}  
> 
> 
> Thanks,
> Miquèl


--
Best regards,
Dongliang Mu