Re: [PATCH v2] net: ieee802154: fix a null pointer in nl802154_trigger_scan

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Dongliang,

dzm91@hust.edu.cn wrote on Tue,  7 Mar 2023 17:05:46 +0800:

> 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.
> 
> Reported-and-tested-by: syzbot+bd85b31816913a32e473@syzkaller.appspotmail.com

Still wrong :)

> Fixes: a0b6106672b5 ("ieee802154: Convert scan error messages to extack")
> Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
> ---
> v1->v2: add 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] ||

Already handled :)

> +	    !nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])) {

Also handled!

>  		NL_SET_ERR_MSG(info->extack, "Malformed request, missing scan type");
>  		return -EINVAL;
>  	}


Thanks,
Miquèl