From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Ahern <dsa@cumulusnetworks.com>
Subject: Re: [PATCH net] net: check and errout if res->fi is NULL when
 RTM_F_FIB_MATCH is set
Date: Tue, 15 Aug 2017 20:56:24 -0600
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References: <1502851818-17811-1-git-send-email-roopa@cumulusnetworks.com>
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To: Roopa Prabhu <roopa@cumulusnetworks.com>, davem@davemloft.net
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On 8/15/17 8:50 PM, Roopa Prabhu wrote:
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 7effa62..49a018f 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -2763,14 +2763,21 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
>  	if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
>  		table_id = rt->rt_table_id;
>  
> -	if (rtm->rtm_flags & RTM_F_FIB_MATCH)
> +	if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
> +		if (!res.fi) {
> +			err = fib_props[res->type].error;
> +			if (!err)
> +				err = -EINVAL;

I think -EHOSTUNREACH is a better error than EINVAL. Nothing about the
user inputs are invalid; rather the lookup is failing, but indirectly.