netdev - Re: [PATCH] net: ethernet: use ip_hdrlen() instead of bit shift

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e792d1b6-b9b5-4e90-801d-ad10893defc1@wanadoo.fr>
Date: Fri, 2 Aug 2024 15:35:37 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Moon Yeounsu <yyyynoom@...il.com>, cooldavid@...ldavid.org,
 davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: ethernet: use ip_hdrlen() instead of bit shift

Le 02/08/2024 à 07:44, Moon Yeounsu a écrit :
> `ip_hdr(skb)->ihl << 2` are the same as `ip_hdrlen(skb)`
> Therefore, we should use a well-defined function not a bit shift
> to find the header length.
> 
> It also compress two lines at a single line.
> 
> Signed-off-by: Moon Yeounsu <yyyynoom@...il.com>
> ---
>   drivers/net/ethernet/jme.c | 8 +++-----
>   1 file changed, 3 insertions(+), 5 deletions(-)
> 

Hi,

> diff --git a/drivers/net/ethernet/jme.c b/drivers/net/ethernet/jme.c
> index b06e24562973..83b185c995df 100644
> --- a/drivers/net/ethernet/jme.c
> +++ b/drivers/net/ethernet/jme.c
> @@ -946,15 +946,13 @@ jme_udpsum(struct sk_buff *skb)
>   	if (skb->protocol != htons(ETH_P_IP))
>   		return csum;
>   	skb_set_network_header(skb, ETH_HLEN);
> +
>   	if ((ip_hdr(skb)->protocol != IPPROTO_UDP) ||
> -	    (skb->len < (ETH_HLEN +
> -			(ip_hdr(skb)->ihl << 2) +
> -			sizeof(struct udphdr)))) {
> +	    (skb->len < (ETH_HLEN + (ip_hdrlen(skb)) + sizeof(struct udphdr)))) {

The extra () around "ip_hdrlen(skb)" can be remove.
Also maybe the ones around "ETH_HLEN + ip_hdrlen(skb)" could also be 
removed.

>   		skb_reset_network_header(skb);
>   		return csum;
>   	}
> -	skb_set_transport_header(skb,
> -			ETH_HLEN + (ip_hdr(skb)->ihl << 2));
> +	skb_set_transport_header(skb, ETH_HLEN + (ip_hdrlen(skb)));

Same here, the extra () around "ip_hdrlen(skb)" can be remove.

CJ

>   	csum = udp_hdr(skb)->check;
>   	skb_reset_transport_header(skb);
>   	skb_reset_network_header(skb);