netdev - Re: [net PATCH 1/2] net: Disable segmentation if checksumming is not supported

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: <CALx6S36=dHesn65aWWiiC=rRjmOW3mZa3ymk0oq5JBncg6SEnA@mail.gmail.com>
Date:	Mon, 2 May 2016 09:33:27 -0700
From:	Tom Herbert <tom@...bertland.com>
To:	Alexander Duyck <aduyck@...antis.com>
Cc:	Linux Kernel Network Developers <netdev@...r.kernel.org>,
	Or Gerlitz <ogerlitz@...lanox.com>,
	"David S. Miller" <davem@...emloft.net>,
	Alexander Duyck <alexander.duyck@...il.com>
Subject: Re: [net PATCH 1/2] net: Disable segmentation if checksumming is not supported

On Mon, May 2, 2016 at 9:25 AM, Alexander Duyck <aduyck@...antis.com> wrote:
> In the case of the mlx4 and mlx5 driver they do not support IPv6 checksum
> offload for tunnels.  With this being the case we should disable GSO in
> addition to the checksum offload features when we find that a device cannot
> perform a checksum on a given packet type.
>
I'm not sure I understand this. If device can't support checksum
offload for tunnels doesn't that mean we have to do the checksum on
host regardless of whether GSO is being done?

Tom

> Signed-off-by: Alexander Duyck <aduyck@...antis.com>
> ---
>  net/core/dev.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 77a71cd68535..5c925ac50b95 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2802,7 +2802,7 @@ static netdev_features_t harmonize_features(struct sk_buff *skb,
>
>         if (skb->ip_summed != CHECKSUM_NONE &&
>             !can_checksum_protocol(features, type)) {
> -               features &= ~NETIF_F_CSUM_MASK;
> +               features &= ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
>         } else if (illegal_highdma(skb->dev, skb)) {
>                 features &= ~NETIF_F_SG;
>         }
>