linux-kernel - Re: [PATCH v5 6/8] netfilter: Remove the now superfluous sentinel elements from ctl

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Message-ID: <d78c6353-99b9-41f8-0c54-19eb86e1fce3@ssi.bg>
Date: Fri, 26 Apr 2024 15:09:45 +0300 (EEST)
From: Julian Anastasov <ja@....bg>
To: Joel Granados <j.granados@...sung.com>
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Subject: Re: [PATCH v5 6/8] netfilter: Remove the now superfluous sentinel
 elements from ctl_table array


	Hello,

On Fri, 26 Apr 2024, Joel Granados via B4 Relay wrote:

> From: Joel Granados <j.granados@...sung.com>
> 
> This commit comes at the tail end of a greater effort to remove the
> empty elements at the end of the ctl_table arrays (sentinels) which will
> reduce the overall build time size of the kernel and run time memory
> bloat by ~64 bytes per sentinel (further information Link :
> https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> 
> * Remove sentinel elements from ctl_table structs
> * Remove instances where an array element is zeroed out to make it look
>   like a sentinel. This is not longer needed and is safe after commit
>   c899710fe7f9 ("networking: Update to register_net_sysctl_sz") added
>   the array size to the ctl_table registration
> * Remove the need for having __NF_SYSCTL_CT_LAST_SYSCTL as the
>   sysctl array size is now in NF_SYSCTL_CT_LAST_SYSCTL
> * Remove extra element in ctl_table arrays declarations
> 
> Acked-by: Kees Cook <keescook@...omium.org> # loadpin & yama
> Signed-off-by: Joel Granados <j.granados@...sung.com>
> ---
>  net/bridge/br_netfilter_hooks.c         | 1 -
>  net/ipv6/netfilter/nf_conntrack_reasm.c | 1 -
>  net/netfilter/ipvs/ip_vs_ctl.c          | 5 +----
>  net/netfilter/ipvs/ip_vs_lblc.c         | 5 +----
>  net/netfilter/ipvs/ip_vs_lblcr.c        | 5 +----
>  net/netfilter/nf_conntrack_standalone.c | 6 +-----
>  net/netfilter/nf_log.c                  | 3 +--
>  7 files changed, 5 insertions(+), 21 deletions(-)

..

> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 143a341bbc0a..50b5dbe40eb8 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c

..

> @@ -4286,10 +4285,8 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
>  			return -ENOMEM;
>  
>  		/* Don't export sysctls to unprivileged users */
> -		if (net->user_ns != &init_user_ns) {
> -			tbl[0].procname = NULL;
> +		if (net->user_ns != &init_user_ns)
>  			ctl_table_size = 0;
> -		}
>  	} else
>  		tbl = vs_vars;
>  	/* Initialize sysctl defaults */

	We are in process of changing this code (not in trees yet):

https://marc.info/?t=171345219600002&r=1&w=2

	As I'm not sure which patch will win, the end result should
be this single if-block/hunk to be removed.

Regards

--
Julian Anastasov <ja@....bg>