Re: [PATCH nf] ipvs: check that ip_vs_conn_tab_bits is between 8 and 20

[Julian Anastasov <ja@ssi.bg>]

	Hello,

On Fri, 10 Sep 2021, Andrea Claudi wrote:

> ip_vs_conn_tab_bits may be provided by the user through the
> conn_tab_bits module parameter. If this value is greater than 31, or
> less than 0, the shift operator used to derive tab_size causes undefined
> behaviour.
> 
> Fix this checking ip_vs_conn_tab_bits value to be in the range specified
> in ipvs Kconfig. If not, simply use default value.
> 
> Fixes: 6f7edb4881bf ("IPVS: Allow boot time change of hash size")
> Reported-by: Yi Chen <yiche@redhat.com>
> Signed-off-by: Andrea Claudi <aclaudi@redhat.com>

	Looks good to me, thanks!

Acked-by: Julian Anastasov <ja@ssi.bg>

> ---
>  net/netfilter/ipvs/ip_vs_conn.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
> index c100c6b112c8..2c467c422dc6 100644
> --- a/net/netfilter/ipvs/ip_vs_conn.c
> +++ b/net/netfilter/ipvs/ip_vs_conn.c
> @@ -1468,6 +1468,10 @@ int __init ip_vs_conn_init(void)
>  	int idx;
>  
>  	/* Compute size and mask */
> +	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) {
> +		pr_info("conn_tab_bits not in [8, 20]. Using default value\n");
> +		ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
> +	}
>  	ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
>  	ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
>  
> -- 
> 2.31.1

Regards

--
Julian Anastasov <ja@ssi.bg>