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From: Florian Westphal <fw@strlen.de>
To: Cole Dishington <Cole.Dishington@alliedtelesis.co.nz>
Cc: pablo@netfilter.org,
	Anthony Lineham <anthony.lineham@alliedtelesis.co.nz>,
	Scott Parlane <scott.parlane@alliedtelesis.co.nz>,
	Blair Steven <blair.steven@alliedtelesis.co.nz>,
	Jozsef Kadlecsik <kadlec@netfilter.org>,
	Florian Westphal <fw@strlen.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: netfilter: Add RFC-7597 Section 5.1 PSID support
Date: Mon, 5 Jul 2021 12:39:59 +0200	[thread overview]
Message-ID: <20210705103959.GG18022@breakpoint.cc> (raw)
In-Reply-To: <20210705040856.25191-3-Cole.Dishington@alliedtelesis.co.nz>

Cole Dishington <Cole.Dishington@alliedtelesis.co.nz> wrote:
> Adds support for masquerading into a smaller subset of ports -
> defined by the PSID values from RFC-7597 Section 5.1. This is part of
> the support for MAP-E and Lightweight 4over6, which allows multiple
> devices to share an IPv4 address by splitting the L4 port / id into
> ranges.
> 
> Co-developed-by: Anthony Lineham <anthony.lineham@alliedtelesis.co.nz>
> Signed-off-by: Anthony Lineham <anthony.lineham@alliedtelesis.co.nz>
> Co-developed-by: Scott Parlane <scott.parlane@alliedtelesis.co.nz>
> Signed-off-by: Scott Parlane <scott.parlane@alliedtelesis.co.nz>
> Signed-off-by: Blair Steven <blair.steven@alliedtelesis.co.nz>
> Signed-off-by: Cole Dishington <Cole.Dishington@alliedtelesis.co.nz>
> ---

Just a quick review:
> +	/* In this case we are in PSID mode, avoid checking all ranges by computing bitmasks */
> +	if (is_psid) {
> +		u16 j = ntohs(max->all) - ntohs(min->all) + 1;
> +		u16 a = (1 << 16) / ntohs(base->all);

This gives crash when base->all is 0.
If this is impossible, please add a comment, otherwise this needs
a sanity test on the divisor.

> @@ -55,8 +55,21 @@ nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
>  	newrange.flags       = range->flags | NF_NAT_RANGE_MAP_IPS;
>  	newrange.min_addr.ip = newsrc;
>  	newrange.max_addr.ip = newsrc;
> -	newrange.min_proto   = range->min_proto;
> -	newrange.max_proto   = range->max_proto;
> +
> +	if (range->flags & NF_NAT_RANGE_PSID) {
> +		u16 off = prandom_u32();
> +		u16 base = ntohs(range->base_proto.all);
> +		u16 min =  ntohs(range->min_proto.all);
> +		u16 max_off = ((1 << 16) / base) - 1;
> +
> +		newrange.flags           = newrange.flags | NF_NAT_RANGE_PROTO_SPECIFIED;
> +		newrange.min_proto.all   = htons(min + base * (off % max_off));

Same here for base and max_off.

  reply	other threads:[~2021-07-05 10:40 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-22  2:35 Cole Dishington
2021-04-26 12:23 ` Florian Westphal
2021-06-29  0:48   ` Cole Dishington
2021-06-30 14:20     ` Florian Westphal
     [not found]       ` <20210705040856.25191-1-Cole.Dishington@alliedtelesis.co.nz>
2021-07-05  4:08         ` [PATCH] net: netfilter: Add RFC-7597 Section 5.1 PSID support xtables API Cole Dishington
2021-07-05  4:08         ` [PATCH] net: netfilter: Add RFC-7597 Section 5.1 PSID support Cole Dishington
2021-07-05 10:39           ` Florian Westphal [this message]
2021-07-16  0:27             ` [PATCH 0/3] " Cole Dishington
2021-07-16  0:27               ` [PATCH 1/3] net: netfilter: Add RFC-7597 Section 5.1 PSID support xtables API Cole Dishington
2021-07-16  0:27               ` [PATCH 2/3] net: netfilter: Add RFC-7597 Section 5.1 PSID support Cole Dishington
2021-07-16 15:18                 ` Florian Westphal
2021-07-19  1:21                   ` Cole Dishington
2021-07-22  7:17                     ` Florian Westphal
2021-07-25 23:28                       ` Cole Dishington
2021-07-26 14:37                         ` Florian Westphal
2021-08-09  4:10                           ` [PATCH net-next 0/3] " Cole Dishington
2021-08-09  4:10                             ` [PATCH net-next 1/3] net: netfilter: Add RFC-7597 Section 5.1 PSID support xtables API Cole Dishington
2021-08-09  4:10                             ` [PATCH net-next 2/3] net: netfilter: Add RFC-7597 Section 5.1 PSID support Cole Dishington
2021-08-25 17:05                               ` Pablo Neira Ayuso
2021-08-29 21:30                                 ` Cole Dishington
2021-08-09  4:10                             ` [PATCH net-next 3/3] selftests: netfilter: Add RFC-7597 Section 5.1 PSID selftests Cole Dishington
2021-07-16  0:27               ` [PATCH " Cole Dishington

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