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module_param: make bool parameters really bool (net & drivers/net)

PATCH Applied Dan Carpenter 3 participants 5 messages Mar 22, 2012 – Mar 23, 2012

Subsystems (3)
Networking Network drivers netfilter
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Dan Carpenter

author
#0 lore raw

Hi Rusty,

The patch eb93992207da: "module_param: make bool parameters really bool (net & drivers/net)" from Dec 19, 2011, leads to the following warning:
net/ipv4/netfilter/iptable_filter.c:90 iptable_filter_init()
warn: 5 is more than 1 (max 'forward' can be) so this is always the same.

It's declared like this:

    54  /* Default to forward because I got too much mail already. */
    55  static bool forward = NF_ACCEPT;
    56  module_param(forward, bool, 0000);

It's used like this:

    66          ((struct ipt_standard *)repl->entries)[1].target.verdict = -forward - 1;

Smatch complains when check that it's larger than 5.

    90          if (forward < 0 || forward > NF_MAX_VERDICT) {
    91                  pr_err("iptables forward must be 0 or 1\n");
    92                  return -EINVAL;
    93          }

regards,
dan carpenter

author
#1 lore raw

The same thing happens in net/ipv6/netfilter/ip6table_filter.c as well.

regards,
dan carpenter

#2 lore raw
In reply to Dan Carpenter
Quoted 17 lines · Dan Carpenter

Hi Rusty,

The patch eb93992207da: "module_param: make bool parameters really bool (net & drivers/net)" from Dec 19, 2011, leads to the following warning:
net/ipv4/netfilter/iptable_filter.c:90 iptable_filter_init()
warn: 5 is more than 1 (max 'forward' can be) so this is always the same.

It's declared like this:

    54  /* Default to forward because I got too much mail already. */
    55  static bool forward = NF_ACCEPT;
    56  module_param(forward, bool, 0000);

It's used like this:

Quoted 8 lines
    66          ((struct ipt_standard *)repl->entries)[1].target.verdict = -forward - 1;

Smatch complains when check that it's larger than 5.

    90          if (forward < 0 || forward > NF_MAX_VERDICT) {
    91                  pr_err("iptables forward must be 0 or 1\n");
    92                  return -EINVAL;
    93          }

Thanks Dan!

This was obviously initially an arbitrary value, but someone
made it a bool module parameter (me?). It works for accept and drop, so let's make it official. Patch coming.

Thanks,
Rusty.

Signature · 1 line
  How could I marry someone with more hair than me?  http://baldalex.org
#3 lore raw

PATCH 1/1 netfilter: remove forward module param confusion.

It used to be an int, and it got changed to a bool parameter at least 7 years ago. It happens that NF_ACCEPT and NF_DROP are 0 and 1, so this works, but it's unclear, and the check that it's in range is not required.

Reported-by Dan Carpenter <[email protected]>
Signed-off-by Rusty Russell <[email protected]>
---
 net/ipv4/netfilter/iptable_filter.c  |    9 ++-------
 net/ipv6/netfilter/ip6table_filter.c |    9 ++-------
 2 files changed, 4 insertions(+), 14 deletions(-)
net/ipv4/netfilter/iptable_filter.c +2 -7
@@ -52,7 +52,7 @@ iptable_filter_hook(unsigned int hook, s
 static struct nf_hook_ops *filter_ops __read_mostly;
 
 /* Default to forward because I got too much mail already. */
-static bool forward = NF_ACCEPT;
+static bool forward = true;
 module_param(forward, bool, 0000);
 
 static int __net_init iptable_filter_net_init(struct net *net)

@@ -64,7 +64,7 @@ static int __net_init iptable_filter_net
 		return -ENOMEM;
 	/* Entry 1 is the FORWARD hook */
 	((struct ipt_standard *)repl->entries)[1].target.verdict =
-		-forward - 1;
+		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
 
 	net->ipv4.iptable_filter =
 		ipt_register_table(net, &packet_filter, repl);

@@ -88,11 +88,6 @@ static int __init iptable_filter_init(vo
 {
 	int ret;
 
-	if (forward < 0 || forward > NF_MAX_VERDICT) {
-		pr_err("iptables forward must be 0 or 1\n");
-		return -EINVAL;
-	}
-
 	ret = register_pernet_subsys(&iptable_filter_net_ops);
 	if (ret < 0)
 		return ret;
net/ipv6/netfilter/ip6table_filter.c +2 -7
@@ -44,7 +44,7 @@ ip6table_filter_hook(unsigned int hook, 
 static struct nf_hook_ops *filter_ops __read_mostly;
 
 /* Default to forward because I got too much mail already. */
-static bool forward = NF_ACCEPT;
+static bool forward = true;
 module_param(forward, bool, 0000);
 
 static int __net_init ip6table_filter_net_init(struct net *net)

@@ -56,7 +56,7 @@ static int __net_init ip6table_filter_ne
 		return -ENOMEM;
 	/* Entry 1 is the FORWARD hook */
 	((struct ip6t_standard *)repl->entries)[1].target.verdict =
-		-forward - 1;
+		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
 
 	net->ipv6.ip6table_filter =
 		ip6t_register_table(net, &packet_filter, repl);

@@ -80,11 +80,6 @@ static int __init ip6table_filter_init(v
 {
 	int ret;
 
-	if (forward < 0 || forward > NF_MAX_VERDICT) {
-		pr_err("iptables forward must be 0 or 1\n");
-		return -EINVAL;
-	}
-
 	ret = register_pernet_subsys(&ip6table_filter_net_ops);
 	if (ret < 0)
 		return ret;
Signature · 1 line
  How could I marry someone with more hair than me?  http://baldalex.org
maintainer Applied
#4 lore raw

Re: [PATCH] netfilter: remove forward module param confusion.

From: Rusty Russell <[email protected]>
Date: Fri, 23 Mar 2012 08:57:06 +1030

Quoted 7 lines

It used to be an int, and it got changed to a bool parameter at least 7 years ago. It happens that NF_ACCEPT and NF_DROP are 0 and 1, so this works, but it's unclear, and the check that it's in range is not required.

Reported-by Dan Carpenter <[email protected]>
Signed-off-by Rusty Russell <[email protected]>

Applied.