Patchwork netfilter: Fix build failure when ipv6 but xt_tproxy is built in

login
register
mail settings
Submitter KOVACS Krisztian
Date April 5, 2011, 2:43 p.m.
Message ID <1302014626.67568.1.camel@nienna.balabit>
Download mbox | patch
Permalink /patch/89878/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

KOVACS Krisztian - April 5, 2011, 2:43 p.m.
Hi,

On Mon, 2011-04-04 at 15:54 +0200, Patrick McHardy wrote:
> >> net/built-in.o: In function `tproxy_tg6_v1':
> >> /home/rostedt/work/autotest/nobackup/linux-test.git/net/netfilter/xt_TPROXY.c:288: undefined reference to `ipv6_find_hdr'
> >>
> >> This happened because the xt_TPROXY code was compiled into the kernel
> >> proper, but the ipv6 netfilter was compiled as a module. The fix is to
> >> only enter the code that calls ipv6_find_hdr if ipv6 netfilter is
> >> compiled into the kernel, or if it is a module, so is the xt_TPROXY
> >> code.
> 
> I don't think this is a good fix for the problem since it may lead to
> the confusing situation that both TPROXY and ip6tables are enabled,
> but TPROXY has no IPv6 support.
> 
> I think we should solve this by either adding a Kconfig dependency
> on (IP6_NF_IPTABLES || IP6_NF_IPTABLES=n) or using ipv6_skip_exthdr()
> instead of ipv6_find_hdr().
> 
> Krisztian, what do you think?

I'd definitely prefer using ipv6_skip_exthdr() instead of playing
various tricks with the config preprocessor macros.

What about something like this?


--
KOVACS Krisztian

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Patrick McHardy - April 5, 2011, 2:49 p.m.
Am 05.04.2011 16:43, schrieb KOVACS Krisztian:
> Hi,
> 
> On Mon, 2011-04-04 at 15:54 +0200, Patrick McHardy wrote:
>>>> net/built-in.o: In function `tproxy_tg6_v1':
>>>> /home/rostedt/work/autotest/nobackup/linux-test.git/net/netfilter/xt_TPROXY.c:288: undefined reference to `ipv6_find_hdr'
>>>>
>>>> This happened because the xt_TPROXY code was compiled into the kernel
>>>> proper, but the ipv6 netfilter was compiled as a module. The fix is to
>>>> only enter the code that calls ipv6_find_hdr if ipv6 netfilter is
>>>> compiled into the kernel, or if it is a module, so is the xt_TPROXY
>>>> code.
>>
>> I don't think this is a good fix for the problem since it may lead to
>> the confusing situation that both TPROXY and ip6tables are enabled,
>> but TPROXY has no IPv6 support.
>>
>> I think we should solve this by either adding a Kconfig dependency
>> on (IP6_NF_IPTABLES || IP6_NF_IPTABLES=n) or using ipv6_skip_exthdr()
>> instead of ipv6_find_hdr().
>>
>> Krisztian, what do you think?
> 
> I'd definitely prefer using ipv6_skip_exthdr() instead of playing
> various tricks with the config preprocessor macros.
> 
> What about something like this?
> 
> diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
> index dcfd57e..1ef0e56 100644
> --- a/net/netfilter/xt_TPROXY.c
> +++ b/net/netfilter/xt_TPROXY.c
> @@ -283,10 +283,10 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
>         const struct in6_addr *laddr;
>         __be16 lport;
>         int thoff;
> -       int tproto;
> +       u8 tproto = iph->nexthdr;
>  
> -       tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
> -       if (tproto < 0) {
> +       thoff = ipv6_skip_exthdr(skb, sizeof(*iph), &tproto);
> +       if (thoff < 0) {
>                 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
>                 return NF_DROP;
>         }

Looks good to me. Please formally submit this including a Signed-off-by:
line and I'll push it upstream.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
KOVACS Krisztian - April 6, 2011, 12:08 p.m.
Hi,

On 04/05/2011 04:49 PM, Patrick McHardy wrote:
>> What about something like this?
>>
>> diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
>> index dcfd57e..1ef0e56 100644
>> --- a/net/netfilter/xt_TPROXY.c
>> +++ b/net/netfilter/xt_TPROXY.c
>> @@ -283,10 +283,10 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
>>         const struct in6_addr *laddr;
>>         __be16 lport;
>>         int thoff;
>> -       int tproto;
>> +       u8 tproto = iph->nexthdr;
>>  
>> -       tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
>> -       if (tproto < 0) {
>> +       thoff = ipv6_skip_exthdr(skb, sizeof(*iph), &tproto);
>> +       if (thoff < 0) {
>>                 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
>>                 return NF_DROP;
>>         }
> 
> Looks good to me. Please formally submit this including a Signed-off-by:
> line and I'll push it upstream.

Will do, as soon as I have a chance to run the test suite. Thanks Patrick.

Patch

diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index dcfd57e..1ef0e56 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -283,10 +283,10 @@  tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
        const struct in6_addr *laddr;
        __be16 lport;
        int thoff;
-       int tproto;
+       u8 tproto = iph->nexthdr;
 
-       tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
-       if (tproto < 0) {
+       thoff = ipv6_skip_exthdr(skb, sizeof(*iph), &tproto);
+       if (thoff < 0) {
                pr_debug("unable to find transport header in IPv6 packet, dropping\n");
                return NF_DROP;
        }