[net-next] ipcomp: Convert struct xt_ipcomp spis into 16bits

On 2014年01月18日 20:24, Pablo Neira Ayuso wrote:
> On Sat, Jan 18, 2014 at 10:16:14AM +0800, Fan Du wrote:
>> >  sparse warnings: (new ones prefixed by>>)
>> >
>>>>>> >  >>  >>  net/netfilter/xt_ipcomp.c:63:26: sparse: restricted __be16 degrades to integer
>>>>>> >  >>  >>  net/netfilter/xt_ipcomp.c:63:26: sparse: cast to restricted __be32
>> >
>> >  Fix this by using 16bits long spi, as IPcomp CPI is only valid for 16bits.
>> >
>> >  Signed-off-by: Fan Du<fan.du@windriver.com>
>> >  ---
>> >    include/uapi/linux/netfilter/xt_ipcomp.h |    2 +-
>> >    net/netfilter/xt_ipcomp.c                |    4 ++--
>> >    2 files changed, 3 insertions(+), 3 deletions(-)
>> >
>> >  diff --git a/include/uapi/linux/netfilter/xt_ipcomp.h b/include/uapi/linux/netfilter/xt_ipcomp.h
>> >  index 45c7e40..ca82ebb 100644
>> >  --- a/include/uapi/linux/netfilter/xt_ipcomp.h
>> >  +++ b/include/uapi/linux/netfilter/xt_ipcomp.h
>> >  @@ -4,7 +4,7 @@
>> >    #include<linux/types.h>
>> >
>> >    struct xt_ipcomp {
>> >  -	__u32 spis[2];	/* Security Parameter Index */
>> >  +	__u16 spis[2];	/* Security Parameter Index */
> This changes the binary interface so it break userspace (iptables
> needs to be recompiled), we're still in time to make such change as
> this is net-next stuff, but what I understand from the patch
> description is that this aims to fix a sparse warning, which is a bit
> of intrusive change.
>
> Didn't you find any way to fix this without change the layout of
> xt_ipcomp?
>

My bad for not catching this in the initial ipcomp version.
It would be easier to just use ntohs here to ease sparse checking.


 From dbf796e63d600256fd40000669b83227ddccebc4 Mon Sep 17 00:00:00 2001
From: Fan Du <fan.du@windriver.com>
Date: Mon, 20 Jan 2014 09:42:12 +0800
Subject: [PATCHv2 net-next] ipcomp: Use ntohs to ease sparse warning

0-DAY kernel build testing backend reported:

sparse warnings: (new ones prefixed by >>)

 >> >> net/netfilter/xt_ipcomp.c:63:26: sparse: restricted __be16 degrades to integer
 >> >> net/netfilter/xt_ipcomp.c:63:26: sparse: cast to restricted __be32

Fix this by using ntohs without shifting.

Tested with: make C=1 CF=-D__CHECK_ENDIAN__

Signed-off-by: Fan Du <fan.du@windriver.com>
---
  net/netfilter/xt_ipcomp.c |    2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

On Mon, Jan 20, 2014 at 09:55:42AM +0800, Fan Du wrote:
> On 2014年01月18日 20:24, Pablo Neira Ayuso wrote:
> >Didn't you find any way to fix this without change the layout of
> >xt_ipcomp?
> 
> My bad for not catching this in the initial ipcomp version.
> It would be easier to just use ntohs here to ease sparse checking.
> 
> 
> From dbf796e63d600256fd40000669b83227ddccebc4 Mon Sep 17 00:00:00 2001
> From: Fan Du <fan.du@windriver.com>
> Date: Mon, 20 Jan 2014 09:42:12 +0800
> Subject: [PATCHv2 net-next] ipcomp: Use ntohs to ease sparse warning
> 
> 0-DAY kernel build testing backend reported:
> 
> sparse warnings: (new ones prefixed by >>)
> 
> >> >> net/netfilter/xt_ipcomp.c:63:26: sparse: restricted __be16 degrades to integer
> >> >> net/netfilter/xt_ipcomp.c:63:26: sparse: cast to restricted __be32
> 
> Fix this by using ntohs without shifting.
> 
> Tested with: make C=1 CF=-D__CHECK_ENDIAN__

Applied to nf-next, thanks.
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