Re: [nftables-kernel PATCH] netfilter: nftables: Fix sparse endianness issue on nft_nat.c

[Patrick McHardy <kaber@trash.net>]

On Fri, Oct 18, 2013 at 12:00:53PM +0300, Tomasz Bursztyka wrote:
> Fixes this:
> 
> CHECK   net/netfilter/nft_nat.c
> net/netfilter/nft_nat.c:50:43: warning: incorrect type in assignment (different base types)
> net/netfilter/nft_nat.c:50:43:    expected restricted __be32 [addressable] [usertype] ip
> net/netfilter/nft_nat.c:50:43:    got unsigned int [unsigned] [usertype] <noident>
> net/netfilter/nft_nat.c:51:43: warning: incorrect type in assignment (different base types)
> net/netfilter/nft_nat.c:51:43:    expected restricted __be32 [addressable] [usertype] ip
> net/netfilter/nft_nat.c:51:43:    got unsigned int [unsigned] [usertype] <noident>
> net/netfilter/nft_nat.c:65:37: warning: incorrect type in assignment (different base types)
> net/netfilter/nft_nat.c:65:37:    expected restricted __be16 [addressable] [assigned] [usertype] all
> net/netfilter/nft_nat.c:65:37:    got unsigned int [unsigned] <noident>
> net/netfilter/nft_nat.c:66:37: warning: incorrect type in assignment (different base types)
> net/netfilter/nft_nat.c:66:37:    expected restricted __be16 [addressable] [assigned] [usertype] all
> net/netfilter/nft_nat.c:66:37:    got unsigned int [unsigned] <noident>
> 
> Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
> ---
> 
> Hi,
> 
> looks a bit ugly, would there be another way to fix this?
> 
> Tomasz
> 
>  net/netfilter/nft_nat.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c
> index b0b87b2..f9d488f 100644
> --- a/net/netfilter/nft_nat.c
> +++ b/net/netfilter/nft_nat.c
> @@ -47,8 +47,12 @@ static void nft_nat_eval(const struct nft_expr *expr,
>  	memset(&range, 0, sizeof(range));
>  	if (priv->sreg_addr_min) {
>  		if (priv->family == AF_INET) {
> -			range.min_addr.ip = data[priv->sreg_addr_min].data[0];
> -			range.max_addr.ip = data[priv->sreg_addr_max].data[0];
> +			range.min_addr.ip =
> +				be32_to_cpup((__be32 *)
> +					data[priv->sreg_addr_min].data);
> +			range.max_addr.ip =
> +				be32_to_cpup((__be32 *)
> +					data[priv->sreg_addr_max].data);

That doesn't seem correct, we don't want to actually switch the byteorder of
the data. I'd suggest to simply use (__force __be32).