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authorYOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org>2013-01-26 08:37:48 +0000
committerPablo Neira Ayuso <pablo@netfilter.org>2013-02-07 18:37:41 +0100
commitf5271fff56c76e92fde122bcc02f102e99da5c8a (patch)
tree88e0f58ea00fbc4f8652f92d915b40403aa38f3e /net/ipv6
parent4b47bc9a9e69141ed3a854c57601f548e82c78ba (diff)
netfilter: ip6t_NPT: Fix adjustment calculation
Cast __wsum from/to __sum16 is wrong. Instead, apply appropriate conversion function: csum_unfold() or csum_fold(). [ The original patch has been modified to undo the final ~ that csum_fold returns. We only need to fold the 32-bit word that results from the checksum calculation into a 16-bit to ensure that the original subnet is restored appropriately. Spotted by Ulrich Weber. ] Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/netfilter/ip6t_NPT.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv6/netfilter/ip6t_NPT.c b/net/ipv6/netfilter/ip6t_NPT.c
index 7302b0b7b64..68788c84aee 100644
--- a/net/ipv6/netfilter/ip6t_NPT.c
+++ b/net/ipv6/netfilter/ip6t_NPT.c
@@ -30,7 +30,7 @@ static int ip6t_npt_checkentry(const struct xt_tgchk_param *par)
(__force __wsum)npt->dst_pfx.in6.s6_addr16[i]);
}
- npt->adjustment = (__force __sum16) csum_sub(src_sum, dst_sum);
+ npt->adjustment = ~csum_fold(csum_sub(src_sum, dst_sum));
return 0;
}
@@ -66,8 +66,8 @@ static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt,
return false;
}
- sum = (__force __sum16) csum_add((__force __wsum)addr->s6_addr16[idx],
- npt->adjustment);
+ sum = ~csum_fold(csum_add(csum_unfold((__force __sum16)addr->s6_addr16[idx]),
+ csum_unfold(npt->adjustment)));
if (sum == CSUM_MANGLED_0)
sum = 0;
*(__force __sum16 *)&addr->s6_addr16[idx] = sum;