netfilter: ip6t_NPT: Fix prefix mangling

Make sure only the bits that are part of the prefix are mangled.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv6/netfilter/ip6t_NPT.c b/net/ipv6/netfilter/ip6t_NPT.c
index 68788c84aee7..87b759c11da5 100644
--- a/net/ipv6/netfilter/ip6t_NPT.c
+++ b/net/ipv6/netfilter/ip6t_NPT.c
@@ -51,7 +51,7 @@ static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt,
 
                 idx = i / 32;
                 addr->s6_addr32[idx] &= mask;
-                addr->s6_addr32[idx] |= npt->dst_pfx.in6.s6_addr32[idx];
+                addr->s6_addr32[idx] |= ~mask & npt->dst_pfx.in6.s6_addr32[idx];
         }
 
         if (pfx_len <= 48)