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[5/5] netfilter: ip6t_NPT: Fix translation for non-multiple of 32 prefix lengths

Message ID 1365080169-6880-6-git-send-email-pablo@netfilter.org
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Pablo Neira Ayuso April 4, 2013, 12:56 p.m. UTC 
From: Matthias Schiffer <mschiffer@universe-factory.net>

The bitmask used for the prefix mangling was being calculated
incorrectly, leading to the wrong part of the address being replaced
when the prefix length wasn't a multiple of 32.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv6/netfilter/ip6t_NPT.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/net/ipv6/netfilter/ip6t_NPT.c b/net/ipv6/netfilter/ip6t_NPT.c
index 33608c6..cb63114 100644
--- a/net/ipv6/netfilter/ip6t_NPT.c
+++ b/net/ipv6/netfilter/ip6t_NPT.c
@@ -57,7 +57,7 @@  static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt,
 		if (pfx_len - i >= 32)
 			mask = 0;
 		else
-			mask = htonl(~((1 << (pfx_len - i)) - 1));
+			mask = htonl((1 << (i - pfx_len + 32)) - 1);
 
 		idx = i / 32;
 		addr->s6_addr32[idx] &= mask;