Patchwork netfilter: ip6t_NPT: Fix translation for non-multiple of 32 prefix lengths

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Submitter Matthias Schiffer
Date March 30, 2013, 8:03 p.m.
Message ID <bba4b68de747f6d3d580232a15592f6ba0fc6722.1364673589.git.mschiffer@universe-factory.net>
Download mbox | patch
Permalink /patch/232551/
State Superseded
Headers show

Comments

Matthias Schiffer - March 30, 2013, 8:03 p.m.
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>
---
Hi, this patch should to 3.9 and, if possible, 3.8-stable.

Regards,
Matthias Schiffer

 net/ipv6/netfilter/ip6t_NPT.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/net/ipv6/netfilter/ip6t_NPT.c b/net/ipv6/netfilter/ip6t_NPT.c
index 33608c6..c476f16 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;