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Commit 429da4c0 authored by Ulrich Weber's avatar Ulrich Weber Committed by Pablo Neira Ayuso
Browse files

netfilter: ip6t_NPT: fix IPv6 NTP checksum calculation 



csum16_add() has a broken carry detection, should be:
sum += sum < (__force u16)b;

Instead of fixing csum16_add, remove the custom checksum
functions and use the generic csum_add/csum_sub ones.

Signed-off-by: default avatarUlrich Weber <ulrich.weber@sophos.com>
Acked-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent fdb184d1

net/ipv6/netfilter/ip6t_NPT.c

+7 −26
Original line number Original line Diff line number Diff line
@@ -14,42 +14,23 @@ 
#include <linux/netfilter_ipv6/ip6t_NPT.h>

#include <linux/netfilter_ipv6/ip6t_NPT.h>

#include <linux/netfilter/x_tables.h>

#include <linux/netfilter/x_tables.h>





static __sum16 csum16_complement(__sum16 a)

{

	return (__force __sum16)(0xffff - (__force u16)a);

}



static __sum16 csum16_add(__sum16 a, __sum16 b)

{

	u16 sum;



	sum = (__force u16)a + (__force u16)b;

	sum += (__force u16)a < (__force u16)b;

	return (__force __sum16)sum;

}



static __sum16 csum16_sub(__sum16 a, __sum16 b)

{

	return csum16_add(a, csum16_complement(b));

}



static int ip6t_npt_checkentry(const struct xt_tgchk_param *par)

static int ip6t_npt_checkentry(const struct xt_tgchk_param *par)

{

{

	struct ip6t_npt_tginfo *npt = par->targinfo;

	struct ip6t_npt_tginfo *npt = par->targinfo;

	__sum16 src_sum = 0, dst_sum = 0;

	__wsum src_sum = 0, dst_sum = 0;

	unsigned int i;

	unsigned int i;





	if (npt->src_pfx_len > 64 || npt->dst_pfx_len > 64)

	if (npt->src_pfx_len > 64 || npt->dst_pfx_len > 64)

		return -EINVAL;

		return -EINVAL;





	for (i = 0; i < ARRAY_SIZE(npt->src_pfx.in6.s6_addr16); i++) {

	for (i = 0; i < ARRAY_SIZE(npt->src_pfx.in6.s6_addr16); i++) {

		src_sum = csum16_add(src_sum,

		src_sum = csum_add(src_sum,

				(__force __sum16)npt->src_pfx.in6.s6_addr16[i]);

				(__force __wsum)npt->src_pfx.in6.s6_addr16[i]);

		dst_sum = csum16_add(dst_sum,

		dst_sum = csum_add(dst_sum,

				(__force __sum16)npt->dst_pfx.in6.s6_addr16[i]);

				(__force __wsum)npt->dst_pfx.in6.s6_addr16[i]);

	}

	}





	npt->adjustment = csum16_sub(src_sum, dst_sum);

	npt->adjustment = (__force __sum16) csum_sub(src_sum, dst_sum);

	return 0;

	return 0;

}

}
@@ -85,7 +66,7 @@ static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt, 
			return false;

			return false;

	}

	}





	sum = csum16_add((__force __sum16)addr->s6_addr16[idx],

	sum = (__force __sum16) csum_add((__force __wsum)addr->s6_addr16[idx],

			 npt->adjustment);

			 npt->adjustment);

	if (sum == CSUM_MANGLED_0)

	if (sum == CSUM_MANGLED_0)

		sum = 0;

		sum = 0;