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netfilter: xt_iprange: Incorrect xt_iprange boundary check for IPv6 

iprange_ipv6_sub was substracting 2 unsigned ints and then casting
the result to int to find out whether they are lt, eq or gt each
other, this doesn't work if the full 32 bits of each part
can be used in IPv6 addresses. Patch should remedy that without
significant performance penalties. Also number of ntohl
calls can be reduced this way (Jozsef Kadlecsik).

Signed-off-by: Thomas Jacob <jacob@internet24.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Thomas Jacob 2011-01-24 21:35:36 +01:00 committed by Patrick McHardy
parent c71caf4114
commit 08b5194b5d
1 changed files with 7 additions and 9 deletions
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16
net/netfilter/xt_iprange.c
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@ -53,15 +53,13 @@ iprange_mt4(const struct sk_buff *skb, struct xt_action_param *par)
}
static inline int
iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
iprange_ipv6_lt(const struct in6_addr *a, const struct in6_addr *b)
{
unsigned int i;
int r;
for (i = 0; i < 4; ++i) {
r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
if (r != 0)
return r;
if (a->s6_addr32[i] != b->s6_addr32[i])
return ntohl(a->s6_addr32[i]) < ntohl(b->s6_addr32[i]);
}
return 0;
@ -75,15 +73,15 @@ iprange_mt6(const struct sk_buff *skb, struct xt_action_param *par)
bool m;
if (info->flags & IPRANGE_SRC) {
m = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
m = iprange_ipv6_lt(&iph->saddr, &info->src_min.in6);
m |= iprange_ipv6_lt(&info->src_max.in6, &iph->saddr);
m ^= !!(info->flags & IPRANGE_SRC_INV);
if (m)
return false;
}
if (info->flags & IPRANGE_DST) {
m = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
m = iprange_ipv6_lt(&iph->daddr, &info->dst_min.in6);
m |= iprange_ipv6_lt(&info->dst_max.in6, &iph->daddr);
m ^= !!(info->flags & IPRANGE_DST_INV);
if (m)
return false;