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ipv6: fix incorrect route 'expires' value passed to userspace

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When userspace use RTM_GETROUTE to dump route table, with an already
expired route entry, we always got an 'expires' value(2147157)
calculated base on INT_MAX.

The reason of this problem is in the following satement:
	rt->dst.expires - jiffies < INT_MAX
gcc promoted the type of both sides of '<' to unsigned long, thus
a small negative value would be considered greater than INT_MAX.

With the help of Eric Dumazet, do the out of bound checks in
rtnl_put_cacheinfo(), _after_ conversion to clock_t.

Signed-off-by: Li Wei <lw@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Li Wei 2012-07-29 16:01:30 +00:00 committed by David S. Miller
parent b41a9a66f6
commit 8253947e2c
2 changed files with 8 additions and 8 deletions
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8
net/core/rtnetlink.c
View file

@ -625,9 +625,13 @@ int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,
.rta_id = id,
};
if (expires)
ci.rta_expires = jiffies_to_clock_t(expires);
if (expires) {
unsigned long clock;
clock = jiffies_to_clock_t(abs(expires));
clock = min_t(unsigned long, clock, INT_MAX);
ci.rta_expires = (expires > 0) ? clock : -clock;
}
return nla_put(skb, RTA_CACHEINFO, sizeof(ci), &ci);
}
EXPORT_SYMBOL_GPL(rtnl_put_cacheinfo);

8
net/ipv6/route.c
View file

@ -2480,12 +2480,8 @@ static int rt6_fill_node(struct net *net,
goto nla_put_failure;
if (nla_put_u32(skb, RTA_PRIORITY, rt->rt6i_metric))
goto nla_put_failure;
if (!(rt->rt6i_flags & RTF_EXPIRES))
expires = 0;
else if (rt->dst.expires - jiffies < INT_MAX)
expires = rt->dst.expires - jiffies;
else
expires = INT_MAX;
expires = (rt->rt6i_flags & RTF_EXPIRES) ? rt->dst.expires - jiffies : 0;
if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, rt->dst.error) < 0)
goto nla_put_failure;