From: Li Wei <lw@cn•fujitsu.com>
To: David Miller <davem@davemloft•net>
Cc: David.Laight@ACULAB•COM, netdev@vger•kernel.org, shemminger@vyatta•com
Subject: [PATCH V3] ipv6: fix incorrect route 'expires' value passed to userspace
Date: Wed, 25 Jul 2012 13:25:42 +0800 [thread overview]
Message-ID: <500F8356.5040008@cn.fujitsu.com> (raw)
In-Reply-To: <20120720.112241.2111041227435292899.davem@davemloft.net>
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.
This patch fix this by use the same trick as time_after macro to
avoid the 'unsigned long' type promotion and deal with jiffies
wrapping.
Also we should do some fix in rtnl_put_cacheinfo() which use
jiffies_to_clock_t(which take an unsigned long as parameter) to
convert jiffies to clock_t to handle the negative expires.
With the help of David Laight, we can make the code a little clean.
Signed-off-by: Li Wei <lw@cn•fujitsu.com>
---
net/core/rtnetlink.c | 3 ++-
net/ipv6/route.c | 11 ++++++-----
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 334b930..2e96396 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -626,7 +626,8 @@ int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,
};
if (expires)
- ci.rta_expires = jiffies_to_clock_t(expires);
+ ci.rta_expires = expires > 0 ? jiffies_to_clock_t(expires)
+ : -jiffies_to_clock_t(-expires);
return nla_put(skb, RTA_CACHEINFO, sizeof(ci), &ci);
}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index cf02cb9..6efeb28 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2480,12 +2480,13 @@ 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))
+ 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;
+ } else {
+ expires = (long)rt->dst.expires - (long)jiffies;
+ if (expires != (int)expires)
+ expires = expires > 0 ? INT_MAX : INT_MIN;
+ }
if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, rt->dst.error) < 0)
goto nla_put_failure;
--
1.7.10.1
next prev parent reply other threads:[~2012-07-25 5:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-16 8:09 [PATCH] ipv6: fix incorrect route 'expires' value passed to userspace Li Wei
2012-07-16 9:56 ` David Miller
2012-07-17 1:55 ` Li Wei
2012-07-19 2:02 ` [PATCH V2] " Li Wei
2012-07-19 17:49 ` David Miller
2012-07-20 1:32 ` Li Wei
2012-07-20 1:42 ` [PATCH V2 resend] " Li Wei
2012-07-20 10:32 ` David Laight
2012-07-20 18:22 ` David Miller
2012-07-23 1:05 ` Li Wei
2012-07-25 5:25 ` Li Wei [this message]
2012-07-25 6:51 ` [PATCH V3] " Eric Dumazet
2012-07-25 7:33 ` Li Wei
2012-07-30 2:01 ` [PATCH v4] " Li Wei
2012-07-30 6:20 ` David Miller
2012-07-23 1:02 ` [PATCH V2 resend] " Li Wei
2012-07-16 16:41 ` [PATCH] " Stephen Hemminger
2012-07-17 1:53 ` Li Wei
2012-07-17 5:26 ` David Miller
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