From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wei Subject: [PATCH v4] ipv6: fix incorrect route 'expires' value passed to userspace Date: Mon, 30 Jul 2012 10:01:30 +0800 Message-ID: <1343613690-3236-1-git-send-email-lw@cn.fujitsu.com> References: <1343199114.2626.11088.camel@edumazet-glaptop> Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org, Li Wei To: davem@davemloft.net Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:20161 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753886Ab2G3CDK (ORCPT ); Sun, 29 Jul 2012 22:03:10 -0400 In-Reply-To: <1343199114.2626.11088.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: 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 --- In fact, all the code was reconstructed by Eric, I just put the commit log and resent it to the maillist, thanks Eric! net/core/rtnetlink.c | 8 ++++++-- net/ipv6/route.c | 8 ++------ 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index bc9e380..5ff949d 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -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); diff --git a/net/ipv6/route.c b/net/ipv6/route.c index cf02cb9..8e80fd2 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -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; -- 1.7.10.1