From 761f60261b4401aa368d71d431b4c218af0efcee Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 14 Nov 2018 00:48:28 +0800 Subject: [PATCH] ipv6: fix a dst leak when removing its exception These is no need to hold dst before calling rt6_remove_exception_rt(). The call to dst_hold_safe() in ip6_link_failure() was for ip6_del_rt(), which has been removed in Commit 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes"). Otherwise, it will cause a dst leak. This patch is to simply remove the dst_hold_safe() call before calling rt6_remove_exception_rt() and also do the same in ip6_del_cached_rt(). It's safe, because the removal of the exception that holds its dst's refcnt is protected by rt6_exception_lock. Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes") Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling") Reported-by: Li Shuang Signed-off-by: Xin Long Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/route.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 2a7423c..14b422f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2232,8 +2232,7 @@ static void ip6_link_failure(struct sk_buff *skb) if (rt) { rcu_read_lock(); if (rt->rt6i_flags & RTF_CACHE) { - if (dst_hold_safe(&rt->dst)) - rt6_remove_exception_rt(rt); + rt6_remove_exception_rt(rt); } else { struct fib6_info *from; struct fib6_node *fn; @@ -3214,8 +3213,8 @@ static int ip6_del_cached_rt(struct rt6_info *rt, struct fib6_config *cfg) if (cfg->fc_flags & RTF_GATEWAY && !ipv6_addr_equal(&cfg->fc_gateway, &rt->rt6i_gateway)) goto out; - if (dst_hold_safe(&rt->dst)) - rc = rt6_remove_exception_rt(rt); + + rc = rt6_remove_exception_rt(rt); out: return rc; } -- 2.7.4