From: Xin Long Date: Tue, 13 Nov 2018 16:48:28 +0000 (+0800) Subject: ipv6: fix a dst leak when removing its exception X-Git-Tag: rel_imx_4.19.35_1.1.0~8501 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=b536dd802a36dd14e8d5e68201cecab46ccb9669;p=linux.git ipv6: fix a dst leak when removing its exception [ Upstream commit 761f60261b4401aa368d71d431b4c218af0efcee ] 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 1cf00d857fc1..ed72ae3c54e7 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2263,8 +2263,7 @@ 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; @@ -3266,8 +3265,8 @@ 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; }