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Commit 193f3685 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

ipv6: route: enforce RCU protection in rt6_update_exception_stamp_rt() 



We must access rt6_info->from under RCU read lock: move the
dereference under such lock, with proper annotation.

v1 -> v2:
 - avoid using multiple, racy, fetch operations for rt->from

Fixes: a68886a6 ("net/ipv6: Make from in rt6_info rcu protected")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Reviewed-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ae3b5641

net/ipv6/route.c

+6 −5
Original line number Diff line number Diff line
@@ -1599,15 +1599,15 @@ static int rt6_remove_exception_rt(struct rt6_info *rt) 
static void rt6_update_exception_stamp_rt(struct rt6_info *rt)

{

	struct rt6_exception_bucket *bucket;

	struct fib6_info *from = rt->from;

	struct in6_addr *src_key = NULL;

	struct rt6_exception *rt6_ex;



	if (!from ||

	    !(rt->rt6i_flags & RTF_CACHE))

		return;

	struct fib6_info *from;



	rcu_read_lock();

	from = rcu_dereference(rt->from);

	if (!from || !(rt->rt6i_flags & RTF_CACHE))

		goto unlock;



	bucket = rcu_dereference(from->rt6i_exception_bucket);



#ifdef CONFIG_IPV6_SUBTREES
@@ -1626,6 +1626,7 @@ static void rt6_update_exception_stamp_rt(struct rt6_info *rt) 
	if (rt6_ex)

		rt6_ex->stamp = jiffies;



unlock:

	rcu_read_unlock();

}