From 82486aa6f1b9bc8145e6d0fa2bc0b44307f3b875 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Thu, 4 May 2017 14:54:17 -0700 Subject: ipv4: restore rt->fi for reference counting IPv4 dst could use fi->fib_metrics to store metrics but fib_info itself is refcnt'ed, so without taking a refcnt fi and fi->fib_metrics could be freed while dst metrics still points to it. This triggers use-after-free as reported by Andrey twice. This patch reverts commit 2860583fe840 ("ipv4: Kill rt->fi") to restore this reference counting. It is a quick fix for -net and -stable, for -net-next, as Eric suggested, we can consider doing reference counting for metrics itself instead of relying on fib_info. IPv6 is very different, it copies or steals the metrics from mx6_config in fib6_commit_metrics() so probably doesn't need a refcnt. Decnet has already done the refcnt'ing, see dn_fib_semantic_match(). Fixes: 2860583fe840 ("ipv4: Kill rt->fi") Reported-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Cong Wang Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/route.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net') diff --git a/include/net/route.h b/include/net/route.h index 2cc0e14c6359..4335eb72a04c 100644 --- a/include/net/route.h +++ b/include/net/route.h @@ -69,6 +69,7 @@ struct rtable { struct list_head rt_uncached; struct uncached_list *rt_uncached_list; + struct fib_info *fi; /* for refcnt to shared metrics */ }; static inline bool rt_is_input_route(const struct rtable *rt) -- cgit v1.2.3