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| author | WANG Cong <xiyou.wangcong@gmail.com> | 2017-05-04 14:54:17 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-05-08 14:35:03 -0400 |
| commit | 82486aa6f1b9bc8145e6d0fa2bc0b44307f3b875 (patch) | |
| tree | 97674aade6f2ac755baebde5255a916028c50125 /include/net | |
| parent | 3013c4983eb15f4ce8958e81922cdfd80f771d3e (diff) | |
| download | linux-82486aa6f1b9bc8145e6d0fa2bc0b44307f3b875.tar.bz2 | |
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 <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/route.h | 1 |
1 files changed, 1 insertions, 0 deletions
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) |