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net: cls_flower: Remove filter from mask before freeing it 

In fl_change(), when adding a new rule (i.e. fold == NULL), a driver may
reject the new rule, for example due to resource exhaustion. By that
point, the new rule was already assigned a mask, and it was added to
that mask's hash table. The clean-up path that's invoked as a result of
the rejection however neglects to undo the hash table addition, and
proceeds to free the new rule, thus leaving a dangling pointer in the
hash table.

Fix by removing fnew from the mask's hash table before it is freed.

Fixes: 35cc3cefc4 ("net/sched: cls_flower: Reject duplicated rules also under skip_sw")
Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Petr Machata 2019-02-04 14:50:38 +00:00 committed by David S. Miller
parent 3e5a7c9814
commit c1f7e02979
1 changed files with 5 additions and 1 deletions
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6
net/sched/cls_flower.c
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@ -1371,7 +1371,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
if (!tc_skip_hw(fnew->flags)) {
err = fl_hw_replace_filter(tp, fnew, extack);
if (err)
goto errout_mask;
goto errout_mask_ht;
}
if (!tc_in_hw(fnew->flags))
@ -1401,6 +1401,10 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
kfree(mask);
return 0;
errout_mask_ht:
rhashtable_remove_fast(&fnew->mask->ht, &fnew->ht_node,
fnew->mask->filter_ht_params);
errout_mask:
fl_mask_put(head, fnew->mask, false);