Commit c1f7e029 authored Feb 04, 2019 by Petr Machata Committed by David S. Miller Feb 04, 2019

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: 35cc3cef ("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>

parent 3e5a7c98

net/sched/cls_flower.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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);

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