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Commit 4ce6a733 authored by Florian Westphal's avatar Florian Westphal Committed by Lee Jones
Browse files

UPSTREAM: netfilter: nft_set_rbtree: fix overlap expiration walk 



commit f718863aca469a109895cb855e6b81fff4827d71 upstream.

The lazy gc on insert that should remove timed-out entries fails to release
the other half of the interval, if any.

Can be reproduced with tests/shell/testcases/sets/0044interval_overlap_0
in nftables.git and kmemleak enabled kernel.

Second bug is the use of rbe_prev vs. prev pointer.
If rbe_prev() returns NULL after at least one iteration, rbe_prev points
to element that is not an end interval, hence it should not be removed.

Lastly, check the genmask of the end interval if this is active in the
current generation.

Bug: 299922216
Fixes: c9e6978e2725 ("netfilter: nft_set_rbtree: Switch to node list walk for overlap detection")
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit acaee227)
Signed-off-by: default avatarLee Jones <joneslee@google.com>
Change-Id: I0c46b46ba4e0811b37dc4e332e97c157c5d452bb
parent 1b7330db

net/netfilter/nft_set_rbtree.c

+14 −6
Original line number Diff line number Diff line
@@ -216,29 +216,37 @@ static void *nft_rbtree_get(const struct net *net, const struct nft_set *set, 


static int nft_rbtree_gc_elem(const struct nft_set *__set,

			      struct nft_rbtree *priv,

			      struct nft_rbtree_elem *rbe)

			      struct nft_rbtree_elem *rbe,

			      u8 genmask)

{

	struct nft_set *set = (struct nft_set *)__set;

	struct rb_node *prev = rb_prev(&rbe->node);

	struct nft_rbtree_elem *rbe_prev = NULL;

	struct nft_rbtree_elem *rbe_prev;

	struct nft_set_gc_batch *gcb;



	gcb = nft_set_gc_batch_check(set, NULL, GFP_ATOMIC);

	if (!gcb)

		return -ENOMEM;



	/* search for expired end interval coming before this element. */

	/* search for end interval coming before this element.

	 * end intervals don't carry a timeout extension, they

	 * are coupled with the interval start element.

	 */

	while (prev) {

		rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);

		if (nft_rbtree_interval_end(rbe_prev))

		if (nft_rbtree_interval_end(rbe_prev) &&

		    nft_set_elem_active(&rbe_prev->ext, genmask))

			break;



		prev = rb_prev(prev);

	}



	if (rbe_prev) {

	if (prev) {

		rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);



		rb_erase(&rbe_prev->node, &priv->root);

		atomic_dec(&set->nelems);

		nft_set_gc_batch_add(gcb, rbe_prev);

	}



	rb_erase(&rbe->node, &priv->root);
@@ -320,7 +328,7 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set, 


		/* perform garbage collection to avoid bogus overlap reports. */

		if (nft_set_elem_expired(&rbe->ext)) {

			err = nft_rbtree_gc_elem(set, priv, rbe);

			err = nft_rbtree_gc_elem(set, priv, rbe, genmask);

			if (err < 0)

				return err;