netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction

commit 2ee52ae94baabf7ee09cf2a8d854b990dac5d0e4 upstream.

New elements in this transaction might expired before such transaction
ends. Skip sync GC for such elements otherwise commit path might walk
over an already released object. Once transaction is finished, async GC
will collect such expired element.

Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name netfilter-nft_set_rbtree-skip-sync-gc-for-new-elemen.patch

diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index 9b0bdd4216152820da4ca1dbc9579f170b10d819..535076b4de53dc224acb1eaf831dfe62b90b07b2 100644 (file)
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -314,6 +314,7 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
        struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
        struct rb_node *node, *next, *parent, **p, *first = NULL;
        struct nft_rbtree *priv = nft_set_priv(set);
+       u8 cur_genmask = nft_genmask_cur(net);
        u8 genmask = nft_genmask_next(net);
        int d, err;
 
@@ -359,8 +360,11 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
                if (!nft_set_elem_active(&rbe->ext, genmask))
                        continue;
 
-               /* perform garbage collection to avoid bogus overlap reports. */
-               if (nft_set_elem_expired(&rbe->ext)) {
+               /* perform garbage collection to avoid bogus overlap reports
+                * but skip new elements in this transaction.
+                */
+               if (nft_set_elem_expired(&rbe->ext) &&
+                   nft_set_elem_active(&rbe->ext, cur_genmask)) {
                        err = nft_rbtree_gc_elem(set, priv, rbe, genmask);
                        if (err < 0)
                                return err;