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[SRU,Jammy,Lunar,1/1] netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction

Message ID 20231002111431.455282-2-cascardo@canonical.com
State New
Headers show
Series CVE-2023-4244 follow up | expand

Commit Message

Thadeu Lima de Souza Cascardo Oct. 2, 2023, 11:14 a.m. UTC 
From: Pablo Neira Ayuso <pablo@netfilter.org>

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>
(cherry picked from commit 2ee52ae94baabf7ee09cf2a8d854b990dac5d0e4)
CVE-2023-4244
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 net/netfilter/nft_set_rbtree.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
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Patch

diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index c6435e709231..f250b5399344 100644
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -312,6 +312,7 @@  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;
 
@@ -357,8 +358,11 @@  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;