From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> commit 552705a3650bbf46a22b1adedc1b04181490fc36 upstream. While the rhashtable set gc runs asynchronously, a race allows it to collect elements from anonymous sets with timeouts while it is being released from the commit path. Mingi Cho originally reported this issue in a different path in 6.1.x with a pipapo set with low timeouts which is not possible upstream since 7395dfacfff6 ("netfilter: nf_tables: use timestamp to check for set element timeout"). Fix this by setting on the dead flag for anonymous sets to skip async gc in this case. According to 08e4c8c5919f ("netfilter: nf_tables: mark newset as dead on transaction abort"), Florian plans to accelerate abort path by releasing objects via workqueue, therefore, this sets on the dead flag for abort path too. Cc: stable@xxxxxxxxxxxxxxx Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane") Reported-by: Mingi Cho <mgcho.minic@xxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/netfilter/nf_tables_api.c | 1 + 1 file changed, 1 insertion(+) --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3943,6 +3943,7 @@ void nf_tables_unbind_set(const struct n if (list_empty(&set->bindings) && nft_set_is_anonymous(set)) { list_del_rcu(&set->list); + set->dead = 1; if (event) nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_KERNEL); Patches currently in stable-queue which might be from kroah.com@xxxxxxxxxxxxxxx are queue-4.19/netfilter-nf_tables-bogus-ebusy-when-deleting-flowtable-after-flush-for-4.19.patch queue-4.19/netfilter-nft_set_rbtree-switch-to-node-list-walk-for-overlap-detection.patch queue-4.19/netfilter-nf_tables-validate-nfproto_-family.patch queue-4.19/netfilter-nf_tables-unregister-flowtable-hooks-on-netns-exit.patch queue-4.19/netfilter-nf_tables-fix-gc-transaction-races-with-netns-and-netlink-event-exit-path.patch queue-4.19/netfilter-nft_set_rbtree-use-read-spinlock-to-avoid-datapath-contention.patch queue-4.19/netfilter-nft_dynset-report-eopnotsupp-on-missing-set-feature.patch queue-4.19/netfilter-nf_tables-discard-table-flag-update-with-pending-basechain-deletion.patch queue-4.19/netfilter-nft_set_rbtree-skip-sync-gc-for-new-elements-in-this-transaction.patch queue-4.19/netfilter-nf_tables-mark-set-as-dead-when-unbinding-anonymous-set-with-timeout.patch queue-4.19/netfilter-nf_tables-reject-new-basechain-after-table-flag-update.patch queue-4.19/netfilter-nf_tables-gc-transaction-race-with-netns-dismantle.patch queue-4.19/netfilter-nftables-update-table-flags-from-the-commit-phase.patch queue-4.19/netfilter-nf_tables-allow-nfproto_inet-in-nft_-match-target-_validate.patch queue-4.19/netfilter-nft_set_rbtree-skip-end-interval-element-from-gc.patch queue-4.19/netfilter-nf_tables-drop-map-element-references-from-preparation-phase.patch queue-4.19/netfilter-nf_tables-gc-transaction-race-with-abort-path.patch queue-4.19/netfilter-nf_tables-fix-memleak-when-more-than-255-elements-expired.patch queue-4.19/netfilter-nft_set_rbtree-add-missing-expired-checks.patch queue-4.19/netfilter-nf_tables-double-hook-unregistration-in-netns-path.patch queue-4.19/netfilter-nft_dynset-relax-superfluous-check-on-set-updates.patch queue-4.19/netfilter-nf_tables-defer-gc-run-if-previous-batch-is-still-pending.patch queue-4.19/netfilter-nft_set_hash-try-later-when-gc-hits-eagain-on-iteration.patch queue-4.19/netfilter-nft_dynset-fix-timeouts-later-than-23-days.patch queue-4.19/netfilter-nf_tables-mark-newset-as-dead-on-transaction-abort.patch queue-4.19/netfilter-nf_tables-don-t-skip-expired-elements-during-walk.patch queue-4.19/netfilter-nftables-rename-set-element-data-activation-deactivation-functions.patch queue-4.19/netfilter-nf_tables-gc-transaction-api-to-avoid-race-with-control-plane.patch queue-4.19/netfilter-nf_tables-set-dormant-flag-on-hook-register-failure.patch queue-4.19/netfilter-nf_tables-remove-busy-mark-and-gc-batch-api.patch queue-4.19/netfilter-nf_tables-skip-dead-set-elements-in-netlink-dump.patch queue-4.19/netfilter-nf_tables-adapt-set-backend-to-use-gc-transaction-api.patch queue-4.19/netfilter-nft_set_rbtree-fix-overlap-expiration-walk.patch queue-4.19/netfilter-nf_tables-fix-table-flag-updates.patch queue-4.19/netfilter-nf_tables-do-not-compare-internal-table-flags-on-updates.patch queue-4.19/netfilter-nft_set_rbtree-allow-loose-matching-of-closing-element-in-interval.patch queue-4.19/netfilter-nftables-exthdr-fix-4-byte-stack-oob-write.patch queue-4.19/netfilter-nft_set_rbtree-fix-null-deref-on-element-insertion.patch queue-4.19/netfilter-nf_tables-pass-context-to-nft_set_destroy.patch queue-4.19/netfilter-nf_tables-disable-toggling-dormant-table-state-more-than-once.patch