[PATCH net v1 1/2] net/sched: act_api: release tail references on DELACTION failure

[Xuanqiang Luo]

From: Xuanqiang Luo <luoxuanqiang@xxxxxxxxxx>

A batched RTM_DELACTION request takes a temporary reference on each
action before attempting any deletion. tcf_action_delete() clears
each processed slot and drops its temporary reference before attempting
the deletion. If deletion fails, tca_action_gd() calls
tcf_action_put_many() to release the remaining references, but its
tcf_act_for_each_action() iterator stops at the first NULL slot.

When a batch stops at an action bound to a filter, this leaks a
reference on each subsequent action. A later delete of an unbound
action can then return success without removing it from the IDR.

Walk the full array in tcf_action_put_many() and skip NULL slots to
release the references held on the unprocessed actions.

Fixes: a0e947c9ccff ("net/sched: act_api: avoid non-contiguous action array")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Xuanqiang Luo <luoxuanqiang@xxxxxxxxxx>
---
 net/sched/act_api.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 37eced84dfa5f..86710a596a0fa 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -1223,11 +1223,16 @@ static int tcf_action_put(struct tc_action *p)
 
 static void tcf_action_put_many(struct tc_action *actions[])
 {
-	struct tc_action *a;
 	int i;
 
-	tcf_act_for_each_action(i, a, actions) {
-		const struct tc_action_ops *ops = a->ops;
+	/* Deletion may have cleared entries before failing. */
+	for (i = 0; i < TCA_ACT_MAX_PRIO; i++) {
+		struct tc_action *a = actions[i];
+		const struct tc_action_ops *ops;
+
+		if (!a)
+			continue;
+		ops = a->ops;
 		if (tcf_action_put(a))
 			module_put(ops->owner);
 	}
-- 
2.43.0