Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mgmt_remove_adv_monitor_sync

[Mazin Alhaddad]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
From 4f5407c8474ed6747d61412b915c949d9d9c6805 Mon Sep 17 00:00:00 2001
From: Mazin AlHaddad <mazin@xxxxxxxxxxxx>
Date: Sun, 8 Dec 2024 18:52:54 +0300
Subject: [PATCH] TEST

---
 net/bluetooth/hci_sync.c |  5 +++--
 net/bluetooth/mgmt.c     | 12 +++++++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index c86f4e42e..aa5aa3fed 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5197,6 +5197,9 @@ int hci_dev_close_sync(struct hci_dev *hdev)
 	 */
 	drain_workqueue(hdev->workqueue);
 
+	/* flush cmd  work */
+	flush_work(&hdev->cmd_work);
+
 	hci_dev_lock(hdev);
 
 	hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
@@ -5234,8 +5237,6 @@ int hci_dev_close_sync(struct hci_dev *hdev)
 		clear_bit(HCI_INIT, &hdev->flags);
 	}
 
-	/* flush cmd  work */
-	flush_work(&hdev->cmd_work);
 
 	/* Drop queues */
 	skb_queue_purge(&hdev->rx_q);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index b31192d47..b417756ac 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -5519,9 +5519,17 @@ static void mgmt_remove_adv_monitor_complete(struct hci_dev *hdev,
 {
 	struct mgmt_rp_remove_adv_monitor rp;
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_cp_remove_adv_monitor *cp = cmd->param;
+	struct mgmt_cp_remove_adv_monitor *cp;
 
 	hci_dev_lock(hdev);
+	// if called while device is closing, status will be invalid.
+	// and cmd is cleared by __mgmt_power_off
+	if (status == -EINVAL || cmd != pending_find(MGMT_OP_REMOVE_ADV_MONITOR, hdev)){
+		hci_dev_unlock(hdev);
+		return;
+	}
+
+	cp = cmd->param;
 
 	rp.monitor_handle = cp->monitor_handle;
 
@@ -5540,6 +5548,8 @@ static void mgmt_remove_adv_monitor_complete(struct hci_dev *hdev,
 static int mgmt_remove_adv_monitor_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
+	if (cmd != pending_find(MGMT_OP_REMOVE_ADV_MONITOR, hdev))
+		return -EINVAL;
 	struct mgmt_cp_remove_adv_monitor *cp = cmd->param;
 	u16 handle = __le16_to_cpu(cp->monitor_handle);
 
-- 
2.46.0