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Date:   Fri,  4 Aug 2023 11:14:45 -0700
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Message-ID: <20230804111444.1.I43aa4bd799a3cf9102f9de8c365ccb3d8e53a9d1@changeid>
Subject: [PATCH] Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_add_adv_monitor()
From:   Manish Mandlik <mmandlik@google.com>
To:     marcel@holtmann.org, luiz.dentz@gmail.com
Cc:     chromeos-bluetooth-upstreaming@chromium.org,
        linux-bluetooth@vger.kernel.org,
        Manish Mandlik <mmandlik@google.com>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Miao-chen Chou <mcchou@google.com>,
        linux-kernel@vger.kernel.org
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Precedence: bulk

KSAN reports use-after-free in hci_add_adv_monitor().

While adding an adv monitor,
    hci_add_adv_monitor() calls ->
    msft_add_monitor_pattern() calls ->
    msft_add_monitor_sync() calls ->
    msft_le_monitor_advertisement_cb() calls in an error case ->
    hci_free_adv_monitor() which frees the *moniter.

This is referenced by bt_dev_dbg() in hci_add_adv_monitor().

Fix the bt_dev_dbg() by using handle instead of monitor->handle.

Fixes: b747a83690c8 ("Bluetooth: hci_sync: Refactor add Adv Monitor")

Signed-off-by: Manish Mandlik <mmandlik@google.com>
---

 net/bluetooth/hci_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 0fefa6788911..c602cfb5be9e 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1957,7 +1957,7 @@ int hci_add_adv_monitor(struct hci_dev *hdev, struct adv_monitor *monitor)
 	case HCI_ADV_MONITOR_EXT_MSFT:
 		status = msft_add_monitor_pattern(hdev, monitor);
 		bt_dev_dbg(hdev, "add monitor %d msft status %d",
-			   monitor->handle, status);
+			   handle, status);
 		break;
 	}
 
-- 
2.41.0.585.gd2178a4bd4-goog