Bluetooth: hci_sync: fix set_local_name race condition

Function set_name_sync() uses hdev->dev_name field to send
HCI_OP_WRITE_LOCAL_NAME command, but copying from data to hdev->dev_name
is called after mgmt cmd was queued, so it is possible that function
set_name_sync() will read old name value.

This change adds name as a parameter for function hci_update_name_sync()
to avoid race condition.

Fixes: 6f6ff38 ("Bluetooth: hci_sync: Convert MGMT_OP_SET_LOCAL_NAME")
Signed-off-by: Pavel Shpakovskiy <[email protected]>
Reviewed-by: Paul Menzel <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: Pavel Shpakovskiy

include/net/bluetooth/hci_sync.h

@@ -93,7 +93,7 @@ int hci_update_class_sync(struct hci_dev *hdev);
 
 int hci_update_eir_sync(struct hci_dev *hdev);
 int hci_update_class_sync(struct hci_dev *hdev);
-int hci_update_name_sync(struct hci_dev *hdev);
+int hci_update_name_sync(struct hci_dev *hdev, const u8 *name);
 int hci_write_ssp_mode_sync(struct hci_dev *hdev, u8 mode);
 
 int hci_get_random_address(struct hci_dev *hdev, bool require_privacy,

net/bluetooth/hci_sync.c

@@ -3481,13 +3481,13 @@ int hci_update_scan_sync(struct hci_dev *hdev)
 	return hci_write_scan_enable_sync(hdev, scan);
 }
 
-int hci_update_name_sync(struct hci_dev *hdev)
+int hci_update_name_sync(struct hci_dev *hdev, const u8 *name)
 {
 	struct hci_cp_write_local_name cp;
 
 	memset(&cp, 0, sizeof(cp));
 
-	memcpy(cp.name, hdev->dev_name, sizeof(cp.name));
+	memcpy(cp.name, name, sizeof(cp.name));
 
 	return __hci_cmd_sync_status(hdev, HCI_OP_WRITE_LOCAL_NAME,
 					    sizeof(cp), &cp,
@@ -3540,7 +3540,7 @@ int hci_powered_update_sync(struct hci_dev *hdev)
 			hci_write_fast_connectable_sync(hdev, false);
 		hci_update_scan_sync(hdev);
 		hci_update_class_sync(hdev);
-		hci_update_name_sync(hdev);
+		hci_update_name_sync(hdev, hdev->dev_name);
 		hci_update_eir_sync(hdev);
 	}
 

net/bluetooth/mgmt.c

@@ -3892,8 +3892,11 @@ static void set_name_complete(struct hci_dev *hdev, void *data, int err)
 
 static int set_name_sync(struct hci_dev *hdev, void *data)
 {
+	struct mgmt_pending_cmd *cmd = data;
+	struct mgmt_cp_set_local_name *cp = cmd->param;
+
 	if (lmp_bredr_capable(hdev)) {
-		hci_update_name_sync(hdev);
+		hci_update_name_sync(hdev, cp->name);
 		hci_update_eir_sync(hdev);
 	}