Re: [PATCH v1] Bluetooth: hci_sync: fix set_local_name race condition

[Paul Menzel <pmenzel@xxxxxxxxxxxxx>]

Dear Pavel,


Thank you for the patch. Some minor style comments below.

Am 21.08.25 um 18:07 schrieb Pavel Shpakovskiy:
> 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 when function set_name_sync() will read old name

… is possible *that* function …?

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

(Using 75 characters per line would save some lines.)

> Fixes: 6f6ff38a1e14 ("Bluetooth: hci_sync: Convert MGMT_OP_SET_LOCAL_NAME")
> Signed-off-by: Pavel Shpakovskiy <pashpakovskii@xxxxxxxxxxxxxxxxx>
> ---
>   include/net/bluetooth/hci_sync.h | 2 +-
>   net/bluetooth/hci_sync.c         | 6 +++---
>   net/bluetooth/mgmt.c             | 5 ++++-
>   3 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/bluetooth/hci_sync.h b/include/net/bluetooth/hci_sync.h
> index 72558c826aa1b..eef12830eaec9 100644
> --- a/include/net/bluetooth/hci_sync.h
> +++ b/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,
> diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
> index e56b1cbedab90..c2a6469e81cdf 100644
> --- a/net/bluetooth/hci_sync.c
> +++ b/net/bluetooth/hci_sync.c
> @@ -3412,13 +3412,13 @@ 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,
> @@ -3471,7 +3471,7 @@ 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);
>   	}
>   
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index 46b22708dfbd2..da662e1823ae5 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -3876,8 +3876,11 @@ 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);
>   	}
>   

Reviewed-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>


Kind regards,

Paul