Subject: Re: [PATCH 3/7] scsi: qedf: replace deprecated strncpy with strscpy

From: Kees Cook <[email-masked]>
Date: Fri, 23 Feb 2024 16:09:28 -0800

On Fri, Feb 23, 2024 at 10:23:08PM +0000, Justin Stitt wrote:
> We expect slowpath_params.name to be NUL-terminated based on its future
> usage with other string APIs:
> 
> |	static int qed_slowpath_start(struct qed_dev *cdev,
> |				      struct qed_slowpath_params *params)
> ...
> |	strscpy(drv_version.name, params->name,
> |		MCP_DRV_VER_STR_SIZE - 4);
> 
> Moreover, NUL-padding is not necessary as the only use for this slowpath
> name parameter is to copy into the drv_version.name field.
> 
> Also, let's prefer using strscpy(src, dest, sizeof(src)) in two
> instances (one of which is outside of the scsi system but it is trivial
> and related to this patch).
> 
> We can see the drv_version.name size here:
> |	struct qed_mcp_drv_version {
> |		u32	version;
> |		u8	name[MCP_DRV_VER_STR_SIZE - 4];
> |	};

What a weird length. :P

> 
> Signed-off-by: Justin Stitt <[email-masked]>
> ---
>  drivers/net/ethernet/qlogic/qed/qed_main.c | 2 +-
>  drivers/scsi/qedf/qedf_main.c              | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qed/qed_main.c b/drivers/net/ethernet/qlogic/qed/qed_main.c
> index c278f8893042..d39e198fe8db 100644
> --- a/drivers/net/ethernet/qlogic/qed/qed_main.c
> +++ b/drivers/net/ethernet/qlogic/qed/qed_main.c
> @@ -1351,7 +1351,7 @@ static int qed_slowpath_start(struct qed_dev *cdev,
>  				      (params->drv_rev << 8) |
>  				      (params->drv_eng);
>  		strscpy(drv_version.name, params->name,
> -			MCP_DRV_VER_STR_SIZE - 4);
> +			sizeof(drv_version.name));
>  		rc = qed_mcp_send_drv_version(hwfn, hwfn->p_main_ptt,
>  					      &drv_version);
>  		if (rc) {
> diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
> index a58353b7b4e8..fd12439cbaab 100644
> --- a/drivers/scsi/qedf/qedf_main.c
> +++ b/drivers/scsi/qedf/qedf_main.c
> @@ -3468,7 +3468,7 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
>  	slowpath_params.drv_minor = QEDF_DRIVER_MINOR_VER;
>  	slowpath_params.drv_rev = QEDF_DRIVER_REV_VER;
>  	slowpath_params.drv_eng = QEDF_DRIVER_ENG_VER;
> -	strncpy(slowpath_params.name, "qedf", QED_DRV_VER_STR_SIZE);
> +	strscpy(slowpath_params.name, "qedf", sizeof(slowpath_params.name));
>  	rc = qed_ops->common->slowpath_start(qedf->cdev, &slowpath_params);
>  	if (rc) {
>  		QEDF_ERR(&(qedf->dbg_ctx), "Cannot start slowpath.\n");

Yeah, looks good.

Reviewed-by: Kees Cook <[email-masked]>

-- 
Kees Cook