On Thu, Oct 05, 2023 at 09:33:19PM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> NUL-padding is not required as drvinfo is memset to 0:
> | memset(drvinfo, 0, sizeof(struct ethtool_drvinfo));
>
> A suitable replacement is `strscpy` [2] due to the fact that it
> guarantees NUL-termination on the destination buffer without
> unnecessarily NUL-padding.
>
> Link:
> https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
> [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
> [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> Note: build-tested only.
> ---
> drivers/net/ethernet/cavium/liquidio/lio_ethtool.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
> b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
> index 9d56181a301f..d3e07b6ed5e1 100644
> --- a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
> +++ b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c
> @@ -442,10 +442,11 @@ lio_get_drvinfo(struct net_device *netdev, struct
> ethtool_drvinfo *drvinfo)
> oct = lio->oct_dev;
>
> memset(drvinfo, 0, sizeof(struct ethtool_drvinfo));
struct ethtool_drvinfo {
char driver[32];
...
char fw_version[ETHTOOL_FWVERS_LEN];
char bus_info[ETHTOOL_BUSINFO_LEN];
> - strcpy(drvinfo->driver, "liquidio");
> + strscpy(drvinfo->driver, "liquidio", sizeof(drvinfo->driver));
Yup, this is basically what FORTIFY_SOURCE will do automatically to
strcpy().
> - strncpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version,
> - ETHTOOL_FWVERS_LEN);
> + strscpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version,
> + sizeof(drvinfo->fw_version));
Yup, ETHTOOL_FWVERS_LEN == sizeof(drvinfo->fw_version)
> - strncpy(drvinfo->bus_info, pci_name(oct->pci_dev), 32);
> + strscpy(drvinfo->bus_info, pci_name(oct->pci_dev),
> + sizeof(drvinfo->bus_info));
Yup, ETHTOOL_BUSINFO_LEN == sizeof(drvinfo->bus_info)
> }
>
> static void
> @@ -458,10 +459,11 @@ lio_get_vf_drvinfo(struct net_device *netdev, struct
> ethtool_drvinfo *drvinfo)
> oct = lio->oct_dev;
>
> memset(drvinfo, 0, sizeof(struct ethtool_drvinfo));
> - strcpy(drvinfo->driver, "liquidio_vf");
> - strncpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version,
> - ETHTOOL_FWVERS_LEN);
> - strncpy(drvinfo->bus_info, pci_name(oct->pci_dev), 32);
> + strscpy(drvinfo->driver, "liquidio_vf", sizeof(drvinfo->driver));
> + strscpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version,
> + sizeof(drvinfo->fw_version));
> + strscpy(drvinfo->bus_info, pci_name(oct->pci_dev),
> + sizeof(drvinfo->bus_info));
> }
Yup, looks good.
Reviewed-by: Kees Cook <[email protected]>
>
> static int
>
> ---
> base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> change-id:
> 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-b6932c0f80f1
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>
>
--
Kees Cook
