[PATCH] liquidio: replace deprecated strncpy/strcpy with strscpy

[PATCH] liquidio: replace deprecated strncpy/strcpy with strscpy

[Justin Stitt]

`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: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
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));
-	strcpy(drvinfo->driver, "liquidio");
-	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", 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));
 }
 
 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));
 }
 
 static int

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-b6932c0f80f1

Best regards,
--
Justin Stitt <justinstitt@google.com>

Re: [PATCH] liquidio: replace deprecated strncpy/strcpy with strscpy

[Kees Cook]

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: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>
> ---
> 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 <keescook@chromium.org>

>  
>  static int
> 
> ---
> base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> change-id: 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-b6932c0f80f1
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
> 
> 

-- 
Kees Cook

Re: [PATCH] liquidio: replace deprecated strncpy/strcpy with strscpy

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 05 Oct 2023 21:33:19 +0000 you 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));
> 
> [...]

Here is the summary with links:
  - liquidio: replace deprecated strncpy/strcpy with strscpy
    https://git.kernel.org/netdev/net-next/c/52cdbea1a54a

You are awesome, thank you!
-- 
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