`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

ethtool_sprintf() is designed specifically for get_strings() usage.
Let's replace strncpy in favor of this more robust and easier to
understand interface.

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/dsa/lantiq_gswip.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
index 3c76a1a14aee..d60bc2e37701 100644
--- a/drivers/net/dsa/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq_gswip.c
@@ -1759,8 +1759,7 @@ static void gswip_get_strings(struct dsa_switch *ds, int port, u32 stringset,
 		return;
 
 	for (i = 0; i < ARRAY_SIZE(gswip_rmon_cnt); i++)
-		strncpy(data + i * ETH_GSTRING_LEN, gswip_rmon_cnt[i].name,
-			ETH_GSTRING_LEN);
+		ethtool_sprintf(&data, "%s", gswip_rmon_cnt[i].name);
 }
 
 static u32 gswip_bcm_ram_entry_read(struct gswip_priv *priv, u32 table,

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231005-strncpy-drivers-net-dsa-lantiq_gswip-c-ece909a364f7

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

Hello:

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

On Mon, 09 Oct 2023 18:24:20 +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.
> 
> ethtool_sprintf() is designed specifically for get_strings() usage.
> Let's replace strncpy in favor of this more robust and easier to
> understand interface.
> 
> [...]

Here is the summary with links:
  - net: dsa: lantiq_gswip: replace deprecated strncpy with ethtool_sprintf
    https://git.kernel.org/netdev/net-next/c/ed9417206de7

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

On 10/9/23 11:24, 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.
> 
> ethtool_sprintf() is designed specifically for get_strings() usage.
> Let's replace strncpy in favor of this more robust and easier to
> understand interface.
> 
> 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>

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
-- 
Florian

On Mon, Oct 09, 2023 at 06:24:20PM +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.
> 
> ethtool_sprintf() is designed specifically for get_strings() usage.
> Let's replace strncpy in favor of this more robust and easier to
> understand interface.
> 
> 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/dsa/lantiq_gswip.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
> index 3c76a1a14aee..d60bc2e37701 100644
> --- a/drivers/net/dsa/lantiq_gswip.c
> +++ b/drivers/net/dsa/lantiq_gswip.c
> @@ -1759,8 +1759,7 @@ static void gswip_get_strings(struct dsa_switch *ds, int port, u32 stringset,
>  		return;
>  
>  	for (i = 0; i < ARRAY_SIZE(gswip_rmon_cnt); i++)
> -		strncpy(data + i * ETH_GSTRING_LEN, gswip_rmon_cnt[i].name,
> -			ETH_GSTRING_LEN);
> +		ethtool_sprintf(&data, "%s", gswip_rmon_cnt[i].name);

Sorry, I read too fast: this should be "data", not "&data", yeah?

-Kees

>  }
>  
>  static u32 gswip_bcm_ram_entry_read(struct gswip_priv *priv, u32 table,
> 
> ---
> base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> change-id: 20231005-strncpy-drivers-net-dsa-lantiq_gswip-c-ece909a364f7
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
> 
> 

-- 
Kees Cook

On Mon, Oct 09, 2023 at 11:34:27AM -0700, Kees Cook wrote:
> On Mon, Oct 09, 2023 at 06:24:20PM +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.
> > 
> > ethtool_sprintf() is designed specifically for get_strings() usage.
> > Let's replace strncpy in favor of this more robust and easier to
> > understand interface.
> > 
> > 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/dsa/lantiq_gswip.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
> > index 3c76a1a14aee..d60bc2e37701 100644
> > --- a/drivers/net/dsa/lantiq_gswip.c
> > +++ b/drivers/net/dsa/lantiq_gswip.c
> > @@ -1759,8 +1759,7 @@ static void gswip_get_strings(struct dsa_switch *ds, int port, u32 stringset,
> >  		return;
> >  
> >  	for (i = 0; i < ARRAY_SIZE(gswip_rmon_cnt); i++)
> > -		strncpy(data + i * ETH_GSTRING_LEN, gswip_rmon_cnt[i].name,
> > -			ETH_GSTRING_LEN);
> > +		ethtool_sprintf(&data, "%s", gswip_rmon_cnt[i].name);
> 
> Sorry, I read too fast: this should be "data", not "&data", yeah?

As I said in the other email, please ignore me. &data is correct. I'm
not used to ethtool_sprintf(), clearly. :) My original Reviewed-by
stands. Sorry for the noise!

-Kees

-- 
Kees Cook

On Mon, Oct 09, 2023 at 06:24:20PM +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.
> 
> ethtool_sprintf() is designed specifically for get_strings() usage.
> Let's replace strncpy in favor of this more robust and easier to
> understand interface.
> 
> 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>

Looks like the expected replacement. Thanks!

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook