[PATCH] ionic: replace deprecated strncpy with strscpy

[PATCH] ionic: replace deprecated strncpy 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 needed due to `ident` being memset'd to 0 just before
the copy.

Considering the above, 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.

Found with: $ rg "strncpy\("
---
 drivers/net/ethernet/pensando/ionic/ionic_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_main.c b/drivers/net/ethernet/pensando/ionic/ionic_main.c
index 1dc79cecc5cc..835577392178 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_main.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_main.c
@@ -554,8 +554,8 @@ int ionic_identify(struct ionic *ionic)
 	memset(ident, 0, sizeof(*ident));
 
 	ident->drv.os_type = cpu_to_le32(IONIC_OS_TYPE_LINUX);
-	strncpy(ident->drv.driver_ver_str, UTS_RELEASE,
-		sizeof(ident->drv.driver_ver_str) - 1);
+	strscpy(ident->drv.driver_ver_str, UTS_RELEASE,
+		sizeof(ident->drv.driver_ver_str));
 
 	mutex_lock(&ionic->dev_cmd_lock);
 

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231011-strncpy-drivers-net-ethernet-pensando-ionic-ionic_main-c-709f8f1ea312

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

Re: [PATCH] ionic: replace deprecated strncpy with strscpy

[Nelson, Shannon]

On 10/11/2023 2:53 PM, 'Justin Stitt' via Pensando Drivers 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 needed due to `ident` being memset'd to 0 just before
> the copy.
> 
> Considering the above, 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>

Thanks, I suspected this was coming soon :-)

Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>


> ---
> Note: build-tested only.
> 
> Found with: $ rg "strncpy\("
> ---
>   drivers/net/ethernet/pensando/ionic/ionic_main.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_main.c b/drivers/net/ethernet/pensando/ionic/ionic_main.c
> index 1dc79cecc5cc..835577392178 100644
> --- a/drivers/net/ethernet/pensando/ionic/ionic_main.c
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_main.c
> @@ -554,8 +554,8 @@ int ionic_identify(struct ionic *ionic)
>          memset(ident, 0, sizeof(*ident));
> 
>          ident->drv.os_type = cpu_to_le32(IONIC_OS_TYPE_LINUX);
> -       strncpy(ident->drv.driver_ver_str, UTS_RELEASE,
> -               sizeof(ident->drv.driver_ver_str) - 1);
> +       strscpy(ident->drv.driver_ver_str, UTS_RELEASE,
> +               sizeof(ident->drv.driver_ver_str));
> 
>          mutex_lock(&ionic->dev_cmd_lock);
> 
> 
> ---
> base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> change-id: 20231011-strncpy-drivers-net-ethernet-pensando-ionic-ionic_main-c-709f8f1ea312
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
> 

Re: [PATCH] ionic: replace deprecated strncpy with strscpy

[Justin Stitt]

On Wed, Oct 11, 2023 at 3:17 PM Nelson, Shannon <shannon.nelson@amd.com> wrote:
>
> On 10/11/2023 2:53 PM, 'Justin Stitt' via Pensando Drivers 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 needed due to `ident` being memset'd to 0 just before
> > the copy.
> >
> > Considering the above, 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>
>
> Thanks, I suspected this was coming soon :-)
>
> Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>

Thanks Shannon!

>
>
> > ---
> > Note: build-tested only.
> >
> > Found with: $ rg "strncpy\("
> > ---
> >   drivers/net/ethernet/pensando/ionic/ionic_main.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/pensando/ionic/ionic_main.c b/drivers/net/ethernet/pensando/ionic/ionic_main.c
> > index 1dc79cecc5cc..835577392178 100644
> > --- a/drivers/net/ethernet/pensando/ionic/ionic_main.c
> > +++ b/drivers/net/ethernet/pensando/ionic/ionic_main.c
> > @@ -554,8 +554,8 @@ int ionic_identify(struct ionic *ionic)
> >          memset(ident, 0, sizeof(*ident));
> >
> >          ident->drv.os_type = cpu_to_le32(IONIC_OS_TYPE_LINUX);
> > -       strncpy(ident->drv.driver_ver_str, UTS_RELEASE,
> > -               sizeof(ident->drv.driver_ver_str) - 1);
> > +       strscpy(ident->drv.driver_ver_str, UTS_RELEASE,
> > +               sizeof(ident->drv.driver_ver_str));
> >
> >          mutex_lock(&ionic->dev_cmd_lock);
> >
> >
> > ---
> > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> > change-id: 20231011-strncpy-drivers-net-ethernet-pensando-ionic-ionic_main-c-709f8f1ea312
> >
> > Best regards,
> > --
> > Justin Stitt <justinstitt@google.com>
> >

Re: [PATCH] ionic: replace deprecated strncpy with strscpy

[Kees Cook]

On Wed, Oct 11, 2023 at 09:53:44PM +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 needed due to `ident` being memset'd to 0 just before
> the copy.
> 
> Considering the above, 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>

Yup, looks like a direct replacement.

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

-- 
Kees Cook

Re: [PATCH] ionic: replace deprecated strncpy with strscpy

[patchwork-bot+netdevbpf]

Hello:

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

On Wed, 11 Oct 2023 21:53:44 +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 needed due to `ident` being memset'd to 0 just before
> the copy.
> 
> [...]

Here is the summary with links:
  - ionic: replace deprecated strncpy with strscpy
    https://git.kernel.org/netdev/net-next/c/ad0ebd8b4457

You are awesome, thank you!
-- 
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