[PATCH v2] bna: replace deprecated strncpy with strscpy_pad

[PATCH v2] bna: replace deprecated strncpy with strscpy_pad

[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.

bfa_ioc_get_adapter_manufacturer() simply copies a string literal into
`manufacturer`.

Another implementation of bfa_ioc_get_adapter_manufacturer() from
drivers/scsi/bfa/bfa_ioc.c uses memset + strscpy:
|	void
|	bfa_ioc_get_adapter_manufacturer(struct bfa_ioc_s *ioc, char *manufacturer)
|	{
|		memset((void *)manufacturer, 0, BFA_ADAPTER_MFG_NAME_LEN);
|			strscpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN);
|	}

Let's use `strscpy_pad` to eliminate some redundant work while still
NUL-terminating and NUL-padding the destination buffer.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Changes in v2:
- don't use sizeof on ptr (thanks Kees)
- strscpy -> strscpy_pad (thanks Kees)
- change subject line + commit msg to reflect above
- Link to v1: https://lore.kernel.org/r/20231005-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-v1-1-8dfd30123afc@google.com
---
Note: build-tested only.
---
 drivers/net/ethernet/brocade/bna/bfa_ioc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/brocade/bna/bfa_ioc.c b/drivers/net/ethernet/brocade/bna/bfa_ioc.c
index b07522ac3e74..9c80ab07a735 100644
--- a/drivers/net/ethernet/brocade/bna/bfa_ioc.c
+++ b/drivers/net/ethernet/brocade/bna/bfa_ioc.c
@@ -2839,7 +2839,7 @@ bfa_ioc_get_adapter_optrom_ver(struct bfa_ioc *ioc, char *optrom_ver)
 static void
 bfa_ioc_get_adapter_manufacturer(struct bfa_ioc *ioc, char *manufacturer)
 {
-	strncpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN);
+	strscpy_pad(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN);
 }
 
 static void

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231005-strncpy-drivers-net-ethernet-brocade-bna-bfa_ioc-c-68f13966f388

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

Re: [PATCH v2] bna: replace deprecated strncpy with strscpy_pad

[Kees Cook]

On Mon, Oct 09, 2023 at 05:45:33PM +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.
> 
> bfa_ioc_get_adapter_manufacturer() simply copies a string literal into
> `manufacturer`.
> 
> Another implementation of bfa_ioc_get_adapter_manufacturer() from
> drivers/scsi/bfa/bfa_ioc.c uses memset + strscpy:
> |	void
> |	bfa_ioc_get_adapter_manufacturer(struct bfa_ioc_s *ioc, char *manufacturer)
> |	{
> |		memset((void *)manufacturer, 0, BFA_ADAPTER_MFG_NAME_LEN);
> |			strscpy(manufacturer, BFA_MFG_NAME, BFA_ADAPTER_MFG_NAME_LEN);
> |	}
> 
> Let's use `strscpy_pad` to eliminate some redundant work while still
> NUL-terminating and NUL-padding the destination buffer.
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

Thanks for the update! Yeah, this looks safe to me now.

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

-- 
Kees Cook

Re: [PATCH v2] bna: replace deprecated strncpy with strscpy_pad

[patchwork-bot+netdevbpf]

Hello:

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

On Mon, 09 Oct 2023 17:45:33 +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.
> 
> bfa_ioc_get_adapter_manufacturer() simply copies a string literal into
> `manufacturer`.
> 
> [...]

Here is the summary with links:
  - [v2] bna: replace deprecated strncpy with strscpy_pad
    https://git.kernel.org/netdev/net-next/c/460c81da66f2

You are awesome, thank you!
-- 
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