[PATCH v2] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy

[PATCH v2] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy

[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.

To keep node->current_state_name and node->prev_state_name NUL-padded
and NUL-terminated let's use strscpy_pad() as this implicitly provides
both.

For the swap between the two, a simple memcpy will suffice.

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>
---
Changes in v2:
- use strscpy_pad (thanks Kees)
- Link to v1: https://lore.kernel.org/r/20231023-strncpy-drivers-scsi-elx-libefc-efc_node-h-v1-1-8b66878b6796@google.com
---
Note: build-tested only.

Found with: $ rg "strncpy\("
---
 drivers/scsi/elx/libefc/efc_node.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/elx/libefc/efc_node.h b/drivers/scsi/elx/libefc/efc_node.h
index e9c600ac45d5..e57579988ba4 100644
--- a/drivers/scsi/elx/libefc/efc_node.h
+++ b/drivers/scsi/elx/libefc/efc_node.h
@@ -26,13 +26,13 @@ efc_node_evt_set(struct efc_sm_ctx *ctx, enum efc_sm_event evt,
 	struct efc_node *node = ctx->app;
 
 	if (evt == EFC_EVT_ENTER) {
-		strncpy(node->current_state_name, handler,
-			sizeof(node->current_state_name));
+		strscpy_pad(node->current_state_name, handler,
+			    sizeof(node->current_state_name));
 	} else if (evt == EFC_EVT_EXIT) {
-		strncpy(node->prev_state_name, node->current_state_name,
-			sizeof(node->prev_state_name));
-		strncpy(node->current_state_name, "invalid",
-			sizeof(node->current_state_name));
+		memcpy(node->prev_state_name, node->current_state_name,
+		       sizeof(node->prev_state_name));
+		strscpy_pad(node->current_state_name, "invalid",
+			    sizeof(node->current_state_name));
 	}
 	node->prev_evt = node->current_evt;
 	node->current_evt = evt;

---
base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c
change-id: 20231023-strncpy-drivers-scsi-elx-libefc-efc_node-h-cbbf753197b7

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

Re: [PATCH v2] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy

[Kees Cook]

On Thu, Oct 26, 2023 at 01:53:13AM +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.
> 
> To keep node->current_state_name and node->prev_state_name NUL-padded
> and NUL-terminated let's use strscpy_pad() as this implicitly provides
> both.
> 
> For the swap between the two, a simple memcpy will suffice.
> 
> 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 think this looks good now.

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

-- 
Kees Cook

Re: [PATCH v2] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy

[Martin K. Petersen]

Justin,

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

Applied to 6.8/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v2] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy

[Martin K. Petersen]

On Thu, 26 Oct 2023 01:53:13 +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.
> 
> To keep node->current_state_name and node->prev_state_name NUL-padded
> and NUL-terminated let's use strscpy_pad() as this implicitly provides
> both.
> 
> [...]

Applied to 6.8/scsi-queue, thanks!

[1/1] scsi: elx: libefc: replace deprecated strncpy with strscpy_pad/memcpy
      https://git.kernel.org/mkp/scsi/c/1057f44137c5

-- 
Martin K. Petersen	Oracle Linux Engineering