[PATCH] scsi: ibmvscsi: replace deprecated strncpy with strscpy

[PATCH] scsi: ibmvscsi: 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.

We expect partition_name to be NUL-terminated based on its usage with
format strings:
|       dev_info(hostdata->dev, "host srp version: %s, "
|                "host partition %s (%d), OS %d, max io %u\n",
|                hostdata->madapter_info.srp_version,
|                hostdata->madapter_info.partition_name,
|                be32_to_cpu(hostdata->madapter_info.partition_number),
|                be32_to_cpu(hostdata->madapter_info.os_type),
|                be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
...
|       len = snprintf(buf, PAGE_SIZE, "%s\n",
|                hostdata->madapter_info.partition_name);

Moreover, NUL-padding is not required as madapter_info is explicitly
memset to 0:
|       memset(&hostdata->madapter_info, 0x00,
|                       sizeof(hostdata->madapter_info));

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/scsi/ibmvscsi/ibmvscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 59599299615d..71f3e9563520 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -266,7 +266,7 @@ static void set_adapter_info(struct ibmvscsi_host_data *hostdata)
 	dev_info(hostdata->dev, "SRP_VERSION: %s\n", SRP_VERSION);
 	strcpy(hostdata->madapter_info.srp_version, SRP_VERSION);
 
-	strncpy(hostdata->madapter_info.partition_name, partition_name,
+	strscpy(hostdata->madapter_info.partition_name, partition_name,
 			sizeof(hostdata->madapter_info.partition_name));
 
 	hostdata->madapter_info.partition_number =

---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231030-strncpy-drivers-scsi-ibmvscsi-ibmvscsi-c-3b5019ce50ad

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

Re: [PATCH] scsi: ibmvscsi: replace deprecated strncpy with strscpy

[Kees Cook]

On Mon, Oct 30, 2023 at 08:40:48PM +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.
> 
> We expect partition_name to be NUL-terminated based on its usage with
> format strings:
> |       dev_info(hostdata->dev, "host srp version: %s, "
> |                "host partition %s (%d), OS %d, max io %u\n",
> |                hostdata->madapter_info.srp_version,
> |                hostdata->madapter_info.partition_name,
> |                be32_to_cpu(hostdata->madapter_info.partition_number),
> |                be32_to_cpu(hostdata->madapter_info.os_type),
> |                be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
> ...
> |       len = snprintf(buf, PAGE_SIZE, "%s\n",
> |                hostdata->madapter_info.partition_name);
> 
> Moreover, NUL-padding is not required as madapter_info is explicitly
> memset to 0:
> |       memset(&hostdata->madapter_info, 0x00,
> |                       sizeof(hostdata->madapter_info));
> 
> 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>

Agreed; this conversion looks correct to me too.

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

-- 
Kees Cook

Re: [PATCH] scsi: ibmvscsi: replace deprecated strncpy with strscpy

[Michael Ellerman]

Justin Stitt <justinstitt@google.com> writes:
> strncpy() is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> We expect partition_name to be NUL-terminated based on its usage with
> format strings:
> |       dev_info(hostdata->dev, "host srp version: %s, "
> |                "host partition %s (%d), OS %d, max io %u\n",
> |                hostdata->madapter_info.srp_version,
> |                hostdata->madapter_info.partition_name,
> |                be32_to_cpu(hostdata->madapter_info.partition_number),
> |                be32_to_cpu(hostdata->madapter_info.os_type),
> |                be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
> ...
> |       len = snprintf(buf, PAGE_SIZE, "%s\n",
> |                hostdata->madapter_info.partition_name);
>
> Moreover, NUL-padding is not required as madapter_info is explicitly
> memset to 0:
> |       memset(&hostdata->madapter_info, 0x00,
> |                       sizeof(hostdata->madapter_info));
>
> 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.

I gave it a quick boot, no issues.

Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers

Re: [PATCH] scsi: ibmvscsi: replace deprecated strncpy with strscpy

[Martin K. Petersen]

Michael,

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

> I gave it a quick boot, no issues.
>
> Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

Applied to 6.8/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH] scsi: ibmvscsi: replace deprecated strncpy with strscpy

[Martin K. Petersen]

On Mon, 30 Oct 2023 20:40:48 +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.
> 
> We expect partition_name to be NUL-terminated based on its usage with
> format strings:
> |       dev_info(hostdata->dev, "host srp version: %s, "
> |                "host partition %s (%d), OS %d, max io %u\n",
> |                hostdata->madapter_info.srp_version,
> |                hostdata->madapter_info.partition_name,
> |                be32_to_cpu(hostdata->madapter_info.partition_number),
> |                be32_to_cpu(hostdata->madapter_info.os_type),
> |                be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
> ...
> |       len = snprintf(buf, PAGE_SIZE, "%s\n",
> |                hostdata->madapter_info.partition_name);
> 
> [...]

Applied to 6.8/scsi-queue, thanks!

[1/1] scsi: ibmvscsi: replace deprecated strncpy with strscpy
      https://git.kernel.org/mkp/scsi/c/712b3f43ba0e

-- 
Martin K. Petersen	Oracle Linux Engineering