[PATCH] crypto: qat - refactor deprecated strncpy

[PATCH] crypto: qat - refactor deprecated strncpy

[Justin Stitt]

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

`buf` is expected to be NUL-terminated for its eventual use in
`kstrtoul()` and NUL-padding is not required.

Due to the above, a suitable replacement is `strscpy` [2] due to the
fact that it guarantees NUL-termination on the destination buffer.

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/crypto/intel/qat/qat_common/qat_uclo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/intel/qat/qat_common/qat_uclo.c b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
index ce837bcc1cab..e2f82128043e 100644
--- a/drivers/crypto/intel/qat/qat_common/qat_uclo.c
+++ b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
@@ -200,7 +200,7 @@ static int qat_uclo_parse_num(char *str, unsigned int *num)
 	unsigned long ae = 0;
 	int i;
 
-	strncpy(buf, str, 15);
+	strscpy(buf, str, sizeof(buf));
 	for (i = 0; i < 16; i++) {
 		if (!isdigit(buf[i])) {
 			buf[i] = '\0';

---
base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
change-id: 20230913-strncpy-drivers-crypto-intel-qat-qat_common-qat_uclo-c-0f4b16830f59

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

Re: [PATCH] crypto: qat - refactor deprecated strncpy

[Giovanni Cabiddu]

On Wed, Sep 13, 2023 at 12:51:05AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> 
> We should prefer more robust and less ambiguous string interfaces.
> 
> `buf` is expected to be NUL-terminated for its eventual use in
> `kstrtoul()` and NUL-padding is not required.
> 
> Due to the above, a suitable replacement is `strscpy` [2] due to the
> fact that it guarantees NUL-termination on the destination buffer.
> 
> 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>
Acked-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>

> ---
> Note: build-tested only.
Reviewed and tested on dh895xcc, the only device impacted by this
change. All good.

Thanks,

-- 
Giovanni

Re: [PATCH] crypto: qat - refactor deprecated strncpy

[Kees Cook]

On Wed, Sep 13, 2023 at 12:51:05AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> 
> We should prefer more robust and less ambiguous string interfaces.
> 
> `buf` is expected to be NUL-terminated for its eventual use in
> `kstrtoul()` and NUL-padding is not required.
> 
> Due to the above, a suitable replacement is `strscpy` [2] due to the
> fact that it guarantees NUL-termination on the destination buffer.
> 
> 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/crypto/intel/qat/qat_common/qat_uclo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/intel/qat/qat_common/qat_uclo.c b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> index ce837bcc1cab..e2f82128043e 100644
> --- a/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> +++ b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> @@ -200,7 +200,7 @@ static int qat_uclo_parse_num(char *str, unsigned int *num)
>  	unsigned long ae = 0;
>  	int i;
>  
> -	strncpy(buf, str, 15);
> +	strscpy(buf, str, sizeof(buf));
>  	for (i = 0; i < 16; i++) {
>  		if (!isdigit(buf[i])) {

I was initially worried when I saw this walking the entire contents, but
I see it is explicitly zeroed on the stack first, so this is fine:

        char buf[16] = {0};


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

-Kees

>  			buf[i] = '\0';
> 
> ---
> base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
> change-id: 20230913-strncpy-drivers-crypto-intel-qat-qat_common-qat_uclo-c-0f4b16830f59
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
> 

-- 
Kees Cook

Re: [PATCH] crypto: qat - refactor deprecated strncpy

[Herbert Xu]

On Wed, Sep 13, 2023 at 12:51:05AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> 
> We should prefer more robust and less ambiguous string interfaces.
> 
> `buf` is expected to be NUL-terminated for its eventual use in
> `kstrtoul()` and NUL-padding is not required.
> 
> Due to the above, a suitable replacement is `strscpy` [2] due to the
> fact that it guarantees NUL-termination on the destination buffer.
> 
> 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/crypto/intel/qat/qat_common/qat_uclo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt