Let's move away from using strncpy() as it is deprecated [1].
Instead use strtomem() as `e.id` is already marked as nonstring:
| char id[4] __nonstring;
We don't need strtomem_pad() because `e` is already memset to 0 --
rendering any additional NUL-padding useless.
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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/s390/char/sclp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 8f74db689a0c..486cf57a1605 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -81,7 +81,7 @@ static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
struct sclp_trace_entry e;
memset(&e, 0, sizeof(e));
- strncpy(e.id, id, sizeof(e.id));
+ strtomem(e.id, id);
e.a = a;
e.b = b;
debug_event(&sclp_debug, prio, &e, sizeof(e));
---
base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c
change-id: 20231023-strncpy-drivers-s390-char-sclp-c-bb66226a7eaa
Best regards,
--
Justin Stitt <[email protected]>
On Mon, Oct 23, 2023 at 07:14:49PM +0000, Justin Stitt wrote:
> Let's move away from using strncpy() as it is deprecated [1].
>
> Instead use strtomem() as `e.id` is already marked as nonstring:
> | char id[4] __nonstring;
I'm surprised the compiler didn't complain about this -- I thought that
was the point of the __nonstring attribute: to diagnose when used with a
string function. Hmpf.
>
> We don't need strtomem_pad() because `e` is already memset to 0 --
> rendering any additional NUL-padding useless.
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> Note: build-tested only.
>
> Found with: $ rg "strncpy\("
> ---
> drivers/s390/char/sclp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
> index 8f74db689a0c..486cf57a1605 100644
> --- a/drivers/s390/char/sclp.c
> +++ b/drivers/s390/char/sclp.c
> @@ -81,7 +81,7 @@ static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
> struct sclp_trace_entry e;
>
> memset(&e, 0, sizeof(e));
> - strncpy(e.id, id, sizeof(e.id));
> + strtomem(e.id, id);
Looks right to me; thanks!
Reviewed-by: Kees Cook <[email protected]>
-Kees
> e.a = a;
> e.b = b;
> debug_event(&sclp_debug, prio, &e, sizeof(e));
>
> ---
> base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c
> change-id: 20231023-strncpy-drivers-s390-char-sclp-c-bb66226a7eaa
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>
>
--
Kees Cook
On Tue, Oct 24, 2023 at 04:46:04PM -0700, Kees Cook wrote:
> > Instead use strtomem() as `e.id` is already marked as nonstring:
> > | char id[4] __nonstring;
>
> I'm surprised the compiler didn't complain about this -- I thought that
> was the point of the __nonstring attribute: to diagnose when used with a
> string function. Hmpf.
Wow. GCC only warns if you call strlen() on it, but literally nothing
else... :(
--
Kees Cook
On Mon, Oct 23, 2023 at 07:14:49PM +0000, Justin Stitt wrote:
> Let's move away from using strncpy() as it is deprecated [1].
>
> Instead use strtomem() as `e.id` is already marked as nonstring:
> | char id[4] __nonstring;
>
> We don't need strtomem_pad() because `e` is already memset to 0 --
> rendering any additional NUL-padding useless.
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> Note: build-tested only.
>
> Found with: $ rg "strncpy\("
> ---
> drivers/s390/char/sclp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied, thank you!