[PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[Kees Cook]

When a character array without a terminating NUL character has a static
initializer, GCC 15's -Wunterminated-string-initialization will only
warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
with __nonstring to and correctly identify the char array as "not a C
string" and thereby eliminate the warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
---
 drivers/scsi/pm8001/pm8001_ctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/pm8001/pm8001_ctl.c b/drivers/scsi/pm8001/pm8001_ctl.c
index 85ff95c6543a..7618f9cc9986 100644
--- a/drivers/scsi/pm8001/pm8001_ctl.c
+++ b/drivers/scsi/pm8001/pm8001_ctl.c
@@ -644,7 +644,7 @@ static DEVICE_ATTR(gsm_log, S_IRUGO, pm8001_ctl_gsm_log_show, NULL);
 #define FLASH_CMD_SET_NVMD    0x02
 
 struct flash_command {
-     u8      command[8];
+     u8      command[8] __nonstring;
      int     code;
 };
 
-- 
2.34.1

Re: [PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[James Bottomley]

On Mon, 2025-03-10 at 15:25 -0700, Kees Cook wrote:
> When a character array without a terminating NUL character has a
> static
> initializer, GCC 15's -Wunterminated-string-initialization will only
> warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
> with __nonstring to and correctly identify the char array as "not a C
> string" and thereby eliminate the warning.
> 
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
> Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---
>  drivers/scsi/pm8001/pm8001_ctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/pm8001/pm8001_ctl.c
> b/drivers/scsi/pm8001/pm8001_ctl.c
> index 85ff95c6543a..7618f9cc9986 100644
> --- a/drivers/scsi/pm8001/pm8001_ctl.c
> +++ b/drivers/scsi/pm8001/pm8001_ctl.c
> @@ -644,7 +644,7 @@ static DEVICE_ATTR(gsm_log, S_IRUGO,
> pm8001_ctl_gsm_log_show, NULL);
>  #define FLASH_CMD_SET_NVMD    0x02
>  
>  struct flash_command {
> -     u8      command[8];
> +     u8      command[8] __nonstring;

This looks a bit suboptimal ... is there anywhere in the kernel u8[] is
actually used for real strings?  In which case it would seem the better
place to put the annotation is in the typedef for u8 arrays.

Regards,

James

Re: [PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[Kees Cook]

On Mon, Mar 10, 2025 at 06:38:01PM -0400, James Bottomley wrote:
> On Mon, 2025-03-10 at 15:25 -0700, Kees Cook wrote:
> > When a character array without a terminating NUL character has a
> > static
> > initializer, GCC 15's -Wunterminated-string-initialization will only
> > warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
> > with __nonstring to and correctly identify the char array as "not a C
> > string" and thereby eliminate the warning.
> > 
> > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
> > Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
> > Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> > Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> > Cc: linux-scsi@vger.kernel.org
> > Signed-off-by: Kees Cook <kees@kernel.org>
> > ---
> >  drivers/scsi/pm8001/pm8001_ctl.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/scsi/pm8001/pm8001_ctl.c
> > b/drivers/scsi/pm8001/pm8001_ctl.c
> > index 85ff95c6543a..7618f9cc9986 100644
> > --- a/drivers/scsi/pm8001/pm8001_ctl.c
> > +++ b/drivers/scsi/pm8001/pm8001_ctl.c
> > @@ -644,7 +644,7 @@ static DEVICE_ATTR(gsm_log, S_IRUGO,
> > pm8001_ctl_gsm_log_show, NULL);
> >  #define FLASH_CMD_SET_NVMD    0x02
> >  
> >  struct flash_command {
> > -     u8      command[8];
> > +     u8      command[8] __nonstring;
> 
> This looks a bit suboptimal ... is there anywhere in the kernel u8[] is
> actually used for real strings?  In which case it would seem the better
> place to put the annotation is in the typedef for u8 arrays.

I answered this in a merged thread[1]. Can this get picked up?

Thanks!

-Kees

[1] https://lore.kernel.org/lkml/202503111520.CF7527A@keescook/

-- 
Kees Cook

Re: [PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[Martin K. Petersen]

Kees,

>> > When a character array without a terminating NUL character has a
>> > static initializer, GCC 15's -Wunterminated-string-initialization
>> > will only warn if the array lacks the "nonstring" attribute[1].
>> > Mark the arrays with __nonstring to and correctly identify the char
>> > array as "not a C string" and thereby eliminate the warning.

Applied to 6.16/scsi-staging, thanks!

-- 
Martin K. Petersen