[PATCH 00/11] address remaining stringop-truncation warnings

[PATCH 00/11] address remaining stringop-truncation warnings

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

We are close to being able to turn on -Wstringop-truncation
unconditionally instead of only at the 'make W=1' level, these ten
warnings are all that I saw in randconfig testing across compiler versions
on arm, arm64 and x86.

The final patch is only there for reference at the moment, I hope
we can merge the other ones through the subsystem trees first,
as there are no dependencies between them.

     Arnd

Arnd Bergmann (11):
  staging: vc04_services: changen strncpy() to strscpy_pad()
  scsi: devinfo: rework scsi_strcpy_devinfo()
  staging: replace weird strncpy() with memcpy()
  orangefs: convert strncpy() to strscpy()
  test_hexdump: avoid string truncation warning
  acpi: avoid warning for truncated string copy
  block/partitions/ldm: convert strncpy() to strscpy()
  blktrace: convert strncpy() to strscpy_pad()
  staging: rtl8723bs: convert strncpy to strscpy
  staging: greybus: change strncpy() to strscpy()
  kbuild: enable -Wstringop-truncation globally

 block/partitions/ldm.c                        |  6 ++--
 drivers/acpi/acpica/tbfind.c                  | 19 +++++------
 drivers/scsi/scsi_devinfo.c                   | 30 +++++++++++------
 drivers/staging/greybus/fw-management.c       |  4 +--
 .../staging/rtl8723bs/os_dep/ioctl_cfg80211.c |  5 ++-
 drivers/staging/rts5208/rtsx_scsi.c           |  2 +-
 .../vc04_services/vchiq-mmal/mmal-vchiq.c     |  4 +--
 fs/orangefs/dcache.c                          |  4 +--
 fs/orangefs/namei.c                           | 33 +++++++++----------
 fs/orangefs/super.c                           | 16 ++++-----
 kernel/trace/blktrace.c                       |  3 +-
 lib/test_hexdump.c                            |  2 +-
 scripts/Makefile.extrawarn                    |  1 -
 13 files changed, 64 insertions(+), 65 deletions(-)

-- 
2.39.2

Cc: "Richard Russon
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Robert Moore <robert.moore@intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Viresh Kumar <vireshk@kernel.org>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
Cc: Mike Marshall <hubcap@omnibond.com>
Cc: Martin Brandenburg <martin@omnibond.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Starikovskiy <astarikovskiy@suse.de>
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: acpica-devel@lists.linux.dev
Cc: linux-scsi@vger.kernel.org
Cc: greybus-dev@lists.linaro.org
Cc: linux-staging@lists.linux.dev
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: devel@lists.orangefs.org
Cc: linux-trace-kernel@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org

[PATCH 02/11] scsi: devinfo: rework scsi_strcpy_devinfo()

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

scsi_strcpy_devinfo() appears to work as intended but its semantics are
so confusing that gcc warns about it when -Wstringop-truncation is enabled:

In function 'scsi_strcpy_devinfo',
    inlined from 'scsi_dev_info_list_add_keyed' at drivers/scsi/scsi_devinfo.c:370:2:
drivers/scsi/scsi_devinfo.c:297:9: error: 'strncpy' specified bound 16 equals destination size [-Werror=stringop-truncation]
  297 |         strncpy(to, from, to_length);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reorganize the function to completely separate the nul-terminated from
the space-padded/non-terminated case. The former is just strscpy_pad(),
while the latter does not have a standard function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/scsi/scsi_devinfo.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index ba7237e83863..58726c15ebac 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -290,18 +290,28 @@ static struct scsi_dev_info_list_table *scsi_devinfo_lookup_by_key(int key)
 static void scsi_strcpy_devinfo(char *name, char *to, size_t to_length,
 				char *from, int compatible)
 {
-	size_t from_length;
+	int ret;
 
-	from_length = strlen(from);
-	/* This zero-pads the destination */
-	strncpy(to, from, to_length);
-	if (from_length < to_length && !compatible) {
-		/*
-		 * space pad the string if it is short.
-		 */
-		memset(&to[from_length], ' ', to_length - from_length);
+	if (compatible) {
+		/* This zero-pads and nul-terminates the destination */
+		ret = strscpy_pad(to, from, to_length);
+	} else {
+		/* no nul-termination but space-padding for short strings */
+		size_t from_length = strlen(from);
+		ret = from_length;
+
+		if (from_length > to_length) {
+			from_length = to_length;
+			ret = -E2BIG;
+		}
+
+		memcpy(to, from, from_length);
+
+		if (from_length < to_length)
+			memset(&to[from_length], ' ', to_length - from_length);
 	}
-	if (from_length > to_length)
+
+	if (ret < 0)
 		 printk(KERN_WARNING "%s: %s string '%s' is too long\n",
 			__func__, name, from);
 }
-- 
2.39.2

Re: [PATCH 02/11] scsi: devinfo: rework scsi_strcpy_devinfo()

[Bart Van Assche]

On 3/28/24 07:04, Arnd Bergmann wrote:
> diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
> index ba7237e83863..58726c15ebac 100644
> --- a/drivers/scsi/scsi_devinfo.c
> +++ b/drivers/scsi/scsi_devinfo.c
> @@ -290,18 +290,28 @@ static struct scsi_dev_info_list_table *scsi_devinfo_lookup_by_key(int key)
>   static void scsi_strcpy_devinfo(char *name, char *to, size_t to_length,
>   				char *from, int compatible)
>   {
> -	size_t from_length;
> +	int ret;
>   
> -	from_length = strlen(from);
> -	/* This zero-pads the destination */
> -	strncpy(to, from, to_length);
> -	if (from_length < to_length && !compatible) {
> -		/*
> -		 * space pad the string if it is short.
> -		 */
> -		memset(&to[from_length], ' ', to_length - from_length);
> +	if (compatible) {
> +		/* This zero-pads and nul-terminates the destination */
> +		ret = strscpy_pad(to, from, to_length);
> +	} else {
> +		/* no nul-termination but space-padding for short strings */
> +		size_t from_length = strlen(from);
> +		ret = from_length;
> +
> +		if (from_length > to_length) {
> +			from_length = to_length;
> +			ret = -E2BIG;
> +		}
> +
> +		memcpy(to, from, from_length);
> +
> +		if (from_length < to_length)
> +			memset(&to[from_length], ' ', to_length - from_length);
>   	}
> -	if (from_length > to_length)
> +
> +	if (ret < 0)
>   		 printk(KERN_WARNING "%s: %s string '%s' is too long\n",
>   			__func__, name, from);
>   }

Please eliminate the variable 'ret'. I think that will improve
readability of the new code.

Thanks,

Bart.

Re: [PATCH 02/11] scsi: devinfo: rework scsi_strcpy_devinfo()

[Justin Stitt]

Hi,

On Thu, Mar 28, 2024 at 03:04:46PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> scsi_strcpy_devinfo() appears to work as intended but its semantics are
> so confusing that gcc warns about it when -Wstringop-truncation is enabled:
> 
> In function 'scsi_strcpy_devinfo',
>     inlined from 'scsi_dev_info_list_add_keyed' at drivers/scsi/scsi_devinfo.c:370:2:
> drivers/scsi/scsi_devinfo.c:297:9: error: 'strncpy' specified bound 16 equals destination size [-Werror=stringop-truncation]
>   297 |         strncpy(to, from, to_length);
>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Reorganize the function to completely separate the nul-terminated from
> the space-padded/non-terminated case. The former is just strscpy_pad(),
> while the latter does not have a standard function.
>

I did the same in a patch sent earlier (few weeks ago):

https://lore.kernel.org/all/20240305-strncpy-drivers-scsi-mpi3mr-mpi3mr_fw-c-v3-5-5b78a13ff984@google.com/

Maybe reviewers can chime in on which version is preferred and go from
there.

> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/scsi/scsi_devinfo.c | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
> index ba7237e83863..58726c15ebac 100644
> --- a/drivers/scsi/scsi_devinfo.c
> +++ b/drivers/scsi/scsi_devinfo.c
> @@ -290,18 +290,28 @@ static struct scsi_dev_info_list_table *scsi_devinfo_lookup_by_key(int key)
>  static void scsi_strcpy_devinfo(char *name, char *to, size_t to_length,
>  				char *from, int compatible)
>  {
> -	size_t from_length;
> +	int ret;
>  
> -	from_length = strlen(from);
> -	/* This zero-pads the destination */
> -	strncpy(to, from, to_length);
> -	if (from_length < to_length && !compatible) {
> -		/*
> -		 * space pad the string if it is short.
> -		 */
> -		memset(&to[from_length], ' ', to_length - from_length);
> +	if (compatible) {
> +		/* This zero-pads and nul-terminates the destination */
> +		ret = strscpy_pad(to, from, to_length);
> +	} else {
> +		/* no nul-termination but space-padding for short strings */
> +		size_t from_length = strlen(from);
> +		ret = from_length;
> +
> +		if (from_length > to_length) {
> +			from_length = to_length;
> +			ret = -E2BIG;
> +		}
> +
> +		memcpy(to, from, from_length);
> +
> +		if (from_length < to_length)
> +			memset(&to[from_length], ' ', to_length - from_length);
>  	}
> -	if (from_length > to_length)
> +
> +	if (ret < 0)
>  		 printk(KERN_WARNING "%s: %s string '%s' is too long\n",
>  			__func__, name, from);
>  }
> -- 
> 2.39.2
> 
Thanks
Justin

Re: [PATCH 02/11] scsi: devinfo: rework scsi_strcpy_devinfo()

[Arnd Bergmann]

On Fri, Mar 29, 2024, at 00:14, Justin Stitt wrote:
>
> On Thu, Mar 28, 2024 at 03:04:46PM +0100, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> scsi_strcpy_devinfo() appears to work as intended but its semantics are
>> so confusing that gcc warns about it when -Wstringop-truncation is enabled:
>> 
>> In function 'scsi_strcpy_devinfo',
>>     inlined from 'scsi_dev_info_list_add_keyed' at drivers/scsi/scsi_devinfo.c:370:2:
>> drivers/scsi/scsi_devinfo.c:297:9: error: 'strncpy' specified bound 16 equals destination size [-Werror=stringop-truncation]
>>   297 |         strncpy(to, from, to_length);
>>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> 
>> Reorganize the function to completely separate the nul-terminated from
>> the space-padded/non-terminated case. The former is just strscpy_pad(),
>> while the latter does not have a standard function.
>>
>
> I did the same in a patch sent earlier (few weeks ago):
>
> https://lore.kernel.org/all/20240305-strncpy-drivers-scsi-mpi3mr-mpi3mr_fw-c-v3-5-5b78a13ff984@google.com/
>
> Maybe reviewers can chime in on which version is preferred and go from
> there.

I'm in favor of your version, it looks nicer and addresses the comment
that Bart had on mine.

     Arnd