[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 08/11] blktrace: convert strncpy() to strscpy_pad()

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

gcc-9 warns about a possibly non-terminated string copy:

kernel/trace/blktrace.c: In function 'do_blk_trace_setup':
kernel/trace/blktrace.c:527:2: error: 'strncpy' specified bound 32 equals destination size [-Werror=stringop-truncation]

Newer versions are fine here because they see the following explicit
nul-termination. Using strscpy_pad() avoids the warning and
simplifies the code a little. The padding helps  give a clean
buffer to userspace.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/trace/blktrace.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index d5d94510afd3..95a00160d465 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -524,8 +524,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	if (!buts->buf_size || !buts->buf_nr)
 		return -EINVAL;
 
-	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
-	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
+	strscpy(buts->name, name, BLKTRACE_BDEV_SIZE);
 
 	/*
 	 * some device names have larger paths - convert the slashes
-- 
2.39.2

Re: [PATCH 08/11] blktrace: convert strncpy() to strscpy_pad()

[Steven Rostedt]

On Thu, 28 Mar 2024 15:04:52 +0100
Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcc-9 warns about a possibly non-terminated string copy:
> 
> kernel/trace/blktrace.c: In function 'do_blk_trace_setup':
> kernel/trace/blktrace.c:527:2: error: 'strncpy' specified bound 32 equals destination size [-Werror=stringop-truncation]
> 
> Newer versions are fine here because they see the following explicit
> nul-termination. Using strscpy_pad() avoids the warning and
> simplifies the code a little. The padding helps  give a clean
> buffer to userspace.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  kernel/trace/blktrace.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index d5d94510afd3..95a00160d465 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -524,8 +524,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
>  	if (!buts->buf_size || !buts->buf_nr)
>  		return -EINVAL;
>  
> -	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
> -	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
> +	strscpy(buts->name, name, BLKTRACE_BDEV_SIZE);

The commit message says "Using strscpy_pad()" but it doesn't do so in the
patch.

Rule 12 of debugging: "When the comment and the code do not match, they are
                       probably both wrong"

-- Steve


>  
>  	/*
>  	 * some device names have larger paths - convert the slashes

Re: [PATCH 08/11] blktrace: convert strncpy() to strscpy_pad()

[Arnd Bergmann]

On Thu, Mar 28, 2024, at 15:14, Steven Rostedt wrote:
> On Thu, 28 Mar 2024 15:04:52 +0100
>> 
>> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
>> index d5d94510afd3..95a00160d465 100644
>> --- a/kernel/trace/blktrace.c
>> +++ b/kernel/trace/blktrace.c
>> @@ -524,8 +524,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
>>  	if (!buts->buf_size || !buts->buf_nr)
>>  		return -EINVAL;
>>  
>> -	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
>> -	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
>> +	strscpy(buts->name, name, BLKTRACE_BDEV_SIZE);
>
> The commit message says "Using strscpy_pad()" but it doesn't do so in the
> patch.
>
> Rule 12 of debugging: "When the comment and the code do not match, they are
>                        probably both wrong"

Thanks for double-checking this, I had a hard time deciding which
one to use here and ended up with an obviously inconsistent version.

I've changed it now to strscpy_pad() for v2, which is the slightly
safer choice here. The non-padding version would still not leak
kernel data but would write back user-provided data after the
padding instead of always zeroing it.

    Arnd