[PATCH 4/5] [v2] blktrace: convert strncpy() to strscpy_pad()

From: Arnd Bergmann <arnd@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>, "Richard Russon" <ldm@flatcap.org>,
	Jens Axboe <axboe@kernel.dk>,
	Robert Moore <robert.moore@intel.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Len Brown <lenb@kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nicolas Schier <nicolas@fjasle.eu>,
	Lin Ming <ming.m.lin@intel.com>,
	Alexey Starikovskiy <astarikovskiy@suse.de>,
	linux-ntfs-dev@lists.sourceforge.net,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org, acpica-devel@lists.linux.dev,
	linux-trace-kernel@vger.kernel.org
Subject: [PATCH 4/5] [v2] blktrace: convert strncpy() to strscpy_pad()
Date: Tue,  9 Apr 2024 16:00:57 +0200	[thread overview]
Message-ID: <20240409140059.3806717-5-arnd@kernel.org> (raw)
In-Reply-To: <20240409140059.3806717-1-arnd@kernel.org>

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>
---
v2: actually use padding version of strscpy.
---
 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..8fd292d34d89 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_pad(buts->name, name, BLKTRACE_BDEV_SIZE);
 
 	/*
 	 * some device names have larger paths - convert the slashes
-- 
2.39.2

