From: Stafford Horne Subject: [RFC PATCH 2/2] kobject: Fix -Wstringop-truncation warning Date: Sat, 23 Jun 2018 11:07:53 +0900 Message-ID: <20180623020753.27266-3-shorne@gmail.com> References: <20180623020753.27266-1-shorne@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Greg KH , arnd@arndb.de, linux-crypto@vger.kernel.org, Stafford Horne To: LKML Return-path: In-Reply-To: <20180623020753.27266-1-shorne@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org When compiling with GCC 9.0.0 I am seeing the following warning: In function ‘fill_kobj_path’, inlined from ‘kobject_get_path’ at lib/kobject.c:155:2: lib/kobject.c:128:3: warning: ‘strncpy’ output truncated before terminating nul copying as many bytes from a string as its length [-Wstringop-truncation] strncpy(path + length, kobject_name(parent), cur); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/kobject.c: In function ‘kobject_get_path’: lib/kobject.c:125:13: note: length computed here int cur = strlen(kobject_name(parent)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is pointing out a bug that the strncpy limit is the source string not the destination buffer remaining length. Fix it. Cc: Greg Kroah-Hartman Cc: Arnd Bergmann Signed-off-by: Stafford Horne --- lib/kobject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/kobject.c b/lib/kobject.c index 18989b5b3b56..15338e5a96f2 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -125,7 +125,7 @@ static void fill_kobj_path(struct kobject *kobj, char *path, int length) int cur = strlen(kobject_name(parent)); /* back up enough to print this name with '/' */ length -= cur; - strncpy(path + length, kobject_name(parent), cur); + strncpy(path + length, kobject_name(parent), length); *(path + --length) = '/'; } -- 2.17.0