From: Dima Stepanov <dmitrii.stepanov@xxxxxxxxxxxxxxx> [ Upstream commit 3db7cf55d532a15ea26b4a14e8f8729ccd96fd22 ] cppcheck report the following error: rnbd/rnbd-clt-sysfs.c:522:36: error: The variable 'buf' is used both as a parameter and as destination in snprintf(). The origin and destination buffers overlap. Quote from glibc (C-library) documentation (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions): "If copying takes place between objects that overlap as a result of a call to sprintf() or snprintf(), the results are undefined." [sprintfOverlappingData] Fix it by initializing the buf variable in the first snprintf call. Fixes: 91f4acb2801c ("block/rnbd-clt: support mapping two devices") Signed-off-by: Dima Stepanov <dmitrii.stepanov@xxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx> Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxx> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx> Link: https://lore.kernel.org/r/20210419073722.15351-19-gi-oh.kim@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/block/rnbd/rnbd-clt-sysfs.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c index 526c77cd7a50..49ad400a5225 100644 --- a/drivers/block/rnbd/rnbd-clt-sysfs.c +++ b/drivers/block/rnbd/rnbd-clt-sysfs.c @@ -483,11 +483,7 @@ static int rnbd_clt_get_path_name(struct rnbd_clt_dev *dev, char *buf, while ((s = strchr(pathname, '/'))) s[0] = '!'; - ret = snprintf(buf, len, "%s", pathname); - if (ret >= len) - return -ENAMETOOLONG; - - ret = snprintf(buf, len, "%s@%s", buf, dev->sess->sessname); + ret = snprintf(buf, len, "%s@%s", pathname, dev->sess->sessname); if (ret >= len) return -ENAMETOOLONG; -- 2.30.2
