drivers: avoid format string in dev_set_name

Calling dev_set_name with a single paramter causes it to be handled as a
format string.  Many callers are passing potentially dynamic string
content, so use "%s" in those cases to avoid any potential accidents,
including wrappers like device_create*() and bdi_register().

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 5025174..d014ee5 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -515,7 +515,6 @@
 int bdi_setup_and_register(struct backing_dev_info *bdi, char *name,
 			   unsigned int cap)
 {
-	char tmp[32];
 	int err;
 
 	bdi->name = name;
@@ -524,8 +523,8 @@
 	if (err)
 		return err;
 
-	sprintf(tmp, "%.28s%s", name, "-%d");
-	err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq));
+	err = bdi_register(bdi, NULL, "%.28s-%ld", name,
+			   atomic_long_inc_return(&bdi_seq));
 	if (err) {
 		bdi_destroy(bdi);
 		return err;