device: Use overflow helpers for devm_kmalloc()

Use the overflow helpers both in existing multiplication-using inlines as
well as the addition-overflow case in the core allocation routine.

Signed-off-by: Kees Cook <keescook@chromium.org>

drivers/base/devres.c

@@ -84,9 +84,14 @@ static struct devres_group * node_to_group(struct devres_node *node)
 static __always_inline struct devres * alloc_dr(dr_release_t release,
 						size_t size, gfp_t gfp, int nid)
 {
-	size_t tot_size = sizeof(struct devres) + size;
+	size_t tot_size;
 	struct devres *dr;
 
+	/* We must catch any near-SIZE_MAX cases that could overflow. */
+	if (unlikely(check_add_overflow(sizeof(struct devres), size,
+					&tot_size)))
+		return NULL;
+
 	dr = kmalloc_node_track_caller(tot_size, gfp, nid);
 	if (unlikely(!dr))
 		return NULL;