params: Use size_add() for kmalloc()

Prevent allocations from integer overflow by using size_add().
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231120151419.1661807-4-andriy.shevchenko@linux.intel.comSigned-off-by: Kees Cook <keescook@chromium.org>

kernel/params.c

@@ -11,6 +11,7 @@
 #include <linux/moduleparam.h>
 #include <linux/device.h>
 #include <linux/err.h>
+#include <linux/overflow.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
 #include <linux/security.h>
@@ -48,7 +49,7 @@ static void *kmalloc_parameter(unsigned int size)
 {
 	struct kmalloced_param *p;
 
-	p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
+	p = kmalloc(size_add(sizeof(*p), size), GFP_KERNEL);
 	if (!p)
 		return NULL;