fix(kernel): Fix memory safety issues in the module list call

kernel/patch/common/supercall.c

@@ -109,11 +109,13 @@ static long call_kpm_nums()
 static long call_kpm_list(char *__user names, int len)
 {
     if (len <= 0) return -EINVAL;
-    char buf[4096];
+    char buf[4096] = { 0 };
     int sz = list_modules(buf, sizeof(buf));
+    if (sz < 0) return sz;
     if (sz > len) return -ENOBUFS;
-    sz = compat_copy_to_user(names, buf, len);
-    return sz;
+    int copy_len = sz > 0 ? sz : 1;
+    int rc = compat_copy_to_user(names, buf, copy_len);
+    return rc == copy_len ? sz : -EFAULT;
 }
 
 static long call_kpm_info(const char *__user uname, char *__user out_info, int out_len)

kernel/patch/module/module.c

@@ -619,6 +619,9 @@ int get_module_nums()
 
 int list_modules(char *out_names, int size)
 {
+    if (!out_names || size <= 0) return -EINVAL;
+    out_names[0] = '\0';
+
     rcu_read_lock();
 
     struct module *pos;