randstruct: Check member structs in is_pure_ops_struct()

While no uses in the kernel triggered this case, it was possible to have
a false negative where a struct contains other structs which contain only
function pointers because of unreachable code in is_pure_ops_struct().

Signed-off-by: Joonwon Kang <kjw1627@gmail.com>
Link: https://lore.kernel.org/r/20190727155841.GA13586@host
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index 6d5bbd31db7f..bd29e4e7a524 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -443,13 +443,13 @@ static int is_pure_ops_struct(const_tree node)
                 if (node == fieldtype)
                         continue;
 
-                if (!is_fptr(fieldtype))
-                        return 0;
-
-                if (code != RECORD_TYPE && code != UNION_TYPE)
+                if (code == RECORD_TYPE || code == UNION_TYPE) {
+                        if (!is_pure_ops_struct(fieldtype))
+                                return 0;
                         continue;
+                }
 
-                if (!is_pure_ops_struct(fieldtype))
+                if (!is_fptr(fieldtype))
                         return 0;
         }