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 <[email protected]>
Link: https://lore.kernel.org/r/20190727155841.GA13586@host
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>

diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index 6d5bbd31db7f2420fff6beb5ca71fc5dcf1eb493..bd29e4e7a5241b738b2d531c1f7803ca413feb1d 100644 (file)
--- 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;
        }