GhostPDF - more work on Info dictionaries....

OSS-fuzz #48205

Now that objects are not always pointers to structures, we can't assume
that we can simply dereference them.

Fortunately the only objects for which we want to store the object
number in this case are the composite objects (array and dictionary) so
we can just store the object number for those.

1 files changed, 10 insertions, 6 deletions

diff --git a/pdf/pdf_doc.c b/pdf/pdf_doc.c
index 969d63b0f..37b58f219 100644
--- a/pdf/pdf_doc.c
+++ b/pdf/pdf_doc.c
@@ -117,19 +117,23 @@ static int Info_check_array(pdf_context *ctx, pdf_array *a)
         if (code < 0)
             goto error;
 
-        if (array_obj->object_num != 0) {
-            code = pdfi_loop_detector_add_object(ctx, array_obj->object_num);
-            if (code < 0)
-                goto error;
-        }
-
         switch(pdfi_type_of(array_obj)) {
             case PDF_DICT:
+                if (array_obj->object_num != 0) {
+                    code = pdfi_loop_detector_add_object(ctx, array_obj->object_num);
+                    if (code < 0)
+                        goto error;
+                }
                 code = Info_check_dict(ctx, (pdf_dict *)array_obj);
                 if (code < 0)
                     goto error;
                 break;
             case PDF_ARRAY:
+                if (array_obj->object_num != 0) {
+                    code = pdfi_loop_detector_add_object(ctx, array_obj->object_num);
+                    if (code < 0)
+                        goto error;
+                }
                 code = Info_check_array(ctx, (pdf_array *)array_obj);
                 if (code < 0)
                     goto error;