--- cups-1.2.7/pdftops/Catalog.cxx.orig	2005-09-17 16:52:15.000000000 +0200
+++ cups-1.2.7/pdftops/Catalog.cxx	2007-01-16 11:15:23.000000000 +0100
@@ -23,6 +23,12 @@
 #include "Link.h"
 #include "Catalog.h"
 
+// This define is used to limit the depth of recursive readPageTree calls
+// This is needed because the page tree nodes can reference their parents
+// leaving us in an infinite loop
+// Most sane pdf documents don't have a call depth higher than 10
+#define MAX_CALL_DEPTH 1000
+
 //------------------------------------------------------------------------
 // Catalog
 //------------------------------------------------------------------------
@@ -71,7 +77,7 @@
     pageRefs[i].num = -1;
     pageRefs[i].gen = -1;
   }
-  numPages = readPageTree(pagesDict.getDict(), NULL, 0);
+  numPages = readPageTree(pagesDict.getDict(), NULL, 0, 0);
   if (numPages != numPages0) {
     error(-1, "Page count in top-level pages object is incorrect");
   }
@@ -169,7 +175,7 @@
   return s;
 }
 
-int Catalog::readPageTree(Dict *pagesDict, PageAttrs *attrs, int start) {
+int Catalog::readPageTree(Dict *pagesDict, PageAttrs *attrs, int start, int callDepth) {
   Object kids;
   Object kid;
   Object kidRef;
@@ -214,9 +220,13 @@
     // This should really be isDict("Pages"), but I've seen at least one
     // PDF file where the /Type entry is missing.
     } else if (kid.isDict()) {
-      if ((start = readPageTree(kid.getDict(), attrs1, start))
-	  < 0)
-	goto err2;
+      if (callDepth > MAX_CALL_DEPTH) {
+        error(-1, "Limit of %d recursive calls reached while reading the page tree. If your document is correct and not a test to try to force a crash, please report a bug.", MAX_CALL_DEPTH);
+      } else {
+        if ((start = readPageTree(kid.getDict(), attrs1, start, callDepth + 1))
+	    < 0)
+	  goto err2;
+      }
     } else {
       error(-1, "Kid object (page %d) is wrong type (%s)",
 	    start+1, kid.getTypeName());
--- cups-1.2.7/pdftops/Catalog.h.orig	2005-09-17 16:52:15.000000000 +0200
+++ cups-1.2.7/pdftops/Catalog.h	2007-01-16 11:15:23.000000000 +0100
@@ -85,7 +85,7 @@
   Object acroForm;		// AcroForm dictionary
   GBool ok;			// true if catalog is valid
 
-  int readPageTree(Dict *pages, PageAttrs *attrs, int start);
+  int readPageTree(Dict *pages, PageAttrs *attrs, int start, int callDepth);
   Object *findDestInTree(Object *tree, GString *name, Object *obj);
 };