Handle /Outlines dictionary being a direct object

Even though this case is not valid according to the spec, it has been
seen, and caused an internal error.

2 files changed, 23 insertions, 1 deletions

diff --git a/libqpdf/QPDF_linearization.cc b/libqpdf/QPDF_linearization.cc
index 4b1f5c09..2c4fefc0 100644
--- a/libqpdf/QPDF_linearization.cc
+++ b/libqpdf/QPDF_linearization.cc
@@ -958,6 +958,15 @@ QPDF::checkHOutlines(std::list<std::string>& warnings)
 	{
 	    // Check length and offset.  Acrobat gets these wrong.
 	    QPDFObjectHandle outlines = getRoot().getKey("/Outlines");
+            if (! outlines.isIndirect())
+            {
+                // This case is not exercised in test suite since not
+                // permitted by the spec, but if this does occur, the
+                // code below would fail.
+		warnings.push_back(
+		    "/Outlines key of root dictionary is not indirect");
+                return;
+            }
 	    QPDFObjGen og(outlines.getObjGen());
 	    assert(this->xref_table.count(og) > 0);
 	    int offset = getLinearizationOffset(og);
diff --git a/libqpdf/QPDF_optimization.cc b/libqpdf/QPDF_optimization.cc
index 0286fdb9..35663c45 100644
--- a/libqpdf/QPDF_optimization.cc
+++ b/libqpdf/QPDF_optimization.cc
@@ -68,6 +68,20 @@ QPDF::optimize(std::map<int, int> const& object_stream_data,
 	return;
     }
 
+    // The PDF specification indicates that /Outlines is supposed to
+    // be an indirect reference.  Force it to be so if it exists and
+    // is direct.  (This has been seen in the wild.)
+    QPDFObjectHandle root = getRoot();
+    if (root.getKey("/Outlines").isDictionary())
+    {
+        QPDFObjectHandle outlines = root.getKey("/Outlines");
+        if (! outlines.isIndirect())
+        {
+            QTC::TC("qpdf", "QPDF_optimization indirect outlines");
+            root.replaceKey("/Outlines", makeIndirectObject(outlines));
+        }
+    }
+
     // Traverse pages tree pushing all inherited resources down to the
     // page level.  This also initializes this->all_pages.
     pushInheritedAttributesToPage(allow_changes, false);
@@ -97,7 +111,6 @@ QPDF::optimize(std::map<int, int> const& object_stream_data,
 	}
     }
 
-    QPDFObjectHandle root = getRoot();
     keys = root.getKeys();
     for (std::set<std::string>::iterator iter = keys.begin();
 	 iter != keys.end(); ++iter)