Protect against coding error of re-entrant parsing

1 files changed, 15 insertions, 0 deletions

diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 068630d1..1d54ef44 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -150,6 +150,7 @@ QPDF::Members::Members() :
     reconstructed_xref(false),
     fixed_dangling_refs(false),
     immediate_copy_from(false),
+    in_parse(false),
     first_xref_item_offset(0),
     uncompressed_after_compressed(false)
 {
@@ -417,6 +418,20 @@ QPDF::parse(char const* password)
 }
 
 void
+QPDF::inParse(bool v)
+{
+    if (this->m->in_parse == v)
+    {
+        // This happens of QPDFObjectHandle::parseInternal tries to
+        // resolve an indirect object while it is parsing.
+        throw std::logic_error(
+            "QPDF: re-entrant parsing detected. This is a qpdf bug."
+            " Please report at https://github.com/qpdf/qpdf/issues.");
+    }
+    this->m->in_parse = v;
+}
+
+void
 QPDF::warn(QPDFExc const& e)
 {
     this->m->warnings.push_back(e);