From ad8a32ce86055b8cf131e3eb85532d7be5e5d3b1 Mon Sep 17 00:00:00 2001
From: Krasimir Angelov <kr.angelov@gmail.com>
Date: Thu, 16 Jun 2022 11:22:15 +0200
Subject: [PATCH] safe parsing of "" and ''

---
 src/runtime/c/pgf/expr.cxx | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/runtime/c/pgf/expr.cxx b/src/runtime/c/pgf/expr.cxx
index 66ccfb13b..c24d1751c 100644
--- a/src/runtime/c/pgf/expr.cxx
+++ b/src/runtime/c/pgf/expr.cxx
@@ -508,6 +508,12 @@ void PgfExprParser::token()
             if (ch == '\'') {
                 getc();
                 token_tag = PGF_TOKEN_IDENT;
+                if (token_value == NULL) {
+                    token_value = (PgfText*)
+                        malloc(sizeof(PgfText)+1);
+                    token_value->size    = 0;
+                    token_value->text[0] = 0;
+                }
             }
         }
 		break;
@@ -521,6 +527,12 @@ void PgfExprParser::token()
             if (ch == '"') {
                 getc();
                 token_tag = PGF_TOKEN_STR;
+                if (token_value == NULL) {
+                    token_value = (PgfText*)
+                        malloc(sizeof(PgfText)+1);
+                    token_value->size    = 0;
+                    token_value->text[0] = 0;
+                }
             }
         }
         break;