From dffc329bb6746c16e580497dda5996ab6e3c9712 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Thu, 22 Jul 2021 09:56:09 +0200
Subject: Don't try to copy past end of field string

---
 fref.lex | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fref.lex b/fref.lex
index e57eb01..2eaa19d 100644
--- a/fref.lex
+++ b/fref.lex
@@ -124,7 +124,11 @@ field()
 	yytext[strcspn(yytext, "\n")] = 0;
 
 	/* Fill corresponding field. */
-	#define FI(s,m) if(strncmp(yytext,s,2) == 0 && (yytext += 3)){	\
+	#define FI(s,m) if(strncmp(yytext,s,2) == 0){			\
+		/* Don't copy empty field. */				\
+		if(strlen(yytext) < 3)					\
+			return;						\
+		yytext += 3;						\
 		strcpy(m, yytext);					\
 		return;							\
 	}
-- 
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