From 7aaddf52cd98589fb0c3ab72a393f8411838438a Mon Sep 17 00:00:00 2001
From: "Emden R. Gansner" <erg@alum.mit.edu>
Date: Fri, 4 Oct 2013 09:06:39 -0400
Subject: [PATCH] Fix buffer overflow problem when reporting a syntax error
with a very long input line
---
lib/cgraph/scan.l | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/lib/cgraph/scan.l b/lib/cgraph/scan.l
index 3cfde0f..2efd203 100644
@@ -16,6 +16,7 @@
%{
#include <grammar.h>
#include <cghdr.h>
+#include <agxbuf.h>
#include <ctype.h>
#define GRAPH_EOF_TOKEN '@' /* lex class must be defined below */
/* this is a workaround for linux flex */
@@ -191,13 +192,21 @@ ID ({NAME}|{NUMBER})
%%
void yyerror(char *str)
{
+ unsigned char xbuf[BUFSIZ];
char buf[BUFSIZ];
- if (InputFile)
- sprintf(buf,"%s:%d: %s in line %d near '%s'\n",InputFile, line_num,
- str,line_num,yytext);
- else
- sprintf(buf," %s in line %d near '%s'\n", str,line_num,yytext);
- agerr(AGWARN,buf);
+ agxbuf xb;
+
+ agxbinit(&xb, BUFSIZ, xbuf);
+ if (InputFile) {
+ agxbput (&xb, InputFile);
+ agxbput (&xb, ": ");
+ }
+ sprintf(buf," %s in line %d near '", str,line_num);
+ agxbput (&xb, buf);
+ agxbput (&xb, yytext);
+ agxbput (&xb,"'\n");
+ agerr(AGWARN,agxbuse(&xb));
+ agxbfree(&xb);
}
/* must be here to see flex's macro defns */
void aglexeof() { unput(GRAPH_EOF_TOKEN); }