--- chkutmp.c   2009-08-24 15:16:40.000000000 +0000
+++ chkutmp.c   2009-08-24 17:08:38.000000000 +0000
@@ -23,6 +23,7 @@
  *
  *  Changelog:
  *   Ighighi X - Improved speed via break command - 2005/03/27
+ *   Stewart Gebbie - fixed buffer overrun bug related to MAXREAD and UT_PIDLENGTH - 2007-10-20
  *   Some overflow fixes by Michael Schwendt - 2009/07/21
  *
  */
@@ -43,7 +44,7 @@
 #endif
 #include <ctype.h>

-#define MAXREAD 1024
+#define MAXREAD 4096
 #define MAXBUF 4096
 #define MAXLENGTH 256
 #define UT_PIDSIZE 12
@@ -58,13 +59,13 @@
 #endif

 struct ps_line {
-    char ps_tty[UT_LINESIZE];
-    char ps_user[UT_NAMESIZE];
-    char ps_args[MAXLENGTH];
+    char ps_tty[UT_LINESIZE+1];
+    char ps_user[UT_NAMESIZE+1];
+    char ps_args[MAXLENGTH+1];
     int ps_pid;
 };
 struct utmp_line {
-    char ut_tty[UT_LINESIZE];
+    char ut_tty[UT_LINESIZE+1];
     int ut_pid;
     int ut_type;
 };
@@ -78,7 +79,7 @@
 int fetchps(struct ps_line *psl_p)
 {
     FILE *ps_fp;
-    char line[MAXREAD + 1], pid[UT_PIDSIZE];
+    char line[MAXREAD + 1], pid[UT_PIDSIZE+1];
     char *s, *d;
     struct ps_line *curp = &psl_p[0];
     struct ps_line *endp = &psl_p[MAXBUF-1];
@@ -98,7 +99,7 @@
                while (isspace(*s))     /* skip spaces */
                    s++;
                d = pid;
-               for (x = 0; (!isspace(*s)) && (*d++ = *s++) && x <= UT_LINESIZE; x++)   /* grab pid */
+               for (x = 0; (!isspace(*s)) && (*d++ = *s++) && x <= UT_PIDSIZE; x++)    /* grab pid */
                    ;
                *d = '\0';
                curp->ps_pid = atoi(pid);