diff -up sudo-1.8.3/src/ttysize.c.pipelist sudo-1.8.3/src/ttysize.c
--- sudo-1.8.3/src/ttysize.c.pipelist	2011-10-21 15:01:26.000000000 +0200
+++ sudo-1.8.3/src/ttysize.c	2011-10-26 02:09:39.582790562 +0200
@@ -20,6 +20,7 @@
 
 #include <sys/types.h>
 #include <sys/ioctl.h>
+#include <sys/stat.h>
 #include <stdio.h>
 #ifdef STDC_HEADERS
 # include <stdlib.h>
@@ -48,6 +49,16 @@ void
 get_ttysize(int *rowp, int *colp)
 {
     char *p;
+    struct stat st;
+
+    if (fstat(STDOUT_FILENO, &st) == 0) {
+	 if (S_ISFIFO(st.st_mode)) {
+	   *rowp = 0;
+	   *colp = 0;
+	   return;
+	 }
+    }
+
 #ifdef TIOCGWINSZ
     struct winsize wsize;