https://bugs.gentoo.org/90679

patch by Michael Hanselmann <hansmi@gentoo.org>

--- a/tcprules.c
+++ b/tcprules.c
@@ -127,6 +127,9 @@
     for (;;) {
       int tmp;
       tmp = byte_chr(x + colon,len - colon,':');
+      if (colon == 0 && tmp == len) {
+        strerr_die2x(111, FATAL, "Unable to find colon on non-empty line.");
+      }
       colon += tmp;
       if (colon == len) continue;
       if (byte_equal(x+colon+1,4,"deny") || byte_equal(x+colon+1,5,"allow")) break;