port ranges can be ambiguous with hypenated port-names.

specify that ranges must be numeric, and only check for range if
first argument is a digit.
identified by danj, fix suggest by sthen

1 files changed, 3 insertions, 2 deletions

diff --git a/src/usr.bin/nc/netcat.c b/src/usr.bin/nc/netcat.c
index e0966f1952..adfad2dcd9 100644
--- a/src/usr.bin/nc/netcat.c
+++ b/src/usr.bin/nc/netcat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: netcat.c,v 1.199 2018/11/29 14:25:06 tedu Exp $ */
+/* $OpenBSD: netcat.c,v 1.200 2018/12/27 17:22:45 tedu Exp $ */
 /*
  * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
  * Copyright (c) 2015 Bob Beck.  All rights reserved.
@@ -42,6 +42,7 @@
 #include <netinet/ip.h>
 #include <arpa/telnet.h>
 
+#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <limits.h>
@@ -1427,7 +1428,7 @@ build_ports(char *p)
         int hi, lo, cp;
         int x = 0;
 
-        if ((n = strchr(p, '-')) != NULL) {
+        if (isdigit((unsigned char)*p) && (n = strchr(p, '-')) != NULL) {
                 *n = '\0';
                 n++;