use strtonum() instead of atoi(), and error out for bad numbersHEADmaster

This generates a host-order number, so the ntohs() for getservbyport()
was wrong, that should always have been htons().  The transform is
the same, but misleading.
ok tb

1 files changed, 7 insertions, 2 deletions

diff --git a/src/usr.bin/nc/netcat.c b/src/usr.bin/nc/netcat.c
index e3c9c939e2..766da6e667 100644
--- a/src/usr.bin/nc/netcat.c
+++ b/src/usr.bin/nc/netcat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: netcat.c,v 1.234 2025/06/24 13:37:11 tb Exp $ */
+/* $OpenBSD: netcat.c,v 1.235 2025/10/11 15:46:06 deraadt Exp $ */
 /*
  * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
  * Copyright (c) 2015 Bob Beck.  All rights reserved.
@@ -1542,7 +1542,12 @@ connection_info(const char *host, const char *port, const char *proto,
 
         /* Look up service name unless -n. */
         if (!nflag) {
-                sv = getservbyport(ntohs(atoi(port)), proto);
+                const char *errstr;
+
+                int p = strtonum(port, 1, PORT_MAX, &errstr);
+                if (errstr)
+                        errx(1, "port number %s: %s", errstr, port);
+                sv = getservbyport(htons(p), proto);
                 if (sv != NULL)
                         service = sv->s_name;
         }