s_client accepts host/port as positional argument.

This allows the user to provide the target host and optional port to
openssl s_client as an optional positional argument, rather than as the
argument to the -connect flag. This rationalises the user experience of
s_client: given that the only logical purpose of s_client is to connect
to a host, it is difficult to understand why there is an (effectively
mandatory) command option to pass to make that happen.

This patch forbids providing *both* -connect and the positional
argument, because it would likely be too difficult to reconcile.
Otherwise, using the positional argument behaves exactly the same as
using -connect does.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1171)

1 files changed, 17 insertions, 3 deletions

diff --git a/apps/s_client.c b/apps/s_client.c
index ad0eaec562..1d11f0932a 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -1421,8 +1421,22 @@ int s_client_main(int argc, char **argv)
         }
     }
     argc = opt_num_rest();
-    if (argc != 0)
+    if (argc == 1) {
+        /* If there's a positional argument, it's the equivalent of
+         * OPT_CONNECT.
+         * Don't allow -connect and a separate argument.
+         */
+        if (connectstr != NULL) {
+            BIO_printf(bio_err,
+                       "%s: must not provide both -connect option and target parameter\n",
+                       prog);
+            goto opthelp;
+        }
+        connect_type = use_inet;
+        connectstr = *opt_rest();
+    } else if (argc != 0) {
         goto opthelp;
+    }
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
     if (min_version == TLS1_3_VERSION && next_proto_neg_in != NULL) {
@@ -1434,7 +1448,7 @@ int s_client_main(int argc, char **argv)
         int res;
         char *tmp_host = host, *tmp_port = port;
         if (connectstr == NULL) {
-            BIO_printf(bio_err, "%s: -proxy requires use of -connect\n", prog);
+            BIO_printf(bio_err, "%s: -proxy requires use of -connect or target parameter\n", prog);
             goto opthelp;
         }
         res = BIO_parse_hostserv(proxystr, &host, &port, BIO_PARSE_PRIO_HOST);
@@ -1459,7 +1473,7 @@ int s_client_main(int argc, char **argv)
             OPENSSL_free(tmp_port);
         if (!res) {
             BIO_printf(bio_err,
-                       "%s: -connect argument malformed or ambiguous\n",
+                       "%s: -connect argument or target parameter malformed or ambiguous\n",
                        prog);
             goto end;
         }