warn if no CN is available if verify is only set to 1

lib/ssluse.c

@@ -1025,11 +1025,19 @@ Curl_SSLConnect(struct connectdata *conn)
                                   NID_commonName,
                                   peer_CN,
                                   sizeof(peer_CN)) < 0) {
+      /* Failed to get the CN field from the server's certificate */
+      if (data->set.ssl.verifyhost > 1) {
         failf(data, "SSL: unable to obtain common name from peer certificate");
         X509_free(conn->ssl.server_cert);
         return CURLE_SSL_PEER_CERTIFICATE;
       }
-
+      else
+        /* Consider verifyhost == 1 as an "OK" for a missing CN field, but we
+           output a note about the situation */
+        infof(data, "\t common name: WARNING couldn't obtain\n");
+    }
+    else {
+      /* Compare the CN field with the remote host name */
       if (!cert_hostcheck(peer_CN, conn->hostname)) {
         if (data->set.ssl.verifyhost > 1) {
           failf(data, "SSL: certificate subject name '%s' does not match "
@@ -1046,6 +1054,7 @@ Curl_SSLConnect(struct connectdata *conn)
       else
         infof(data, "\t common name: %s (matched)\n", peer_CN);
     }
+  }
 
   str = X509_NAME_oneline (X509_get_issuer_name  (conn->ssl.server_cert),
                            NULL, 0);