MINOR: ssl: set ssl-min-ver in ambiguous configurations

Using ssl-max-ver without ssl-min-ver is ambiguous.

When the ssl-min-ver is not configured, and ssl-max-ver is set to a
value lower than the default ssl-min-ver (which is TLSv1.2 currently),
set the ssl-min-ver to the value of ssl-max-ver, and emit a warning.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 0a6086c2c4dfab33dcd8259f67cb651e71e863df..837862c5e2818f9fde0910fb027bbd0e44ca0257 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -12568,13 +12568,16 @@ ssl
 
 ssl-max-ver [ SSLv3 | TLSv1.0 | TLSv1.1 | TLSv1.2 | TLSv1.3 ]
   This option enforces use of <version> or lower on SSL connections instantiated
-  from this listener. This option is also available on global statement
+  from this listener. Using this setting without "ssl-min-ver" can be
+  ambiguous because the default ssl-min-ver value could change in future HAProxy
+  versions. This option is also available on global statement
   "ssl-default-bind-options". See also "ssl-min-ver".
 
 ssl-min-ver [ SSLv3 | TLSv1.0 | TLSv1.1 | TLSv1.2 | TLSv1.3 ]
-  This option enforces use of <version> or upper on SSL connections instantiated
-  from this listener. This option is also available on global statement
-  "ssl-default-bind-options". See also "ssl-max-ver".
+  This option enforces use of <version> or upper on SSL connections
+  instantiated from this listener. The default value is "TLSv1.2". This option
+  is also available on global statement "ssl-default-bind-options".
+  See also "ssl-max-ver".
 
 strict-sni
   This setting is only available when support for OpenSSL was built in. The

diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index b52f2ec6ae42963517a99d3e649e4465ff787c8b..8f16463ca25c4af1fbed8505bcb3fe140feafc67 100644 (file)
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -3650,6 +3650,7 @@ ssl_sock_initial_ctx(struct bind_conf *bind_conf)
        int i, min, max, hole;
        int flags = MC_SSL_O_ALL;
        int cfgerr = 0;
+       const int default_min_ver = CONF_TLSV12;
 
        ctx = SSL_CTX_new(SSLv23_server_method());
        bind_conf->initial_ctx = ctx;
@@ -3663,9 +3664,18 @@ ssl_sock_initial_ctx(struct bind_conf *bind_conf)
 
        min = conf_ssl_methods->min;
        max = conf_ssl_methods->max;
-       /* start with TLSv12 to remove SSLv3,TLSv10,TLSv11 per default */
-       if (!min && (!max || max >= CONF_TLSV12))
-               min = CONF_TLSV12;
+
+       /* default minimum is TLSV12,  */
+       if (!min) {
+               if (!max || (max >= default_min_ver)) {
+                       min = default_min_ver;
+               } else {
+                       ha_warning("Proxy '%s': Ambiguous configuration for bind '%s' at [%s:%d]: the ssl-min-ver value is not configured and the ssl-max-ver value is lower than the default ssl-min-ver value (%s). "
+                                  "Setting the ssl-min-ver to %s. Use 'ssl-min-ver' to fix this.\n",
+                                  bind_conf->frontend->id, bind_conf->arg, bind_conf->file, bind_conf->line, methodVersions[default_min_ver].name, methodVersions[max].name);
+                       min = max;
+               }
+       }
        /* Real min and max should be determinate with configuration and openssl's capabilities */
        if (min)
                flags |= (methodVersions[min].flag - 1);