SSL: ssl_session_tickets directive.

This adds support so it's possible to explicitly disable SSL Session
Tickets. In order to have good Forward Secrecy support either the
session ticket key has to be reloaded by using nginx' binary upgrade
process or using an external key file and reloading the configuration.
This directive adds another possibility to have good support by
disabling session tickets altogether.

If session tickets are enabled and the process lives for a long a time,
an attacker can grab the session ticket from the process and use that to
decrypt any traffic that occured during the entire lifetime of the
process.

diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
index a0d258c8ab8f807a914e8ffc822338043f1fa1bd..593111ca68058283fae3c88499bdfb16826f3d82 100644 (file)
--- a/src/http/modules/ngx_http_ssl_module.c
+++ b/src/http/modules/ngx_http_ssl_module.c
@@ -160,6 +160,13 @@ static ngx_command_t  ngx_http_ssl_commands[] = {
       0,
       NULL },
 
+    { ngx_string("ssl_session_tickets"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_ssl_srv_conf_t, session_tickets),
+      NULL },
+
     { ngx_string("ssl_session_ticket_key"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_str_array_slot,
@@ -436,6 +443,7 @@ ngx_http_ssl_create_srv_conf(ngx_conf_t *cf)
     sscf->verify_depth = NGX_CONF_UNSET_UINT;
     sscf->builtin_session_cache = NGX_CONF_UNSET;
     sscf->session_timeout = NGX_CONF_UNSET;
+    sscf->session_tickets = NGX_CONF_UNSET;
     sscf->session_ticket_keys = NGX_CONF_UNSET_PTR;
     sscf->stapling = NGX_CONF_UNSET;
     sscf->stapling_verify = NGX_CONF_UNSET;
@@ -644,6 +652,14 @@ ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
         return NGX_CONF_ERROR;
     }
 
+    ngx_conf_merge_value(conf->session_tickets, prev->session_tickets, 1);
+
+#ifdef SSL_OP_NO_TICKET
+    if (!conf->session_tickets) {
+        SSL_CTX_set_options(conf->ssl.ctx, SSL_OP_NO_TICKET);
+    }
+#endif
+
     ngx_conf_merge_ptr_value(conf->session_ticket_keys,
                          prev->session_ticket_keys, NULL);
 

diff --git a/src/http/modules/ngx_http_ssl_module.h b/src/http/modules/ngx_http_ssl_module.h
index e72b921acc96841bbaed5346c8f9661b96126aea..ec2c62f6fb5df38c2f2e4c587b20227f28c9db5c 100644 (file)
--- a/src/http/modules/ngx_http_ssl_module.h
+++ b/src/http/modules/ngx_http_ssl_module.h
@@ -44,6 +44,7 @@ typedef struct {
 
     ngx_shm_zone_t                 *shm_zone;
 
+    ngx_flag_t                      session_tickets;
     ngx_array_t                    *session_ticket_keys;
 
     ngx_flag_t                      stapling;

diff --git a/src/mail/ngx_mail_ssl_module.c b/src/mail/ngx_mail_ssl_module.c
index 94c015700e78a3761e40dd326fc7aad4073c005c..fe88f48e43b1cbe1ee98122c0fa6a72e01be7a9f 100644 (file)
--- a/src/mail/ngx_mail_ssl_module.c
+++ b/src/mail/ngx_mail_ssl_module.c
@@ -116,6 +116,13 @@ static ngx_command_t  ngx_mail_ssl_commands[] = {
       0,
       NULL },
 
+    { ngx_string("ssl_session_tickets"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_ssl_conf_t, session_tickets),
+      NULL },
+
     { ngx_string("ssl_session_ticket_key"),
       NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_str_array_slot,
@@ -191,6 +198,7 @@ ngx_mail_ssl_create_conf(ngx_conf_t *cf)
     scf->prefer_server_ciphers = NGX_CONF_UNSET;
     scf->builtin_session_cache = NGX_CONF_UNSET;
     scf->session_timeout = NGX_CONF_UNSET;
+    scf->session_tickets = NGX_CONF_UNSET;
     scf->session_ticket_keys = NGX_CONF_UNSET_PTR;
 
     return scf;
@@ -339,6 +347,15 @@ ngx_mail_ssl_merge_conf(ngx_conf_t *cf, void *parent, void *child)
         return NGX_CONF_ERROR;
     }
 
+    ngx_conf_merge_value(conf->session_tickets,
+                         prev->session_tickets, 1);
+
+#ifdef SSL_OP_NO_TICKET
+    if (!conf->session_tickets) {
+        SSL_CTX_set_options(conf->ssl.ctx, SSL_OP_NO_TICKET);
+    }
+#endif
+
     ngx_conf_merge_ptr_value(conf->session_ticket_keys,
                          prev->session_ticket_keys, NULL);
 

diff --git a/src/mail/ngx_mail_ssl_module.h b/src/mail/ngx_mail_ssl_module.h
index 54e057721945186e2c3b4735d009e38540218580..bef0e515a02ba003777104164bfc29df838e0785 100644 (file)
--- a/src/mail/ngx_mail_ssl_module.h
+++ b/src/mail/ngx_mail_ssl_module.h
@@ -41,6 +41,7 @@ typedef struct {
 
     ngx_shm_zone_t  *shm_zone;
 
+    ngx_flag_t       session_tickets;
     ngx_array_t     *session_ticket_keys;
 
     u_char          *file;