SSL: ssl_reject_handshake directive (ticket #195). In some cases it might be needed to reject SSL handshake based on SNI server name provided, for example, to make sure an invalid certificate is not returned to clients trying to contact a name-based virtual server without SSL configured. Previously, a "ssl_ciphers aNULL;" was used for this. This workaround, however, is not compatible with TLSv1.3, in particular, when using BoringSSL, where it is not possible to configure TLSv1.3 ciphers at all. With this change, the ssl_reject_handshake directive is introduced, which instructs nginx to reject SSL handshakes with an "unrecognized_name" alert in a particular server block. For example, to reject handshake with names other than example.com, one can use the following configuration: server { listen 443 ssl; ssl_reject_handshake on; } server { listen 443 ssl; server_name example.com; ssl_certificate example.com.crt; ssl_certificate_key example.com.key; } The following configuration can be used to reject all SSL handshakes without SNI server name provided: server { listen 443 ssl; ssl_reject_handshake on; } server { listen 443 ssl; server_name ~^; ssl_certificate example.crt; ssl_certificate_key example.key; } Additionally, the ssl_reject_handshake directive makes configuring certificates for the default server block optional. If no certificates are configured in the default server for a given listening socket, certificates must be defined in all non-default server blocks with the listening socket in question.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_MAIL_SSL_H_INCLUDED_
#define _NGX_MAIL_SSL_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_mail.h>


#define NGX_MAIL_STARTTLS_OFF   0
#define NGX_MAIL_STARTTLS_ON    1
#define NGX_MAIL_STARTTLS_ONLY  2


typedef struct {
    ngx_flag_t       enable;
    ngx_flag_t       prefer_server_ciphers;

    ngx_ssl_t        ssl;

    ngx_uint_t       starttls;
    ngx_uint_t       listen;
    ngx_uint_t       protocols;

    ngx_uint_t       verify;
    ngx_uint_t       verify_depth;

    ssize_t          builtin_session_cache;

    time_t           session_timeout;

    ngx_array_t     *certificates;
    ngx_array_t     *certificate_keys;

    ngx_str_t        dhparam;
    ngx_str_t        ecdh_curve;
    ngx_str_t        client_certificate;
    ngx_str_t        trusted_certificate;
    ngx_str_t        crl;

    ngx_str_t        ciphers;

    ngx_array_t     *passwords;
    ngx_array_t     *conf_commands;

    ngx_shm_zone_t  *shm_zone;

    ngx_flag_t       session_tickets;
    ngx_array_t     *session_ticket_keys;

    u_char          *file;
    ngx_uint_t       line;
} ngx_mail_ssl_conf_t;


extern ngx_module_t  ngx_mail_ssl_module;


#endif /* _NGX_MAIL_SSL_H_INCLUDED_ */