SNI: reset to default server if requested host was not found. Not only this is consistent with a case without SNI, but this also prevents abusing configurations that assume that the $host variable is limited to one of the configured names for a server. An example of potentially unsafe configuration: server { listen 443 ssl default_server; ... } server { listen 443; server_name example.com; location / { proxy_pass http://$host; } } Note: it is possible to negotiate "example.com" by SNI, and to request arbitrary host name that does not exist in the configuration above.

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


#ifndef _NGX_SHMEM_H_INCLUDED_
#define _NGX_SHMEM_H_INCLUDED_


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


typedef struct {
    u_char      *addr;
    size_t       size;
    ngx_str_t    name;
    ngx_log_t   *log;
    ngx_uint_t   exists;   /* unsigned  exists:1;  */
} ngx_shm_t;


ngx_int_t ngx_shm_alloc(ngx_shm_t *shm);
void ngx_shm_free(ngx_shm_t *shm);


#endif /* _NGX_SHMEM_H_INCLUDED_ */