SSL: disabled renegotiation detection in client mode. CVE-2009-3555 is no longer relevant and mitigated by the renegotiation info extension (secure renegotiation). On the other hand, unexpected renegotiation still introduces potential security risks, and hence we do not allow renegotiation on the server side, as we never request renegotiation. On the client side the situation is different though. There are backends which explicitly request renegotiation, and disabled renegotiation introduces interoperability problems. This change allows renegotiation on the client side, and fixes interoperability problems as observed with such backends (ticket #872). Additionally, with TLSv1.3 the SSL_CB_HANDSHAKE_START flag is currently set by OpenSSL when receiving a NewSessionTicket message, and was detected by nginx as a renegotiation attempt. This looks like a bug in OpenSSL, though this change also allows better interoperability till the problem is fixed.

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


#ifndef _NGX_SHMTX_H_INCLUDED_
#define _NGX_SHMTX_H_INCLUDED_


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


typedef struct {
    ngx_atomic_t   lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t   wait;
#endif
} ngx_shmtx_sh_t;


typedef struct {
#if (NGX_HAVE_ATOMIC_OPS)
    ngx_atomic_t  *lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t  *wait;
    ngx_uint_t     semaphore;
    sem_t          sem;
#endif
#else
    ngx_fd_t       fd;
    u_char        *name;
#endif
    ngx_uint_t     spin;
} ngx_shmtx_t;


ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr,
    u_char *name);
void ngx_shmtx_destroy(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx);
void ngx_shmtx_lock(ngx_shmtx_t *mtx);
void ngx_shmtx_unlock(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid);


#endif /* _NGX_SHMTX_H_INCLUDED_ */