Upstream: fixed X-Accel-Redirect handling from cache files. The X-Accel-Redirect header might appear in cache files if its handling is ignored with the "proxy_ignore_headers" directive. If the cache file is later served with different settings, ngx_http_upstream_process_headers() used to call ngx_http_upstream_finalize_request(NGX_DECLINED), which is not expected to happen before the cleanup handler is installed and resulted in ngx_http_finalize_request(NGX_DONE) (after 5994:5abf5af257a7, nginx 1.7.11), leading to unexpected request counter decrement, "request count is zero" alerts, and segmentation faults. Similarly, errors in ngx_http_upstream_process_headers() resulted in ngx_http_upstream_finalize_request(NGX_HTTP_INTERNAL_SERVER_ERROR) being called. This is also not expected to happen before the cleanup handler is installed, and resulted in ngx_http_finalize_request(NGX_DONE) without proper request finalization. Fix is to avoid calling ngx_http_upstream_finalize_request() from ngx_http_upstream_process_headers(), notably when the cleanup handler is not yet installed. Errors are now simply return NGX_ERROR, so the caller is responsible for proper finalization by calling either ngx_http_finalize_request() or ngx_http_upstream_finalize_request(). And X-Accel-Redirect handling now does not call ngx_http_upstream_finalize_request(NGX_DECLINED) if no cleanup handler is installed. Reported by Jiří Setnička (https://mailman.nginx.org/pipermail/nginx-devel/2024-February/HWLYHOO3DDB3XTFT6X3GRMXIEJ3SJRUA.html).

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


#ifndef _NGX_STREAM_SSL_H_INCLUDED_
#define _NGX_STREAM_SSL_H_INCLUDED_


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


typedef struct {
    ngx_msec_t       handshake_timeout;

    ngx_flag_t       prefer_server_ciphers;

    ngx_ssl_t        ssl;

    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_array_t     *certificate_values;
    ngx_array_t     *certificate_key_values;

    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        alpn;

    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_stream_ssl_conf_t;


extern ngx_module_t  ngx_stream_ssl_module;


#endif /* _NGX_STREAM_SSL_H_INCLUDED_ */