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如果我们不关闭 cgi.fix_pathinfo，服务器是否仍然容易受到攻击？

tag-icon • tag-icon nginx security php-fpm fastcgi
如果我们不关闭 cgi.fix_pathinfo，服务器是否仍然容易受到攻击？

nginx安装自带的文件/etc/nginx/sites-available/default内容如下：

# You may add here your
# server {
#   ...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    root /usr/share/nginx/html;
    index index.html index.htm;

    # Make site accessible from http://localhost/
    server_name localhost;

    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ =404;
        # Uncomment to enable naxsi on this location
        # include /etc/nginx/naxsi.rules
    }

    # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
    #location /RequestDenied {
    #   proxy_pass http://127.0.0.1:8080;    
    #}

    #error_page 404 /404.html;

    # redirect server error pages to the static page /50x.html
    #
    #error_page 500 502 503 504 /50x.html;
    #location = /50x.html {
    #   root /usr/share/nginx/html;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #   fastcgi_split_path_info ^(.+\.php)(/.+)$;
    #   # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
    #
    #   # With php5-cgi alone:
    #   fastcgi_pass 127.0.0.1:9000;
    #   # With php5-fpm:
    #   fastcgi_pass unix:/var/run/php5-fpm.sock;
    #   fastcgi_index index.php;
    #   include fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #   deny all;
    #}
}


# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
#   listen 8000;
#   listen somename:8080;
#   server_name somename alias another.alias;
#   root html;
#   index index.html index.htm;
#
#   location / {
#       try_files $uri $uri/ =404;
#   }
#}


# HTTPS server
#
#server {
#   listen 443;
#   server_name localhost;
#
#   root html;
#   index index.html index.htm;
#
#   ssl on;
#   ssl_certificate cert.pem;
#   ssl_certificate_key cert.key;
#
#   ssl_session_timeout 5m;
#
#   ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2;
#   ssl_ciphers "HIGH:!aNULL:!MD5 or HIGH:!aNULL:!MD5:!3DES";
#   ssl_prefer_server_ciphers on;
#
#   location / {
#       try_files $uri $uri/ =404;
#   }
#}

您可以看到有一条注释“您应该在 php.ini 中设置“cgi.fix_pathinfo = 0;”。在它上面，我们还有这一行：

fastcgi_split_path_info ^(.+\.php)(/.+)$;

根据帖子Nginx、PHP 和 fastcgi_split_path_info 的安全问题，我们可以减轻路径信息漏洞通过关闭cgi.fix_pathinfo或使用fastcgi_split_path_info。

既然已经利用了该fastcgi_split_path_info指令来应对此类漏洞，为什么还说我们应该关闭cgi.fix_pathinfo？如果我们不这样做，我们的服务器是否容易受到攻击？

答案1

Nginx 维基百科PHP-FPM 页面配置建议转动cgi.fix_pathinfo注意使用的正则表达式：

fastcgi_split_path_info ^(.+?\.php)(/.*)$;

该页面还提供了一个测试，您可以访问下面列出的不同 URL，并检查 REQUEST_URI、SCRIPT_NAME、PATH_INFO 和 PHP_SELF 的正确值。

/test.php
/test.php/
/test.php/foo
/test.php/foo/bar.php
/test.php/foo/bar.php?v=1

test.php 仅包含<?php var_export($_SERVER)?>。这有助于确定您的设置是否安全。在所有 URL 上，您的 SCRIPT_NAME 应该是测试.php无论如何，你不应该看到栏位那里。

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