nginx php403错误的解决办法：1、修改文件权限或开启selinux；2、修改php-fpm.conf，加入需要的文件扩展名；3、修改php.ini内容为“cgi.fix_pathinfo = 0”；4、重启php-fpm即可。
本教程操作环境：linux5.9.8系统、PHP8.1版、Dell G3电脑。
nginx + php 403 原因分析
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问题：
配置的网站，访问出现报错：Access Denied (403)
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常见解决方法:
1、文件权限问题
可能是文件权限问题，没有读权限。
或者selinux没有关闭。
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2、security.limit_extensions
查看nginx的错误日志error.log，发现有如下错误：
2016/07/07 10:20:13 [error] 17710#0: *2145 FastCGI sent in stderr: "Access to the script '/home/www/game/10313156.html' has been denied (see security.limi t_extensions)" while reading response header from......
从5.3.9开始，php官方加入了一个配置"security.limit_extensions"，默认只允许执行扩展名为".php"的文件，造成了其他类型的文件不支持的问题。
官方说明 ：
; Limits the extensions of the main script FPM will allow to parse. This can ; prevent configuration mistakes on the web server side. You should only limit ; FPM to .php extensions to prevent malicious users to use other extensions to ; exectute php code. ; Note: set an empty value to allow all extensions. ; Default Value: .php ;security.limit_extensions = .php .php3 .php4 .php5
修改php-fpm.conf：（加入需要的文件扩展名）
security.limit_extensions = .php .html .js .css .jpg .jpeg .gif .png .htm
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3、cgi.fix_pathinfo
通过这种url访问，显示Acess denied 错误。
nginx错误日志：
2016/07/08 09:47:12 [error] 24297#0: *3348 FastCGI sent in stderr: "Access to the script '/home/www/home.php/game/qr' has been denied (see security.limit_extensions)" while reading response header......
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修改php.ini ：（cgi.fix_pathinfo 默认为1 ）
cgi.fix_pathinfo = 1
官方说明 ：
; cgi.fix_pathinfo provides *real* PATH_INFO/PATH_TRANSLATED support for CGI. PHP's ; previous behaviour was to set PATH_TRANSLATED to SCRIPT_FILENAME, and to not grok ; what PATH_INFO is. For more information on PATH_INFO, see the cgi specs. Setting ; this to 1 will cause PHP CGI to fix its paths to conform to the spec. A setting ; of zero causes PHP to behave as before. Default is 1. You should fix your scripts ; to use SCRIPT_FILENAME rather than PATH_TRANSLATED. ; http://php.net/cgi.fix-pathinfo
其实cgi.fix_pathinfo = 1 会引发文件类型错误解析漏洞，建议是设置 cgi.fix_pathinfo = 0 。
( 关于漏洞的理解：
当cgi.fix_pathinfo=1时，访问路径：/foo.jpg/file.php ，如果file.php文件不存在，则php解析器会试图猜测你要执行哪个文件，沿着路径往回找。如果foo.jpg存在， 并且包含php代码，php解析器就会去执行foo.jpg 。
当cgi.fix_pathinfo=0时，PHP 解释器仅尝试给出的路径，如果文件没有找到就停止处理。
)
但将 cgi.fix_pathinfo = 0 ，可能会导致很多MVC框架（如ThinkPHP）无法正常运行。
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4、
在php.ini上设置了：open_basedir=/home:/tmp/:/proc/
重启php-fpm
访问网页，按ctrl + F5频繁刷新的时候，会报 Access Denied错误。Access Denied是偶尔才会出现，不是一直403 。
nginx错误日志记录：
2016/07/09 08:32:40 [error] 26954#0: *2127721 FastCGI sent in stderr: "PHP message: PHP Warning: Unknown: open_basedir restriction in effect. File(/home/www/touch/web/index.php) is not within the allowed path(s): (/home/wwwroot:/tmp/:/proc/) in Unknown on line 0 PHP message: PHP Warning: Unknown: failed to open stream: Operation not permitted in Unknown on line 0 Unable to open primary script: /home/www/touch/web/index.php (Permission denied)" while reading response header from upstream, client: 117.136.1.22, server: test.hjq.com, request: "GET /index.php?c=Zs&a=getcontent HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "test.hjq.com"
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2、In your nginx config file set fastcgi_pass to your socket address (e.g. unix:/var/run/php-fpm/php-fpm.sock;) instead of your server address and port. 3、Check your SCRIPT_FILENAME fastcgi param and set it according to the location of your files. 4、In your nginx config file include fastcgi_split_path_info ^(.+\.php)(/.+)$; in the location block where all the other fastcgi params are defined.
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