nginx error connect to php5-fpm.sock failed (13: Permission denied)

I update nginx to 1.4.7 and php to 5.5.12, After that I got the 502 error. Before I update everything works fine.

nginx-error.log

2014/05/03 13:27:41 [crit] 4202#0: *1 connect() to unix:/var/run/php5-fpm.sock failed (13: Permission denied) while connecting to upstream, client: xx.xxx.xx.xx, server: localhost, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "xx.xx.xx.xx"

nginx.conf

user  www www;
worker_processes  1;

        location / {
            root   /usr/home/user/public_html;
            index  index.php index.html index.htm;
        }
        location ~ [^/].php(/|$) {
            fastcgi_split_path_info ^(.+?.php)(/.*)$;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            fastcgi_index index.php;
            fastcgi_param  SCRIPT_FILENAME    /usr/home/user/public_html$fastcgi_script_name;
            include fastcgi_params;
        }

Answer

I had a similar error after php update. PHP fixed a security bug where o had rw permission to the socket file.

1. Open /etc/php5/fpm/pool.d/www.conf or /etc/php/7.0/fpm/pool.d/www.conf, depending on your version.

2. Uncomment all permission lines, like:

   listen.owner = www-data
   listen.group = www-data
   listen.mode = 0660
   

3. Restart fpm – sudo service php5-fpm restart or sudo service php7.0-fpm restart

Note: if your webserver runs as user other than www-data, you will need to update the www.conf file accordingly