wildcard .htaccess and reject some address on subdomain - regex

Question

I want all file or directory existed under up.example.com subdomain rejected and show 404 error.
Also I want all another request point to index.php.
I write this code:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^up\.(.+)$ [NC]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.*)$ - [R=404,L,NS]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [L,QSA]
When I test this code for http://up.example.com/test.jpg
If test.jpg file existed on root server, show me this error:
Not Found
The requested URL /test.jpg was not found on this server.
Apache Server at up.example.com Port 80
It's ok!
But when test.jpg not existed, give me this error:
Not Found
The requested URL /index.php was not found on this server.
Apache Server at up.example.com Port 80
Instead open index.php (index.php exist on root)
Why? and how can I fix it?

Answer 1

Actually the problem is that you write everything to index.php and that becomes a valid file in the request. When mod_rewrite runs next time first rule sends it to 404.
To overcome this error have your rules like this:
RewriteEngine On
# if it is valid file or directory except for index.php
# then send 404 to browser
RewriteCond %{HTTP_HOST} ^up\. [NC]
RewriteCond %{THE_REQUEST} \s/+index\.php[?\s] [NC]
RewriteRule ^index\.php$ - [R=404,L,NC]
RewriteCond %{HTTP_HOST} ^up\. [NC]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule !^index\.php$ - [R=404,L,NC]
# send all non-file/directories to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [L]

Answer 2

Try this one
RewriteEngine On
RewriteCond %{HTTP_HOST} ^up\.(.+)$ [NC] # remove if it is not related to subdomain
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [L,QSA]
RewriteCond %{HTTP_HOST} ^up\.(.+)$ [NC]
RewriteCond %{REQUEST_URI} !^/index\.php
RewriteRule ^(.*)$ - [R=404,L,NS]