Hello,

I have a question about file permissions.

The documentation explains 2 solutions :

• Using ACL
• Without ACL, with umask

If ACL is used, we can see :

getfacl var/cache/prod/url_generating_routes.php

# file: var/cache/prod/url_generating_routes.php
# owner: myuser
# group: myuser
user::rw-
user:myuser:rwx	#effective:r--
user:www-data:rwx	#effective:r--
group::r-x			#effective:r--
mask::r--
other::r--

• myuser can write file (file author)
• www-data can't write file (effective:r-- by ACL mask r--)

So, if a file is created by www-data, it cannot be edited by myuser.

If ACL is used WITH umask(0002), we can see :

getfacl var/cache/prod/url_generating_routes.php

# file: var/cache/prod/url_generating_routes.php
# owner: myuser
# group: myuser
user::rw-
user:myuser:rwx		#effective:rw-
user:www-data:rwx	#effective:rw-
group::r-x			#effective:r--
mask::rw-
other::r--

• myuser can write file (file author)
• www-data can write file (umask changes the ACL mask to rw- and effective:rw-)

In my case :

• Use ACL without umask : Incorrect rights
• Use ACL with umask : Correct rights

But the documentation says Changing the umask is not thread-safe.

Did you have this problem ?

Thank you in advance.