How to find files or folders that are inaccessible to a certain user?

Question

I am trying to install some package in my Joomla but got an error saying "error trying to delete inaccessible file". I checked with the package developer, they said I need to make sure all files and folders under my Joomla installation is accessible to the web server. I was reading some tutorial about find command and its -perm parameter, but the articles I read didn't mention how do I check permission against a particular user; Also they are all about checking files with permission but not without. So how do I find out which file/folder is causing the CMS to throw out this "inaccessible" error?

Answer 1

Access to directory is controlled by x - execute - bit in the permissions. The issue could be due to the user having no executable permissions as owner or a group to which user belongs has no executable permissions set on the directory.

In order to use find for that task, it's sufficient to specify -user as the owner of the directory and -not -executable flags.:

~$ find -type d -user $USER -not -executable
./foo/bar
./test_access
~$ ls -ld ./foo/bar ./test_access
drw-r-xr-- 2 admin admin 4096 Jan 15 03:36 ./foo/bar
drw-r--r-- 2 admin admin 4096 Jan  4 15:38 ./test_access

For cases where group part off the permissions is of interest, you could find groups the user belongs to and iterate over them:

for i in $(groups $USER | cut -d':' -f2) ; do find -type d -group "$i" -not -executable ; done

If neither case turns any potential results, the issue could be due to user not belonging to a group which has access to the directory that gives the issue.

Note also that web servers typically use www-data user/group. You probably want to be checking permissions using that username or group name.