2

I'm trying to set up a directory where a user can traverse a directory but not prove the existence of anything in the directory. I have tried setting permissions such that the user has execute but not read permissions. Unfortunately the error returned (either "No such file or directory" or "Permission denied") will confirm whether a given item exists in the directory.

For example, here is what I currently see:

$ sudo ls -l permTest/
total 4
drwxr-x--- 2 root root 4096 Aug 10 12:35 exists
$ ls -ld permTest
drwxr-x--x 3 root root 4096 Aug 10 12:35 permTest/
$ ls permTest
ls: cannot open directory 'permTest': Permission denied
$ ls permTest/doesnotexist
ls: cannot access 'permTest/doesnotexist': No such file or directory
$ ls permTest/exists
ls: cannot open directory 'permTest/exists': Permission denied

I would like the error messages in the final line to be identical.

I'm trying to set this up on MapRFS if that's relevant. It is broadly POSIX compliant.

I have read the answers at How does one create a directory that can't be seen and can only be accessed via its absolute path name?, but did not find a solution to my problem.

2

It is not possible to hide the existence of a file if the user could list it:

$ ls -l permTest/insidedir/doesexist
-rw-r--r-- 1 root root 0 Aug 10 01:55 permTest/insidedir/doesexist

even if both directories (permTest and insidedir) are own by root and have only x permissions:

$ sudo ls -la permTest/insidedir/
total 8
d--x--x--x 2 root root 4096 Aug 10 01:55 .
d--x--x--x 3 root root 4096 Aug 10 01:54 ..
-rw-r--r-- 1 root root    0 Aug 10 01:55 doesexist


$ ls -la permTest/
ls: cannot open directory permTest/: Permission denied

$ ls -la permTest/insidedir/
ls: cannot open directory permTest/insidedir/: Permission denied

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