Edit - Unix & Linux Stack Exchange

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

Rev

Title*

Body*

i have simple test.php page: 

    <pre><?php system("ls -la /tmp"); ?></pre>

which always shows just: `.` and `..` folders and nothing else in browser.

in the command line:

    1) ls -la /tmp
    2) sudo -u http ls -la /tmp
    3) php test.php
    4) sudo -u http php test.php

all this commands returns full list of directory files/subdirs.

What is the reason for this???

And problem is "/tmp" folder related because `ls -lah /usr` works OK.

i tested this on 4 comps (one of them was debian with php 5.0.6 and there php shows all files OK like i expected, other 3 comps has php7 and shows empty /tmp). 

**update:**

even after adding http to sudoers file and running 'sudo ls /tmp', problem is the same on php versions >7. 

but runing 'system("echo aaa > /tmp/aaa.txt; ls -la /tmp") shows `.` , `..` , and `aaa.txt` file owned by http:http. So is this some new php restriction and how it is posible to interfere on /tmp files only.

**update2:**

but aaa.txt is not inside /tmp, and by running `find /tmp -name aaa.txt`, i see that it is inside `/tmp/systemd-private-2cf1853410ad4ade980ec17e883771c3-httpd.service-lZ22gS/tmp/aaa.txt` .

so finaly it is related to something called "**systemd /tmp isolation**"... that i need to learn about.

Changing `true` to `false` inside: `/etc/systemd/system/multi-user.target.wants/httpd.service`:

    [Service]
    PrivateTmp=false
    ...

solves my problem, but i am wondering is it possible to avoid this without changing service file.