[SOLVED] What permissions take precedence when dealing with softlinks?

JockVSJock · 04-13-2016, 02:52 PM

This is on RHEL5.

I've changed permissions on /bin/traceroute from 0755 to 0700, however when running ls

Code:

[root@server bin]# stat traceroute
  File: `traceroute'
  Size: 41248           Blocks: 96         IO Block: 4096   regular file
Device: fd00h/64768d    Inode: 196616      Links: 1
Access: (0700/-rwx------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2016-04-09 02:24:58.000000000 -0500
Modify: 2011-03-28 14:29:47.000000000 -0500
Change: 2016-04-13 14:47:51.000000000 -0500

[root@server bin]# ls -al | grep -i traceroute
lrwxrwxrwx  1 root root      10 Aug 25  2015 tcptraceroute -> traceroute
-rwx------  1 root root   41248 Mar 28  2011 traceroute
lrwxrwxrwx  1 root root      10 Aug 25  2015 traceroute6 -> traceroute
lrwxrwxrwx  1 root root      10 Aug 25  2015 tracert -> traceroute

There are three softlinks that point to /bin/traceroute and all of them are 777, so does the softlink permissions override /bin/traceroute or will this be a non-issue?

thanks

Wells · 04-13-2016, 03:49 PM

This is a non-issue. The permissions for /bin/traceroute take precedence.

Wells · 04-13-2016, 03:51 PM

Actually, here is a full-on demonstration that it is a non-issue:

Code:

jka@bonzai:~$ sudo bash
[root@bonzai jka]# cd /var/tmp/
[root@bonzai tmp]# ls
[root@bonzai tmp]# touch a
[root@bonzai tmp]# ls -l a
-rw-r--r-- 1 root root 0 Apr 13 17:01 a
[root@bonzai tmp]# chmod 600 a
[root@bonzai tmp]# ln -s a b
[root@bonzai tmp]# ls -l
total 0
-rw------- 1 root root 0 Apr 13 17:01 a
lrwxrwxrwx 1 root root 1 Apr 13 17:02 b -> a
[root@bonzai tmp]# exit
jka@bonzai:~$ cd /var/tmp/
jka@bonzai:/var/tmp$ touch b
touch: cannot touch `b': Permission denied
jka@bonzai:/var/tmp$ touch a
touch: cannot touch `a': Permission denied