LinuxQuestions.org
LinuxAnswers - the LQ Linux tutorial section.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software
User Name
Password
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.

Notices

Reply
 
Search this Thread
Old 04-20-2010, 01:33 AM   #1
aeternitas
LQ Newbie
 
Registered: Sep 2006
Distribution: Ubuntu Lucid 10.04 LTS
Posts: 23

Rep: Reputation: 15
Member of group root, but root group permissions don't apply?


A bit of an oddity that I've recently run into with my storage folder in my system; it's a newly installed drive that I've set to mount at /storage. When I first tried to use it, programs that I used that attempted to write to it tossed Access Denied errors at me in their own way.

Checking the permissions (at the Terminal, ls -l / | grep storage) showed that /storage was set to 'rwxrwxr--'--Owner and Group were given full read/write/execute, but Others could only read. However, my logon to my system is a member of group root. Why, then, with the above bits set, would I not be able to write to it? Changing Others permissions to rwx (and presumably rw would have worked out for me since I don't leave anything executable there) allowed me to write to it, but I don't understand why that would have been necessary. So far as I'm aware, the prior drive that was in my system--mounted at the same location--did not need this treatment.
 
Old 04-20-2010, 06:14 PM   #2
irishbitte
Senior Member
 
Registered: Oct 2007
Location: Brighton, UK
Distribution: Ubuntu Hardy, Ubuntu Jaunty, Eeebuntu, Debian, SME-Server
Posts: 1,213
Blog Entries: 1

Rep: Reputation: 82
Can you show us the mount command or script that you used to mount the drive, for example, is it mounted in
Code:
/etc/fstab
Possibly the mount command used had the readonly flag set?
 
Old 04-20-2010, 10:07 PM   #3
aeternitas
LQ Newbie
 
Registered: Sep 2006
Distribution: Ubuntu Lucid 10.04 LTS
Posts: 23

Original Poster
Rep: Reputation: 15
The drive is mounted by /etc/fstab; when I changed the physical drive out, I simply changed the UUID to it's current value, everything else is the same as it had been:

Code:
# /storage was on /dev/sdb1 during installation
UUID=f3f00e48-17bc-45ac-8568-14c5cd4df273 /storage        ext3    relatime        0       2
On a side note, I'd ended up having to change the permissions of my /tmp folder to be able to log in to my system, about a day later (symptoms matched this bug at Ubuntu's Launchpad (#269215), and changing the permissions is one pretty consistently mentioned fix). The permission change used and prior permissions were the same as the above hard drive (drwxrwxr-- prior, changed to drwxrwxrwx to allow /tmp to be written to)--also owned by user root with group root.
 
Old 04-21-2010, 04:24 AM   #4
irishbitte
Senior Member
 
Registered: Oct 2007
Location: Brighton, UK
Distribution: Ubuntu Hardy, Ubuntu Jaunty, Eeebuntu, Debian, SME-Server
Posts: 1,213
Blog Entries: 1

Rep: Reputation: 82
That's an interesting one, and I don't think I've come across it before. Do you use ACL's?
 
Old 04-21-2010, 04:31 AM   #5
aeternitas
LQ Newbie
 
Registered: Sep 2006
Distribution: Ubuntu Lucid 10.04 LTS
Posts: 23

Original Poster
Rep: Reputation: 15
Not familiar with what you mean by ACLs, so I'd presume no on that.
 
Old 04-21-2010, 04:42 AM   #6
Sayan Acharjee
Member
 
Registered: Feb 2010
Location: Bangalore, India
Distribution: Linux Mint 13
Posts: 590

Rep: Reputation: 64
Quote:
Originally Posted by aeternitas View Post
A bit of an oddity that I've recently run into with my storage folder in my system; it's a newly installed drive that I've set to mount at /storage. When I first tried to use it, programs that I used that attempted to write to it tossed Access Denied errors at me in their own way.

Checking the permissions (at the Terminal, ls -l / | grep storage) showed that /storage was set to 'rwxrwxr--'--Owner and Group were given full read/write/execute, but Others could only read. However, my logon to my system is a member of group root. Why, then, with the above bits set, would I not be able to write to it? Changing Others permissions to rwx (and presumably rw would have worked out for me since I don't leave anything executable there) allowed me to write to it, but I don't understand why that would have been necessary. So far as I'm aware, the prior drive that was in my system--mounted at the same location--did not need this treatment.
can you please post the outputs of the following commands:
Quote:
#ls -ld /storage
and

Quote:
#getfacl /storage
 
Old 04-21-2010, 08:53 AM   #7
irishbitte
Senior Member
 
Registered: Oct 2007
Location: Brighton, UK
Distribution: Ubuntu Hardy, Ubuntu Jaunty, Eeebuntu, Debian, SME-Server
Posts: 1,213
Blog Entries: 1

Rep: Reputation: 82
ACL's: Access Control Lists, they allow for finer grained control over file permissions, think of them as UNIX permissions on steroids. Interestingly, MS use ACL's in their NTFS file system, and they form the basis of the 'New Technology' aspect of NTFS vs FAT32.

PS, the previous post illustrates how to check for this with the getfacl command.

This may be a recurrence of the bug you describe here:
Quote:
(symptoms matched this bug at Ubuntu's Launchpad (#269215), and changing the permissions is one pretty consistently mentioned fix)
might be worth opening a launchpad query about it.

Last edited by irishbitte; 04-21-2010 at 08:55 AM.
 
Old 04-21-2010, 11:06 PM   #8
aeternitas
LQ Newbie
 
Registered: Sep 2006
Distribution: Ubuntu Lucid 10.04 LTS
Posts: 23

Original Poster
Rep: Reputation: 15
@sayan_acharjee:
The output of those commands came out as such:

Code:
ms9477@BETA:~$ ls -ld /storage
drwxrwxrwt 4 root root 4096 2010-04-21 13:02 /storage
ms9477@BETA:~$ getfacl /storage
getfacl: Removing leading '/' from absolute path names
# file: storage
# owner: root
# group: root
user::rwx
group::rwx
other::rwx
@irishbitte: I'm beginning to think that's the most likely case, although I wouldn't really call it a recurrence since it doesn't seem to have been really 'fixed', so to speak--just worked around sufficiently. I'll probably weigh in over there in a bit, see what other thoughts might be out there. Just seems rather odd that out of nowhere a permissions change would be needed, doesn't seem quite right to me...but I'm not much of an expert, to tell the truth

Thanks for the input!
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
AIX: root group and system group quanba AIX 6 09-01-2009 02:10 AM
How do I enforce in Red hat linux that only root user be a member of the "root" group sultf Linux - Security 4 01-08-2009 04:42 PM
Giving a user root permission via the root group louisb Linux - Security 6 07-23-2007 12:56 AM
Permissions problem - setting up dirs for root + group access ericcarlson Red Hat 1 03-26-2006 03:03 AM
Group Admin, Group Root, or God over Group crickett Linux - General 5 07-12-2004 04:01 PM


All times are GMT -5. The time now is 08:12 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration