LinuxQuestions.org
Help answer threads with 0 replies.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 06-17-2009, 04:52 AM   #1
Hiperi0n
LQ Newbie
 
Registered: Jun 2008
Distribution: archlinux,ubuntu
Posts: 6

Rep: Reputation: 0
Question User permissions on removable media


Hello. I have been wondering about the issues of user permissions on removable media.

Let's say I have an external HD (ext3 formatted, let's assume) and I create some files/folders with read/write permissions just for myself. Later, I plug that drive in another computer, for example, a lab PC at the university. With no root access, would I be able to read/write those files/folders? The user (id, name...) is not the same.

And another question related to this. Let's say that I have the same drive. If I give it to a friend, can he simply create a user with the same name in his PC and be able to access those files/folders? What I mean is, what is exactly taken into account when checking for permissions in Linux? Just the username? The UID?

I know that in case I don't want anyone to peek into my folders I should take more advanced measures such as encryption, but these questions make me wonder if the whole users/permissions "thing" (forgive me linux wise men makes sense when using removable media.

Thank you in advance.
 
Old 06-17-2009, 05:14 AM   #2
Dinithion
Member
 
Registered: Oct 2007
Location: Norway
Distribution: Slackware 14.1
Posts: 446

Rep: Reputation: 59
The file system keep track of file permissions with the UID. So in order for that to work, I guess you would need to use the same UID at home and at your school. But, if that's a problem, you can always override with permissions. You can set 'others' to rw(x) to give your account at school/work the permission to do what you like. Or you could add a group on your home computer with the same GID as your primary group at school.

So, to summarize;the file system use UID, and not names to identify users. But of course your friend with a GNU/Linux box can make a new user with what ever UID he likes..
 
Old 06-17-2009, 06:29 AM   #3
Hiperi0n
LQ Newbie
 
Registered: Jun 2008
Distribution: archlinux,ubuntu
Posts: 6

Original Poster
Rep: Reputation: 0
Thanks Dinithion. That is what I thought. As a security measure it is not very effective, permissions can be easily overriden. If I need to use the drive in another computer with a different user I'd simply give read/write permissions to the files. I was simply unsure about how Linux handled the permissions.
 
  


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
Removable Media zalibidas Slackware 2 01-24-2009 09:09 AM
SUSE 10.2 and removable media izquierdista SUSE / openSUSE 4 04-05-2007 08:38 AM
Install without removable media MaizeNBlue2 Slackware 3 12-06-2006 02:40 PM
mounting removable media matthewa Linux - Hardware 2 11-12-2005 09:44 PM
How to mount a removable media using C skie_knite007 Programming 1 10-02-2005 12:49 AM


All times are GMT -5. The time now is 07:38 AM.

Main Menu
Advertisement
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
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration