Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Unix File Permissions
Top Forums UNIX for Beginners Questions & Answers Answers to Frequently Asked Questions Tips and Tutorials Unix File Permissions Post 73755 by Perderabo on Friday 3rd of June 2005 07:20:56 PM
Old 06-03-2005
Set GID Bit on Directories
We briefly mentioned that files have a user and group associated with them. Originally, it was just the user and group of whoever created them. But originally, a user could be in only one group at a time. BSD introduced the concept that a user could be in multiple groups simutaneously. So in BSD, which group was used? BSD decided to use the group of the directory that contained the newly created file.

Many modern versions of unix try to have it both ways. A newly created file gets the group of the user unless the directory has the setgid bit. In that case, the newly created file gets the group of the directory.

And there is an exception to that! Changing the owner or group of a file has security concerns. For that reason, some versions of unix will, optionally, prohibit a user other than root from changing the owner of a file. Additionally, a user is prohibited from changing the group of a file unless he is a member of the new group. This restriction will override the setgid bit on a directory if needed.
These 3 Users Gave Thanks to Perderabo For This Post:
kingdream Neo shekhar_4_u
 

8 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Unix permissions

I am currently running jsp pages on unix server. At the top of my page is the import statement: <%@ page import="survey.*"%>. This imports the survey folder which i have placed in the same directory as my jsp page- jsp-servlet. However, when i try to run the page, its gives me an error saying that... (2 Replies)
Discussion started by: moukoko
2 Replies

2. UNIX for Advanced & Expert Users

UNIX File Permissions

Hello, What does the following mean in terms of file permissions. -rw-rwSrw- 1 owner group 999 May 25 2004 file_name What does the "S" stand for. Thanks in advance for your input. :) (3 Replies)
Discussion started by: jerardfjay
3 Replies

3. Solaris

Unix permissions

Is anyone aware of a tool that would produce a report or an extract file of all users, the files thry are allowed to access and their associated rights permitted (Read,Write etc.) (0 Replies)
Discussion started by: mobershaw
0 Replies

4. UNIX for Dummies Questions & Answers

Unix permissions for a newbie

Okay, this may turn out to be something quite simple, but I haven't found the answer so far: 1) Is it possible to retrieve a list of user(ID) file permissions? and then... 2) What is the most efficient way to create an alert/error message when/if those file permissions are denied? ... (2 Replies)
Discussion started by: hades1013
2 Replies

5. Shell Programming and Scripting

Unix File Permissions

I want to change one of my Dir permissions to drwx--S--- Can you tell me which number i have to use. Thanks in Advance (4 Replies)
Discussion started by: veeru
4 Replies

6. UNIX for Dummies Questions & Answers

Unix Permissions

We have a user group ‘norkgrp’ which is having 2 users ‘norkadm’ and ‘oracle’. Further we have a directory ‘fstf_blobs’ where ‘norkadm’ is the owner and ‘norkgrp’ is the group owner. The permission is set as 770. $ ls -lrt drwxrwx--- 2 norkadm norkgrp 1024 Jun 24 05:03 fstf_blobs We... (5 Replies)
Discussion started by: varunrbs
5 Replies

7. Solaris

Unix file, folder permissions, security auditing tools.

I want to periodically check if ASCII password/config files on Unix have 400 or 600 access. Folders and files are owned by designated group and user. Folders and Files do not have world write access. Are there any tools/scripts available for this kind of auditing that I can use on Solaris? (7 Replies)
Discussion started by: kchinnam
7 Replies

8. Shell Programming and Scripting

ksh; Change file permissions, update file, change permissions back?

Hi, I am creating a ksh script to search for a string of text inside files within a directory tree. Some of these file are going to be read/execute only. I know to use chmod to change the permissions of the file, but I want to preserve the original permissions after writing to the file. How can I... (3 Replies)
Discussion started by: right_coaster
3 Replies

LEARN ABOUT NETBSD

newgrp

NEWGRP(1)						    BSD General Commands Manual 						 NEWGRP(1)

NAME

     newgrp -- change to a new primary group

SYNOPSIS

     newgrp [-l] [group]

DESCRIPTION

     The newgrp command changes a user to a new primary group (real and effective group ID) by starting a new shell.  The user remains logged in
     and the current directory and file creation mask remain unchanged.  The user is always given a new shell even if the primary group change
     fails.

     The newgrp command accepts the following options:

     -l      The environment is changed to what would be expected if the user actually logged in again.  This simulates a full login.

     The group is a group name or non-negative numeric group ID from the group database.  The real and effective group IDs are set to group or the
     group ID associated with the group name.

     If group is not specified, newgrp restores the user's real and effective group IDs to the user's primary group specified in the password
     database.	The user's supplementary group IDs are restored to the set specified for the user in the group database.

     If the user is not a member of the specified group, and the group requires a password, the user will be prompted for the group password.

FILES

     /etc/group 	 The group database
     /etc/master.passwd  The user database
     /etc/passwd	 A Version 7 format password file

EXIT STATUS

     If a new shell is started the exit status is the exit status of the shell.  Otherwise the exit status will be >0.

SEE ALSO

     csh(1), groups(1), login(1), sh(1), su(1), umask(2), group(5), passwd(5), environ(7)

STANDARDS

     The newgrp command conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

HISTORY

     A newgrp command appeared in Version 6 AT&T UNIX.	A newgrp command appeared in NetBSD 5.0.

BUGS

     There is no convenient way to enter a password into /etc/group.  The use of group passwords is strongly discouraged since they are inherently
     insecure.	It is not possible to stop users from obtaining the encrypted password from the group database.

BSD
								   June 6, 2007 							       BSD
All times are GMT -4. The time now is 09:02 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy