All about Unix groups and access control.

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3
votes
3answers
75 views

Can I forbid the creation of files with certain permissions?

I have a directory with a certain group ID, and I only want files with the same ID to be in that directory. So I set the SGID bit on that directory, so that everytime a file is created inside it, it ...
3
votes
1answer
327 views

Is it a bad idea to add myself to the sudo group?

Members of the sudo group in my Debian install can execute anything without entering a password. This is convenient, but seems like a bad idea. NOTE: My computer is an ordinary desktop, not a server ...
2
votes
3answers
2k views

CentOS can't remove user from group

Asked and answered many times, but I can't get it working!!! (On CentOS) I have the user userA and I want to remove it from group sftponly. #groups userA userA : sftponly #id -Gn userA sftponly ...
1
vote
0answers
122 views

Udev rule- change group

I would like to change group of /dev/nvidia0. I was write udev rule: KERNEL="nvidia[0-9]", GROUP="video", MODE="0666" But it does't change group, after reboot file is in rootgroup. How do this?
0
votes
1answer
380 views

Which tasks/commands can't be executed with user gid=0 but not uid=0 on Linux [duplicate]

In a Linux server I will have an user with gid=0 but it's uid won't be 0. As there are many commands with root:root and execute permissions for group I know there will be a lot of administrative task ...
3
votes
1answer
3k views

Give default write permission to group to any newly created files and folders

Let's say that we have 2 users: a and b, that are both part of group general. I would like that any file or folder that A creates, would have write permission to the group GENERAL. How can I do it? ...
3
votes
2answers
143 views

how to initialize `/etc/group`?

After editing /etc/group, How this update starts functioning without restarting the system in Unix? Is there any command we need to run?
2
votes
2answers
817 views

group option in fstab not working

I'm trying to take advantage of the "group" option for fstab entries and not having any success. From the mount man page: Normally, only the superuser can mount filesystems. However, when fstab ...
3
votes
1answer
523 views

File owner must belong to file group?

I have a rather simplistic understanding of file permissions on *nix systems. I understand that there is a file owner and file group, but is there a hard and fast rule on whether the said file owner ...
1
vote
1answer
92 views

Function of owning group versus ACL group permissions

Given the fact that we can give any number of groups rwx via POSIX ACL's is there any special privileges given to the owning group? For example, we can set any number of users with ACL's but only the ...
4
votes
2answers
168 views

How to run script with the privileges expected of the script's general “intended user”?

During the development of a script, some bugs remain "latent" until the script is run by a different user. (For example, the script may access a file that only the person developing the script has ...
1
vote
1answer
1k views

Allow all group members to create directories and files

There are 2 users sftp_user apache Both users belong to the updaters group as well as other groups. New directories and files are created in the /updates/ directory. drwxrwsr-x 8 sftp updaters ...
2
votes
3answers
1k views

newgrp asks for password [duplicate]

I don't understand why newgrp prompts me for password when I want to change my group. I don't even know what password it is asking for but certainly not mine (user clime). $ id uid=500(clime) ...
1
vote
2answers
365 views

Modify Default Group for new Users in Solaris 11

I would like to change the default group for new users which are added to the system. Does anybody know in which file this is stored? I'm using Solaris 11
1
vote
3answers
104 views

group file and everything related to it [closed]

I'm quite new to *nix OS. I understand the format and usage (at least what the man pages says) of the /etc/group file. One day I was trying to replace my group file with a backup copy. I changed the ...
1
vote
1answer
273 views

Several groups can have the same groupID?

0:root@SERVER:/root # grep 300 /etc/group ipsec:!:300:admgrp 0:root@SERVER:/root # ?? Several groups (ipsec/admgrp) can have the same groupID (300)?? how can this be? /AIX 6.1/
0
votes
3answers
4k views

What is the function of user group root? [duplicate]

Possible Duplicate: What does it mean to be in group 0? I wanted to avoid using SSH root login to backup my remote server. Thus I set up a non-root user account on the server and place it ...
1
vote
1answer
125 views

Securely running LAMP under a specific user

I'm setting up a sandbox type of server that will be used by a couple users as a development environment and knowledge base. The server will have a web frontend so I've installed Apache, MySQL and ...
5
votes
1answer
203 views

Can I add to my groups in the current (shell) process? [duplicate]

If I add myself to a group, it applies only to newly launched processes. Actually it's more restricted than that; it seems to apply only to new logins. I'm not sure what the exact mechanism is, but ...
1
vote
1answer
375 views

Group permissions ineffective, permission still denied

I've got a problem with UNIX permissions : I'm working under Debian Squeeze, and one of my scripts, run by www-data, needs to move a file, 23550.zip, placed in the home directory of another user, ...
11
votes
4answers
703 views

Groups differ from the local ones when logging in remotely

We store our users in LDAP, alongside some groups that have meaning across different systems (organizational roles including wheel). There are also groups local to workstations, e.g. audio or video ...
1
vote
1answer
4k views

Trouble adding existing user to existing group in ubuntu

I was trying to add a user called bill to www group useradd -G www bill It gives me error UX: useradd: ERROR: bill is already in use. Choose another. I checked if this user already in the group ...
1
vote
2answers
846 views

How to handle user permission issue?

We have created an asset management application web app using php. This app allows users to browse, upload, rename, replace assets (binary files like images and 3d models) We developed in windows ...
2
votes
1answer
206 views

Delete every users from a group

I search a clean way to delete every users from the 'sudo' group. On several distributions the user created during the installation process has sudo rights, I don't want this. I search for an ...
0
votes
2answers
134 views

Change/Create permissions for a folder

How can I create (if the folder is new) or change (if the folder was already existent) permissions for a folder? In particular, I want to create a subdirectory in /etc/bind/ where I can put the ...
5
votes
3answers
1k views

how to login as a member of specific group

i want to login as a member of non primary group to create files whose owner as a member of non primary group of current user. -rwxr-xr-x 2 gowtham gowtham 4096 Sep 5 14:48 defaultNewFile ...
1
vote
1answer
1k views

Accessing another user's files

I have a file "abc" with permissions 440 .The owner of this file is "root" and the group of this file is "groupabc" . I have a user "user1" .Is their anyway I can see the contents of files "abc" using ...
1
vote
2answers
4k views

wireshark: Couldn't run /usr/sbin/dumpcap in child process [duplicate]

Possible Duplicate: How to add write permissions for a group? When I run Wireshark, It shows the following message: Couldn't run /usr/sbin/dumpcap in child process: Permission denied Are ...
7
votes
1answer
5k views

addgroup vs groupadd

I happen to know there is a slight difference between adduser and useradd. (i.e., adduser has additional features to useradd, such as creating a home directory.) Then what is the relation between ...
4
votes
2answers
1k views

Why don't /etc/group and /etc/password match?

OK this is a basic question showing my ignorance of sysadmin matters... Looking at the UNIX system I work on, my /etc/passwd entry says my_name:x:uid:gid:comments:home directory:login shell Then ...
2
votes
1answer
9k views

Error message id: cannot find name for group ID after logging in

BACKGROUND Trevor logs into his account on ssh://foobar.university.edu as one of the developers on the box, and he gets the message: id: cannot find name for group ID 131 Trevor then checks this ...
3
votes
1answer
3k views

How to ensure that anonymous FTP has been disabled on a Solaris 10 system?

What line in which configuration files in the /etc/ftpd directory do I have to check to ensure that anonymous FTP has been disabled? From my understanding now, to ensure that anonymous FTP is ...
1
vote
1answer
202 views

How to disable messages in unix if mesg and chgrp not allowed?

This is one of my questions for my exam .. We are not supposed to use mesg y/n for this but we should effectively avoid mesgs along with the problem of not being able to change groups.
6
votes
3answers
1k views

Can't read a file although it's in my group and permissions for group read are set

I encounter a strange problem on a unix/linux machine: I'm member of a group, let's call it group A and a certain file (which has a different owner) belongs to group A as well. The permissions of ...
2
votes
0answers
223 views

Samba: system group mapping

I have w2008R2 PDC and Linux server with samba and winbind. Now I'd like to add some domain users to Unix adm group in AD. Let's say I have adm group defined in AD, and every user from this group ...
1
vote
1answer
235 views

How to filter group membership from the ldap server?

Context : We have a Ubuntu 12.04 with authentication done on a ldap server. Unfortunately, one (ldap) user belongs to a (ldap) group named "admin". I know there is the option ...
2
votes
1answer
285 views

Why does newgrp change my PS1 and how to prevent it?

I have a customized PS1 to show several parameters. When I switch to a different group using newgrp, it switched my PS1 to default ($) and that is annoying. The default remains even when I switch ...
0
votes
1answer
4k views

Full access by group user of /var/www/html [duplicate]

Possible Duplicate: How to add write permissions for a group? On Centos 6 I'm trying to give full access to make and delete by the user mitch for /var/www/http. I did addgroup www and then ...
8
votes
1answer
7k views

Group within group file permissions

I tried finding this on here, but couldn't so sorry if it's a duplicate. Say I have 2 groups and a user: group1, group2, user1 with the following structure: group1 is a member of group 2, user1 is a ...
4
votes
1answer
295 views

In my secure log there is a new group added that Im unsure about after adding semanage

I installed semanage onto my CentOS 6.2 box and I was going through my secure log after the install and noticed this entry: Aug 31 22:12:17 xxxx groupadd[12929]: group added to /etc/group: ...
10
votes
1answer
3k views

In /etc/group what is the meaning of the second field?

A sample /etc/group file contains the following entries: root:*:0: adm:!:4:logcheck antoine:x:1000: The man pages I've read (Debian & OSX) says the second field is to store a group password. ...
1
vote
1answer
477 views

Group Permission on public_html [duplicate]

Possible Duplicate: Permissions: What's the right way to give Apache more user permissions? Before I knew better, I used /home/someuser/public_html/scripts as a place from which shared ...
2
votes
1answer
5k views

Why this error: “cannot create directory `foo': Permission denied”

I get this error when I try creating a directory: [rex <03:57 PM> /var/tmp/pb82]$ mkdir foo mkdir: cannot create directory `foo': Permission denied But doesn't the following output indicate ...
2
votes
3answers
1k views

Limited SSH user on Ubuntu 12

I'm running Minecraft on a server. How can I give my friend SSH access just to the minecraft folder (a root folder), the screen command, and some ports?
6
votes
3answers
3k views

What does it mean to be in group 0?

Several users in a system I inherited have their group set to 0 in /etc/passwd. What does that mean? Do they essentially get full root privileges? The system is running CentOS 5, and the users ...
4
votes
3answers
8k views

What does GID mean?

What does GID actually mean? I have Googled it and this is what linux.about.com said: Group identification number for the process. Valid group numbers are given in /etc/group, and in the ...
1
vote
2answers
302 views

How to maintain file ownership when running 'yum update'

I'm running CentOS 6.2 and installed nginx as root. After the install I changed the owner and group of the install to it's own user and group to keep thing a bit more secure. I logged in as root and ...
4
votes
2answers
480 views

Group ID 501 cannot be found

A file in a directory has a Group ID "501" After checking /etc/group, Group ID "501" was not found how is that possible ?
2
votes
1answer
3k views

How do I set permissions for a directory so that files and directories created under it maintain group write permissions? [duplicate]

Possible Duplicate: Make all new files in a directory accessible to a group I have a directory in which collaborative files / directories are stored. Say directory abc is owned by root and ...
2
votes
5answers
13k views

What is the command for listing all users who are members of the admin group?

I am looking for the name of the superusers list on Fedora. (On Ubuntu is seems to be "sudo".) I want to add one of the users to the superusers list. The groups command only lists the groups of the ...