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11
votes
3answers
3k views

How to check if a user can access a given file?

*nix user permissions are really simple, but things can get messy when you have to take in account all the parent directory access before reaching a given file. How can I check if the user has enough ...
7
votes
1answer
712 views

How to stop users from Switching to Root user

I have disabled the root user login from Sshd.conf file so now no one can login using root user even if they know the password SOMEHOW. Now I have 3 users in server ROOT,EMERG and ORACLE. I want to ...
6
votes
2answers
222 views

Restrict particular applications from accessing certain files

Normally the private files stored in the home directory of a user can be accessed by applications running with the effective UID of the user. How can I restrict a particular application from accessing ...
6
votes
4answers
2k views

When does chmod fail?

Under what circumstances will chmod fail? I looked at the man page but it only specifies usage and doesn't go into details about what circumstances it won't work in. I'd assume chmod will work if: ...
5
votes
2answers
319 views

Can a user brute-force a directory listing without having read permission on the directory?

I noticed that when a user is working in a directory to which he does not have read permission that using cd produces different error messages, depending on whether or not a subdirectory exists: $ ls ...
5
votes
1answer
1k views

How can I enable URL rewriting on a DD-WRT router?

I would like to be able to add a parameter to certain URL requests that go through my DD-WRT router. Specifically, I'm trying to figure out how to force safe search in Google, which means I have to ...
5
votes
1answer
443 views

How can I setup a wifi access point to only allow users if they accept an EULA?

I need to setup an access point to only allow users through if they first accept an EULA. To make things slightly simpler, I'm looking into doing this with a unix machine that shares the connection ...
5
votes
3answers
7k views

How can I block a specific URL on a DD-WRT router?

I've been looking everywhere for this. Does anyone know how to block a specific URL on a DD-WRT router? For example, I want to block website.com/whatever but not website.com, blah.website.com, or ...
4
votes
2answers
318 views

Password protecting a system file? (e.g. /etc/resolv.conf)

I am trying to parental control myself by restricting web access via OpenDNS. The OpenDNS account password will be handed to someone trustworthy. Now, I want to put some restriction on the ...
4
votes
1answer
56 views

allowing users to access certain ports on server

I have an RHEL 6 system which has 20 users. I have 20 ports on which separate versions of a service is running. I want user a to access port a, but not other ports. Is there a way to do this? ...
4
votes
1answer
176 views

Myth or reality: SELinux can confine the root user?

I read or heard somewhere (maybe in LinuxCBT's SELinux course; but I'm not sure) that there are online Linux servers, for which the password of the root user is also given. The Linux server is ...
3
votes
3answers
167 views

How to prohibit from changing an owner of modifiable files?

I sometimes need to run a Qt Creator from root. After that, some config files of Qt Creator suddenly have a root as an owner. Therefore when running Qt Creator as user, I am getting nag warnings about ...
3
votes
1answer
57 views

Can systemd do some setup before forking as a user?

Having written several small daemons or web applications for my personal use, I like to manage them using systemd (I am using Arch Linux, if that matters). So I write service files like the one below: ...
3
votes
1answer
107 views

Can I force myself to enter a password when run certain processes?

I frequently work in an environment where, lets call them "pranksters" may gain access to my console. I am diligent in locking my screen whenever I walk away, but given enough time someone gets the ...
3
votes
2answers
910 views

Chroot SFTP users who require access to multiple directories under same parent folder

I have a RHEL 6 server with a /Documents directory, and it has child directories 1 2 3 4 5.... right under the /Documents directory. Is it possible to create an SFTP chroot jail that only gives a ...
3
votes
1answer
2k views

Redirect linux serial console

I want to redirect my serial port while telnet session in linux. I have an embedded Linux box which is has a serial console. After I do a telnet to the box, I can type in both the serial console as ...
2
votes
4answers
2k views

Permissions to deny SSH users from accessing other user's folders

I am currently running Fedora on a network computer, acting as a host to other users who will SSH into my terminal to do their work. However I realised that they are also able to access my /home ...
2
votes
2answers
487 views

How to password-protect a script on Linux?

How do you set a password to execute a command or script in Linux? I need to avoid a script (in which user and password details are included) from being used/executed from unauthorized users. So is ...
2
votes
2answers
33 views

Specialized access control for directories in RedHat

I have a requirement where I want to change permissions for a directory so that the directory owner (user/group) would be able to create files inside the directory and modify them, but won't be able ...
2
votes
2answers
318 views

Add ssh user with minimum rights for backup [duplicate]

I have a small server running Debian and I want to add an account with SSH access for backups. The user of this account should have no console access. He can only transfer (backup) data via SCP ...
2
votes
1answer
66 views

Optimal way to setup user account / accesses?

I have a (home) Ubuntu machine; upon installation I created the "x" user during the installation (who is not the root) so often when I want to run apt-get or other things that require write access to ...
2
votes
1answer
183 views

Overwrite file and apply file system rights of overwritten files?

I backed up some linux configuration files to a windows machine, so the file system rights were lost. Now I would like to restore my backed up configuration by overwriting the configuration currently ...
2
votes
0answers
37 views

Easiest way to sandbox an user

I'd like to sandbox a user so that they can only read files under /media/shared/somefolder. What's the easiest way to accomplish this? Users/groups? ACL? AppArmor? Some context: Plex Media Server is ...
2
votes
0answers
36 views

Set list of applications allowed for execution by unprivileged user

I am working on a project of security enforced Linux-based system (kernel 2.6.32 + Gnome 2 + Centos package base mostly). We need to implement the restriction of execution of unallowed executables. ...
2
votes
0answers
65 views

CUPS and printer security

I would like some help on securing a networked printer. Specifically, I'm interested in the following: 1) Preventing unauthorized access to the printer: I would like only certain laptops that connect ...
1
vote
2answers
907 views

How to stop telnet access for a particular IP address?

How can I stop telnet access for a particular IP address on the command line?
1
vote
4answers
130 views

LD_PRELOAD or similar to warn user about modifications to a file?

I am running a (complex) script that seems to modify at some point a file. I would like to get warnings whenever the script / program tries to write, chmod, chown or perform any other attempt that I ...
1
vote
3answers
97 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
2answers
2k views

How to allow www-data to create a folder without giving read access to the parent folder

I'm not exactly sure the right question to ask, so I'll try to explain what I'm trying to do. I have an internal web application (in PHP) that I want to be able to create a folder. The trouble is ...
1
vote
2answers
41 views
+50

How to allow access to a directory and don't allow access to a sub-directory in Apache?‏

I have asked this question on apache mailing-list but I didn't get the answer I want. I want to allow a directory " /var/www/html/ldap" to two users according to IPs (192.168.1.2 192.168.1.7): ...
1
vote
1answer
55 views

How do I isolate my file system data from another system root?

I have a linux machine(kubuntu 13.04) A my friend asked me give him an account with being able to use sudo. So, I made an account for him and put the account in /etc/group for him to use sudo I don't ...
1
vote
1answer
152 views

Set up proper programming environment

I'm starting to think how to set up the most convenient environment for programming, with the following conditions. I run Linux Mint 14. I've got a computer at work but would like to have access to ...
1
vote
1answer
600 views

mousekeys is too slow in gnome3 fedora

Today I had to use mousekeys feature and tried it but it was very slow and unsusable, can I incerase the speed of my cursor while using mousekeys?
1
vote
2answers
26 views

What is “access control” with X Server?

What is an access control restriction with an X Server? There is the -ac option that "disable access control restrictions" with e.g. Xephyr. I saw some example using that option, but I have no idea ...
1
vote
0answers
23 views

How can I use iptables to block certain processes from accessing the network? [duplicate]

I can set the processes to run under special uid's and use the technique from this SF answer: -A OUTPUT -m owner --uid-owner 400 -j DROP ...But are there any other ways to blacklist based on the ...
1
vote
0answers
13 views

What forms of discretionary access control are there?

I know it's kind of an unguided question, but just so I have a broader sense of how things are I was interested in getting a reasonably complete list of discretionary access controls available on Unix ...
0
votes
2answers
85 views

Problem accessing an Apache-hosted folder

I'm running Centos 6.2, and Apache. I'm running into an error to do with access rights/permissions when trying to navigate to a webpage. I'm trying to go to the URL http://localhost/repos, but I get ...
0
votes
1answer
64 views

not able to login by ftp

I've installed vsftp and set the home directory of user ftp with sudo usermod -d /var/www/ ftp , I've also set the password with sudo passwd ftp and restarted the server but I can not login with user ...
0
votes
1answer
71 views

Removing access privileges to backup while maintaining current setup

I have a giant directory, and I am dealing with a backup. I would like to store this backup in as safe of a way as possible. One of the ways of doing that is removing rwx privileges through chmod. ...
0
votes
0answers
18 views

Permisison/Ownership issue with secondary FTP account

I have Centos 6.5 final. I have chroot setup and working properly and I also installed vsftpd. I now need to create a new user named extDeveloper and give this user access to a specific account. I ...
0
votes
0answers
59 views

How do i block USB devices based on device class in Linux

Problem Statement In windows server to provide access to USB devices are managed by GFI EndpointSecurity. Is there any open source tool in Linux which can do the same job. I want to block USB ...