A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name (and therefore normally not access) files outside the designated directory tree.

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27
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2answers
15k views

Getting “Not found” message when running a 32-bit binary on a 64-bit system

I have currently a strange problem on debian (wheezy/amd64). I have created a chroot to install a server (i can't give any more detail about it, sorry). Let's call its path /chr_path/. To make things ...
22
votes
3answers
20k views

Restricting an SSH/SCP/SFTP user to a directory

Is there a simple way to restrict an SCP/SFTP user to a directory? All methods that I've come across require me to set a chroot jail up by copying binaries, but I don't think that should be necessary. ...
20
votes
3answers
3k views

chroot “jail” - what is it and how do I use it?

I have heard/read a lot about the chroot jail under linux but have never yet used it (I use Fedora day-to-day), so what is a chroot "jail"? When and why might I use it/not use it and is there anything ...
20
votes
2answers
6k views

How do I tell I'm running in a chroot?

I have a unix installation that's supposed to be usable both as a chroot and as a standalone system. If it's running as a chroot, I don't want to run any service (cron, inetd, and so on), because they ...
17
votes
2answers
4k views

What to use to harden Linux box? Apparmor, SELinux, grsecurity, SMACK, chroot?

I am planning to go back to Linux as a Desktop machine. I would like to make it more secure. And try a few hardening techniques, especially since I plan to get my own server. What would be a good, ...
11
votes
1answer
4k views

How can I access a directory outside a chroot from within it?

I have a user which is chrooted to her home directory, but I want her to also be able to manage files within /var/www. As such, I did the following: root@server:/home/username# ln -s /var/www www ...
11
votes
4answers
56k views

How to create a FTP user with specific /dir/ access only on a Centos / linux installation

So I'm on a VPS - CentOS Linux installation. I have vsFTPd on the server. I currently have SFTP access to the server via my root user, but am now trying to create a new user with FTP access to a ...
10
votes
4answers
3k views

Lightweight isolated linux environment

I want an isolated (guest) Linux environment on my computer that I can mess up without worrying about the host. E.g. install a lot of stuff from source without package management, pollute environment ...
10
votes
4answers
12k views

How can I chroot into a filesystem with a different architechture?

I'm trying to chroot into a Arch Linux ARM filesystem from x86_64. I've seen that it's possible to do using static qemu by copying the binary into the chroot system: $ cp /usr/bin/qemu-arm ...
8
votes
2answers
366 views

Boot into a chroot?

I have Linux (Debian Jessie) installed on a hard drive. Drive - sda1, ext4fs, and sda2 - swap I have a /chroot folder. There is installed another system, in /chroot folder. Question: How to tell ...
7
votes
2answers
1k views

Providing /bin and /lib inside a chroot jail

I need to be able to provide the /bin and /lib directories inside a chroot jail so that programs can dynamically link properly. Is there a way to accomplish this without making a copy of the /bin and ...
6
votes
3answers
40k views

Limit FTP access only to the /var/www with vsftpd

I am running vsftpd as ftp server on my linux (rasbian), I log in to the machine as a root user. I would like to be still locked to using only /var/www, how can I configure vsftpd conf to accomplish ...
6
votes
4answers
887 views

Is there a pbuilder-like environment for RedHat?

I would like to know if is there any utility like Debian's pbuilder, to build RPM packages on RedHat using a clean environment (chroot). I've found mach which has support for something like this but ...
6
votes
3answers
426 views

Why are web servers traditionally started as superuser?

Thinking about a future web server setup, it struck me that for some reason web servers usually start as root and then drop certain rights (setuid) for the worker processes. In addition there is often ...
6
votes
2answers
327 views

Which of proc, sys etc. should be bind-mounted (or not) when chrooting into a “replacement” distribution?

This answer to another question basically boils down to chrooting into another Linux distribution in order to mainly use that as a replacement to its too restricted (but irreplaceable) parent. The ...
6
votes
1answer
2k views

chroot fails with --userspec when chroot is i686

I'm experiencing a problem with chroot... I'm running on Arch Linux x86_64. I have a 64 bit chroot and a 32 bit chroot. They are identical except that one is 32 bit and one is 64 bit. I can enter ...
5
votes
1answer
373 views

Why is it possible to leave CHROOT with this sftp config?

I'm trying to create the user lenny, that has read and write permissions in the folder /home/lenny/ and has no shell but only access via SFTP. I'm doing the following: useradd lenny mkdir /home/lenny ...
4
votes
2answers
4k views

How to unmount a formerly chroot'd filesystem?

I'm using a rescue-live-system (similar to a live-cd) to fix some issues with my Debian server, like that: # mkdir -p /mnt/rescue # mount /dev/md2 /mnt/rescue # mount --bind /dev /mnt/rescue/dev/ # ...
4
votes
1answer
3k views

deleting a 'file' under /proc or /dev

I am using a cowdancer/debootstrap setup to generate a chroot. Of course, as I iterate, I generate some chroot configurations that are bad. I have found myself in an awkward situation where I have ...
4
votes
3answers
6k views

What to do to run GUI Java app in chrooted environment?

In my case Java app is JDownloader. I prepared chroot environment as explained here: http://www.0x61.com/forum/post5240333.html#p5240333 and here: http://interreality.org/~reed/java-chroot.html ...
4
votes
3answers
2k views

Boot Linux system from a subdirectory on a partition?

I would like to try to set up a computer so that it has multiple Linux installs all in the same filesystem. For example, the filesytem would have 3 folders: /Ubuntu_Precise, /Ubuntu_Oneiric, and ...
4
votes
1answer
562 views

How to disable certain system calls for a given user?

I am creating a web app similar to codepad and for each run-action my app copies a directory (/home/radeks/voidptr/private/chroot-root) to /tmp/voidptr/[random-id]/chroot-root. This chroot directory ...
4
votes
2answers
112 views

Could you explain this “chroot” /tmp directory creation?

In the following linked article they explain how to create a "chroot" /tmp directory. I'm a bit confused by what they did. Could someone explain what the following commands are doing? Noexec and /tmp ...
4
votes
1answer
80 views

Automate chroot into broken system

Every time you have to mount a system with a live-boot-CD and chroot into the system to repair grub, you have to type so many lines to mount into the right partition: fdisk -l find the right ...
4
votes
1answer
344 views

Can you Chroot a program from an OpenVZ environment?

I just recently purchased a Virtual Private Server, and it is OpenVZ virtualization. I am setting up my LAMP stack, and in the past I have always just set up my BIND dns set up in a chrooted ...
4
votes
2answers
5k views

Disable direct login for normal users (like oracle) in linux but allow scp and sftp?

Is it possible to disable direct login for normal users (like oracle) in linux but allow scp and sftp for that use?
4
votes
2answers
110 views

How to prevent schroot from overridding passwd file and others files already present on the chrooted system?

When I had to repair my Debian system, I tried to use schroot due the convenience of not having to mount bind several partitions. But, contrary to my expectations, schroot decided to override my ...
4
votes
1answer
57 views

Seperate messages of multiple sshds in syslog-ng

Is there a common way of distinguishing between the messages of multiple processes in syslog-ng beside setting different facilities? +1 if filtering and therefore logging in different files would be ...
4
votes
1answer
2k views

How can I mount a directory of the host system for use inside a FreeBSD jail?

I am performing the following on FreeBSD 9.0-STABLE: mount_nullfs /foo /jail/foo After that, from within the host system, the mount works. So this works: touch /foo/bar && ls /jail/foo/bar ...
4
votes
2answers
575 views

How to rsync a chroot without breaking symlinks?

I'd like to rsync (backup) a chroot environment from outside the chroot. For that I first make a lvm snapshot of the chroot volume and then run rsync on that. The only problem with this approach: ...
4
votes
1answer
6k views

Chrooted SFTP with full access to SSH stopped working (Debian)

I've got a home server on Debian 6 for backups. I'd like to setup chrooted SFTP environment with SSH access for some users (only for my knowledge, there are two users now). It almost works or rather ...
4
votes
1answer
103 views

Real chroot on a systemd machine

I'm trying to get used to systemd, because it seems to be the way that Debian is going. I want to run Xorg in a chroot on hardware, rather than using networking (which seems to be the canonical way ...
4
votes
3answers
1k views

Restrict ssh login from LDAP to users who have a /home directory

I have an Apache server (RHEL 6) hosting multiple user web pages which currently is connected to my Active Directory environment to authenticate users. The server is used to automatically host content ...
4
votes
0answers
136 views

Unable to view mounted directories in a chroot [closed]

Here is a quick description of what I have done: I have a chrooted user (username: clientdev) which I have jailed inside their home directory. This chroot directory is /home/clientdev/ which is ...
4
votes
1answer
424 views

Simulate chroot with unshare

I am trying to write a bootstrapper for a minimal, from-source linux distribution. I would like to build in a chroot-like environment. This should simplify packaging. I do not care about security at ...
3
votes
1answer
949 views

When can one reboot from inside a chroot environment?

Sometimes when I chroot into some folder , I could use reboot to reset my box, but sometimes I can't. So I want to know why I could do that sometimes and why. UPDATE The chroot environment is ...
3
votes
3answers
907 views

Is there a drawback when using a chroot in high performance computing?

My (small) company uses an out-of-date linux (centos) software stack to run a proprietary software on a small cluster. Understandingly, IT is reluctant to upgrade since everything works now. I'd like ...
3
votes
1answer
1k views

Chroot debian squeeze for shell access

A user requires shell access to an Ubuntu server from the WAN side. There are many shell accounts with simple passwords. So shell port (port 22) is blocked in the firewall. For my WAN side user I am ...
3
votes
1answer
116 views

Error message: unknown user 'geoclue' in statoverride file

I obtained a strange error message inside a chroot: unknown user 'geoclue' in statoverride file when running apt-get install or apt-get upgrade. I use schroot to enter this chroot. I found that I ...
3
votes
2answers
194 views

chroot jail that can access the filesystem

chroot jails seem to be simply a different world, with no interaction with the actual filesystem. Thus, the entire environment has to be replicated inside the chroot, which would mean making a full ...
3
votes
2answers
268 views

replicate and isolating user environments on the fly

I will be using Ubuntu Linux for this project. For training of a particular application at a conference I need: To have each student be able to ssh into the same user account on a server Upon each ...
3
votes
1answer
111 views

chroot into a sshfs folder

I am trying to chroot into a sshfs-mounted directory: mkdir remoteroot sshfs remote:/ remoteroot/ sudo chroot remoteroot/ but I get chroot: cannot change root directory to remoteroot/: Permission ...
3
votes
1answer
10k views

How to restrict ssh users to browse only /home/%u contents

Can I confine my users to their /home/%u directory using only OpenSSH configuration? From instructions I found on the Internet, I stopped the SSH server and appended the following to the sshd_config ...
3
votes
3answers
605 views

Unabled to get rid of BIND 9 chroot

I had installed bind-chroot from yum not long ago, and saw that there were errors in the daily logs from named. Under further investigation, I noticed a directory loop. The named files resided under ...
3
votes
2answers
2k 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
2answers
3k views

getting 553 - cannot create file in vsftpd (ubuntu 12.04)

I'm trying to setup a ftp account for a user that has read/write access to one folder: /items/myuser I've set up the account with username 'myuser' in Linux with the adduser command. After that, I've ...
3
votes
1answer
301 views

Backing up chroots for host reinstall

I've had my workstation for a couple of years now and its slowly become a complex beast, taking on many roles for my dev and test work. I have done some research and was thinking of setting up some ...
3
votes
1answer
389 views

Are there any differences between mounting a /proc filesystem inside a chroot compared to mounting it from the outside?

Compare the following: mount -t proc none ./my_chroot/proc and: chroot ./mychroot mount -t proc none /proc
3
votes
2answers
95 views

How can I force chrooted programs to use a virtual ethernet device?

First off, this is not for security reasons, or for use in a production environment. It's because I want to mess around with different configuration management systems on relatively low-spec ...
3
votes
1answer
155 views

Backtrace of “git clone” running inside qemu-user-emulation based arm-chroot

I'm running a wheezy:armhf chroot using qemu user emulation on my jessie:x86_64 system. Somehow, a git clone on a particular private repository will hang inside the chroot, while succeed natively. ...