LinuxQuestions.org
Latest LQ Deal: Latest LQ Deals
Home Forums Tutorials Articles Register
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Security
User Name
Password
Linux - Security This forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here.

Notices


Reply
  Search this Thread
Old 08-13-2004, 08:03 PM   #1
drolic
LQ Newbie
 
Registered: Aug 2004
Posts: 13

Rep: Reputation: 0
Angry sftp chroot jail, not able to find lib files


Im trying to create a chroot jail for an sftp server. I have the jail set up using this website.
I have created the jail and installed openssh3.8.1 with the patched tarball for the chroot on my RedHat 9 system

when i log in via psftp client using root i get the sftp server up and running like it should, but when i try and log in using my chroot'ed user the sftp-server is not starting, i think this is because it is not able to access the lib files it needs to execute, but they are in the chrooted jail where they should be

when i chroot to my chroot jail /sftp2/ root and try and start the sftpserver i get an error this
[root@localhost sftp2]# chroot /sftp2/ /bin/sh
sh-2.05b# /usr/local/libexec/sftp-server
/usr/local/libexec/sftp-server: error while loading shared libraries: libgssapi_krb5.so.2: cannot open shared object file: No such file or directory


i am including am including a cut and past of the ldd against /usr/local/libexe/sftp-server
and
ls -la /usr/kerberos/lib/libgss*
and
ls -la /sftp2/kerberos/lib/l*

since the right files seem to be in the right chrooted location i would think that
it should work

if anyone else has seen this plz give input

--------------------------------------------------------------------------------------------------
[root@localhost sftp2]# ls -la /usr/kerberos/lib/libgss*
-rw-r--r-- 1 root root 145482 Mar 6 2003 /usr/kerberos/lib/libgssapi_krb5.a
lrwxrwxrwx 1 root root 21 Oct 4 2003 /usr/kerberos/lib/libgssapi_krb5.so -> libgssapi_krb5.so.2.2
lrwxrwxrwx 1 root root 21 Oct 4 2003 /usr/kerberos/lib/libgssapi_krb5.so.2 -> libgssapi_krb5.so.2.2
-rwxr-xr-x 1 root root 73756 Mar 6 2003 /usr/kerberos/lib/libgssapi_krb5.so.2.2
-rw-r--r-- 1 root root 145518 Mar 6 2003 /usr/kerberos/lib/libgssrpc.a
lrwxrwxrwx 1 root root 16 Oct 4 2003 /usr/kerberos/lib/libgssrpc.so -> libgssrpc.so.3.0
lrwxrwxrwx 1 root root 16 Oct 4 2003 /usr/kerberos/lib/libgssrpc.so.3 -> libgssrpc.so.3.0
-rwxr-xr-x 1 root root 78336 Mar 6 2003 /usr/kerberos/lib/libgssrpc.so.3.0

[root@localhost sftp2]# ls -la /sftp2/usr/kerberos/lib/
total 548
drwxr-xr-x 2 root root 4096 Aug 13 19:25 .
drwxr-xr-x 3 root root 4096 Aug 13 19:25 ..
-rwxr-xr-x 1 root root 5572 Aug 13 19:25 libcom_err.so.3
-rwxr-xr-x 1 root root 73756 Aug 13 19:25 libgssapi_krb5.so.2
-rwxr-xr-x 1 root root 63880 Aug 13 19:25 libk5crypto.so.3
-rwxr-xr-x 1 root root 385220 Aug 13 19:25 libkrb5.so.3

[root@localhost sftp2]# ldd /usr/local/libexec/sftp-server
libresolv.so.2 => /lib/libresolv.so.2 (0x40029000)
libcrypto.so.4 => /lib/libcrypto.so.4 (0x4003b000)
libutil.so.1 => /lib/libutil.so.1 (0x4012c000)
libz.so.1 => /usr/lib/libz.so.1 (0x4012f000)
libnsl.so.1 => /lib/libnsl.so.1 (0x4013d000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x40152000)
libc.so.6 => /lib/tls/libc.so.6 (0x42000000)
libgssapi_krb5.so.2 => /usr/kerberos/lib/libgssapi_krb5.so.2 (0x40180000)
libkrb5.so.3 => /usr/kerberos/lib/libkrb5.so.3 (0x40193000)
libk5crypto.so.3 => /usr/kerberos/lib/libk5crypto.so.3 (0x401f1000)
libcom_err.so.3 => /usr/kerberos/lib/libcom_err.so.3 (0x40201000)
libdl.so.2 => /lib/libdl.so.2 (0x40203000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

[root@localhost sftp2]# chroot /sftp2/ /bin/sh

sh-2.05b# /usr/local/libexec/sftp-server
/usr/local/libexec/sftp-server: error while loading shared libraries: libgssapi_krb5.so.2: cannot open shared object file: No such file or directory
 
Old 08-13-2004, 08:09 PM   #2
drolic
LQ Newbie
 
Registered: Aug 2004
Posts: 13

Original Poster
Rep: Reputation: 0
sorry forgot to add the link
http://www.brandonhutchinson.com/chroot_ssh.html
this is the website i referanced while making my chroot jail
i used the script here to make my jail
 
Old 10-18-2005, 04:26 AM   #3
mmorrey
LQ Newbie
 
Registered: Oct 2005
Posts: 1

Rep: Reputation: 0
This is definitely my first, and probably my last ever (useful?) contribution to a Linux forum, but I have just suffered and got round exactly this problem.

Found a helpful entry which explained the use of the "strace" command to check what dependencies are being loaded at runtime. Turns out "ldd" cannot pick up all the dependencies. You an run "strace" in your normal environment, and in your chrooted environement (if you copy it across) and compare what is happening.

I don't really know what I'm doing, but this is what I did.

$ strace -eopen,stat,stat64,access /usr/libexec/openssh/sfp-server

The output included the line:

open("/etc/ld.so.cache", O_RDONLY) = 3

On a hunch, I copied /etc/ld.so.cache into my chroot jail, and guess what, it worked. I can now give access to my chrooted accounts via sftp and scp.

Someone more knowledgeable can hopefully explain why....

Martin
Intrallect: Learning Object Repository software

Last edited by mmorrey; 10-18-2005 at 04:28 AM.
 
Old 11-23-2005, 11:57 AM   #4
zoomzoom
Member
 
Registered: Aug 2003
Posts: 55

Rep: Reputation: 15
That was indeed useful! With this information, I was finally able spawn a fcgi-process with lighttpd! strace stated I forgot to copy /bin/sh to the chroot jail.

To cut a long story short: Thank you!
 
  


Reply



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
Chroot jail pachanga Linux - General 12 09-26-2008 05:15 AM
Jail and chroot rogk Linux - Security 2 10-16-2005 02:20 AM
chroot jail etc. f1uke Linux - Security 5 08-24-2005 03:12 AM
chroot jail sftp users f1uke Linux - Security 1 07-28-2003 10:29 AM
chroot jail simon Linux - Security 3 08-05-2001 08:21 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Security

All times are GMT -5. The time now is 07:27 PM.

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
Open Source Consulting | Domain Registration