Problem when using SSH

codingfreak · #1 21st July 2009, 08:59 AM

Hi

I have a strange problem when I do SSH to a FEDORA9 based Linux Server.

Code:

$ ls -al /home/
total 68
drwxr-xr-x 16 root    root         4096 2009-07-21 09:30 .
drwxr-xr-x 22 root    root         4096 2009-07-21 08:36 ..
lrwxrwxrwx  1 root    root           25 2009-06-19 10:52 adah -> /media/disk-1/home/adah
lrwxrwxrwx  1 root    root           24 2009-06-19 10:45 ajsin -> /media/disk-1/home/ajsin
lrwxrwxrwx  1 root    root           25 2009-06-19 10:53 akhtam -> /media/disk-1/home/akhtam

As you see from the above information that symbolic links were created for accounts adah, akhtam and so on.

When I login using "adah" username in TELNET I am automatically directed to my home directory at location "/media/disk-1/home/adah".

But when I use SSH to login using the same username I get the following message

Code:

Could not chdir to home directory /home/adahaj: Permission denied

How can I rectify above problem ???

John5342 · #2 21st July 2009, 11:36 AM

SSH is very strict about the permissions and requirements of certain directories and files for security reasons. This includes no symlinks in the path.

What you should really do instead is instead of using symlinks mount the appropriate drive in the correct place. so mount /media/disk-1/home/adah as /home/adah and /media/disk-1/home/ajsin as /home/ajsin etc

If you dont have any other directories under /home/ then you would be even better mounting /media/disk-1/home as /home

Also the directories will probably have the wrong labels at the moment so once you have the mounts sorted you will probably want to as root 'touch /.autorelabel' and then reboot.

John5342 · #3 21st July 2009, 11:42 AM

Also another issue is that those directories have the wrong ownership. Each of the directories you listed should be owned by the appropriate user.

Code:

# chown adah:adah /home/adah
# chown ajsin:ajsin /home/ajsin
# chwon akhtam:ahhtam /home/akhtam

stevea · #4 21st July 2009, 12:28 PM

I don't know who started this rumor, but this has nothing to do with ssh. The only thing ssh cares about wrt to your home directory is that it exists. If the permissions are too lax it will ignore your authentication keys too, but it doesn't prevent login.

Ssh exec's a shell and the shell lacks permission to cd(chdir syscall) to that directory.

It's a clear permissions error. You can't chdir to a directory unless you (the user account) have 'x' search permission for that directory. You don't.

The home directory of each account should have directory owner and group-owner of that account and 700 permissions,, but this is NOT necessary for ssh to work correctly.

stevea · #5 21st July 2009, 12:36 PM

Quote:

Originally Posted by John5342

Also another issue is that those directories have the wrong ownership. Each of the directories you listed should be owned by the appropriate user.

Code:

# chown adah:adah /home/adah
# chown ajsin:ajsin /home/ajsin
# chwon akhtam:ahhtam /home/akhtam

John is leading you down another bad path here. The ownership and permission on these **symbolic links** DO NOT reflect the actual directory permissions.

You *may* need to do this:
chown adah:adah /media/disk-1/home/adah
chmod 700 /media/disk-1/home/adah

and so on, but we cannot say from your information. All we know is that user adah does not have 'x' (search) permission to /media/disk-1/home/adah.

Perhaps you should post the output of ls -l /media/disk-1 for comment.

codingfreak · #6 21st July 2009, 12:40 PM

Quote:

Originally Posted by John5342

Also another issue is that those directories have the wrong ownership. Each of the directories you listed should be owned by the appropriate user.

Code:

# chown adah:adah /home/adah
# chown ajsin:ajsin /home/ajsin
# chwon akhtam:ahhtam /home/akhtam

I have used "chown" command and changed for the user "adah"

Code:

$ ls -al /home/
total 68
drwxr-xr-x 16 root    root         4096 2009-07-21 09:30 .
drwxr-xr-x 22 root    root         4096 2009-07-21 08:36 ..
lrwxrwxrwx  1 adah  users          25 2009-06-19 10:52 adah -> /media/disk-1/home/adah

But still I get the "permission denied error" when I use SSH to login for the user "adah".

NOTE: I am getting "permission denied error" when I logged into server using SSH. Once logged in through SSH I am still able to access my home directory.

output of "ls -al /media/disk-1/home"

Code:

$ ls -al /media/disk-1/home
total 80
drwxr-xr-x 20 root     root  4096 2009-07-21 09:29 .
drwxr-xr-x  4 root     root  4096 2009-06-19 08:46 ..
drwx------ 32 adah   users 4096 2009-07-21 17:02 adah
drwx------  8 ajsin    users 4096 2009-07-15 16:08 ajsin
drwx------  4 akhtam   users 4096 2009-06-18 17:54 akhtam

stevea · #7 22nd July 2009, 10:29 AM

First, please give the complete and accurate error message. Is the error still referencing chdir ? No one can diagnose with only part of the error message.

Here is an example on my system. My home directory /home/stevea is a soft link to /home/xxx

Code:

[mdi@lycoperdon home]$ ls -ld /home/stevea /home/xxx
lrwxrwxrwx  1 root   root      3 2009-07-22 05:15 /home/stevea -> xxx
drwx------ 58 stevea stevea 4096 2009-07-22 05:14 /home/xxx
[mdi@lycoperdon home]$ ssh stevea@localhost
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
stevea@localhost's password: 
Last login: Wed Jul 22 05:15:23 2009 from localhost.localdomain
[stevea@lycoperdon ~]$ pwd
/home/stevea

So ssh is not the problem.

If I mess up the link ownership, as you have done then it still works.

Code:

[root@lycoperdon home]# ls -ld  /home/stevea /home/xxx
lrwxrwxrwx  1 stevea stevea    3 2009-07-22 05:28 /home/stevea -> xxx
drwx------ 58 stevea stevea 4096 2009-07-22 05:14 /home/xxx
[root@lycoperdon home]# ssh stevea@localhost
stevea@localhost's password: 
Last login: Wed Jul 22 05:19:44 2009 from localhost.localdomain

Cut and paste your exact error messages.

My *guess* is this. The files under /media/disk-1/adah are not owned by adah. If you did
ls -l /media/disk-1/adah
you should see this.

If this is the case then you may want to do
chown -R adah:user /media/disk-1/adah
to recursively change the ownership of all files in this directory.

codingfreak · #8 22nd July 2009, 10:43 AM

Quote:

Originally Posted by stevea

First, please give the complete and accurate error message. Is the error still referencing chdir ? No one can diagnose with only part of the error message.

Here is an example on my system. My home directory /home/stevea is a soft link to /home/xxx

Code:

[mdi@lycoperdon home]$ ls -ld /home/stevea /home/xxx
lrwxrwxrwx  1 root   root      3 2009-07-22 05:15 /home/stevea -> xxx
drwx------ 58 stevea stevea 4096 2009-07-22 05:14 /home/xxx
[mdi@lycoperdon home]$ ssh stevea@localhost
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
stevea@localhost's password: 
Last login: Wed Jul 22 05:15:23 2009 from localhost.localdomain
[stevea@lycoperdon ~]$ pwd
/home/stevea

Code:

$ ssh adah@localhost
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
adah@localhost's password: 
Last login: Wed Jul 22 15:05:38 2009 from 

WELCOME TO LINUX SERVER ....

Could not chdir to home directory /home/adah: Permission denied
[adah@localhost /]$ pwd
/
[adah@localhost /]$