SSH client closes on non-root login

[Enrico Rovere]

DNS-320L, RC5, PuTTY.

I can't login to a SSH with anything but root and webUI password. When I try logging in as a configured user, the terminal window closes after entering the password. 

I'm not sure what I'm doing wrong here, can anyone help me? I'd rather not have my dad use SFTP as root.

Thanks in advance (:

[João Cardoso]

On Sunday, 15 January 2017 13:17:45 UTC, Enrico Rovere wrote:

DNS-320L, RC5, PuTTY.

I can't login to a SSH with anything but root and webUI password. When I try logging in as a configured user, the terminal window closes after entering the password. 

Generally that means that user home folder is not available. Examine the system log (System->Utilities, Logs)

[Enrico Rovere]

Jan 15 13:50:58 DNS-320L-032050 authpriv.info dropbear[880]: Exit (enrico): Error changing directory
Jan 15 13:50:58 DNS-320L-032050 authpriv.err dropbear[880]: chown /dev/pts/0 0 0 failed: Operation not permitted
Jan 15 13:50:58 DNS-320L-032050 authpriv.info dropbear[872]: Exit (enrico): Exited normally

I found this in the log,but I don't know what to do to fix the issue. Could you please point me in the right direction?

[João Cardoso]

I can't reproduce that.

Can you post more "dropbear" lines from the log?

Can "enrico" use telnet to login the box, instead of ssh (putty?)

And what is the output of

id enrico

grep enrico /etc/passwd

grep enrico /etc/group

ls -l /home

Can you create a dummy test user using the webUI, Setup->Users, and see if he can login?

[Enrico Rovere]

Can "enrico" use telnet to login the box, instead of ssh (putty?)

Still using putty to telnet on port 23. I can, but I get:

DNS-320L-032050 login: enrico

Password:

login: can't chdir to home directory '/home/Enrico'

$ whoami

enrico

 

Can you create a dummy test user using the webUI, Setup->Users, and see if he can login?

Created another user, 'maurizio', same thing.

Jan 15 23:29:44 DNS-320L-032050 authpriv.info dropbear[755]: Child connection from $PUBLICIP
Jan 15 23:29:50 DNS-320L-032050 authpriv.notice dropbear[755]: Password auth succeeded for 'maurizio' from $PUBLICIP
Jan 15 23:29:50 DNS-320L-032050 authpriv.info dropbear[758]: Exit (maurizio): Error changing directory
Jan 15 23:29:50 DNS-320L-032050 authpriv.err dropbear[758]: chown /dev/pts/0 0 0 failed: Operation not permitted 

Jan 15 23:29:50 DNS-320L-032050 authpriv.info dropbear[755]: Exit (maurizio): Exited normally 

Also:

[root@DNS-320L-032050]# id enrico

uid=1000(enrico) gid=100(users) groups=100(users),34(backup)

[root@DNS-320L-032050]# grep enrico /etc/passwd

enrico:x:1000:100:Enrico:/home/Enrico:/bin/sh

[root@DNS-320L-032050]# grep enrico /etc/group

backup:x:34:enrico,maurizio

users:x:100:enrico,maurizio

[root@DNS-320L-032050]# ls -l home

ls: home: No such file or directory

[Enrico Rovere]

I renamed the disks SDA and SDB when I configured the box, could it be relevant?

[João Cardoso]

So, users don't have a home directory, they can't login.

A 'Users' folder should have been created by the webUI first login wizard in the base of the specified filesystem, and each created user has a directory with its Real Name there.  When the "Users" is found at disk discovery/mount time, it is mapped to /home:

[root@dns-323]# ls -l /home

lrwxrwxrwx    1 root     root            15 Jan 10 19:10 /home -> /mnt/sda2/Users

 

[root@dns-323]# ls -l //mnt/sda2/Users

total 16

drwxr-xr-x    4 root     root          4096 Jun 25  2016 .

drwxr-xr-x    8 root     root          4096 Jan 10 19:11 ..

drwx--s--x    2 jcard    users         4096 Jan 15 18:51 Joao Cardoso

drwx--s--x    2 manulima users         4096 Dec 16 20:37 Manuela Lima

So, whatever happened it has to do with your renaming. What exactly have you done?

You cant rename disks, only give a label to a filesystem, which changes the "mountpoint", i.e., a filesystem is mounted at /mnt/filesystem_device_name, such as /mnt/sda2, or /mnt/filesystem_label, such as /mnt/Videos; a folder named "Users" must exists at the base of one filesystem, e.g. /mnt/sda2/Users

Have you already save settings and rebooted after the renaming? The discovery is done at boot time.

[Enrico Rovere]

So, users don't have a home directory, they can't login.

A 'Users' folder should have been created by the webUI first login wizard in the base of the specified filesystem, and each created user has a directory with its Real Name there.  When the "Users" is found at disk discovery/mount time, it is mapped to /home:

[root@dns-323]# ls -l /home

lrwxrwxrwx    1 root     root            15 Jan 10 19:10 /home -> /mnt/sda2/Users

 

[root@dns-323]# ls -l //mnt/sda2/Users

total 16

drwxr-xr-x    4 root     root          4096 Jun 25  2016 .

drwxr-xr-x    8 root     root          4096 Jan 10 19:11 ..

drwx--s--x    2 jcard    users         4096 Jan 15 18:51 Joao Cardoso

drwx--s--x    2 manulima users         4096 Dec 16 20:37 Manuela Lima

So, whatever happened it has to do with your renaming. What exactly have you done?

You cant rename disks, only give a label to a filesystem, which changes the "mountpoint", i.e., a filesystem is mounted at /mnt/filesystem_device_name, such as /mnt/sda2, or /mnt/filesystem_label, such as /mnt/Videos; a folder named "Users" must exists at the base of one filesystem, e.g. /mnt/sda2/Users

Have you already save settings and rebooted after the renaming? The discovery is done at boot time.

Sorry, I meant I set a label for the left and right disks, SDA and SDB, respectively, using the WebUI. From my prospective, everything is mounted correctly, at /mnt/SDA and /mnt/SDB. 

A folder for each user is created correctly under /mnt/SDA/Users. I already saved and rebooted the box multiple times, since I did this change a while back.

Here's the folder structure:

[root@DNS-320L-032050]# cd /mnt
[root@DNS-320L-032050]# ls -l
total 8
drwxr-xr-x 7 root root 4096 Jan 15 10:42 SDA
drwxr-xr-x 5 root root 4096 Jan 15 10:42 SDB
[root@DNS-320L-032050]# cd /mnt/SDA
[root@DNS-320L-032050]# ls -l
total 132
drwxr-xr-x 9 root root 4096 Jan 15 13:37 Alt-F
drwxr-xr-x 2 root root 4096 Dec 12 19:13 Logs
dr-xr-xr-x 4 root root 4096 Dec 2 10:08 Public
drwxr-xr-x 4 root root 4096 Jan 15 13:36 Users
-rw-rw-rw- 1 root root 48363 Jan 15 10:42 alt-f.log
-rw-rw-rw- 1 root root 48487 Jan 11 12:04 alt-f.log-previous
drwx------ 2 root root 16384 Dec 2 10:07 lost+found
-rwxr--r-- 1 root root 332 Dec 6 23:46 user.sh

Sorry for all the trouble.

[João Cardoso]

You missed looking at what is under /mnt/SDA/Users, users directories (named after their real names, not their nick name) should be found there, with the correct ownership and permissions, that's why I show you what I find in my system.

login: can't chdir to home directory '/home/Enrico'

Does /mnt/SDA/Users/Enrico exists? belonging to 'enrico' (Enrico nick name)?

It is also possible that the Users directory has not been detected, you can see that at /var/log/hot_aux.log. In my log, I can see

hot_aux: Start  fscking sda4

hot_aux: Users directory found in sda2

hot_aux: Public directory found in sda2

and then a link should automatically be created to it:

[root@dns-323]# ls -l /home

lrwxrwxrwx    1 root     root            15 Jan 10 19:10 /home -> /mnt/sda2/Users

So, you need to check

-that each user directory is found under /mnt/SDA/Users/

-that it was discovered in hot_aux.log

-the link from /home to  /mnt/SDA/Users exists.

please post the output of:

ls -l / /mnt/SDA/Users/

Sorry for all the trouble.

No problem 

[Enrico Rovere]

Does /mnt/SDA/Users/Enrico exists? belonging to 'enrico' (Enrico nick name)?

root@DNS-320L-032050]# cd /mnt/SDA/Users

[root@DNS-320L-032050]# ls -l

total 8

drwx--s--x   17 enrico   users         4096 Jan  9 19:15 Enrico

drwx--s--x    2 maurizio users         4096 Jan 15 13:36 Maurizio

I believe it does, and I believe it's got the right permissions, since I can correctly access the relative Samba share from Windows, using 'Enrico' 's credentials. Still:

[root@DNS-320L-032050]# ls -l /home

ls: /home: No such file or directory

It is also possible that the Users directory has not been detected, you can see that at /var/log/hot_aux.log. In my log, I can see

hot_aux: Start  fscking sda4

hot_aux: Users directory found in sda2

hot_aux: Public directory found in sda2

and then a link should automatically be created to it:

[root@dns-323]# ls -l /home

lrwxrwxrwx    1 root     root            15 Jan 10 19:10 /home -> /mnt/sda2/Users

 

Here's the content of hot_aux.log:

DATE=Sun Jan 15 10:42:22 CET 2017
USER=root
HOME=/
OLDPWD=/
MDEV=sda2
TERM=vt102
SUBSYSTEM=sda
PATH=/sbin:/usr/sbin:/bin:/usr/bin
SHELL=/bin/sh
PWD=/dev
hot_aux: Start  fscking sda2
hot_aux: Finish fscking sda2: fsck 1.41.14 (22-Dec-2010)
SDA: clean, 47767/122068992 files, 306956579/488246928 blocks
hot_aux: Users directory found in SDA

DATE=Sun Jan 15 10:42:23 CET 2017
USER=root
HOME=/
OLDPWD=/
MDEV=sdb2
TERM=vt102
SUBSYSTEM=sdb
PATH=/sbin:/usr/sbin:/bin:/usr/bin
SHELL=/bin/sh
PWD=/dev
hot_aux: Start  fscking sdb2
hot_aux: Public directory found in SDA
hot_aux: Alt-F directory found in SDA
hot_aux: Finish fscking sdb2: fsck 1.41.14 (22-Dec-2010)
SDB: clean, 217214/122068992 files, 388147116/488246928 blocks
hot_aux: Backup directory found in SDB
hot_aux: Alt-F directory found in SDB but not used, as file NOAUFS exists on it.
hot_aux: Executing "/mnt/SDB/user.sh start" in background
Downloading https://downloads.sourceforge.net/project/alt-f/pkgs/stable/Packages
Updated list of available packages in /usr/lib/ipkg/lists/feed_1
Downloading https://downloads.sourceforge.net/project/alt-f/pkgs/unstable/Packages
Updated list of available packages in /usr/lib/ipkg/lists/feed_2
Successfully terminated.
hot_aux: Restarting transmission-daemon: 
Stopping transmission-daemon: OK.
Starting transmission-daemon: OK.

[João Cardoso]

On Monday, 16 January 2017 18:43:25 UTC, Enrico Rovere wrote:

Does /mnt/SDA/Users/Enrico exists? belonging to 'enrico' (Enrico nick name)?

root@DNS-320L-032050]# cd /mnt/SDA/Users

[root@DNS-320L-032050]# ls -l

total 8

drwx--s--x   17 enrico   users         4096 Jan  9 19:15 Enrico

drwx--s--x    2 maurizio users         4096 Jan 15 13:36 Maurizio

That's OK, the Users folder exists and has the users home folders with the correct permissions and ownership.

 

I believe it does, and I believe it's got the right permissions, since I can correctly access the relative Samba share from Windows, using 'Enrico' 's credentials. Still:

[root@DNS-320L-032050]# ls -l /home

ls: /home: No such file or directory

This should exists, it should be created by hot_aux.sh when the Users folder is discovered. This is the reason why login fails.

It is also possible that the Users directory has not been detected, you can see that at /var/log/hot_aux.log. In my log, I can see

hot_aux: Start  fscking sda4

hot_aux: Users directory found in sda2

 

hot_aux: Public directory found in sda2

and then a link should automatically be created to it:

[root@dns-323]# ls -l /home

lrwxrwxrwx    1 root     root            15 Jan 10 19:10 /home -> /mnt/sda2/Users

 

Here's the content of hot_aux.log:

DATE=Sun Jan 15 10:42:22 CET 2017
USER=root
HOME=/
OLDPWD=/
MDEV=sda2
TERM=vt102
SUBSYSTEM=sda
PATH=/sbin:/usr/sbin:/bin:/usr/bin
SHELL=/bin/sh
PWD=/dev
hot_aux: Start  fscking sda2
hot_aux: Finish fscking sda2: fsck 1.41.14 (22-Dec-2010)
SDA: clean, 47767/122068992 files, 306956579/488246928 blocks
hot_aux: Users directory found in SDA

OK, hot_aux.sh founds it and the /home link should be created linking to it.

 

DATE=Sun Jan 15 10:42:23 CET 2017
USER=root
HOME=/
OLDPWD=/
MDEV=sdb2
TERM=vt102
SUBSYSTEM=sdb
PATH=/sbin:/usr/sbin:/bin:/usr/bin
SHELL=/bin/sh
PWD=/dev
hot_aux: Start  fscking sdb2
hot_aux: Public directory found in SDA
hot_aux: Alt-F directory found in SDA

Now, if a /mnt/SDA/Alt-F/home (or /Alt-F/home)  *folder* exists here or a link named 'home' has been every deleted here, things might fail.

Please post the output of the command

ls -la /Alt-F

to confirm the existence (or not) of a 'home' folder or link.

I think that you can recover by executing the command

ln -s /mnt/SDA/Users /home

Please post its output. If that succeeds without error messages, you should be able to login as a normal user

For diagnose please post also the again the output of:

ls -l /

ls -la /Alt-F

I still don't know what the issue cause is, perhaps direct manipulation of the Alt-F folder by you? Please read the /Alt-F/README.txt file.

 

hot_aux: Finish fscking sdb2: fsck 1.41.14 (22-Dec-2010)
SDB: clean, 217214/122068992 files, 388147116/488246928 blocks
hot_aux: Backup directory found in SDB
hot_aux: Alt-F directory found in SDB but not used, as file NOAUFS exists on it.

You have a non-active folder Alt-F folder in SDB, the one from SDA is being used as it is found earlier. There is no harm, but if you don't need the SDB one it you can delete it (Packages->Alt-F, "Packages Installed On" section)

[Enrico Rovere]

I think that you can recover by executing the command

ln -s /mnt/SDA/Users /home

Please post its output. If that succeeds without error messages, you should be able to login as a normal user

For diagnose please post also the again the output of:

ls -l /

ls -la /Alt-F

I ran:

[root@DNS-320L-032050]# ln -s /mnt/SDA/Users /home

[root@DNS-320L-032050]# ls -l /

total 41

lrwxrwxrwx    1 root     root            14 Jan 15 10:42 Alt-F -> /mnt/SDA/Alt-F

lrwxrwxrwx    1 root     root            15 Jan 15 10:42 Backup -> /mnt/SDB/Backup

-rw-r--r--    1 root     root         15122 Mar 18  2015 COPYING

-rw-r--r--    1 root     root           329 Apr 19  2016 LICENSE

-rw-r--r--    1 root     root           126 Jan 15 10:42 README.txt

drwxr-xr-x    2 root     root           973 Jun 25  2016 bin

drwxr-xr-x    2 root     root             3 Jun 17  2016 boot

drwxr-xr-x    3 root     root          1700 Jan 16 19:38 dev

drwxr-xr-x   29 root     root          4096 Jan 17 02:26 etc

lrwxrwxrwx    1 root     root            14 Jan 17 17:49 home -> /mnt/SDA/Users

-rwxr-xr-x    1 root     root          5343 Dec 20  2015 init

drwxr-xr-x    2 root     root           596 Jun 25  2016 lib

drwxr-xr-x    4 root     root            80 Jan 15 10:42 mnt

drwxr-xr-x    2 root     root          4096 Dec 10 15:59 opt

dr-xr-xr-x   63 root     root             0 Jan  1  1970 proc

drwxr-x---    2 root     root           100 Jan 17 02:26 root

drwxrwxrwt    5 root     root           100 Jan  1  1970 rootmnt

drwxr-xr-x    2 root     root           760 Jan 15 10:42 sbin

dr-xr-xr-x   11 root     root             0 Jan  1  1970 sys

drwxrwxrwt   11 root     root           340 Jan 17 17:45 tmp

drwxr-xr-x   22 root     root          4096 Jul  4  2016 usr

drwxr-xr-x    3 root     root          4096 Dec  2 10:13 var

[root@DNS-320L-032050]# ls -la /Alt-F

lrwxrwxrwx    1 root     root            14 Jan 15 10:42 /Alt-F -> /mnt/SDA/Alt-F

I'm now able to login as both 'enrico' and 'maurizio', both via SSH and telnet.

login as: enrico

enrico@$DOMAIN's password:

$ whoami

enrico

You have a non-active folder Alt-F folder in SDB, the one from SDA is being used as it is found earlier. There is no harm, but if you don't need the SDB one it you can delete it (Packages->Alt-F, "Packages Installed On" section)

Yes, I originally had packages installed on SDB, then I moved them to SDA. I now deleted the SDB folder via the WebUI.

Not being a Linux expert, I assume /home and /mnt/SDA/Users were not symlinked as expected, and creating a link fixed the issue. I already tried rebooting the box, and I can still login fine. I'm sure I didn't touch the contents of /Alt-F, so I can't tell what caused the issue. Do I need to do anything else?

[João Cardoso]

Yes. But to know why it was not created you had to run the 'ls -la /Alt-F' command before creating the symlink.

The symlink is always automatically created when the Users folder is find at boot time, and I would like to know why did that failed for you before.

and creating a link fixed the issue. I already tried rebooting the box, and I can still login fine. I'm sure I didn't touch the contents of /Alt-F,

You might not done that intentionally, but if you have defined SDA to be a network share the Alt-F folder will then appear when browsing.

 

so I can't tell what caused the issue.

 

Do I need to do anything else?

If you have already rebooted and are able to ssh/telnet login as a normal user without issues, you are OK.

 

[Enrico Rovere]

Yes. But to know why it was not created you had to run the 'ls -la /Alt-F' command before creating the symlink.

The symlink is always automatically created when the Users folder is find at boot time, and I would like to know why did that failed for you before.

 

I understand. I ran the commands on mobile, and didn't save the log for that part. I'm quite sure no /Alt-F/home was present, but again, I can't prove it.

 

You might not done that intentionally, but if you have defined SDA to be a network share the Alt-F folder will then appear when browsing.

Only the folders relative to the users are being shared on the network, so I'd rule that option out as well. Being my first NAS, I naively believed a user couldn't use SSH, so I used root for a while, and I'm convinced I've never been able to log in as a non-root user. 

 

If you have already rebooted and are able to ssh/telnet login as a normal user without issues, you are OK.

Thank you very much for your patience, and for your great firmware. If I ever come across anything that could be useful to find out why this happened, I'll update this thread.