chsh always asking a password , and get `PAM: Authentication failure`

Question

Today I tried to switch to another shell.

First I tried fish, and used chsh -s fish to change fish to default. After some time I found it cannot use ~/.bashrc (&& needs to be replaced by and).

Because I prefer to reusing ~/.bashrc, I found zsh which seems an easier one and followed this documentation to switch to zsh.

While I was running sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)", suddenly it asked me to enter Password:. I entered the root password but got PAM: Authentication failure.

Then I tried chsh -s bash and chsh -s zsh, it always asked me for a password and threw PAM: Authentication failure (not system password). I can't figure this out.

Check if you have an alias or something with sudo in your .bashrc/.zshrc/.etcrc — Lucas Serafim, Mar 01 '19 at 12:10
This is obviously a bug: I have to enter my password even as root, and the correct password still leads to a permission denied. Sudo must not be invoked when the user is already root. — Markus Bawidamann, Sep 01 '21 at 01:52

score 77 · Accepted Answer · edited Aug 25 '22 at 20:17

77

Thanks to this question on Server Fault, I worked around this by:

Replacing

auth       required   pam_shells.so

with

auth       sufficient   pam_shells.so

in /etc/pam.d/chsh.

Then it doesn't ask for a password anymore. But I think it better to restore chsh settings after switching the shell.

edited Aug 25 '22 at 20:17

Roj

105
5

answered Aug 15 '16 at 07:30

Mithril

2,191
3
21
30

4

using sed: sudo sed s/required/sufficient/g -i /etc/pam.d/chsh – ospider Jan 15 '19 at 02:28
Did unfortunately not work. But I commented that line out, changed the shell and removed the comment, again. So your hint was the right one for me. – Markus Zeller Jun 03 '19 at 06:26

score 32 · Answer 2 · edited Apr 12 '21 at 15:32

32

Try this:

sudo chsh -s $(which zsh) $(whoami)

edited Apr 12 '21 at 15:32

Grammargeek

2,762
2
14
24

answered Mar 24 '21 at 09:08

Roitmaster

321
3
2

2

this is the way – william_grisaitis Jul 02 '21 at 16:49
exactly what I was looking for! – igops Feb 10 '23 at 09:20

score 8 · Answer 3 · edited Sep 11 '17 at 08:50

8

Use which zshto find your zsh location.
```
$ which zsh
/usr/bin/zsh
```
Add /usr/bin/zsh to /etc/shells
Check in /etc/passwd that your config is /usr/bin/zsh
Run chsh -s /usr/bin/zsh

edited Sep 11 '17 at 08:50

Zanna

69,223
56
216
327

answered Sep 10 '17 at 23:11

Xu Radman

81
1
1

This only works for the normal user, but not for `root`. Is it a security feature? – Timo Jan 04 '20 at 07:40
1

could you expand on step 3 please, what if it isn't there? – baxx Aug 16 '20 at 12:51

score 3 · Answer 4 · answered Dec 09 '20 at 02:05

3

An alternate work around –

My /etc/pam.d/chsh file has this section:

# This allows root to change user shell without being
# prompted for a password
auth        sufficient  pam_rootok.so

As the comment suggests, it lets root change the shell without needing to product the password. As such I was able to change my shell (to zsh) by running chsh as root and specifying my user account, eg:

sudo chsh $USER -s $(which zsh)

answered Dec 09 '20 at 02:05

Molomby

131
2

For me, comment out this line: `# auth required pam_shells.so` , then run `chsh`, then uncomment that line back. – Eric Jan 31 '22 at 18:57

score 1 · Answer 5 · answered Nov 14 '20 at 23:32

1

Try adding at bottom of your $HOME/.bashrc

export SHELL=`which sh`
zsh
exit

This works for me! if you want you can put a welcome text in your shell, but you must install figlet using:

sudo apt install figlet

And overwrite the previous code at bottom of your $HOME/.bashrc

export SHELL=`which zsh`
figlet 'Your welcome message LIKE FOR ME: Welcome'
zsh
exit

answered Nov 14 '20 at 23:32

Alpha

11
3

1

nice, quick and easy. The first line where you export should be export SHELL=`which zsh` as in the second block, not which sh – melchi Aug 05 '22 at 05:28

score 1 · Answer 6 · answered Jan 30 '22 at 22:44

I had this issue when switching to fish. I accidentally executed chsh -s /usr/local/bin/fish while on my system it should have been chsh -s /usr/bin/fish, but even though the first command warned that the shell did not exist, it still changed it to /usr/local/bin/fish in /etc/passwd. This meant that the second, correct, command failed to authenticate (just like new SSH logins) as the shell did not exist.

The solution for me was to first correct the shell to an existing one in /etc/passwd, and then run the correct chsh command again.

score 0 · Answer 7 · edited Feb 10 '21 at 08:20

0

For those for whom the top two solutions did not work. I've found my solution here: https://askubuntu.com/a/950531/1168898

There is a workaround for gnome-terminal:

Go to Edit → Profile preferences → Title and Command.

Check Run a custom command instead of my shell.

Provide bash as the Custom command (or fish, or anything).

edited Feb 10 '21 at 08:20

BeastOfCaerbannog

12,964
10
49
77

answered Feb 09 '21 at 16:36

mailivres

1
1

score 0 · Answer 8 · answered Jan 31 '22 at 19:35

This is my solution:

grep -qxF "$(which zsh)" "/etc/shells" || sudo bash -c "echo $(which zsh) >> /etc/shells"
grep -qxF "$(which zsh)" "/etc/shells" && sudo chsh -s "$(which zsh)" "$(whoami)"

Check whether /etc/shells contains the zsh executable you want. If it doesn't, append it to the file.
If /etc/shells contains the shell you want, change your user's shell to that.

I have some parts abstracted into variables but for simplicity's sake, I included the full logic as plainly as possible.

score 0 · Answer 9 · answered Dec 24 '22 at 11:40

0

i had the same problem when i try to change my shell, what i did is go to your /etc/shells , find your user and than change the /bin/bash for what you want.

answered Dec 24 '22 at 11:40

Fabricio Villas Boas Rosa

1

chsh always asking a password , and get `PAM: Authentication failure`

9 Answers9

Linked