Arch Linux

deltasquared

Member

Registered: 2014-09-12

Posts: 12

Unable to login using mksh as shell

I recently decided that I wanted to try using the MirBSD korn shell (mksh) as my primary shell. It seems to do everything I needed, and it seemed a good idea considering the recent bash vulnerabilities (proving the man page's point about it being buggy!).

So, after finding the path to the binary using the which command (which of course spat out /usr/bin/mksh, but I like to check these things), I then ran

sudo chsh -s /usr/bin/mksh $user

to set my new shell, then logged out.

Upon attempting to log back in, my username+password combination (which has always worked fine) was rejected with "login incorrect".
I didn't believe this to be true, so I switched to tty12 (I have journald printing logs there) and there was a message there about "authentication failure".

rebooting didn't fix it (I had just pacman -Syu'd before this). I booted the Arch Live CD and changed my password from there, but upon rebooting, again my new password wasn't accepted.

Realising I would need my computer back, I decided to use the CD to change my user's shell back to the default of /bin/bash. Upon rebooting I could log in once again, without any sign of a hitch.

What gives? I'm not aware of changing a shell affecting the login, unless mksh does strange stuff, which I can't really test (because I don't know what to look for!).

Ideas, anyone?

ids1024

Member

From: California

Registered: 2013-08-16

Posts: 243

Website

Re: Unable to login using mksh as shell

Add mksh to /etc/shells.

---

"Only wimps use tape backup: _real_ men just upload their important stuff on ftp, and let the rest of the world mirror it."—Linus Torvalds
s/ftp/git/

https://iandouglasscott.com | https://github.org/ids1024 | https://keybase.io/ids1024

deltasquared

Member

Registered: 2014-09-12

Posts: 12

Re: Unable to login using mksh as shell

Huh, thanks for that. I know that chsh issues a warning for shells not in /etc/shells, but I didn't think that it would be cause to reject my login considering that I (the admin) set the shell to this anyway.
I've changed the shell to use /bin/mksh, as that is what is in /etc/shells. I found a bug entry related to this issue, and I agree with the comments there that the path names ought to be a little more consistent!