superbox:/root>chsh Changing shell for root. New shell [/bin/ksh]: / Warning: "/" is not listed in /etc/shells Shell changed. superbox:/root>echo $? 0 superbox:/root>grep root /etc/passwd /root:x:0:0:root:/root:/ <----- ouch! operator:x:11:0:operator:/root:etc/passwd
chsh will accept whatever root tells it. It's allowing you to shoot yourself in the foot. chsh for normal users does limit them to /etc/shells.