Copiei tudo isso do Ubuntu para o Fedora e agora funciona:
unix password sync = yes
passwd program = passwd %u
passwd program = /usr/bin/passwd %u
workgroup = WORKGROUP
server string = %h server (Samba, Fedora)
dns proxy = no
syslog = 0
server role = standalone server
obey pam restrictions = yes
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
map to guest = bad user
usershare allow guests = yes