これでどうよ？
modify an existing user:
# usermod -g sftpusers -d /public_html -s /sbin/nologin moro

/etc/ssh/sshd_config 変更:
#Subsystem sftp /usr/libexec/openssh/sftp-server
Subsystem sftp internal-sftp
追加：
Match Group sftpusers
ChrootDirectory /home/%u
ForceCommand internal-sftp

Set the owenership:
# chown moro:sftpusers /home/moro/public_html
# chown root:root /home/moro/