Jailed SFTP only share with chroot using mount –bind to share directory
1) Setup SSH jail in /etc/ssh/sshd_config
Match User JAILED_USER_NAME
ForceCommand internal-sftp
ChrootDirectory /jailed/directory
AllowTcpForwarding no
X11Forwarding no
2) Restart SSHD
systemctl restart sshd
3) Test
4) Setup dir share from somewhere else in filesystem using:
mount --bind /jailed/directory /somewhere/else
Remember that path to jailed dir must be owned by root and the share dir must be in a group that is writable by the jailed user. This will also only stick around till the next reboot, if you need something more permanent look into using fstab.