SlackBuildsOrg/network/mysecureshell

MySecureShell (sftp server based on OpenSSH's internal sftp-server)

MySecureShell is a replacement for the OpenSSH sftp-server subsystem that
offers advanced features such as jailing, group-based access controls,
and up/download limits.  The configuration file is easy to read and
resembles apache/ProFTPd.

After installing the package, add the following to your sshd_config,
commenting out the previous sftp entry if there was one:

Subsystem sftp /bin/MySecureShell -c sftp-server

and restart sshd (/etc/rc.d/rc.sshd restart)