I have chrooted sftp setup as below.
# Package generated configuration file # See the sshd_config(5) manpage for details # What ports, IPs and protocols we listen for Port 22 # Use these options to restrict which interfaces/protocols sshd will bind to #ListenAddress :: #ListenAddress 0.0.0.0 Protocol 2 # HostKeys for protocol version 2 HostKey /etc/ssh/ssh_host_rsa_key HostKey /etc/ssh/ssh_host_dsa_key #Privilege Separation is turned on for security UsePrivilegeSeparation yes # Lifetime and size of ephemeral version 1 server key KeyRegenerationInterval 3600 ServerKeyBits 768 # Logging SyslogFacility AUTH LogLevel INFO # Authentication: LoginGraceTime 120 PermitRootLogin without-password StrictModes yes AllowGroups admins clients RSAAuthentication yes PubkeyAuthentication yes #AuthorizedKeysFile %h/.ssh/authorized_keys # Don't read the user's ~/.rhosts and ~/.shosts files IgnoreRhosts yes # For this to work you will also need host keys in /etc/ssh_known_hosts RhostsRSAAuthentication no # similar for protocol version 2 HostbasedAuthentication no # Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication #IgnoreUserKnownHosts yes # To enable empty passwords, change to yes (NOT RECOMMENDED) PermitEmptyPasswords no # Change to yes to enable challenge-response passwords (beware issues with # some PAM modules and threads) ChallengeResponseAuthentication no # Change to no to disable tunnelled clear text passwords #PasswordAuthentication yes # Kerberos options #KerberosAuthentication no #KerberosGetAFSToken no #KerberosOrLocalPasswd yes #KerberosTicketCleanup yes # GSSAPI options #GSSAPIAuthentication no #GSSAPICleanupCredentials yes X11Forwarding yes X11DisplayOffset 10 PrintMotd no PrintLastLog yes TCPKeepAlive yes #UseLogin no #MaxStartups 10:30:60 #Banner /etc/issue.net # Allow client to pass locale environment variables AcceptEnv LANG LC_* #Subsystem sftp /usr/lib/openssh/sftp-server # Set this to 'yes' to enable PAM authentication, account processing, # and session processing. If this is enabled, PAM authentication will # be allowed through the ChallengeResponseAuthentication and # PasswordAuthentication. Depending on your PAM configuration, # PAM authentication via ChallengeResponseAuthentication may bypass # the setting of "PermitRootLogin without-password". # If you just want the PAM account and session checks to run without # PAM authentication, then enable this but set PasswordAuthentication # and ChallengeResponseAuthentication to 'no'. UsePAM yes Subsystem sftp internal-sftp Match group clients ChrootDirectory /var/chroot-home X11Forwarding no AllowTcpForwarding no ForceCommand internal-sftp
a dummy user
root:~# tail -n1 /etc/passwd david:x:1000:1001::/david:/bin/sh
Now in this case david can sftp using say filezilla client and he is chrooted to /var/chroot-home/david/. But what if i was to setup a passwordless auth? I have tried pasting his key in /var/chroot-home/david/.ssh/authorized_keys but no use, tried ssh'ing as david to the box and it just stops at "debug1: Sending env LC_CTYPE = C" after i supply it password and there is nothing shown in auth.log, may be because it can't find the homedir. If i do "su - david" as root i see "No directory, logging in with HOME=/" which makes sense. Symlink doesn't help either.
I have also tried with:
Match group clients ChrootDirectory /var/chroot-home/%u X11Forwarding no AllowTcpForwarding no ForceCommand internal-sftp
a dummy user
root:~# tail -n1 /etc/passwd david:x:1000:1001::/var/chroot-home/david:/bin/sh
This way if i don't change /var/chroot-home/david to root:root sshd complains about bad ownership or permission modes, and if i do, david can no longer upload/delete anything directly in his home while using sftp from filezilla.