proftpd

configure proftpd to serve ftp and sftp simultaneously

Using Ubuntu 18.04 LTS and ProFTPD 1.3.5e.

I have ProFTPD serving FTP on ports 20, 21 and running just fine.

When I add in /etc/proftpd/conf.d/sftp.conf, FTP quits working. When I delete the sftp.conf and restart proftpd, FTP starts working again. I conclude that there is something wrong with this conf file.

Also, I want sftp to accept just a login id and password for authentication. How do I do that? I have looked at the SFTPAuthMethods directive and it looks like if I leave it out then it will allow all authentication methods and that is okay with me.

Here is the sftp.conf file:

<IfModule mod_sftp.c>

        SFTPEngine on
        Port 2222
        SFTPLog /var/log/proftpd/sftp.log

        # Configure both the RSA and DSA host keys, using the same host key
        # files that OpenSSH uses.
        SFTPHostKey /etc/ssh/ssh_host_rsa_key
        SFTPHostKey /etc/ssh/ssh_host_dsa_key

        SFTPAuthorizedUserKeys file:/etc/proftpd/authorized_keys/%u

        # Enable compression
        SFTPCompression delayed

</IfModule>

What should I change to get SFTP running on port 2222 and continue to have FTP running on ports 20 & 21?

Thanks in advance!

Update:

Based on the excellent feedback I have received in the notes, instead of using the sftp.conf file I have above, I added a wrapper and some other configuration parameters and have put that config into the proftpd.conf file. It reads as follows:

<snip>

 <IfModule mod_sftp.c>
    <VirtualHost 0.0.0.0>
      # The SFTP configuration

        SFTPEngine on
        Port 2222
        SFTPLog /var/log/proftpd/sftp.log
        Include /etc/proftpd/sql.conf

        SFTPAuthMethods password keyboard-interactive hostbased publickey

        # Configure both the RSA and DSA host keys, using the same host key
        # files that OpenSSH uses.
        SFTPHostKey /etc/ssh/ssh_host_rsa_key
        SFTPHostKey /etc/ssh/ssh_host_dsa_key

        SFTPAuthorizedUserKeys file:/etc/proftpd/authorized_keys/%u

        # Enable compression
        SFTPCompression delayed
    </VirtualHost>
  </IfModule>

So now the server is answering on FTP ports normally and on port 2222. When I attempt to connect to port 2222 using WinSCP, it fails authentication. Here is the sftp.log file snipped that is generated each time I try to connect. 

2020-04-21 21:03:50,340 mod_sftp/0.9.9[13017]: sent server version 'SSH-2.0-mod_sftp/0.9.9'
2020-04-21 21:03:50,355 mod_sftp/0.9.9[13017]: received client version 'SSH-2.0-WinSCP_release_5.17.3'
2020-04-21 21:03:50,355 mod_sftp/0.9.9[13017]: handling connection from SSH2 client 'WinSCP_release_5.17.3'
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session key exchange: ecdh-sha2-nistp256
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session server hostkey: ssh-rsa
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session client-to-server encryption: aes256-ctr
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session server-to-client encryption: aes256-ctr
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session client-to-server MAC: hmac-sha2-256
2020-04-21 21:03:51,284 mod_sftp/0.9.9[13017]:  + Session server-to-client MAC: hmac-sha2-256
2020-04-21 21:03:51,285 mod_sftp/0.9.9[13017]:  + Session client-to-server compression: none
2020-04-21 21:03:51,285 mod_sftp/0.9.9[13017]:  + Session server-to-client compression: none
2020-04-21 21:03:51,957 mod_sftp/0.9.9[13017]: sending acceptable userauth methods: password,keyboard-interactive,hostbased,publickey
2020-04-21 21:03:52,302 mod_sftp/0.9.9[13017]: expecting USER_AUTH_INFO_RESP message, received SSH_MSG_IGNORE (2)
2020-04-21 21:03:52,322 mod_sftp_pam/0.3[13017]: PAM authentication error (7) for user 'test': Authentication failure

For FTP, I am authenticating successfully from a MySQL database. But the last line of the sftp.log file says that PAM authentication failed for my SFTP attempt. I am just trying to authenticate in the WinSCP client with a login and password that come from MySQL. Does that involve PAM authentication?

I think I am getting close!

Thanks in advance!

Solution

  • Here is the full /etc/proftpd/proftpd.conf that accomplishes my goals as stated above.

    Note that I am also using mod_sql to provide for authentication via MySQL. So there are other configuration files referenced by this config file but are not listed in this posting.

    # cat /etc/proftpd/proftpd.conf



# /etc/proftpd/proftpd.conf -- This is a basic ProFTPD configuration file.
# To really apply changes, reload proftpd after modifications, if
# it runs in daemon mode. It is not required in inetd/xinetd mode.
#

# Includes DSO modules
Include /etc/proftpd/modules.conf

# Set off to disable IPv6 support which is annoying on IPv4 only boxes.
UseIPv6                         on
# If set on you can experience a longer connection delay in many cases.
IdentLookups                    off

ServerName                      "hostname"
# Set to inetd only if you would run proftpd by inetd/xinetd.
# Read README.Debian for more information on proper configuration.
ServerType                      standalone
DeferWelcome                    off

MultilineRFC2228                on
DefaultServer                   on
ShowSymlinks                    on

TimeoutNoTransfer               600
TimeoutStalled                  600
TimeoutIdle                     1200

DisplayLogin                    welcome.msg
DisplayChdir                    .message true
ListOptions                     "-l"

DenyFilter                      \*.*/

# Use this to jail all users in their homes
DefaultRoot                     ~

# This line will create the user directories of an FTP user if they successfully authenticate but do not have a user directory.
# See http://www.proftpd.org/docs/howto/CreateHome.html
# CreateHome off|on [<mode>] [skel <path>] [dirmode <mode>] [uid <uid>] [gid <gid>] [homegid <gid>] [NoRootPrivs]
CreateHome                      on dirmode 750

# Users require a valid shell listed in /etc/shells to login.
# Use this directive to release that constrain.
RequireValidShell               off

# Port 21 is the standard FTP port.
Port                            21

# In some cases you have to specify passive ports range to by-pass
# firewall limitations. Ephemeral ports can be used for that, but
# feel free to use a more narrow range.
# PassivePorts                  49152 65534

# If your host was NATted, this option is useful in order to
# allow passive transfers to work. You have to use your public
# address and opening the passive ports used on your firewall as well.
# MasqueradeAddress             1.2.3.4

# This is useful for masquerading address with dynamic IPs:
# refresh any configured MasqueradeAddress directives every 8 hours
<IfModule mod_dynmasq.c>
# DynMasqRefresh 28800
</IfModule>

# To prevent DoS attacks, set the maximum number of child processes
# to 30.  If you need to allow more than 30 concurrent connections
# at once, simply increase this value.  Note that this ONLY works
# in standalone mode, in inetd mode you should use an inetd server
# that allows you to limit maximum number of processes per service
# (such as xinetd)
MaxInstances                    50

# Set the user and group that the server normally runs at.
User                            proftpd
Group                           nogroup

# Umask 022 is a good standard umask to prevent new files and dirs
# (second parm) from being group and world writable.
Umask                           022  022
# Normally, we want files to be overwriteable.
AllowOverwrite                  on

# Uncomment this if you are using NIS or LDAP via NSS to retrieve passwords:
# PersistentPasswd              off

# This is required to use both PAM-based authentication and local passwords
# AuthOrder                     mod_auth_pam.c* mod_auth_unix.c

# Be warned: use of this directive impacts CPU average load!
# Uncomment this if you like to see progress and transfer rate with ftpwho
# in downloads. That is not needed for uploads rates.
#
# UseSendFile                   off

TransferLog /var/log/proftpd/xferlog
SystemLog   /var/log/proftpd/proftpd.log

# Logging onto /var/log/lastlog is enabled but set to off by default
#UseLastlog on

# In order to keep log file dates consistent after chroot, use timezone info
# from /etc/localtime.  If this is not set, and proftpd is configured to
# chroot (e.g. DefaultRoot or <Anonymous>), it will use the non-daylight
# savings timezone regardless of whether DST is in effect.
#SetEnv TZ :/etc/localtime

<IfModule mod_quotatab.c>
QuotaEngine off
</IfModule>

<IfModule mod_ratio.c>
Ratios off
</IfModule>


# Delay engine reduces impact of the so-called Timing Attack described in
# http://www.securityfocus.com/bid/11430/discuss
# It is on by default.
<IfModule mod_delay.c>
DelayEngine on
</IfModule>

<IfModule mod_ctrls.c>
ControlsEngine        off
ControlsMaxClients    2
ControlsLog           /var/log/proftpd/controls.log
ControlsInterval      5
ControlsSocket        /var/run/proftpd/proftpd.sock
</IfModule>

<IfModule mod_ctrls_admin.c>
AdminControlsEngine off
</IfModule>

#
# Alternative authentication frameworks
#
#Include /etc/proftpd/ldap.conf
Include /etc/proftpd/sql.conf

#
# This is used for FTPS connections
#
#Include /etc/proftpd/tls.conf

#
# Useful to keep VirtualHost/VirtualRoot directives separated
#
#Include /etc/proftpd/virtuals.conf

# A basic anonymous configuration, no upload directories.

# <Anonymous ~ftp>
#   User                                ftp
#   Group                               nogroup
#   # We want clients to be able to login with "anonymous" as well as "ftp"
#   UserAlias                   anonymous ftp
#   # Cosmetic changes, all files belongs to ftp user
#   DirFakeUser on ftp
#   DirFakeGroup on ftp
#
#   RequireValidShell           off
#
#   # Limit the maximum number of anonymous logins
#   MaxClients                  10
#
#   # We want 'welcome.msg' displayed at login, and '.message' displayed
#   # in each newly chdired directory.
#   DisplayLogin                        welcome.msg
#   DisplayChdir                .message
#
#   # Limit WRITE everywhere in the anonymous chroot
#   <Directory *>
#     <Limit WRITE>
#       DenyAll
#     </Limit>
#   </Directory>
#
#   # Uncomment this if you're brave.
#   # <Directory incoming>
#   #   # Umask 022 is a good standard umask to prevent new files and dirs
#   #   # (second parm) from being group and world writable.
#   #   Umask                           022  022
#   #            <Limit READ WRITE>
#   #            DenyAll
#   #            </Limit>
#   #            <Limit STOR>
#   #            AllowAll
#   #            </Limit>
#   # </Directory>
#
# </Anonymous>

# Include other custom configuration files
Include /etc/proftpd/conf.d/

  <IfModule mod_sftp.c>
    <VirtualHost 0.0.0.0>
      # The SFTP configuration

        SFTPEngine on
        Port 2222
        SFTPAuthMethods password
        RequireValidShell               off
        SFTPLog /var/log/proftpd/sftp.log
        Include /etc/proftpd/sql.conf

        # Configure both the RSA and DSA host keys, using the same host key
        # files that OpenSSH uses.
        SFTPHostKey /etc/ssh/ssh_host_rsa_key
        SFTPHostKey /etc/ssh/ssh_host_dsa_key

        #SFTPAuthorizedUserKeys file:/etc/proftpd/authorized_keys/%u

        # Enable compression
        SFTPCompression delayed
        DefaultRoot                     ~
    </VirtualHost>
  </IfModule>

# Time stamp - IP Address - Protocol - User Name - UID - Filename - File Sizeo - Response Time in Milliseconds - Transfer Time in Seconds - Transfer Status - Reason for failure if applicable
#  http://www.proftpd.org/docs/modules/mod_log.html#LogFormat
LogFormat custom "%{iso8601} %a %{protocol} %u %{uid} %f %{file-size} %R %T %{transfer-status} %{transfer-failure}"
ExtendedLog /var/log/proftpd/custom.log READ,WRITE custom