ProFTPD module mod_sftp_pam



The mod_sftp_pam module provides support for the "SSH Keyboard-Interactive Authentication" RFC (RFC4256). How is mod_sftp_pam different from ProFTPD's existing PAM support, in the form of mod_auth_pam? The difference is that the mod_auth_pam module does not echo the prompt, provided by the underlying PAM library/modules, back to the FTP client; this mod_sftp_pam module will echo any prompt back to the connecting SSH2 client. This makes using onetime-password PAM modules, for example, work very easily for authenticating SSH2 logins.

This module is contained in the mod_sftp_pam.c file for ProFTPD 1.3.x, and is not compiled by default. Installation instructions are discussed here; a discussion on usage is also available.

The most current version of mod_sftp_pam is distributed with the ProFTPD source code.

Author

Please contact TJ Saunders <tj at castaglia.org> with any questions, concerns, or suggestions regarding this module.

Directives


SFTPPAMEngine

Syntax: SFTPPAMEngine on|off
Default: On
Context: "server config", <VirtualHost>, <Global>
Module: mod_sftp_pam
Compatibility: 1.3.2rc2 and later

The SFTPPAMEngine directive toggles the use of the PAM library for supporting a keyboard-interactive authentication mechanism for SSH2 logins. By default mod_sftp_pam is enabled.


SFTPPAMOptions

Syntax: SFTPPAMOptions opt1 opt2 ... optN
Default: None
Context: "server config", <VirtualHost>, <Global>
Module: mod_sftp_pam
Compatibility: 1.3.2rc2 and later

The SFTPPAMOptions directive is used to configure various optional behaviors of mod_sftp_pam; it is directly analogous to mod_auth_pam's AuthPAMOptions directive.

The currently supported options are:


SFTPPAMServiceName

Syntax: SFTPPAMServiceName service
Default: SFTPPAMServiceName sshd
Context: "server config", <VirtualHost>, <Global>
Module: mod_sftp_pam
Compatibility: 1.3.2rc2 and later

The SFTPPAMConfig directive is used to specify the name of the service used when performing the PAM check; PAM configurations can vary depending on the service. By default, the "sshd" service is used.

Here's an example of changing the service used:

  <IfModule mod_sftp_pam.c>
    SFTPPAMEngine on
    SFTPPAMServiceName ftpd
  </IfModule>

The SFTPPAMServiceName directive is directly analogous to mod_auth_pam's AuthPAMConfig directive.


Installation

The mod_sftp_pam module is distributed with ProFTPD. Simply follow the normal steps for using third-party modules in proftpd:
  ./configure --with-modules=mod_sftp:mod_sftp_pam ...
  make
  make install
Alternatively, mod_sftp_pam can be built as a DSO module:
  ./configure --enable-dso --with-shared=mod_sftp_pam ...
Then follow the usual steps:
  make
  make install

For those with an existing ProFTPD installation, you can use the prxs tool to add mod_sftp_pam, as a DSO module, to your existing server:

  # prxs -c -i -d mod_sftp_pam.c



Usage

To use mod_sftp_pam, simply configure it to use the correct PAM service name, e.g.:
  <IfModule mod_sftp_pam.c>
    SFTPPAMEngine on
    SFTPPAMServiceName sftp
  </IfModule>
There is no requirement that mod_sftp_pam use the same PAM service name as the mod_auth_pam module; this allows you to have different PAM configurations for FTP versus SSH2 logins.



Author: $Author: castaglia $
Last Updated: $Date: 2013/10/03 05:21:56 $


© Copyright 2008-2013 TJ Saunders
All Rights Reserved