The mod_procfs module affects the visibility and usage of the /proc filesystem directory.

This module is contained in the mod_procfs file for ProFTPD 1.3.x, and is not compiled by default. Installation instructions are discussed here. More examples of mod_procfs usage can be found here.

The most current version of mod_procfs can be found at:

  https://github.com/Castaglia/proftpd-mod_procfs

Author

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

Directives

• ProcfsEngine
• ProcfsLog

ProcfsEngine

The ProcfsEngine directive enables or disables the module's hiding of the /proc filesystem. When enabled, mod_procfs works to prevent access to the /proc filesystem, returning "No such file or directory" errors for such access attempts.

Note that ProcfsEngine is automatically enabled if the module detects, on startup, that the /proc filesystem is present. If the /proc filesystem is not present on startup, then ProcfsEngine is automatically disabled. Explicitly setting this directive overrides the automatic behavior.

ProcfsLog

The ProcfsLog directive is used to a specify a log file for mod_procfs reporting and debugging, and can be done a per-server basis. The file parameter must be the full path to the file to use for logging. Note that this path must not be to a world-writeable directory and, unless AllowLogSymlinks is explicitly set to on (generally a bad idea), the path must not be a symbolic link.

If file is "none", no logging will be done at all; this setting can be used to override a ProcfsLog setting inherited from a <Global> context.

Installation

  proftpd-dir/contrib/

  ./configure --with-modules=mod_procfs

  ./configure --enable-dso --with-shared=mod_procfs

  make
  make install

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

  # prxs -c -i -d mod_procfs.c

Usage

The mod_procfs module works by using the ProFTPD FSIO API to intercept all stat(2) and lstat(2) system calls; if the paths being checked reference the /proc filesystem, those system calls will fail with a "No such file or directory" error.

Example configuration:

  <IfModule mod_procfs.c>
    ProcfsEngine on
    ProcfsLog /var/log/proftpd/procfs.log
  </IfModule>

Logging
The mod_procfs module supports different forms of logging. The main module logging is done via the ProcfsLog directive. For debugging purposes, the module also uses trace logging, via the module-specific channels:

• procfs

Thus for trace logging, to aid in debugging, you would use the following in your proftpd.conf:

  TraceLog /path/to/proftpd-trace.log
  Trace fsio:20 procfs:20