DefaultRoot

Description

The DefaultRoot directive controls the default root directory assigned to a user upon login. If DefaultRoot is set to a directory other than "/", a chroot operation is performed immediately after a client authenticates. This can be used to effectively isolate the client from a portion of the host system filespace. The specified root directory must begin with a / or can be the magic character '~'; meaning that the client is chroot jailed into their home directory.

When the specified chroot directory is a symlink this will be resolved to it's parent first before setting up the chroot. This can have unwanted side effects. For example if a chroot is to be configured within space to which a user as shell access, the chroot directory could be converted to a symlink pointing at '/'. Thus the chroot would be to the root directory of the server.

If the DefaultRoot directive specifies a directory which disallows access to the logged-in user's home directory, the user's current working directory after login is set to the DefaultRoot instead of their normal home directory. DefaultRoot cannot be used in <Anonymous> configuration blocks, as the <Anonymous> directive explicitly contains a root directory used for Anonymous logins. The special character '~' is replaced with the authenticating user's home directory immediately after login. Note that the default root may be a subdirectory of the home directory, such as "~/anon-ftp".

The optional group-expression argument can be used to restrict the DefaultRoot directive to a unix group, groups or subset of groups. The expression takes the format: [!]group-name1[,[!]group-name2[,...]]. The expression is parsed in a logical boolean AND fashion, such that each member of the expression must evaluate to logically TRUE in order for the DefaultRoot directive to apply. The special character '!' is used to negate group membership.

Care should be taken when using DefaultRoot. Chroot "jails" should not be used as methods for implementing general system security as there are potentially ways that a user can "escape" the jail.

See also

Examples

Example of a DefaultRoot configuration:
ServerName "A test ProFTPD Server"
ServerType inetd
User ftp
Group ftp
#
# This causes proftpd to perform a chroot into the authenticating user's directory 
immediately after login.
# Once this happens, the user is unable to "see" higher level directories.
# Because a group-expression is included, only users who are a member of
# the group 'users' and NOT a member of 'staff' will have their default
# root directory set to '~'.
DefaultRoot ~ users,!staff
...