Name

splashy — Mandos plugin to use splashy to get a password.

Synopsis

splashy

DESCRIPTION

This program prompts for a password using splashy_update(8) and outputs any given password to standard output. If no splashy(8) process can be found, this program will immediately exit with an exit code indicating failure.

This program is not very useful on its own. This program is really meant to run as a plugin in the Mandos client-side system, where it is used as a fallback and alternative to retrieving passwords from a Mandos server.

If this program is killed (presumably by plugin-runner(8mandos) because some other plugin provided the password), it cannot tell splashy(8) to abort requesting a password, because splashy(8) does not support this. Therefore, this program will then kill the running splashy(8) process and start a new one, using boot as the only argument.

OPTIONS

This program takes no options.

EXIT STATUS

If exit status is 0, the output from the program is the password as it was read. Otherwise, if exit status is other than 0, the program was interrupted or encountered an error, and any output so far could be corrupt and/or truncated, and should therefore be ignored.

ENVIRONMENT

cryptsource, crypttarget

If set, these environment variables will be assumed to contain the source device name and the target device mapper name, respectively, and will be shown as part of the prompt.

These variables will normally be inherited from plugin-runner(8mandos), which will normally have inherited them from /scripts/local-top/cryptroot in the initial RAM disk environment, which will have set them from parsing kernel arguments and /conf/conf.d/cryptroot (also in the initial RAM disk environment), which in turn will have been created when the initial RAM disk image was created by /usr/share/initramfs-tools/hooks/cryptroot, by extracting the information of the root file system from /etc/crypttab.

This behavior is meant to exactly mirror the behavior of askpass, the default password prompter.

FILES

/sbin/splashy_update

This is the command run to retrieve a password from splashy(8). See splashy_update(8).

/proc

To find the running splashy(8), this directory will be searched for numeric entries which will be assumed to be directories. In all those directories, the exe entry will be used to determine the name of the running binary and the effective user and group ID of the process. See proc(5).

/sbin/splashy

This is the name of the binary which will be searched for in the process list. See splashy(8).

BUGS

Killing splashy(8) and starting a new one is ugly, but necessary as long as it does not support aborting a password request.

EXAMPLE

Note that normally, this program will not be invoked directly, but instead started by the Mandos plugin-runner(8mandos).

This program takes no options.

splashy

SECURITY

If this program is killed by a signal, it will kill the process ID which at the start of this program was determined to run splashy(8) as root (see also the section called “FILES”). There is a very slight risk that, in the time between those events, that process ID was freed and then taken up by another process; the wrong process would then be killed. Now, this program can only be killed by the user who started it; see plugin-runner(8mandos). This program should therefore be started by a completely separate non-privileged user, and no other programs should be allowed to run as that special user. This means that it is not recommended to use the user "nobody" to start this program, as other possibly less trusted programs could be running as "nobody", and they would then be able to kill this program, triggering the killing of the process ID which may or may not be splashy(8).

The only other thing that could be considered worthy of note is this: This program is meant to be run by plugin-runner(8mandos), and will, when run standalone, outside, in a normal environment, immediately output on its standard output any presumably secret password it just received. Therefore, when running this program standalone (which should never normally be done), take care not to type in any real secret password by force of habit, since it would then immediately be shown as output.

SEE ALSO

intro(8mandos), crypttab(5), plugin-runner(8mandos), proc(5), splashy(8), splashy_update(8)