NAME
Passwd::Keyring::Auto - interface to secure password storage(s)
VERSION
Version 1.0000
SYNOPSIS
Passwd::Keyring is about securely preserving passwords and other
sensitive data (for example API keys, OAuth tokens etc) in backends
like Gnome Keyring, KDE Wallet, OSX/Keychain etc.
While modules like Passwd::Keyring::Gnome handle specific backends,
Passwd::Keyring::Auto tries to pick the best backend available,
considering the current desktop environment, program options, and user
configuration.
use Passwd::Keyring::Auto; # get_keyring
my $keyring = get_keyring(app=>"My super scraper", group=>"Social passwords");
my $username = "someuser";
my $password = $keyring->get_password($username, "mylostspace.com");
unless($password) {
# ... somehow interactively prompt for password
$keyring->set_password($username, $password, "mylostspace.com");
}
login_somewhere_using($username, $password);
if( password_was_wrong ) {
$keyring->clear_password($username, "mylostspace.com");
}
If any secure backend is available, password is preserved for
successive runs, and user need not be prompted again.
The choice can be impacted by configuration file, some environment
variables and/or additional parameters, see "BACKEND SELECTION
CRITERIA".
One can skip this module and be explicit if he or she knows which
keyring is to be used:
use Passwd::Keyring::Gnome;
my $keyring = Passwd::Keyring::Gnome->new();
# ... from there as above
SUBROUTINES/METHODS
get_keyring
my $ring = get_keyring()
my $ring = get_keyring(app=>'MyApp', group=>'SyncPasswords');
my $ring = get_keyring(app=>'MyApp', group=>'Uploads',
config=>"$ENV{HOME}/.passwd-keyring-business.cfg");
my $ring = get_keyring(app=>'MyApp', group=>'Scrappers',
prefer=>['Gnome', 'PWSafe3'],
forbid=>['KDEWallet']);
my $ring = get_keyring(app=>'MyApp', group=>'Scrappers',
force=>['KDEWallet']);
my $ring = get_keyring(app=>'MyApp', group=>'SyncPasswords',
%backend_specific_options);
Returns the keyring object most appropriate for the current system (and
matching specified criteria, and applying user configuration) and
initiates it.
The function inspects context the application runs in (operating
system, presence of GUI sessions etc), decides which backends seem
suitable and in what order of preference, then tries all suitable
backends and returns first succesfully loaded and initialized (or
croaks if there is none). See "BACKEND SELECTION CRITERIA" for info
about criteria used.
All parameters are optional, but it is strongly recommended to set app
and group.
General parameters:
app => 'App Name'
Symbolic application name, which - depending on backend - may appear
in interactive prompts (like dialog box "Application APP-NAME wants
to access secure data..." popped up by KDE Wallet) and may be
preserved as comment ("Created by ...") in secure storage (so may be
seen in GUI password management apps like seahorse). Also, if config
file is in use, it can override some settings on per-application
basis.
group => 'PasswordFolder'
The name of the passwords folder. Can be visualised as folder or
group by some GUIs (seahorse, pwsafe3) but it's most important role
is to let one separate passwords used for different purposes. A few
apps/scripts will share passwords if they use the same group name,
but will use different and unrelated passwords if they specify
different group.
config => "/some/where/passwd_keyring.cfg"
Config file location.
Parameters impacting backend selection (usually not recommended as they
limit user choice, but hardcode choices if you like):
force => 'Backend'
Try only given backend and nothing else. Expects short backend name.
For example force='Gnome'> means Passwd::Keyring::Gnome is to be used
and nothing else.
prefer=>'Backend' or prefer => ['Backend1', 'Backend2', ...]
Try this/those backends first, and in the specified order (and try
them even if by default they are not considered suitable for OS in
use).
For example prefer=['OSXKeychain', 'KDEWallet']> asks module to try
Passwd::Keyring::OSXKeychain first, then Passwd::Keyring::KDEWallet,
then other options (if any) in module own preference.
forbid=>'Backend' or forbid => ['Backend1', 'Backend2', ...]
Never use specified backend(s).
For example forbid=['Gnome', 'KDEWallet']> will cause method not to
consider those GUI keyrings even if we run on Linux and have Gnome or
KDE session active.
Backend-specific parameters:
other parameters
All other parameters are passed as such to actual keyring backend. To
check whether/which may be used, consult backends documentation.
Backends ignore params they do not understand, so some superset of
possibly useful params is OK.
It is recommended to use configuration file instead.
The function in it's simplest form should not fail (it falls back to
Passwd::Keyring::Memory if everything else fails), but it may croak if
some keyring is enforced or if Memory is forbidden or uninstalled.
KEYRING METHODS
See Passwd::Keyring::Auto::KeyringAPI for operations available on
keyring objects.
CONFIGURATION FILE
The recommended way to impact backend selection on per-system (and
user) basis is to use configuration file, which let the user set
default keyring selection rules, and per-application overrides.
It's initial version can be created by passwd_keyring script:
passwd_keyring config_create
and edited afterwards.
See "BACKEND SELECTION CRITERIA" for info how configuration settings
relate to other backend selection methods.
CONFIGURATION FILE LOCATION
By default, config file is looked in ~/.passwd-keyring.cfg on
Linux/Unix and ~/Local Settings/Application Data/.passwd-keyring.cfg on
Windows (more exactly: .passwd-keyring.cfg in directory reported by
my_data function from File::HomeDir).
Environment variable PASSWD_KEYRING_CONFIG can be used to override this
setting (and should contain path of the configuration file). Also,
config parameter can be used in get_keyring method (and takes
precedence even over env variable).
Note that while it is OK not to have config file at all, but it is an
error (and causes exception) to have non-existing or inaccessible file
pointed by parameter or environment variable.
CONFIGURATION FILE SYNTAX
Example:
; Default settings
prefer=KDEWallet PWSafe3 Memory
forbid=Gnome
PWSafe3.file=~/passwd-keyring.pwsafe3
; Overrides for app named WebScrapers
[WebScrapers]
force=Gnome
; Overrides for app named XYZTests
[XYZTests]
force=PWSafe3
PWSafe3.file=~/tests/xyz/passwd-keyring-tokens.pwsafe3
prefer, forbid and force define appropriate steering values, as
documented in Passwd::Keyring::Auto. Space is used to separate multiple
values.
; can be used to start line comments.
ENVIRONMENT VARIABLES
The following environment variables can be used to impact the module
behaviour.
General configuration variables:
PASSWD_KEYRING_CONFIG
Defines location of the config file.
PASSWD_KEYRING_DEBUG
Log on stderr details about tried and selected backends (and errors
faced while they are tried).
Backend-selection variables (see "BACKEND SELECTION CRITERIA" for info
how they relate to other methods and note that using configuration file
is usually recommended over setting those variables):
PASSWD_KEYRING_FORCE
Use given backend and nothing else. For example, by setting
PASSWD_KEYRING_FORCE=KDEWallet user may enforce use of
Passwd::Keyring::KDEWallet.
This variable is completely ignored if force parameter was specified,
and causes runtime error if specified backend is not present, not
working, or present on the forbid list.
PASSWD_KEYRING_FORBID
Space separated list of backends to forbid, for example
PASSWD_KEYRING_FORBID="Gnome KDEWallet".
Ignored if force parameter was specified, otherwise works as this
param.
PASSWD_KEYRING_PREFER
Space separated names of backends to prefer.
Ignored if prefer parameter was specified, otherwise works as this
param.
BACKEND SELECTION CRITERIA
Backend selection is organized around 3 steering parameters: force,
forbid, and prefer. For each of those, the value is looked in the
following places (first found is returned):
hardcoded value (get_keyring param),
environment variable (PASSWD_KEYRING_...)
configuration file per-application setting
configuration file default setting
library default
Each param is calculated separately, so one can have prefer initialized
from hardcoded value, forbid taken from the config file and force
defined by PASSWD_KEYRING_FORCE environment variable. This may
sometimes be confusing so use sparingly (and limit to config file
unless you really have reason to do otherwise).
Once calculated, those params are used in the following way:
if force is set, this is just used and remaining params are ignored -
module tries to load this backend and either returns it, or (if it
failed) raises an exception;
elsewhere, all known backends are enumerated, and filtered by forbid
(so only those not forbidden remain)
the remaining list is sorted according to position on prefer
those modules are tried in order, first which succesfully loaded and
initialized is returned
if nothing was found, module raises exception.
The following library defaults are used:
there is no default for force;
forbid is calculated according to the operating system (so
Passwd::Keyring::OSXKeychain is forbidden everywhere except Mac OS/X,
Passwd::Keyring::Gnome is forbidden on Windows and Mac, etc);
prefer is calculated according to operating system and detected session
characteristics (so, if Gnome or Ubuntu session is detected,
Passwd::Keyring::Gnome is preferred, and if we have KDE, we prefer
Passwd::Keyring:KDEWallet, etc).
FURTHER INFORMATION
Passwd::Keyring::Auto::KeyringAPI describes methods available on
keyring objects and provides some additional detail on keyring
construction.
AUTHOR
Marcin Kasperski
BUGS
Please report any bugs or feature requests to issue tracker at
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Passwd::Keyring::Auto
You can also look for information at:
Source code is tracked at:
LICENSE AND COPYRIGHT
Copyright 2012-2015 Marcin Kasperski.
This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.