@copying
This file describes the Emacs auth-source library.
-Copyright @copyright{} 2008-2011 Free Software Foundation, Inc.
+Copyright @copyright{} 2008-2012 Free Software Foundation, Inc.
@quotation
Permission is granted to copy, distribute and/or modify this document
@menu
* Overview:: Overview of the auth-source library.
-* Help for users::
-* Secret Service API::
-* Help for developers::
-* GnuPG and EasyPG Assistant Configuration::
-* Index::
-* Function Index::
-* Variable Index::
+* Help for users::
+* Secret Service API::
+* Help for developers::
+* GnuPG and EasyPG Assistant Configuration::
+* Index::
+* Function Index::
+* Variable Index::
@end menu
@end ifnottex
Spaces are always OK as far as auth-source is concerned (but other
programs may not like them). Just put the data in quotes, escaping
-quotes as you'd expect with @code{\}.
+quotes as you'd expect with @samp{\}.
All these are optional. You could just say (but we don't recommend
it, we're just showing that it's possible)
to use the same password everywhere. Again, @emph{DO NOT DO THIS} or
you will be pwned as the kids say.
-``Netrc'' files are usually called @code{.authinfo} or @code{.netrc};
-nowadays @code{.authinfo} seems to be more popular and the auth-source
-library encourages this confusion by making it the default, as you'll
-see later.
+``Netrc'' files are usually called @file{.authinfo} or @file{.netrc};
+nowadays @file{.authinfo} seems to be more popular and the auth-source
+library encourages this confusion by accepting both, as you'll see
+later.
If you have problems with the search, set @code{auth-source-debug} to
-@code{t} and see what host, port, and user the library is checking in
-the @code{*Messages*} buffer. Ditto for any other problems, your
-first step is always to see what's being checked. The second step, of
-course, is to write a blog entry about it and wait for the answer in
-the comments.
+@code{'trivia} and see what host, port, and user the library is
+checking in the @samp{*Messages*} buffer. Ditto for any other
+problems, your first step is always to see what's being checked. The
+second step, of course, is to write a blog entry about it and wait for
+the answer in the comments.
You can customize the variable @code{auth-sources}. The following may
be needed if you are using an older version of Emacs or if the
;;; mostly equivalent (see below about fallbacks) but shorter:
(setq auth-sources '((:source "~/.authinfo.gpg")))
;;; even shorter and the @emph{default}:
-(setq auth-sources '("~/.authinfo.gpg" "~/.authinfo"))
+(setq auth-sources '("~/.authinfo.gpg" "~/.authinfo" "~/.netrc"))
;;; use the Secrets API @var{Login} collection (@pxref{Secret Service API})
(setq auth-sources '("secrets:Login"))
@end lisp
If you don't customize @code{auth-sources}, you'll have to live with
the defaults: any host and any port are looked up in the netrc
-file @code{~/.authinfo.gpg}, which is a GnuPG encrypted file
-(@pxref{GnuPG and EasyPG Assistant Configuration}).
+file @file{~/.authinfo.gpg}, which is a GnuPG encrypted file
+(@pxref{GnuPG and EasyPG Assistant Configuration}).
-If that fails, the unencrypted netrc file @code{~/.authinfo} will
-be used.
+If that fails, the unencrypted netrc files @file{~/.authinfo} and
+@file{~/.netrc} will be used.
The typical netrc line example is without a port.
@node Secret Service API
@chapter Secret Service API
-TODO: how does it work generally, how does secrets.el work, some examples.
+The @dfn{Secret Service API} is a standard from
+@uref{http://www.freedesktop.org/wiki/Specifications/secret-storage-spec,,freedesktop.org}
+to securely store passwords and other confidential information.
+Implementations of compliant daemons are the GNOME Keyring and the KDE
+Wallet.
-@node Help for developers
-@chapter Help for developers
+The auth-source library uses the @file{secrets.el} library as an
+interface to this feature. You can also use that library in other
+packages.
-The auth-source library only has a few functions for external use.
+@defvar secrets-enabled
+After loading @file{secrets.el}, a non-@code{nil} value of this
+variable indicates the existence of a daemon providing the Secret
+Service API.
+@end defvar
+
+@deffn Command secrets-show-secrets
+This command inspects all collections, items, and their attributes.
+@end deffn
+
+The atomic objects to be managed by the Secret Service API are
+@dfn{secret items}, which are something an application wishes to store
+securely. A good example is a password that an application needs to
+save and use at a later date.
+
+Secret items are grouped in @dfn{collections}. A collection is
+similar in concept to the terms @samp{keyring} or @samp{wallet}. A
+common collection is called @samp{"login"}. A collection is stored
+permanently under the user's permissions, and can be accessed in a
+user session context.
+
+A collection can have an alias name. The use case for this is to
+set the alias @samp{"default"} for a given collection, making it
+transparent to clients as to which collection is used. Other aliases
+are not supported (yet). Since an alias is visible to all
+applications, this setting should be performed with care.
+
+@defun secrets-list-collections
+This function returns a list of collection names.
+@end defun
+
+@defun secrets-set-alias collection alias
+Set @var{alias} as alias of collection labeled @var{collection}.
+For the time being, only the alias @samp{"default"} is supported.
+@end defun
+
+@defun secrets-get-alias alias
+Return the collection name @var{alias} is referencing to.
+For the time being, only the alias @samp{"default"} is supported.
+@end defun
+
+Collections can be created and deleted by the functions
+@code{secrets-create-collection} and @code{secrets-delete-collection}.
+Usually, this is not applied from within Emacs. Common collections,
+like @samp{"login"}, should never be deleted.
+
+There exists a special collection called @samp{"session"}, which has
+the lifetime of the corresponding client session (aka Emacs's
+lifetime). It is created automatically when Emacs uses the Secret
+Service interface, and it is deleted when Emacs is killed. Therefore,
+it can be used to store and retrieve secret items temporarily. This
+should be preferred over creation of a persistent collection, when the
+information should not live longer than Emacs. The session collection
+can be addressed either by the string @samp{"session"}, or by
+@code{nil}, whenever a collection parameter is needed in the following
+functions.
+
+As already said, a collection is a group of secret items. A secret
+item has a label, the @dfn{secret} (which is a string), and a set of
+lookup attributes. The attributes can be used to search and retrieve
+a secret item at a later date.
+
+@defun secrets-list-items collection
+Returns a list of all item labels of @var{collection}.
+@end defun
+
+@defun secrets-create-item collection item password &rest attributes
+This function creates a new item in @var{collection} with label
+@var{item} and password @var{password}. @var{attributes} are
+key-value pairs set for the created item. The keys are keyword
+symbols, starting with a colon. Example:
-@defun auth-source-search SPEC
+@example
+(secrets-create-item "session" "my item" "geheim"
+ :method "sudo" :user "joe" :host "remote-host")
+@end example
+@end defun
-TODO: how to include docstring?
+@defun secrets-get-secret collection item
+Return the secret of item labeled @var{item} in @var{collection}.
+If there is no such item, return @code{nil}.
+@end defun
+@defun secrets-delete-item collection item
+This function deletes item @var{item} in @var{collection}.
@end defun
-@defun auth-source-delete SPEC
+The lookup attributes, which are specified during creation of a
+secret item, must be a key-value pair. Keys are keyword symbols,
+starting with a colon; values are strings. They can be retrieved
+from a given secret item, and they can be used for searching of items.
+
+@defun secrets-get-attribute collection item attribute
+Returns the value of key @var{attribute} of item labeled @var{item} in
+@var{collection}. If there is no such item, or the item doesn't own
+this key, the function returns @code{nil}.
+@end defun
+
+@defun secrets-get-attributes collection item
+Return the lookup attributes of item labeled @var{item} in
+@var{collection}. If there is no such item, or the item has no
+attributes, it returns @code{nil}. Example:
+
+@example
+(secrets-get-attributes "session" "my item")
+ @result{} ((:user . "joe") (:host ."remote-host"))
+@end example
+@end defun
-TODO: how to include docstring?
+@defun secrets-search-items collection &rest attributes
+Search items in @var{collection} with @var{attributes}.
+@var{attributes} are key-value pairs, as used in
+@code{secrets-create-item}. Example:
+@example
+(secrets-search-items "session" :user "joe")
+ @result{} ("my item" "another item")
+@end example
@end defun
-@defun auth-source-forget SPEC
+@node Help for developers
+@chapter Help for developers
-TODO: how to include docstring?
+The auth-source library lets you control logging output easily.
+@defvar auth-source-debug
+Set this variable to @code{'trivia} to see lots of output in
+@samp{*Messages*}, or set it to a function that behaves like
+@code{message} to do your own logging.
+@end defvar
+
+The auth-source library only has a few functions for external use.
+
+@defun auth-source-search &rest spec &key type max host user port secret require create delete &allow-other-keys
+This function searches (or modifies) authentication backends according
+to @var{spec}. See the function's doc-string for details.
+@c TODO more details.
@end defun
-@defun auth-source-forget+ SPEC
+Let's take a look at an example of using @code{auth-source-search}
+from Gnus's @code{nnimap.el}.
+
+@example
+(defun nnimap-credentials (address ports)
+ (let* ((auth-source-creation-prompts
+ '((user . "IMAP user at %h: ")
+ (secret . "IMAP password for %u@@%h: ")))
+ (found (nth 0 (auth-source-search :max 1
+ :host address
+ :port ports
+ :require '(:user :secret)
+ :create t))))
+ (if found
+ (list (plist-get found :user)
+ (let ((secret (plist-get found :secret)))
+ (if (functionp secret)
+ (funcall secret)
+ secret))
+ (plist-get found :save-function))
+ nil)))
+@end example
+
+This call requires the user and password (secret) to be in the
+results. It also requests that an entry be created if it doesn't
+exist already. While the created entry is being assembled, the shown
+prompts will be used to interact with the user. The caller can also
+pass data in @code{auth-source-creation-defaults} to supply defaults
+for any of the prompts.
-TODO: how to include docstring?
+Note that the password needs to be evaluated if it's a function. It's
+wrapped in a function to provide some security.
+
+Later, after a successful login, @code{nnimap.el} calls the
+@code{:save-function} like so:
+
+@example
+(when (functionp (nth 2 credentials))
+ (funcall (nth 2 credentials)))
+@end example
+
+This will work whether the @code{:save-function} was provided or not.
+@code{:save-function} will be provided only when a new entry was
+created, so this effectively says ``after a successful login, save the
+authentication information we just used, if it was newly created.''
+
+After the first time it's called, the @code{:save-function} will not
+run again (but it will log something if you have set
+@code{auth-source-debug} to @code{'trivia}). This is so it won't ask
+the same question again, which is annoying. This is so it won't ask
+the same question again, which is annoying. This is so it won't ask
+the same question again, which is annoying.
+
+So the responsibility of the API user that specified @code{:create t}
+is to call the @code{:save-function} if it's provided.
+
+@defun auth-source-delete &rest spec &key delete &allow-other-keys
+This function deletes entries matching @var{spec} from the
+authentication backends. It returns the entries that were deleted.
+The backend may not actually delete the entries.
+@end defun
+
+@defun auth-source-forget spec
+This function forgets any cached data that exactly matches @var{spec}.
+It returns @code{t} if it forget some data, and @code{nil} if no
+matching data was found.
+@end defun
+@defun auth-source-forget+ &rest spec &allow-other-keys
+This function forgets any cached data matching @var{spec}.
+It returns the number of items forgotten.
@end defun
@node GnuPG and EasyPG Assistant Configuration
@appendix GnuPG and EasyPG Assistant Configuration
If you don't customize @code{auth-sources}, the auth-source library
-reads @code{~/.authinfo.gpg}, which is a GnuPG encrypted file. Then
-it will check @code{~/.authinfo} but it's not recommended to use such
+reads @file{~/.authinfo.gpg}, which is a GnuPG encrypted file. Then
+it will check @file{~/.authinfo} but it's not recommended to use such
an unencrypted file.
In Emacs 23 or later there is an option @code{auto-encryption-mode} to
-automatically decrypt @code{*.gpg} files. It is enabled by default.
+automatically decrypt @file{*.gpg} files. It is enabled by default.
If you are using earlier versions of Emacs, you will need:
@lisp
@end lisp
If you want your GnuPG passwords to be cached, set up @code{gpg-agent}
-or EasyPG Assitant
+or EasyPG Assistant
(@pxref{Caching Passphrases, , Caching Passphrases, epa}).
To quick start, here are some questions:
projects / gnus / blobdiff