X-Git-Url: https://cgit.sxemacs.org/?a=blobdiff_plain;f=texi%2Fauth.texi;h=30083d301ce33f8725cd84c9554413d4fcf265ca;hb=f2827115bd6160ad866d432031b8bb9ce5bf1d11;hp=d1208d504931b69a7a88b42cf20ff45a0a357744;hpb=c66426e1fb22d2f7767c57015af4ea5eff9fa6ea;p=gnus diff --git a/texi/auth.texi b/texi/auth.texi index d1208d504..30083d301 100644 --- a/texi/auth.texi +++ b/texi/auth.texi @@ -10,7 +10,7 @@ @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 @@ -32,7 +32,7 @@ license to the document, as described in section 6 of the license. @end quotation @end copying -@dircategory Emacs +@dircategory Emacs lisp libraries @direntry * Auth-source: (auth). The Emacs auth-source library. @end direntry @@ -64,13 +64,13 @@ It is a way for multiple applications to share a single configuration @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 @@ -105,8 +105,7 @@ It's known as @var{:host} in @code{auth-source-search} queries. You can also use @code{host}. The @code{port} is the connection port or protocol. It's known as -@var{:port} in @code{auth-source-search} queries. You can also use -@code{protocol}. +@var{:port} in @code{auth-source-search} queries. The @code{user} is the user name. It's known as @var{:user} in @code{auth-source-search} queries. You can also use @code{login} and @@ -114,7 +113,7 @@ The @code{user} is the user name. It's known as @var{:user} in 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) @@ -126,17 +125,17 @@ password @var{mypassword} 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 @@ -155,12 +154,12 @@ particular host and protocol. While you can get fancy, the default and simplest configuration is: @lisp -;;; old default: required :host and :protocol, not needed anymore -(setq auth-sources '((:source "~/.authinfo.gpg" :host t :protocol t))) +;;; old default: required :host and :port, not needed anymore +(setq auth-sources '((:source "~/.authinfo.gpg" :host t :port t))) ;;; 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 @@ -182,11 +181,11 @@ Here's a mixed example using two sources: 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. @@ -228,45 +227,238 @@ necessary if you have an unusual (see earlier comment on those) setup. @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. +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 @@ -275,7 +467,7 @@ If you are using earlier versions of Emacs, you will need: @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: