Provided by: dacs_1.4.28b-3ubuntu1_amd64 
NAME
dacs_select_credentials - temporarily disable DACS credentials
SYNOPSIS
dacs_select_credentials [dacsoptions[1]]
DESCRIPTION
This program is part of the DACS suite.
A user may concurrently possess more than one set of DACS credentials during a session,
with each representing a different identity. Zero or more credentials may be submitted
with a request for a DACS-wrapped web service. It is sometimes desirable or necessary for
a user to switch between identities, or to be considered unauthenticated. Middleware
(software situated between a user agent and a DACS-capable web server) and more
sophisticated user agents might provide this functionality simply by sending some DACS
HTTP cookies and not sending others, under user control. With standard browsers or in
other situations where this functionality is not available, achieving this by repeatedly
authenticating and signing off (or by manually deleting cookies) would be inconvenient at
best.
The dacs_select_credentials web service can be used to temporarily disable credentials,
leaving the remaining credentials selected for access control purposes. The user agent
continues to send all DACS HTTP cookies as usual, but dacs_acs(8)[2] will ignore disabled
identities before deciding to grant or deny access. This feature can be used to work
around the maximum number of identities that DACS allows to be associated with a request -
determined by the ACS_CREDENTIALS_LIMIT[3] directive - or for administrative, testing, or
other reasons. There are similarities between dacs_select_credentials and su(1)[4].
A selected identity is handled normally, but a disabled identity is "hidden"; it is not
considered for access control purposes and is not reported by
dacs_current_credentials(8)[5]. A disabled identity may be re-enabled by
dacs_select_credentials, however, and dacs_signout(8)[6] will work with disabled
identities. All identities are considered for the purposes of revoking access, however,
and in other situations described below.
The selected credentials are identified by a cryptographically protected cookie that is
issued by dacs_select_credentials. The HTTP cookie name has the following format:
DACS:Federation-Name:::SELECTED
where Federation-Name is the official name assigned to the federation for which the cookie
is valid. This cookie confers no identity or access control rights to its possessor. If
this cookie is deleted, or just not sent with a request, all credentials accompanying the
request are used for access control. If dacs_signout(8)[6] asks the browser to delete all
credentials (i.e., no more credentials exist that dacs_signout is aware of), it will also
ask the browser to delete the selected credentials cookie.
The FORMAT argument (see dacs(1)[7]) determines the type of output, with the default being
HTML, using the style sheet dacs_select_credentials.css[8]. If XML output is selected, a
document conforming to dacs_select_credentials.dtd[9] is returned.
OPTIONS
Web Service Arguments
dacs_select_credentials accepts the following arguments in addition to the standard CGI
arguments[10].
OPERATION
This parameter is required and must be one of (case-insensitively):
SELECT
This operation replaces the current set of selected credentials, if any, with the
set that match the DACS_USERNAME and DACS_JURISDICTION arguments. It is an error
if no credentials match the arguments.
DESELECT
This operation disables the specified enabled credentials. If no credentials
remain selected, the user is effectively unauthenticated as if by the
SELECT_UNAUTH operation. Non-matching arguments are ignored.
ADD
The ADD operation adds the specified disabled credentials to the set of enabled
credentials.
LIST
This operation lists the selection status.
CLEAR
This operation results in no selection, with all credentials available again.
SELECT_UNAUTH
This operation makes the user effectively unauthenticated; all credentials are
disabled.
DESELECT_UNAUTH
This operation reverses SELECT_UNAUTH, resulting in there being no selection and
all credentials are again available. It is an error if the user is not effectively
unauthenticated when the operation is invoked.
DACS_USERNAME
This argument specifies a username to match against existing credentials for the
SELECT, DESELECT, and ADD operations. Exact string matching is used. If this argument
is absent, all usernames will be selected.
DACS_JURISDICTION
This argument specifies a jurisdiction name to match against existing credentials for
the SELECT, DESELECT, and ADD operations. Exact string matching is used. If this
argument is absent, all jurisdictions will be selected.
COOKIE_SYNTAX
This parameter has the same semantics as with the dacs_authenticate(8)[11] service.
Tip
The dacs_authenticate(8)[12] web service takes an optional argument, OPERATION, that
can have the value SELECT. If authentication succeeds and this argument is present,
the resulting credentials are selected as described above.
FILES
dacs_select_credentials.css[8]
DIAGNOSTICS
The program exits 0 if everything was fine, 1 if an error occurred.
BUGS
It might be useful to be able to temporarily suppress one or more specific roles of a
given identity.
AUTHOR
Distributed Systems Software (www.dss.ca[13])
COPYING
Copyright2003-2013 Distributed Systems Software. See the LICENSE[14] file that accompanies
the distribution for licensing information.
NOTES
1. dacsoptions
http://dacs.dss.ca/man/dacs.1.html#dacsoptions
2. dacs_acs(8)
http://dacs.dss.ca/man/dacs_acs.8.html
3. ACS_CREDENTIALS_LIMIT
http://dacs.dss.ca/man/dacs.conf.5.html#ACS_CREDENTIALS_LIMIT
4. su(1)
http://www.freebsd.org/cgi/man.cgi?query=su&apropos=0&sektion=1&manpath=FreeBSD+9.1-RELEASE&format=html
5. dacs_current_credentials(8)
http://dacs.dss.ca/man/dacs_current_credentials.8.html
6. dacs_signout(8)
http://dacs.dss.ca/man/dacs_signout.8.html
7. dacs(1)
http://dacs.dss.ca/man/dacs.1.html
8. dacs_select_credentials.css
http://dacs.dss.ca/man//css/dacs_select_credentials.css
9. dacs_select_credentials.dtd
http://dacs.dss.ca/man/../dtd-xsd/dacs_select_credentials.dtd
10. standard CGI arguments
http://dacs.dss.ca/man/dacs.services.8.html#standard_cgi_args
11. dacs_authenticate(8)
http://dacs.dss.ca/man/dacs_authenticate.8.html#COOKIE_SYNTAX
12. dacs_authenticate(8)
http://dacs.dss.ca/man/dacs_authenticate.8.html
13. www.dss.ca
http://www.dss.ca
14. LICENSE
http://dacs.dss.ca/man/../misc/LICENSE