saslauthd(8) System Manager's Manual saslauthd(8)
NAME
saslauthd - sasl authentication server
SYNOPSIS
saslauthd -a authmech [-Tvdchlr] [-O option] [-m mux_path] [-n threads]
[-s size] [-t timeout]
DESCRIPTION
saslauthd is a daemon process that handles plaintext authentication
requests on behalf of the SASL library.
The server fulfills two roles: it isolates all code requiring superuser
privileges into a single process, and it can be used to provide proxy
authentication services to clients that do not understand SASL based
authentication.
saslauthd should be started from the system boot scripts when going to
multi-user mode. When running against a protected authentication database
(e.g. the shadow mechanism), it must be run as the superuser. Otherwise it
is recommended to run daemon unprivileged as saslauth:saslauth, requiring
the runtime directory to have root:saslauthd owner. You can do so by
following these steps in machines using systemd(1) :
1. create directory /etc/systemd/system/saslauthd.service.d/
2. create file /etc/systemd/system/saslauthd.service.d/user.conf with
content
[Service]
User=saslauth
Group=saslauth
3. Reload systemd service file: run "systemctl daemon-reload"
Options
Options named by lower-case letters configure the server itself.
Upper-case options control the behavior of specific authentication
mechanisms; their applicability to a particular authentication mechanism is
described in the AUTHENTICATION MECHANISMS section.
-a authmech
Use authmech as the authentication mechanism. (See the
AUTHENTICATION MECHANISMS section below.) This parameter is
mandatory.
-O option
A mechanism specific option (e.g. rimap hostname or config file
path)
-H hostname
The remote host to be contacted by the rimap authentication
mechanism. (Deprecated, use -O instead)
-m path
Use path as the pathname to the named socket to listen on for
connection requests. This must be an absolute pathname, and MUST
NOT include the trailing "/mux". Note that the default for this
value is "/var/state/saslauthd" (or what was specified at compile
time) and that this directory must exist for saslauthd to function.
-n threads
Use threads processes for responding to authentication queries.
(default: 5) A value of zero will indicate that saslauthd should
fork an individual process for each connection. This can solve
leaks that occur in some deployments.
-s size
Use size as the table size of the hash table (in kilobytes)
-t timeout
Use timeout as the expiration time of the authentication cache (in
seconds)
-T Honour time-of-day login restrictions.
-h Show usage information
-c Enable caching of authentication credentials
-l Disable the use of a lock file for controlling access to accept().
-r Combine the realm with the login (with an '@' sign in between).
e.g. login: "foo" realm: "bar" will get passed as login:
"foo@bar". Note that the realm will still be passed, which may
lead to unexpected behavior for authentication mechanisms that make
use of the realm, however for mechanisms which don't, such as
getpwent, this is the only way to authenticate domain-specific
users sharing the same userid.
-v Print the version number and available authentication mechanisms on
standard error, then exit.
-d Debugging mode.
Logging
saslauthd logs its activities via syslogd using the LOG_AUTH facility.
AUTHENTICATION MECHANISMS
saslauthd supports one or more "authentication mechanisms", dependent upon
the facilities provided by the underlying operating system. The mechanism
is selected by the -a flag from the following list of choices:
dce (AIX)
Authenticate using the DCE authentication environment.
getpwent (All platforms)
Authenticate using the getpwent() library function. Typically
this authenticates against the local password file. See your
system's getpwent(3) man page for details.
kerberos4 (All platforms)
Authenticate against the local Kerberos 4 realm. (See the NOTES
section for caveats about this driver.)
kerberos5 (All platforms)
Authenticate against the local Kerberos 5 realm.
pam (Linux, Solaris)
Authenticate using Pluggable Authentication Modules (PAM).
rimap (All platforms)
Forward authentication requests to a remote IMAP server. This
driver connects to a remote IMAP server, specified using the -O
flag, and attempts to login (via an IMAP `LOGIN' command) using
the credentials supplied to the local server. If the remote
authentication succeeds the local connection is also considered
to be authenticated. The remote connection is closed as soon as
the tagged response from the `LOGIN' command is received from
the remote server.
The option parameter to the -O flag describes the remote server
to forward authentication requests to. hostname can be a
hostname (imap.example.com) or a dotted-quad IP address
(192.168.0.1). The latter is useful if the remote server is
multi-homed and has network interfaces that are unreachable from
the local IMAP server. The remote host is contacted on the
`imap' service port. A non-default port can be specified by
appending a slash and the port name or number to the hostname
argument.
The -O flag and argument are mandatory when using the rimap
mechanism.
shadow (AIX, Irix, Linux, Solaris)
Authenticate against the local "shadow password file". The
exact mechanism is system dependent. saslauthd currently
understands the getspnam() and getuserpw() library routines.
Some systems honour the -T flag.
sasldb (All platforms)
Authenticate against the SASL authentication database. Note
that this is probably not what you want to use, and is even
disabled at compile-time by default. If you want to use sasldb
with the SASL library, you probably want to use the
pwcheck_method of "auxprop" along with the sasldb auxprop plugin
instead.
ldap (All platforms that support OpenLDAP 2.0 or higher)
Authenticate against an ldap server. The ldap configuration
parameters are read from /usr/local/etc/saslauthd.conf. The
location of this file can be changed with the -O parameter. See
the LDAP_SASLAUTHD file included with the distribution for the
list of available parameters.
sia (Digital UNIX)
Authenticate using the Digital UNIX Security Integration
Architecture (a.k.a. "enhanced security").
NOTES
The kerberos4 authentication driver consumes considerable resources. To
perform an authentication it must obtain a ticket granting ticket from the
TGT server on every authentication request. The Kerberos library routines
that obtain the TGT also create a local ticket file, on the reasonable
assumption that you will want to save the TGT for use by other Kerberos
applications. These ticket files are unusable by saslauthd , however there
is no way not to create them. The overhead of creating and removing these
ticket files can cause serious performance degradation on busy servers.
(Kerberos was never intended to be used in this manner, anyway.)
FILES
/var/run/saslauthd/mux The default communications socket.
/usr/local/etc/saslauthd.conf
The default configuration file for ldap support.
SEE ALSO
passwd(1), getpwent(3), getspnam(3), getuserpw(3), sasl_checkpass(3)
sia_authenticate_user(3),
CMU-SASL 12 12 2005 CMU-SASL
cyrus-sasl2 2.1.28 - Generated Sat Sep 24 05:50:48 CDT 2022