Provided by: munge_0.5.11-3ubuntu0.1_amd64 
NAME
munged - MUNGE daemon
SYNOPSIS
munged [OPTION]...
DESCRIPTION
The munged daemon is responsible for authenticating local MUNGE clients and servicing their credential
encode & decode requests. All munged daemons within a security realm share a secret key. This key is
used to protect the contents of a credential.
When a credential is created, munged embeds metadata within it including the effective UID and GID of the
requesting client (as determined by munged) and the current time (as determined by the local clock). It
then compresses the data, computes a message authentication code, encrypts the data, and base64-encodes
the result before returning the credential to the client.
When a credential is validated, munged first checks the message authentication code to ensure the
credential has not been subsequently altered. Next, it checks the embedded UID/GID restrictions to
determine whether the requesting client is allowed to decode it. Then, it checks the embedded encode
time against the current time; if this difference exceeds the embedded time-to-live, the credential has
expired. Finally, it checks whether this credential has been previously decoded on this host; if so, the
credential has been replayed. If all checks pass, the credential metadata and payload are returned to
the client.
OPTIONS
-h, --help
Display a summary of the command-line options.
-L, --license
Display license information.
-V, --version
Display version information.
-f, --force
Force the daemon to run if at all possible. This overrides warnings for an existing local domain
socket, a lack of entropy for the PRNG, and insecure file/directory permissions. Use with caution
as overriding these warnings can affect security.
-F, --foreground
Run the daemon in the foreground.
-M, --mlockall
Lock all current and future pages in the virtual memory address space. Access to locked pages
will never be delayed by a page fault. This can improve performance and help the daemon remain
responsive when the system is under heavy memory pressure. This typically requires root
privileges or the CAP_IPC_LOCK capability.
-S, --socket path
Specify the local domain socket for communicating with clients.
--auth-server-dir directory
Specify an alternate directory in which the daemon will create the pipe used to authenticate
clients. The recommended permissions for this directory are 0711. This option is only valid on
platforms where client authentication is performed via a file-descriptor passing mechanism.
--auth-client-dir directory
Specify an alternate directory in which clients will create the file used to authenticate
themselves to the daemon. The recommended permissions for this directory are 1733. This option
is only valid on platforms where client authentication is performed via a file-descriptor passing
mechanism.
--benchmark
Disable recurring timers in order to reduce some noise while benchmarking. This affects the PRNG
entropy pool, supplementary group mapping, and credential replay hash. Do not enable this option
when running in production.
--group-check-mtime boolean
Specify whether the modification time of /etc/group should be checked before updating the
supplementary group membership mapping. If this value is non-zero, the check will be enabled and
the mapping will not be updated unless the file has been modified since the last update.
--group-update-time integer
Specify the number of seconds between updates to the supplementary group membership mapping; this
mapping is used when restricting credentials by GID. A value of 0 causes it to be computed
initially but never updated (unless triggered by a SIGHUP). A value of -1 causes it to be
disabled.
--key-file file
Specify an alternate secret key file.
--num-threads integer
Specify the number of threads to spawn for processing credential requests.
--syslog
Redirect log messages to syslog when the daemon is running in the background.
SIGNALS
SIGHUP Immediately update the supplementary group membership mapping instead of waiting for the next
scheduled update; this mapping is used when restricting credentials by GID.
SIGTERM
Terminate the daemon.
NOTES
All clocks within a security realm must be kept in sync within the credential time-to-live setting.
While munged prevents a given credential from being decoded on a particular host more than once, nothing
prevents a credential from being decoded on multiple hosts within the security realm before it expires.
AUTHOR
Chris Dunlap <cdunlap@llnl.gov>
COPYRIGHT
Copyright (C) 2007-2013 Lawrence Livermore National Security, LLC.
Copyright (C) 2002-2007 The Regents of the University of California.
MUNGE is free software: you can redistribute it and/or modify it under the terms of the GNU General
Public License as published by the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
Additionally for the MUNGE library (libmunge), you can redistribute it and/or modify it under the terms
of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3
of the License, or (at your option) any later version.
SEE ALSO
munge(1), remunge(1), unmunge(1), munge(3), munge_ctx(3), munge_enum(3), munge(7).
https://munge.googlecode.com/
munge-0.5.11 2013-08-27 MUNGED(8)