munged - MUNGE daemon

       Chris Dunlap <cdunlap@llnl.gov>

       Copyright (C) 2007-2024 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.

       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 common key.  All hosts within this realm are  expected
       to have common users/UIDs and groups/GIDs.  The key is used to cryptographically protect the credentials;
       it is created with the mungekey command.

       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.

       munged - MUNGE daemon

       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.

-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,--stop
              Stop the daemon bound to the socket and wait for it to shut down.  Use with the --socket option to
              target a daemon bound to a non-default socket location.  This option exits with a zero  status  if
              the specified daemon was successfully stopped, or a non-zero status otherwise.

       -S,--socketpath
              Specify the local domain socket for communicating with clients.

       -v,--verbose
              Be verbose.

       --auth-server-dirdirectory
              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-dirdirectory
              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-mtimeboolean
              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-timeseconds
              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-filepath
              Specify an alternate pathname to the key file.

       --listen-backloginteger
              Specify the socket's listen backlog limit; note that the kernel may impose a lower limit.  A value
              of  0  uses  the  software default.  A value of -1 specifies SOMAXCONN, the maximum listen backlog
              queue length defined in <sys/socket.h>.

       --log-filepath
              Specify an alternate pathname to the log file.

       --max-ttlinteger
              Specify the maximum allowable time-to-live value (in seconds) for a credential.  This setting  has
              an  upper-bound  imposed  by  the  hard-coded MUNGE_MAXIMUM_TTL value.  Reducing it will limit the
              maximum growth of the credential replay cache.  This is viable if clocks within  the  MUNGE  realm
              can be kept in sync with minimal skew.

       --num-threadsinteger
              Specify the number of threads to spawn for processing credential requests.

       --originaddress
              Specify  the origin address that will be encoded into credential metadata.  This can be a hostname
              or IPv4 address; it can also be the name of a local network interface, in  which  case  the  first
              IPv4 address found assigned to that interface will be used.  The default value is the IPv4 address
              of the hostname returned by gethostname().  Failure to lookup the address will result in an error;
              if overridden, the origin will be set to the null address.

       --pid-filepath
              Specify an alternate pathname for storing the Process ID of the daemon.

       --seed-filepath
              Specify an alternate pathname to the PRNG seed file.

       --syslog
              Redirect log messages to syslog when the daemon is running in the background.

       --trusted-groupgroup
              Specify  the  group  name  or GID of the "trusted group".  This is used for permission checks on a
              directory hierarchy.  Directories with group write permissions are allowed if they  are  owned  by
              the trusted group (or the sticky bit is set).

munge(1), remunge(1), unmunge(1), munge(3), munge_ctx(3), munge_enum(3), munge(7), mungekey(8).

       https://github.com/dun/munge

munge-0.5.16                                       2024-03-15                                          MUNGED(8)

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.

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