.\"**************************************************************************** .\" Written by Chris Dunlap . .\" Copyright (C) 2007-2022 Lawrence Livermore National Security, LLC. .\" Copyright (C) 2002-2007 The Regents of the University of California. .\" UCRL-CODE-155910. .\" .\" This file is part of the MUNGE Uid 'N' Gid Emporium (MUNGE). .\" For details, see . .\" .\" 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. .\" .\" MUNGE is distributed in the hope that it will be useful, but WITHOUT .\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or .\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License .\" and GNU Lesser General Public License for more details. .\" .\" You should have received a copy of the GNU General Public License .\" and GNU Lesser General Public License along with MUNGE. If not, see .\" . .\"**************************************************************************** .TH MUNGED 8 "2022-06-22" "munge-0.5.15" "MUNGE Uid 'N' Gid Emporium" .SH NAME munged \- MUNGE daemon .SH SYNOPSIS .B munged [\fIOPTION\fR]... .SH DESCRIPTION The \fBmunged\fR daemon is responsible for authenticating local MUNGE clients and servicing their credential encode & decode requests. .PP All \fBmunged\fR 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 \fBmungekey\fR command. .PP When a credential is created, \fBmunged\fR embeds metadata within it including the effective UID and GID of the requesting client (as determined by \fBmunged\fR) 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. .PP When a credential is validated, \fBmunged\fR 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. .SH OPTIONS .TP .BI "\-h, \-\-help" Display a summary of the command-line options. .TP .BI "\-L, \-\-license" Display license information. .TP .BI "\-V, \-\-version" Display version information. .TP .BI "\-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. .TP .BI "\-F, \-\-foreground" Run the daemon in the foreground. .TP .BI "\-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. .TP .BI "\-s, \-\-stop" Stop the daemon bound to the socket and wait for it to shut down. Use with the \fB\-\-socket\fR 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. .TP .BI "\-S, \-\-socket " path Specify the local domain socket for communicating with clients. .TP .BI "\-v, \-\-verbose" Be verbose. .TP .BI "\-\-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. .TP .BI "\-\-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. .TP .BI "\-\-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. .TP .BI "\-\-group\-check\-mtime " boolean Specify whether the modification time of \fI/etc/group\fR 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. .TP .BI "\-\-group\-update\-time " seconds 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 \fBSIGHUP\fR). A value of \-1 causes it to be disabled. .TP .BI "\-\-key\-file " path Specify an alternate pathname to the key file. .TP .BI "\-\-log\-file " path Specify an alternate pathname to the log file. .TP .BI "\-\-max\-ttl " integer 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. .TP .BI "\-\-num\-threads " integer Specify the number of threads to spawn for processing credential requests. .TP .BI "\-\-origin " address 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 \fBgethostname()\fR. Failure to lookup the address will result in an error; if overridden, the origin will be set to the null address. .TP .BI "\-\-pid\-file " path Specify an alternate pathname for storing the Process ID of the daemon. .TP .BI "\-\-seed\-file " path Specify an alternate pathname to the PRNG seed file. .TP .BI "\-\-syslog" Redirect log messages to syslog when the daemon is running in the background. .TP .BI "\-\-trusted\-group " group 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). .SH SIGNALS .TP .B 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. .TP .B SIGTERM Terminate the daemon. .\" .SH FILES .SH NOTES All clocks within a security realm must be kept in sync within the credential time-to-live setting. .PP While \fBmunged\fR 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. .SH AUTHOR Chris Dunlap .SH COPYRIGHT Copyright (C) 2007-2022 Lawrence Livermore National Security, LLC. .br Copyright (C) 2002-2007 The Regents of the University of California. .PP 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. .PP 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. .SH "SEE ALSO" .BR munge (1), .BR remunge (1), .BR unmunge (1), .BR munge (3), .BR munge_ctx (3), .BR munge_enum (3), .BR munge (7), .BR mungekey (8). .PP \fBhttps://dun.github.io/munge/\fR