|lcas_lcmaps_gt_interface(8)||Site Access Control||lcas_lcmaps_gt_interface(8)|
lcas_lcmaps_gt_interface - A Globus GSI-AuthZ plug-in to run LCAS and LCMAPS
This is a plug-in to be loaded from a GSI-AuthZ capable Globus service. The feature was introduced in Globus GT4 and is available for GT5 and GT6. The purpose of this call-out is to authorize a user by optionally running the LCAS framework and subsequently running the LCMAPS framework to map the user credentials to a Unix account. Both LCAS and LCMAPS are plug-in frameworks, where the plug-ins to do the real work.
Some of these plug-ins are capable of imposing a certain policy on the user credentials, others are capable of off-loading the decision to a centralized service to make the decision or even provide an account mapping in the process.
This plug-in is dynamically loaded during each interaction that requires an account mapping in the GSI-AuthZ interface of a Globus service. It has no configuration file for itself, it is configured via environment variables and the LCAS and LCMAPS configuration files. It can be enabled for use in the GSI-AuthZ interface using the gsi-authz.conf file, by configuring it to call the function lcmaps_callout(), which can be done using gt4-interface-install(8).
- When this variable is set and it can be opened as file, log output will go to the given file instead of to syslog. When either $LCAS_LOG_FILE or $LCMAPS_LOG_FILE is unset, it will also be set to this same file.
- Change the default logging facility with the $LLGT_LOG_FACILITY environment variable. Use the name of (standard syslog) facility names. Example: LOG_DAEMON, LOG_LOCAL1, etc.
- The $LLGT_LOG_IDENT can (optionally) be set as the syslog ident value. This will be the identifying string in syslog for the current process. Not using this option will let syslog (or one of the GT services) to set these options. By default the syslog ident will be set to the executable name.
- Set the environment variable $LLGT_RUN_LCAS to "no",
"disabled" or "disable" to avoid LCAS to run prior to
There is a matching ./configure option "--enable-lcas" which can be used to change the default behaviour to run LCAS or not. The $LLGT_RUN_LCAS environment variable can still influence the LCAS run.
- Normally the callout, after LCMAPS has finished, checks whether it is
(still) running with root privileges (uid, euid, gid or egid) and fails if
that is the case. This is to prevent erroneous configurations to silently
result in a root-account mapping in services that do not have their own
checks for this.
When the environment variable $LLGT_LIFT_PRIVILEGED_PROTECTION is set, this check is disabled. This is NEEDED for services that:
1.) don't user switch, and run as root.
2.) services that expect only a username to be returned and perform the user switch themselves, e.g. the Globus GSI-OpenSSHd.
- Set the environment variable $LLGT_CACHE_CALLOUT to "no", "disabled" or "disable" to disable reusing the result of the `localname' callout for the `userok' callout. This results in calling the LCAS/LCMAPS authorization twice for e.g. gsisshd.
- Set the environment variable $LLGT_DLCLOSE_LCMAPS to "no", "disabled" or "disable" to prevent calling dlclose() on the LCMAPS library. This might be needed as a workaround on RH5-based systems in an installation for gsisshd, when the use of PAM is enabled ("UsePAM Yes" in the /etc/gsissh/sshd_config). The underlying bug is a combination between the OpenSSL, VOMS and PAM libraries, which can trigger a segfault when VOMS is initialized twice.
- Set the environment variable $LLGT_DLCLOSE_LCAS to "no", "disabled" or "disable" to prevent calling dlclose() on the LCAS library. This might be needed as a workaround on RH5-based systems. The underlying bug is a combination between the OpenSSL, VOMS and Globus libraries, which can trigger a segfault when VOMS is initialized twice, which can happen when LCAS is using a VOMS based plugin. Normally should not be needed as LCAS is now dlclosed and terminated after LCMAPS.
- LLGT_NO_CHANGE_USER (deprecated)
- Deprecated $LLGT_NO_CHANGE_USER in favour of $LLGT_LIFT_PRIVILEGED_PROTECTION. (Deprecation does not mean non-functional anymore)
- LLGT4_NO_CHANGE_USER (deprecated)
- Deprecated $LLGT4_NO_CHANGE_USER in favour of $LLGT_LIFT_PRIVILEGED_PROTECTION. (Depreciation does not mean non-functional anymore)
- The VOMS credentials are verified by the LCMAPS framework before further processing is done in the plug-ins. The LCMAPS framework has an API to enable or disable the verification of the VOMS credentials and this option will disable the verification of the VOMS credentials. A vanilla LCMAPS build will verify the VOMS credentials by default.
- Similar to the $LLGT_VOMS_DISABLE_CREDENTIAL_CHECK environment variable, this setting will enable the verification of the VOMS credentials, overriding the LCMAPS default setting to have the verification of VOMS credentials to be disabled. A vanilla LCMAPS build will verify the VOMS credentials by default, the OSG build has is disabled by default.
- Support for an alternative LCAS_LIBDIR as a run-time setting by exporting such as $LLGT_LCAS_LIBDIR="/usr/lib/x86_64-linux-gnu/liblcas.so"
- When set, used as suffix instead of the default /lcas when setting the $LCAS_MODULES_DIR variable based on the $LLGT_LCAS_LIBDIR variable. Default /lcas. NOTE: current versions of LCAS do not yet use the $LCAS_MODULES_DIR variable.
- Support for an alternative LCMAPS_LIBDIR as a run-time setting by exporting such as $LLGT_LCMAPS_LIBDIR="/usr/lib/x86_64-linux-gnu/liblcmaps.so". Must be an absolute path. Setting this variable will also set the LCMAPS variable $LCMAPS_MODULES_DIR to the given libdir followed by either the default /lcmaps or the value of $LLGT_LCMAPS_MODULEDIR_SFX.
- When set, used as suffix instead of the default /lcmaps when setting the $LCMAPS_MODULES_DIR variable based on the $LLGT_LCMAPS_LIBDIR variable. Default /lcmaps.
- If the $LLGT_ENABLE_DEBUG environment variable is set, then the debugging message logged at level LOG_DEBUG are passed to the log. The scope of this setting is only within the LCAS-LCMAPS-GT-interface
INTERNAL ENVIRONMENT VARIABLES¶
LCAS ENVIRONMENT VARIABLES¶
The following list of LCAS environment variables are handled specially by the interface.
- Default directory for LCAS to look for in plug-ins (not yet supported by LCAS). Will be set based on the values of $LLGT_LCAS_LIBDIR and $LLGT_LCAS_MODULEDIR_SFX or their defaults.
- When set, LCAS will log there instead of syslog. When unset, it will get the value of $LLGT_LOG_FILE when that one is set. When compiled with LCAS_LCMAPS_FORCE_LOG_TO_FILE defined, it will get set to /var/log/gt_lcas_lcmaps.log.
- LCAS log level. Default: 3.
- Location of the LCAS configuration file. Default for the interface: /etc/lcas/lcas.db
LCMAPS ENVIRONMENT VARIABLES¶
The following list of LCMAPS environment variables are handled specially by the interface.
- Default directory for LCMAPS to look for in plug-ins. Will be set based on the values of $LLGT_LCMAPS_LIBDIR and $LLGT_LCMAPS_MODULEDIR_SFX or their defaults.
- When set, LCMAPS will log there instead of syslog. When unset, it will get the value of $LLGT_LOG_FILE when that one is set. When compiled with LCAS_LCMAPS_FORCE_LOG_TO_FILE defined, it will get set to /var/log/gt_lcas_lcmaps.log.
- For LCMAPS 1.5.0 (and newer) the value "5" corresponds to syslog LOG_DEBUG, "4" corresponds to LOG_INFO, "3" to LOG_NOTICE and so on. The LCMAPS default is to log up to LOG_INFO.
- Location of the LCMAPS configuration file. Default for the interface: /etc/lcmaps/lcmaps.db
From version 0.3.1 onwards, the interface supports the 'sharing' service: it then expects an additional argument, (a PEM string) containing the credential on which the mapping should be based.
From version 0.3.0 onwards, the interface tries to forward the requested username to LCMAPS (for version 1.6.0 and up). The mapping plugins can use this to support multiple username entries in the grid-mapfile, or enforcing pool account mappings to a specific pool account.
Please report any errors to the Nikhef Grid Middleware Security Team <firstname.lastname@example.org>.
LCMAPS and the LCMAPS plug-ins were written by the Grid Middleware Security Team <email@example.com>.
|February 11, 2015||lcas-lcmaps-gt4-interface 0.3.1|