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GSSPROXY.CONF(5) GssProxy Manual pages GSSPROXY.CONF(5)

gssproxy.conf - GssProxy Daemon Configuration file

Optional configuration directives for the gssproxy daemon.

GSS-Proxy conf files are classic ini-style configuration files. Each option consist of a key = value pair. Any characters behind '#' will be treated as comments and will be ignored. Boolean parameters accept "1", "true", "yes" and "on" as positive values. All other values will be considered as negative values.

GSS-Proxy conf files must either be named "gssproxy.conf", or be of the form "##-foo.conf" (that is, start with two numbers followed by a dash, and end in ".conf"). Files not conforming to this will be ignored unless specifically requested through command line parameters.

A section in a GSS-Proxy conf file is identified by the sectionname in square brackets ([sectionname]).

There is one special section for global gssproxy settings, called [gssproxy].

Services such as nfs, apache, ssh, etc. are represented by sections like [service/nfs], [service/apache], etc. and are identified by the "euid" setting (see below).

String parameters may contain substitution patterns. This allows gssproxy to deal with patterns for the storage location of keytabs or credential caches easier.

The supported patterns are:

%U

substitutes to the user's numeric uid (e.g. 123)

%u

substitutes to the user's username (e.g. john).

gssproxy supports the following options:

allow_any_uid (boolean)

Allow any process of any user to use this service.

Note that absent a custom socket option this option may cause a service definition to mask access to following services. To avoid issues change the order of services in your configuation file so that services with allow_any_uid enabled are listed last, or define a custom socket for other services.

Default: false

allow_protocol_transition (boolean)

Allow clients to request a ticket to self for an arbitrary user.

This option controls whether s4u2self requests are allowed for the requesting client. The configured keytab is used as the service identity for which a ticket is requested. The KDC still needs to allow the operation for it to succeed.

Default: false

allow_constrained_delegation (boolean)

Allow clients to request a ticket to another service using an evidence ticket.

This option controls whether s4u2proxy requests are allowed for the requesting client. The KDC still needs to allow the operation for it to succeed.

Default: false

allow_client_ccache_sync (boolean)

Allow clients to request credentials to be sent back for better caching.

This option allows the proxy, in certain circumstances, to send back an additional option in the response structure of certain calls when it determines that a new ticket may have been added to the internal ccache. Clients can then replace their (encrypted) copy with the updated ccache.

Default: false

cred_store (string)

This parameter allows to control in which way gssproxy should use the cred_store interface provided by GSSAPI. The parameter can be defined multiple times per service.

The syntax of the cred_store parameter is as follows: cred_store = <cred_store_option>:<cred_store_value>

Currently this interface supports the following options:

keytab

Defines the keytab the service should use. Example: cred_store = keytab:/path/to/keytab

client_keytab

Defines a client keytab the service should use. Example: cred_store = client_keytab:/path/to/client_keytab.

ccache

Defines a credential cache the service should use. Example: cred_store = ccache:/path/to/ccache.

Notably the client_keytab and the ccache setting typically are used with variable substitution placeholders (see above). For example:



    cred_store = keytab:/etc/krb5.keytab


    cred_store = ccache:FILE:/var/lib/gssproxy/krb5cc_%U


    cred_store = client_keytab:/var/lib/gssproxy/%U.keytab

Default: cred_store =

cred_usage (string)

Allow to restrict the kind of operations permitted for this service.

The allowed options are: initiate, accept, both

Default: cred_usage = both

debug (boolean)

Enable debugging to syslog. Setting to true is identical to setting debug_level to 1.

Default: debug = false

debug_level (integer)

Detail level at which to log debugging messages. 0 corresponds to no logging, while 1 turns on basic debug logging. Level 2 increases verbosity, including more detailed credential verification.

At level 3 and above, KRB5_TRACE output is logged. If KRB5_TRACE was already set in the execution environment, trace output is sent to its value instead.

Default: 1 if debug is true, otherwise 0

enforce_flags (string)

A list of GSS Request Flags that are added unconditionally to every context initialization call. Flags can only be added to the list or removed from the list by prepending a +/- sign to the flag name or value.

Recognized flag names: DELEGATE, MUTUAL_AUTH, REPLAY_DETECT, SEQUENCE, CONFIDENTIALITY, INTEGRITY, ANONYMOUS

Examples:



    enforce_flags = +REPLAY_DETECT


    enforce_flags = -0x0001

Default: enforce_flags =

euid (integer or string)

Either the numeric (e.g., 48) or symbolic (e.g., apache) effective uid of a running process, required to identify a service.

The "euid" parameter is imperative, any section without it will be discarded.

Default: euid =

filter_flags (string)

A list of GSS Request Flags that are filtered unconditionally from every context initialization call. Flags can only be added to the list or removed from the list by prepending a +/- sign to the flag name or value.

NOTE: Because often gssproxy is used to withold access to credentials the Delegate Flag is filtered by default. To allow a service to delegate credentials use the first example below.

Recognized flag names: DELEGATE, MUTUAL_AUTH, REPLAY_DETECT, SEQUENCE, CONFIDENTIALITY, INTEGRITY, ANONYMOUS

Examples:



    filter_flags = -DELEGATE


    filter_flags = -0x0001 +ANONYMOUS

Default: filter_flags = +DELEGATE

impersonate (boolean)

Use impersonation (s4u2self + s4u2proxy) to obtain credentials

Default: impersonate = false

kernel_nfsd (boolean)

Boolean flag that allows the Linux kernel to check if gssproxy is running (via /proc/net/rpc/use-gss-proxy).

Default: kernel_nfsd = false

krb5_principal (string)

The krb5 principal to be used preferred for this service, if one isn't requested by the application. Note that this does not enforce use of this specific name; it only sets a default.

Default: krb5_principal =

mechs (string)

Currently only krb5 is supported.

The "mechs" parameter is imperative, any section without it will be discarded.

Default: mechs =

program (string)

If specified, this service will only match when the program being run is the specified string.

Programs are assumed to be specified as canonical paths (i.e., no relative paths, no symlinks). Additionally, the '|' character is reserved for future use and therefore forbidden.

run_as_user (string)

The name of the user gssproxy will drop privileges to.

This option is only available in the global section.

Default: run_as_user =

selinux_context (string)

This option is deprecated. Use a custom socket or euid instead.

socket (string)

This parameter allows to create a per-service socket file over which gssproxy client and server components communicate.

When this parameter is not set, gssproxy will use a compiled-in default.

trusted (boolean)

Defines whether this service is considered trusted. Use with caution, this enables impersonation.

Default: trusted = false

worker threads (integer)

Defines the amount of worker threads gssproxy will create at startup.

Default: worker threads =

gssproxy(8) and gssproxy-mech(8).

GSS-Proxy - http://fedorahosted.org/gss-proxy

03/30/2020 GSS Proxy