heimdal/lib/gssapi/krb5/gssapi.3

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.Dd April 20, 2005
.Dt GSSAPI 3
.Os
.Sh NAME
.Nm gssapi
.Nd Generic Security Service Application Program Interface library
.Sh LIBRARY
GSS-API Library (libgssapi, -lgssapi)
.Sh DESCRIPTION
The Generic Security Service Application Program Interface (GSS-API)
provides security services to callers in a generic fashion,
supportable with a range of underlying mechanisms and technologies and
hence allowing source-level portability of applications to different
environments.
.Pp
The GSS-API implementation in Heimdal implements the Kerberos 5 and
the SPNEGO GSS-API security mechanisms.
.Sh LIST OF FUNCTIONS
These functions constitute the gssapi library,
.Em libgssapi .
Declarations for these functions may be obtained from the include file
.Pa gssapi.h .
.sp 2
.nf
.ta \w'gss_inquire_names_for_mech'u+2n +\w'Description goes here'u
\fIName/Page\fP	\fIDescription\fP
.ta \w'gss_inquire_names_for_mech'u+2n +\w'Description goes here'u+6nC
.sp 5p
gss_accept_sec_context.3
gss_acquire_cred.3
gss_add_cred.3
gss_add_oid_set_member.3
gss_canonicalize_name.3
gss_compare_name.3
gss_context_time.3
gss_create_empty_oid_set.3
gss_delete_sec_context.3
gss_display_name.3
gss_display_status.3
gss_duplicate_name.3
gss_export_name.3
gss_export_sec_context.3
gss_get_mic.3
gss_import_name.3
gss_import_sec_context.3
gss_indicate_mechs.3
gss_init_sec_context.3
gss_inquire_context.3
gss_inquire_cred.3
gss_inquire_cred_by_mech.3
gss_inquire_mechs_for_name.3
gss_inquire_names_for_mech.3
gss_krb5_ccache_name.3
gss_krb5_compat_des3_mic.3
gss_krb5_copy_ccache.3
gss_krb5_extract_authz_data_from_sec_context.3
gss_krb5_import_ccache.3
gss_process_context_token.3
gss_release_buffer.3
gss_release_cred.3
gss_release_name.3
gss_release_oid_set.3
gss_seal.3
gss_sign.3
gss_test_oid_set_member.3
gss_unseal.3
gss_unwrap.3
gss_verify.3
gss_verify_mic.3
gss_wrap.3
gss_wrap_size_limit.3
.ta
.Fi
.Sh COMPATIBILITY
The
.Nm Heimdal
GSS-API implementation had a bug in releases before 0.6 that made it
fail to inter-operate when using DES3 with other GSS-API
implementations when using
.Fn gss_get_mic
/
.Fn gss_verify_mic .
It is possible to modify the behavior of the generator of the MIC with
the
.Pa krb5.conf
configuration file so that old clients/servers will still
work.
.Pp
New clients/servers will try both the old and new MIC in Heimdal 0.6.
In 0.7 it will check only if configured - the compatibility code will
be removed in 0.8.
.Pp
Heimdal 0.6 still generates by default the broken GSS-API DES3 mic,
this will change in 0.7 to generate correct des3 mic.
.Pp
To turn on compatibility with older clients and servers, change the
.Nm [gssapi]
.Ar broken_des3_mic
in
.Pa krb5.conf
that contains a list of globbing expressions that will be matched
against the server name.
To turn off generation of the old (incompatible) mic of the MIC use
.Nm [gssapi]
.Ar correct_des3_mic .
.Pp
If a match for a entry is in both
.Nm [gssapi]
.Ar correct_des3_mic
and
.Nm [gssapi]
.Ar broken_des3_mic ,
the later will override.
.Pp
This config option modifies behaviour for both clients and servers.
.Pp
Microsoft implemented SPNEGO to Windows2000, however, they manage to
get it wrong, their implementation didn't fill in the MechListMIC in
the reply token with the right content.
There is a work around for this problem, but not all implementation
support it.
.Pp
Heimdal defaults to correct SPNEGO when the the kerberos
implementation uses CFX, or when its configured by the user.
To turn on compatibility with peers, use option
.Nm [gssapi]
.Ar require_mechlist_mic .
.Sh EXAMPLES
.Bd -literal -offset indent
[gssapi]
	broken_des3_mic = cvs/*@SU.SE
	broken_des3_mic = host/*@E.KTH.SE
	correct_des3_mic = host/*@SU.SE
	require_mechlist_mic = host/*@SU.SE
.Ed
.Sh BUGS
All of 0.5.x versions of
.Nm heimdal
had broken token delegations in the client side, the server side was
correct.
.Sh SEE ALSO
.Xr krb5 3 ,
.Xr krb5.conf 5 ,
.Xr kerberos 8