GSS-API Library (libgssapi, -lgssapi)

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.

The GSS-API implementation in Heimdal implements the Kerberos 5 and the SPNEGO GSS-API security mechanisms.

These functions constitute the gssapi library, Declarations for these functions may be obtained from the include file gssapi.h .

Name/Page	Description

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_copy_ccache.3
gss_krb5_compat_des3_mic.3
gss_krb5_extract_authz_data_from_sec_context.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

The 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 gss_get_mic / gss_verify_mic . It is possible to modify the behavior of the generator of the MIC with the krb5.conf configuration file so that old clients/servers will still work.

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.

Heimdal 0.6 still generates by default the broken GSS-API DES3 mic, this will change in 0.7 to generate correct des3 mic.

To turn on compatibility with older clients and servers, change the [gssapi] broken_des3_mic in 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 [gssapi] correct_des3_mic .

If a match for a entry is in both [gssapi] correct_des3_mic and [gssapi] broken_des3_mic , the later will override.

This config option modifies behaviour for both clients and servers.

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.

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 [gssapi] require_mechlist_mic .

[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

All of 0.5.x versions of heimdal had broken token delegations in the client side, the server side was correct.