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.Dd October 26, 2005
.Dt GSS_ACQUIRE_CRED 3
.Os HEIMDAL
.Sh NAME
.Nm gss_accept_sec_context ,
.Nm gss_acquire_cred ,
.Nm gss_add_cred ,
.Nm gss_add_oid_set_member ,
.Nm gss_canonicalize_name ,
.Nm gss_compare_name ,
.Nm gss_context_time ,
.Nm gss_create_empty_oid_set ,
.Nm gss_delete_sec_context ,
.Nm gss_display_name ,
.Nm gss_display_status ,
.Nm gss_duplicate_name ,
.Nm gss_export_name ,
.Nm gss_export_sec_context ,
.Nm gss_get_mic ,
.Nm gss_import_name ,
.Nm gss_import_sec_context ,
.Nm gss_indicate_mechs ,
.Nm gss_init_sec_context ,
.Nm gss_inquire_context ,
.Nm gss_inquire_cred ,
.Nm gss_inquire_cred_by_mech ,
.Nm gss_inquire_mechs_for_name ,
.Nm gss_inquire_names_for_mech ,
.Nm gss_krb5_ccache_name ,
.Nm gss_krb5_compat_des3_mic ,
.Nm gss_krb5_copy_ccache ,
.Nm gss_krb5_import_cred
.Nm gsskrb5_extract_authz_data_from_sec_context ,
.Nm gsskrb5_register_acceptor_identity ,
.Nm gss_krb5_import_ccache ,
.Nm gss_krb5_get_tkt_flags ,
.Nm gss_process_context_token ,
.Nm gss_release_buffer ,
.Nm gss_release_cred ,
.Nm gss_release_name ,
.Nm gss_release_oid_set ,
.Nm gss_seal ,
.Nm gss_sign ,
.Nm gss_test_oid_set_member ,
.Nm gss_unseal ,
.Nm gss_unwrap ,
.Nm gss_verify ,
.Nm gss_verify_mic ,
.Nm gss_wrap ,
.Nm gss_wrap_size_limit
.Nd Generic Security Service Application Program Interface library
.Sh LIBRARY
GSS-API library (libgssapi, -lgssapi)
.Sh SYNOPSIS
.In gssapi.h
.Pp
.Ft OM_uint32
.Fo gss_accept_sec_context
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t * context_handle"
.Fa "const gss_cred_id_t acceptor_cred_handle"
.Fa "const gss_buffer_t input_token_buffer"
.Fa "const gss_channel_bindings_t input_chan_bindings"
.Fa "gss_name_t * src_name"
.Fa "gss_OID * mech_type"
.Fa "gss_buffer_t output_token"
.Fa "OM_uint32 * ret_flags"
.Fa "OM_uint32 * time_rec"
.Fa "gss_cred_id_t * delegated_cred_handle"
.Fc
.Pp
.Ft OM_uint32
.Fo gss_acquire_cred
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t desired_name"
.Fa "OM_uint32 time_req"
.Fa "const gss_OID_set desired_mechs"
.Fa "gss_cred_usage_t cred_usage"
.Fa "gss_cred_id_t * output_cred_handle"
.Fa "gss_OID_set * actual_mechs"
.Fa "OM_uint32 * time_rec"
.Fc
.Ft OM_uint32
.Fo gss_add_cred
.Fa "OM_uint32 *minor_status"
.Fa "const gss_cred_id_t input_cred_handle"
.Fa "const gss_name_t desired_name"
.Fa "const gss_OID desired_mech"
.Fa "gss_cred_usage_t cred_usage"
.Fa "OM_uint32 initiator_time_req"
.Fa "OM_uint32 acceptor_time_req"
.Fa "gss_cred_id_t *output_cred_handle"
.Fa "gss_OID_set *actual_mechs"
.Fa "OM_uint32 *initiator_time_rec"
.Fa "OM_uint32 *acceptor_time_rec"
.Fc
.Ft OM_uint32
.Fo gss_add_oid_set_member
.Fa "OM_uint32 * minor_status"
.Fa "const gss_OID member_oid"
.Fa "gss_OID_set * oid_set"
.Fc
.Ft OM_uint32
.Fo gss_canonicalize_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t input_name"
.Fa "const gss_OID mech_type"
.Fa "gss_name_t * output_name"
.Fc
.Ft OM_uint32
.Fo gss_compare_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t name1"
.Fa "const gss_name_t name2"
.Fa "int * name_equal"
.Fc
.Ft OM_uint32
.Fo gss_context_time
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "OM_uint32 * time_rec"
.Fc
.Ft OM_uint32
.Fo gss_create_empty_oid_set
.Fa "OM_uint32 * minor_status"
.Fa "gss_OID_set * oid_set"
.Fc
.Ft OM_uint32
.Fo gss_delete_sec_context
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t * context_handle"
.Fa "gss_buffer_t output_token"
.Fc
.Ft OM_uint32
.Fo gss_display_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t input_name"
.Fa "gss_buffer_t output_name_buffer"
.Fa "gss_OID * output_name_type"
.Fc
.Ft OM_uint32
.Fo gss_display_status
.Fa "OM_uint32 *minor_status"
.Fa "OM_uint32 status_value"
.Fa "int status_type"
.Fa "const gss_OID mech_type"
.Fa "OM_uint32 *message_context"
.Fa "gss_buffer_t status_string"
.Fc
.Ft OM_uint32
.Fo gss_duplicate_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t src_name"
.Fa "gss_name_t * dest_name"
.Fc
.Ft OM_uint32
.Fo gss_export_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t input_name"
.Fa "gss_buffer_t exported_name"
.Fc
.Ft OM_uint32
.Fo gss_export_sec_context
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t * context_handle"
.Fa "gss_buffer_t interprocess_token"
.Fc
.Ft OM_uint32
.Fo gss_get_mic
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "gss_qop_t qop_req"
.Fa "const gss_buffer_t message_buffer"
.Fa "gss_buffer_t message_token"
.Fc
.Ft OM_uint32
.Fo gss_import_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_buffer_t input_name_buffer"
.Fa "const gss_OID input_name_type"
.Fa "gss_name_t * output_name"
.Fc
.Ft OM_uint32
.Fo gss_import_sec_context
.Fa "OM_uint32 * minor_status"
.Fa "const gss_buffer_t interprocess_token"
.Fa "gss_ctx_id_t * context_handle"
.Fc
.Ft OM_uint32
.Fo gss_indicate_mechs
.Fa "OM_uint32 * minor_status"
.Fa "gss_OID_set * mech_set"
.Fc
.Ft OM_uint32
.Fo gss_init_sec_context
.Fa "OM_uint32 * minor_status"
.Fa "const gss_cred_id_t initiator_cred_handle"
.Fa "gss_ctx_id_t * context_handle"
.Fa "const gss_name_t target_name"
.Fa "const gss_OID mech_type"
.Fa "OM_uint32 req_flags"
.Fa "OM_uint32 time_req"
.Fa "const gss_channel_bindings_t input_chan_bindings"
.Fa "const gss_buffer_t input_token"
.Fa "gss_OID * actual_mech_type"
.Fa "gss_buffer_t output_token"
.Fa "OM_uint32 * ret_flags"
.Fa "OM_uint32 * time_rec"
.Fc
.Ft OM_uint32
.Fo gss_inquire_context
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "gss_name_t * src_name"
.Fa "gss_name_t * targ_name"
.Fa "OM_uint32 * lifetime_rec"
.Fa "gss_OID * mech_type"
.Fa "OM_uint32 * ctx_flags"
.Fa "int * locally_initiated"
.Fa "int * open_context"
.Fc
.Ft OM_uint32
.Fo gss_inquire_cred
.Fa "OM_uint32 * minor_status"
.Fa "const gss_cred_id_t cred_handle"
.Fa "gss_name_t * name"
.Fa "OM_uint32 * lifetime"
.Fa "gss_cred_usage_t * cred_usage"
.Fa "gss_OID_set * mechanisms"
.Fc
.Ft OM_uint32
.Fo gss_inquire_cred_by_mech
.Fa "OM_uint32 * minor_status"
.Fa "const gss_cred_id_t cred_handle"
.Fa "const gss_OID mech_type"
.Fa "gss_name_t * name"
.Fa "OM_uint32 * initiator_lifetime"
.Fa "OM_uint32 * acceptor_lifetime"
.Fa "gss_cred_usage_t * cred_usage"
.Fc
.Ft OM_uint32
.Fo gss_inquire_mechs_for_name
.Fa "OM_uint32 * minor_status"
.Fa "const gss_name_t input_name"
.Fa "gss_OID_set * mech_types"
.Fc
.Ft OM_uint32
.Fo gss_inquire_names_for_mech
.Fa "OM_uint32 * minor_status"
.Fa "const gss_OID mechanism"
.Fa "gss_OID_set * name_types"
.Fc
.Ft OM_uint32
.Fo gss_krb5_ccache_name
.Fa "OM_uint32 *minor"
.Fa "const char *name"
.Fa "const char **old_name"
.Fc
.Ft OM_uint32
.Fo gss_krb5_copy_ccache
.Fa "OM_uint32 *minor"
.Fa "gss_cred_id_t cred"
.Fa "krb5_ccache out"
.Fc
.Ft OM_uint32
.Fo gss_krb5_import_cred
.Fa "OM_uint32 *minor_status"
.Fa "krb5_ccache id"
.Fa "krb5_principal keytab_principal"
.Fa "krb5_keytab keytab"
.Fa "gss_cred_id_t *cred"
.Fc
.Ft OM_uint32
.Fo gss_krb5_compat_des3_mic
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "int onoff"
.Fc
.Ft OM_uint32
.Fo gsskrb5_extract_authz_data_from_sec_context
.Fa "OM_uint32 *minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "int ad_type"
.Fa "gss_buffer_t ad_data"
.Fc
.Ft OM_uint32
.Fo gsskrb5_register_acceptor_identity
.Fa "const char *identity"
.Fc
.Ft OM_uint32
.Fo gss_krb5_import_cache
.Fa "OM_uint32 *minor"
.Fa "krb5_ccache id"
.Fa "krb5_keytab keytab"
.Fa "gss_cred_id_t *cred"
.Fc
.Ft OM_uint32
.Fo gss_krb5_get_tkt_flags
.Fa "OM_uint32 *minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "OM_uint32 *tkt_flags"
.Fc
.Ft OM_uint32
.Fo gss_process_context_token
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "const gss_buffer_t token_buffer"
.Fc
.Ft OM_uint32
.Fo gss_release_buffer
.Fa "OM_uint32 * minor_status"
.Fa "gss_buffer_t buffer"
.Fc
.Ft OM_uint32
.Fo gss_release_cred
.Fa "OM_uint32 * minor_status"
.Fa "gss_cred_id_t * cred_handle"
.Fc
.Ft OM_uint32
.Fo gss_release_name
.Fa "OM_uint32 * minor_status"
.Fa "gss_name_t * input_name"
.Fc
.Ft OM_uint32
.Fo gss_release_oid_set
.Fa "OM_uint32 * minor_status"
.Fa "gss_OID_set * set"
.Fc
.Ft OM_uint32
.Fo gss_seal
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "int conf_req_flag"
.Fa "int qop_req"
.Fa "gss_buffer_t input_message_buffer"
.Fa "int * conf_state"
.Fa "gss_buffer_t output_message_buffer"
.Fc
.Ft OM_uint32
.Fo gss_sign
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "int qop_req"
.Fa "gss_buffer_t message_buffer"
.Fa "gss_buffer_t message_token"
.Fc
.Ft OM_uint32
.Fo gss_test_oid_set_member
.Fa "OM_uint32 * minor_status"
.Fa "const gss_OID member"
.Fa "const gss_OID_set set"
.Fa "int * present"
.Fc
.Ft OM_uint32
.Fo gss_unseal
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "gss_buffer_t input_message_buffer"
.Fa "gss_buffer_t output_message_buffer"
.Fa "int * conf_state"
.Fa "int * qop_state"
.Fc
.Ft OM_uint32
.Fo gss_unwrap
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "const gss_buffer_t input_message_buffer"
.Fa "gss_buffer_t output_message_buffer"
.Fa "int * conf_state"
.Fa "gss_qop_t * qop_state"
.Fc
.Ft OM_uint32
.Fo gss_verify
.Fa "OM_uint32 * minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "gss_buffer_t message_buffer"
.Fa "gss_buffer_t token_buffer"
.Fa "int * qop_state"
.Fc
.Ft OM_uint32
.Fo gss_verify_mic
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "const gss_buffer_t message_buffer"
.Fa "const gss_buffer_t token_buffer"
.Fa "gss_qop_t * qop_state"
.Fc
.Ft OM_uint32
.Fo gss_wrap
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "int conf_req_flag"
.Fa "gss_qop_t qop_req"
.Fa "const gss_buffer_t input_message_buffer"
.Fa "int * conf_state"
.Fa "gss_buffer_t output_message_buffer"
.Fc
.Ft OM_uint32
.Fo gss_wrap_size_limit
.Fa "OM_uint32 * minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "int conf_req_flag"
.Fa "gss_qop_t qop_req"
.Fa "OM_uint32 req_output_size"
.Fa "OM_uint32 * max_input_size"
.Fc
.Sh DESCRIPTION
Generic Security Service API (GSS-API) version 2, and its C binding,
is described in
.Li RFC2743
and
.Li RFC2744 .
Version 1 (deprecated) of the C binding is described in
.Li RFC1509 .
.Pp
Heimdals GSS-API implementation supports the following mechanisms
.Bl -bullet
.It
.Li GSS_KRB5_MECHANISM
.It
.Li GSS_SPNEGO_MECHANISM
.El
.Pp
GSS-API have generic name types that all mechanism are supposed to
implement (if possible):
.Bl -bullet
.It
.Li GSS_C_NT_USER_NAME
.It
.Li GSS_C_NT_MACHINE_UID_NAME
.It
.Li GSS_C_NT_STRING_UID_NAME
.It
.Li GSS_C_NT_HOSTBASED_SERVICE
.It
.Li GSS_C_NT_ANONYMOUS
.It
.Li GSS_C_NT_EXPORT_NAME
.El
.Pp
GSS-API implementations that supports Kerberos 5 have some additional
name types:
.Bl -bullet
.It
.Li GSS_KRB5_NT_PRINCIPAL_NAME
.It
.Li GSS_KRB5_NT_USER_NAME
.It
.Li GSS_KRB5_NT_MACHINE_UID_NAME
.It
.Li GSS_KRB5_NT_STRING_UID_NAME
.El
.Pp
In GSS-API, names have two forms, internal names and contiguous string
names.
.Bl -bullet
.It
.Li Internal name and mechanism name
.Pp
Internal names are implementation specific representation of
a GSS-API name.
.Li Mechanism names
special form of internal names corresponds to one and only one mechanism.
.Pp
In GSS-API an internal name is stored in a
.Dv gss_name_t .
.It
.Li Contiguous string name and exported name
.Pp
Contiguous string names are gssapi names stored in a
.Dv OCTET STRING
that together with a name type identifier (OID) uniquely specifies a
gss-name.
A special form of the contiguous string name is the exported name that
have a OID embedded in the string to make it unique.
Exported name have the nametype
.Dv GSS_C_NT_EXPORT_NAME .
.Pp
In GSS-API an contiguous string name is stored in a
.Dv gss_buffer_t .
.Pp
Exported names also have the property that they are specified by the
mechanism itself and compatible between different GSS-API
implementations.
.El
.Sh ACCESS CONTROL
There are two ways of comparing GSS-API names, either comparing two
internal names with each other or two contiguous string names with
either other.
.Pp
To compare two internal names with each other, import (if needed) the
names with
.Fn gss_import_name
into the GSS-API implementation and the compare the imported name with
.Fn gss_compare_name .
.Pp
Importing names can be slow, so when its possible to store exported
names in the access control list, comparing contiguous string name
might be better.
.Pp
when comparing contiguous string name, first export them into a
.Dv GSS_C_NT_EXPORT_NAME
name with
.Fn gss_export_name
and then compare with
.Xr memcmp 3 .
.Pp
Note that there are might be a difference between the two methods of
comparing names.
The first (using
.Fn gss_compare_name )
will compare to (unauthenticated) names are the same.
The second will compare if a mechanism will authenticate them as the
same principal.
.Pp
For example, if
.Fn gss_import_name
name was used with
.Dv GSS_C_NO_OID
the default syntax is used for all mechanism the GSS-API
implementation supports.
When compare the imported name of
.Dv GSS_C_NO_OID
it may match serveral mechanism names (MN).
.Pp
The resulting name from
.Fn gss_display_name
must not be used for acccess control.
.Sh FUNCTIONS
.Fn gss_display_name
takes the gss name in
.Fa input_name
and puts a printable form in
.Fa output_name_buffer .
.Fa output_name_buffer
should be freed when done using
.Fn gss_release_buffer .
.Fa output_name_type
can either be
.Dv NULL
or a pointer to a
.Li gss_OID
and will in the latter case contain the OID type of the name.
The name must only be used for printing.
If access control is needed, see section
.Sx ACCESS CONTROL .
.Pp
.Fn gss_inquire_context
returns information about the context.
Information is available even after the context have expired.
.Fa lifetime_rec
argument is set to
.Dv GSS_C_INDEFINITE
(dont expire) or the number of seconds that the context is still valid.
A value of 0 means that the context is expired.
.Fa mech_type
argument should be considered readonly and must not be released.
.Fa src_name
and
.Fn dest_name
are both mechanims names and must be released with
.Fn gss_release_name
when no longer used.
.Pp
.Nm gss_context_time
will return the amount of time (in seconds) of the context is still
valid.
If its expired
.Fa time_rec
will be set to 0 and
.Dv GSS_S_CONTEXT_EXPIRED
returned.
.Pp
.Fn gss_sign ,
.Fn gss_verify ,
.Fn gss_seal ,
and
.Fn gss_unseal
are part of the GSS-API V1 interface and are obsolete.
The functions should not be used for new applications.
They are provided so that version 1 applications can link against the
library.
.Sh EXTENSIONS
.Fn gss_krb5_ccache_name
sets the internal kerberos 5 credential cache name to
.Fa name .
The old name is returned in
.Fa old_name ,
and must not be freed.
The data allocated for
.Fa old_name
is free upon next call to
.Fn gss_krb5_ccache_name .
This function is not threadsafe if
.Fa old_name
argument is used.
.Pp
.Fn gss_krb5_copy_ccache
will extract the krb5 credentials that are transferred from the
initiator to the acceptor when using token delegation in the Kerberos
mechanism.
The acceptor receives the delegated token in the last argument to
.Fn gss_accept_sec_context .
.Pp
.Fn gss_krb5_import_cred
will import the krb5 credentials (both keytab and/or credential cache)
into gss credential so it can be used withing GSS-API.
The
.Fa ccache
is copied by reference and thus shared, so if the credential is destroyed
with
.Fa krb5_cc_destroy ,
all users of thep
.Fa gss_cred_id_t
returned by
.Fn gss_krb5_import_ccache
will fail.
.Pp
.Fn gsskrb5_register_acceptor_identity
sets the Kerberos 5 filebased keytab that the acceptor will use.  The
.Fa identifier
is the file name.
.Pp
.Fn gsskrb5_extract_authz_data_from_sec_context
extracts the Kerberos authorizationdata that may be stored within the
context.
Tha caller must free the returned buffer
.Fa ad_data
with
.Fn gss_release_buffer
upon success.
.Pp
.Fn gss_krb5_get_tkt_flags
return the ticket flags for the kerberos ticket receive when
authenticating the initiator.
Only valid on the acceptor context.
.Pp
.Fn gss_krb5_compat_des3_mic
turns on or off the compatibility with older version of Heimdal using
des3 get and verify mic, this is way to programmatically set the
[gssapi]broken_des3_mic and [gssapi]correct_des3_mic flags (see
COMPATIBILITY section in
.Xr gssapi 3 ) .
If the CPP symbol
.Dv GSS_C_KRB5_COMPAT_DES3_MIC
is present,
.Fn gss_krb5_compat_des3_mic
exists.
.Fn gss_krb5_compat_des3_mic
will be removed in a later version of the GSS-API library.
.Sh SEE ALSO
.Xr gssapi 3 ,
.Xr krb5 3 ,
.Xr krb5_ccache 3 ,
.Xr kerberos 8