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Internet draft J.Wray
IETF Common Authentication Technology WG Digital Equipment Corporation
<draft-ietf-cat-gssv2-cbind-03.txt> November 1996
Generic Security Service API Version 2 : C-bindings
1. STATUS OF THIS MEMO
This document is an Internet Draft. Internet Drafts are working
documents of the Internet Engineering Task Force (IETF), its Areas, and
its Working Groups. Note that other groups may also distribute working
documents as Internet Drafts. Internet Drafts are draft documents valid
for a maximum of six months. Internet Drafts may be updated, replaced,
or obsoleted by other documents at any time. It is not appropriate to
use Internet Drafts as reference material or to cite them other than as
a "working draft" or "work in progress." Please check the I-D abstract
listing contained in each Internet Draft directory to learn the current
status of this or any other Internet Draft.
Comments on this document should be sent to "cat-ietf@MIT.EDU", the IETF
Common Authentication Technology WG discussion list.
2. ABSTRACT
This draft document specifies C language bindings for Version 2 of the
Generic Security Service Application Program Interface (GSSAPI), which
is described at a language-independent conceptual level in other drafts
[GSSAPI]. It revises RFC-1509, making specific incremental changes in
response to implementation experience and liaison requests. It is
intended, therefore, that this draft or a successor version thereof will
become the basis for subsequent progression of the GSS-API specification
on the standards track.
The Generic Security Service Application Programming Interface provides
security services to its callers, and is intended for implementation
atop a variety of underlying cryptographic mechanisms. Typically,
GSSAPI callers will be application protocols into which security
enhancements are integrated through invocation of services provided by
the GSSAPI. The GSSAPI allows a caller application to authenticate a
principal identity associated with a peer application, to delegate
rights to a peer, and to apply security services such as confidentiality
and integrity on a per-message basis.
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3. INTRODUCTION
The Generic Security Service Application Programming Interface [GSSAPI]
provides security services to calling applications. It allows a
communicating application to authenticate the user associated with
another application, to delegate rights to another application, and to
apply security services such as confidentiality and integrity on a per-
message basis.
There are four stages to using the GSSAPI:
(a) The application acquires a set of credentials with which it may
prove its identity to other processes. The application's
credentials vouch for its global identity, which may or may not be
related to any local username under which it may be running.
(b) A pair of communicating applications establish a joint security
context using their credentials. The security context is a pair
of GSSAPI data structures that contain shared state information,
which is required in order that per-message security services may
be provided. Examples of state that might be shared between
applications as part of a security context are cryptographic keys,
and message sequence numbers. As part of the establishment of a
security context, the context initiator is authenticated to the
responder, and may require that the responder is authenticated in
turn. The initiator may optionally give the responder the right
to initiate further security contexts, acting as an agent or
delegate of the initiator. This transfer of rights is termed
delegation, and is achieved by creating a set of credentials,
similar to those used by the initiating application, but which may
be used by the responder.
To establish and maintain the shared information that makes up the
security context, certain GSSAPI calls will return a token data
structure, which is a cryptographically protected opaque data
type. The caller of such a GSSAPI routine is responsible for
transferring the token to the peer application, encapsulated if
necessary in an application-application protocol. On receipt of
such a token, the peer application should pass it to a
corresponding GSSAPI routine which will decode the token and
extract the information, updating the security context state
information accordingly.
(c) Per-message services are invoked to apply either:
(i) integrity and data origin authentication, or
(ii) confidentiality, integrity and data origin authentication
to application data, which are treated by GSSAPI as arbitrary
octet-strings. An application transmitting a message that it
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wishes to protect will call the appropriate GSSAPI routine
(gss_get_mic or gss_wrap) to apply protection, specifying the
appropriate security context, and send the resulting token to the
receiving application. The receiver will pass the received token
(and, in the case of data protected by gss_get_mic, the
accompanying message-data) to the corresponding decoding routine
(gss_verify_mic or gss_unwrap) to remove the protection and
validate the data.
(d) At the completion of a communications session (which may extend
across several transport connections), each application calls a
GSSAPI routine to delete the security context. Multiple contexts
may also be used (either successively or simultaneously) within a
single communications association, at the option of the
applications.
4. GSSAPI ROUTINES
This section lists the routines that make up the GSSAPI, and offers a
brief description of the purpose of each routine. Detailed descriptions
of each routine are listed in alphabetical order in section 7.
Table 4-1 GSSAPI Credential-management Routines
ROUTINE SECTION FUNCTION
gss_acquire_cred 7.2 Assume a global identity;
Obtain a GSSAPI credential
handle for pre-existing
credentials.
gss_add_cred 7.3 Construct credentials
incrementally
gss_inquire_cred 7.21 Obtain information about
a credential.
gss_inquire_cred_by_mech 7.22 Obtain per-mechanism information
about a credential.
gss_release_cred 7.28 Discard a credential handle.
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Table 4-2 GSSAPI Context-level Routines
ROUTINE SECTION FUNCTION
gss_init_sec_context 7.19 Initiate a security context
with a peer application
gss_accept_sec_context 7.1 Accept a security context
initiated by a peer
application
gss_delete_sec_context 7.9 Discard a security context
gss_process_context_token 7.26 Process a token on a security
context from a peer
application
gss_context_time 7.7 Determine for how long a
context will remain valid
gss_inquire_context 7.20 Obtain information about a
security context
gss_wrap_size_limit 7.37 Determine token-size limit for
gss_wrap on a context
gss_export_sec_context 7.14 Transfer a security context to
another process
gss_import_sec_context 7.17 Import a transferred context
Table 4-3 GSSAPI Per-message Routines
ROUTINE SECTION FUNCTION
gss_get_mic 7.15 Calculate a cryptographic
Message Integrity Code (MIC)
for a message; integrity service
gss_verify_mic 7.35 Check a MIC against a message;
verify integrity of a received
message
gss_wrap 7.36 Attach a MIC to a message, and
optionally encrypt the message
content; confidentiality service
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gss_unwrap 7.34 Verify a message with attached
MIC, and decrypt message
content if necessary.
Table 4-4 GSSAPI Name manipulation Routines
ROUTINE SECTION FUNCTION
gss_import_name 7.16 Convert a contiguous string name
to internal-form
gss_display_name 7.10 Convert internal-form name
to text
gss_compare_name 7.6 Compare two internal-form names
gss_release_name 7.29 Discard an internal-form name
gss_inquire_names_for_mech 7.24 List the name-types supported
by a specified mechanism
gss_inquire_mechs_for_name 7.23 List mechanisms that support
by a given nametype
gss_canonicalize_name 7.5 Convert an internal name to
an MN.
gss_export_name 7.13 Convert an MN to export form
gss_duplicate_name 7.12 Create a copy of an internal name
Table 4-5 GSSAPI Miscellaneous Routines
ROUTINE SECTION FUNCTION
gss_display_status 7.11 Convert a GSSAPI status code
to text
gss_indicate_mechs 7.18 Determine available underlying
authentication mechanisms
gss_release_buffer 7.27 Discard a buffer
gss_release_oid 7.30 Discard an object identifier
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gss_release_oid_set 7.31 Discard a set of object
identifiers
gss_create_empty_oid_set 7.8 Create a set containing no
object identifiers
gss_add_oid_set_member 7.4 Add an object identifier to
a set
gss_test_oid_set_member 7.33 Determines whether an object
identifier is a member of a set
gss_oid_to_str 7.25 Create a printable
representation of an object
identifier
gss_str_to_oid 7.32 Create an object identifier from
its printable representation
Individual GSSAPI implementations may augment these routines by
providing additional mechanism-specific routines if required
functionality is not available from the generic forms. Applications are
encouraged to use the generic routines wherever possible on portability
grounds.
5. DATA TYPES AND CALLING CONVENTIONS
The following conventions are used by the GSSAPI C-language bindings:
5.1. Integer types
GSSAPI uses the following integer data type:
OM_uint32 32-bit unsigned integer
Where guaranteed minimum bit-count is important, this portable data type
is used by the GSSAPI routine definitions. Individual GSSAPI
implementations will include appropriate typedef definitions to map this
type onto a built-in data type. If the platform supports the X/Open
xom.h header file, the OM_uint32 definition contained therein should be
used; the GSSAPI header file in Appendix A contains logic that will
detect the prior inclusion of xom.h, and will not attempt to re-declare
OM_uint32. If the X/Open header file is not available on the platform,
the GSSAPI implementation should use the smallest natural unsigned
integer type that provides at least 32 bits of precision.
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5.2. String and similar data
Many of the GSSAPI routines take arguments and return values that
describe contiguous octet-strings. All such data is passed between the
GSSAPI and the caller using the gss_buffer_t data type. This data type
is a pointer to a buffer descriptor, which consists of a length field
that contains the total number of bytes in the datum, and a value field
which contains a pointer to the actual datum:
typedef struct gss_buffer_desc_struct {
size_t length;
void *value;
} gss_buffer_desc, *gss_buffer_t;
Storage for data passed to the application by a GSSAPI routine using the
gss_buffer_t conventions is allocated by the GSSAPI routine. The
application may free this storage by invoking the gss_release_buffer
routine. Allocation of the gss_buffer_desc object is always the
responsibility of the application; unused gss_buffer_desc objects may
be initialized to the value GSS_C_EMPTY_BUFFER.
5.2.1. Opaque data types
Certain multiple-word data items are considered opaque data types at the
GSSAPI, because their internal structure has no significance either to
the GSSAPI or to the caller. Examples of such opaque data types are the
input_token parameter to gss_init_sec_context (which is opaque to the
caller), and the input_message parameter to gss_wrap (which is opaque to
the GSSAPI). Opaque data is passed between the GSSAPI and the
application using the gss_buffer_t datatype.
5.2.2. Character strings
Certain multiple-word data items may be regarded as simple ISO Latin-1
character strings. Examples are the printable strings passed to
gss_import_name via the input_name_buffer parameter. Some GSSAPI
routines also return character strings. All such character strings are
passed between the application and the GSSAPI implementation using the
gss_buffer_t datatype, which is a pointer to a gss_buffer_desc object.
When a gss_buffer_desc object describes a printable string, the length
field of the gss_buffer_desc should only count printable characters
within the string. In particular, a trailing NUL character should NOT
be included in the length count, nor should either the GSSAPI
implementation or the application assume the presence of an uncounted
trailing NUL.
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5.3. Object Identifiers
Certain GSSAPI procedures take parameters of the type gss_OID, or Object
identifier. This is a type containing ISO-defined tree-structured
values, and is used by the GSSAPI caller to select an underlying
security mechanism and to specify namespaces. A value of type gss_OID
has the following structure:
typedef struct gss_OID_desc_struct {
OM_uint32 length;
void *elements;
} gss_OID_desc, *gss_OID;
The elements field of this structure points to the first byte of an
octet string containing the ASN.1 BER encoding of the value portion of
the normal BER TLV encoding of the gss_OID. The length field contains
the number of bytes in this value. For example, the gss_OID value
corresponding to {iso(1) identified-organization(3) icd-ecma(12)
member-company(2) dec(1011) cryptoAlgorithms(7) DASS(5)}, meaning the
DASS X.509 authentication mechanism, has a length field of 7 and an
elements field pointing to seven octets containing the following octal
values: 53,14,2,207,163,7,5. GSSAPI implementations should provide
constant gss_OID values to allow callers to request any supported
mechanism, although applications are encouraged on portability grounds
to accept the default mechanism. gss_OID values should also be provided
to allow applications to specify particular name types (see section
5.9). Applications should treat gss_OID_desc values returned by GSSAPI
routines as read-only. In particular, the application should not
attempt to deallocate them with free(), although they can be safely
passed to the gss_release_oid routine. The gss_OID_desc datatype is
equivalent to the X/Open OM_object_identifier datatype[XOM].
5.4. Object Identifier Sets
Certain GSSAPI procedures take parameters of the type gss_OID_set. This
type represents one or more object identifiers (section 5.3). A
gss_OID_set object has the following structure:
typedef struct gss_OID_set_desc_struct {
size_t count;
gss_OID elements;
} gss_OID_set_desc, *gss_OID_set;
The count field contains the number of OIDs within the set. The
elements field is a pointer to an array of gss_OID_desc objects, each of
which describes a single OID. gss_OID_set values are used to name the
available mechanisms supported by the GSSAPI, to request the use of
specific mechanisms, and to indicate which mechanisms a given credential
supports. Storage associated with gss_OID_set values returned to the
application by the GSSAPI may be deallocated by the gss_release_oid_set
routine.
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5.5. Credentials
A credential handle is a caller-opaque atomic datum that identifies a
GSSAPI credential data structure. It is represented by the caller-
opaque type gss_cred_id_t, which should be implemented as a pointer or
arithmetic type. If a pointer implementation is chosen, care must be
taken to ensure that two gss_cred_id_t values may be compared with the
== operator.
GSSAPI credentials can contain mechanism-specific principal
authentication data for multiple mechanisms. A GSSAPI credential is
composed of a set of credential-elements, each of which is applicable to
a single mechanism. A credential may contain at most one credential-
element for each supported mechanism. A credential-element identifies
the data needed by a single mechanism to authenticate a single
principal, and conceptually contains two credential-references that
describing the actual mechanism-specific authentication data, one to be
used by GSSAPI for initiating contexts, and one to be used for
accepting contexts. For mechanisms that do not distinguish between
acceptor and initiator credentials, both references would point to the
same underlying mechanism-specific authentication data.
Credentials describe a set of mechanism-specific principals, and give
their holder the ability to act as any of those principals. All
principal identities asserted by a single GSSAPI credential should
belong to the same entity, although enforcement of this property is an
implementation-specific matter. The GSSAPI does not make the actual
credentials available to applications; instead a credential handle is
used to identify a particular credential, held internally by GSSAPI.
The combination of GSSAPI credential handle and mechanism identifies the
principal whose identity will be asserted by the credential when used
with that mechanism.
The gss_init_sec_context and gss_accept_sec_context routines allow the
value GSS_C_NO_CREDENTIAL to be specified as their credential handle
parameter. This special credential-handle indicates a desire by the
application to act as a default principal. While individual GSSAPI
implementations are free to determine such default behavior as
appropriate to the mechanism, the following default behavior by these
routines is recommended for portability:
(a) gss_init_sec_context
(i) If there is only a single principal capable of initiating
security contexts for the chosen mechanism that the
application is authorized to act on behalf of, then that
principal shall be used, otherwise
(ii) If the platform maintains a concept of a default network-
identity for the chosen mechanism, and if the application is
authorized to act on behalf of that identity for the purpose
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of initiating security contexts, then the principal
corresponding to that identity shall be used, otherwise
(iii) If the platform maintains a concept of a default local
identity, and provides a means to map local identities into
network-identities for the chosen mechanism, and if the
application is authorized to act on behalf of the network-
identity image of the default local identity for the purpose
of initiating security contexts using the chosen mechanism,
then the principal corresponding to that identity shall be
used, otherwise
(iv) A user-configurable default identity should be used.
(b) gss_accept_sec_context
(i) If there is only a single authorized principal identity
capable of accepting security contexts for the chosen
mechanism, then that principal shall be used, otherwise
(ii) If the mechanism can determine the identity of the target
principal by examining the context-establishment token, and
if the accepting application is authorized to act as that
principal for the purpose of accepting security contexts
using the chosen mechanism, then that principal identity
shall be used, otherwise
(iii) If the mechanism supports context acceptance by any
principal, and if mutual authentication was not requested,
any principal that the application is authorized to accept
security contexts under using the chosen mechanismmay be
used, otherwise
(iv) A user-configurable default identity shall be used.
The purpose of the above rules is to allow security contexts to be
established by both initiator and acceptor using the default behavior
wherever possible. Applications requesting default behavior are likely
to be more portable across mechanisms and platforms than ones that use
gss_acquire_cred to request a specific identity.
5.6. Contexts
The gss_ctx_id_t data type contains a caller-opaque atomic value that
identifies one end of a GSSAPI security context. It should be
implemented as a pointer or arithmetic type. If a pointer type is
chosen, care should be taken to ensure that two gss_ctx_id_t values may
be compared with the == operator.
The security context holds state information about each end of a peer
communication, including cryptographic state information.
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5.7. Authentication tokens
A token is a caller-opaque type that GSSAPI uses to maintain
synchronization between the context data structures at each end of a
GSSAPI security context. The token is a cryptographically protected
octet-string, generated by the underlying mechanism at one end of a
GSSAPI security context for use by the peer mechanism at the other end.
Encapsulation (if required) and transfer of the token are the
responsibility of the peer applications. A token is passed between the
GSSAPI and the application using the gss_buffer_t conventions.
5.8. Interprocess tokens
Certain GSSAPI routines are intended to transfer data between processes
in multi-process programs. These routines use a caller-opaque octet-
string, generated by the GSSAPI in one process for use by the GSSAPI in
another process. The calling application is responsible for
transferring such tokens between processes in an OS-specific manner.
Note that, while GSSAPI implementors are encouraged to avoid placing
sensitive information within interprocess tokens, or to
cryptographically protect them, many implementations will be unable to
avoid placing key material or other sensitive data within them. It is
the application's responsibility to ensure that interprocess tokens are
protected in transit, and transferred only to processes that are
trustworthy. An interprocess token is passed between the GSSAPI and the
application using the gss_buffer_t conventions.
5.9. Status values
One or more status codes are returned by each GSSAPI routine. Two
distinct sorts of status codes are returned. These are termed GSS
status codes and Mechanism status codes.
5.9.1. GSS status codes
GSSAPI routines return GSS status codes as their OM_uint32 function
value. These codes indicate errors that are independent of the
underlying mechanism(s) used to provide the security service. The
errors that can be indicated via a GSS status code are either generic
API routine errors (errors that are defined in the GSS-API
specification) or calling errors (errors that are specific to these
language bindings).
A GSS status code can indicate a single fatal generic API error from the
routine and a single calling error. In addition, supplementary status
information may be indicated via the setting of bits in the
supplementary info field of a GSS status code.
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These errors are encoded into the 32-bit GSS status code as follows:
MSB LSB
|------------------------------------------------------------|
| Calling Error | Routine Error | Supplementary Info |
|------------------------------------------------------------|
Bit 31 24 23 16 15 0
Hence if a GSS-API routine returns a GSS status code whose upper 16 bits
contain a non-zero value, the call failed. If the calling error field
is non-zero, the invoking application's call of the routine was
erroneous. Calling errors are defined in table 5-1. If the routine
error field is non-zero, the routine failed for one of the routine-
specific reasons listed below in table 5-2. Whether or not the upper 16
bits indicate a failure or a success, the routine may indicate
additional information by setting bits in the supplementary info field
of the status code. The meaning of individual bits is listed below in
table 5-3.
Table 5-1 Calling Errors
Name Value in Meaning
Field
GSS_S_CALL_INACCESSIBLE_READ 1 A required input
parameter could
not be read.
GSS_S_CALL_INACCESSIBLE_WRITE 2 A required output
parameter could
not be written.
GSS_S_CALL_BAD_STRUCTURE 3 A parameter was
malformed
Table 5-2 Routine Errors
Name Value in Meaning
Field
GSS_S_BAD_MECH 1 An unsupported mechanism was
requested
GSS_S_BAD_NAME 2 An invalid name was supplied
GSS_S_BAD_NAMETYPE 3 A supplied name was of an
unsupported type
GSS_S_BAD_BINDINGS 4 Incorrect channel bindings
were supplied
GSS_S_BAD_STATUS 5 An invalid status code was
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supplied
GSS_S_BAD_SIG 6 A token had an invalid
signature or MIC
GSS_S_NO_CRED 7 No credentials were supplied
GSS_S_NO_CONTEXT 8 No context has been
established
GSS_S_DEFECTIVE_TOKEN 9 A token was invalid
GSS_S_DEFECTIVE_CREDENTIAL 10 A credential was invalid
GSS_S_CREDENTIALS_EXPIRED 11 The referenced credentials
have expired
GSS_S_CONTEXT_EXPIRED 12 The context has expired
GSS_S_FAILURE 13 Miscellaneous failure
(see text)
GSS_S_BAD_QOP 14 The quality-of-protection
requested could not be
provide
GSS_S_UNAUTHORIZED 15 The operation is forbidden by
local security policy
GSS_S_UNAVAILABLE 16 The operation or option is not
available
GSS_S_DUPLICATE_ELEMENT 17 The requested credential element
already exists
GSS_S_NAME_NOT_MN 18 The provided name was not a
mechanism name.
Table 5-3 Supplementary Status Bits
Name Bit Number Meaning
GSS_S_CONTINUE_NEEDED 0 (LSB) The routine must be called
again to complete its function.
See routine documentation for
detailed description.
GSS_S_DUPLICATE_TOKEN 1 The token was a duplicate of
an earlier token
GSS_S_OLD_TOKEN 2 The token's validity period
has expired
GSS_S_UNSEQ_TOKEN 3 A later token has already been
processed
GSS_S_GAP_TOKEN 4 An expected per-message token
was not received
The routine documentation also uses the name GSS_S_COMPLETE, which is a
zero value, to indicate an absence of any API errors or supplementary
information bits.
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All GSS_S_xxx symbols equate to complete OM_uint32 status codes, rather
than to bitfield values. For example, the actual value of the symbol
GSS_S_BAD_NAMETYPE (value 3 in the routine error field) is 3 << 16.
The macros GSS_CALLING_ERROR(), GSS_ROUTINE_ERROR() and
GSS_SUPPLEMENTARY_INFO() are provided, each of which takes a GSS status
code and removes all but the relevant field. For example, the value
obtained by applying GSS_ROUTINE_ERROR to a status code removes the
calling errors and supplementary info fields, leaving only the routine
errors field. The values delivered by these macros may be directly
compared with a GSS_S_xxx symbol of the appropriate type. The macro
GSS_ERROR() is also provided, which when applied to a GSS status code
returns a non-zero value if the status code indicated a calling or
routine error, and a zero value otherwise. All macros defined by GSS-
API evaluate their argument(s) exactly once.
A GSS-API implementation may choose to signal calling errors in a
platform-specific manner instead of, or in addition to the routine
value; routine errors and supplementary info should be returned via
routine status values only.
5.9.2. Mechanism-specific status codes
GSS-API routines return a minor_status parameter, which is used to
indicate specialized errors from the underlying security mechanism.
This parameter may contain a single mechanism-specific error, indicated
by a OM_uint32 value.
The minor_status parameter will always be set by a GSS-API routine, even
if it returns a calling error or one of the generic API errors indicated
above as fatal, although most other output parameters may remain unset
in such cases. However, output parameters that are expected to return
pointers to storage allocated by a routine must always be set by the
routine, even in the event of an error, although in such cases the GSS-
API routine may elect to set the returned parameter value to NULL to
indicate that no storage was actually allocated. Any length field
associated with such pointers (as in a gss_buffer_desc structure) should
also be set to zero in such cases.
The GSS status code GSS_S_FAILURE is used to indicate that the
underlying mechanism detected an error for which no specific GSS status
code is defined. The mechanism status code will provide more details
about the error.
5.10. Names
A name is used to identify a person or entity. GSS-API authenticates
the relationship between a name and the entity claiming the name.
Since different authentication mechanisms may employ different
namespaces for identifying their principals, GSSAPI's naming support is
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necessarily complex in multi-mechanism environments (or even in some
single-mechanism environments where the underlying mechanism supports
multiple namespaces).
Two distinct representations are defined for names:
(a) An internal form. This is the GSSAPI "native" format for names,
represented by the implementation-specific gss_name_t type. It is
opaque to GSSAPI callers. A single gss_name_t object may contain
multiple names from different namespaces, but all names should
refer to the same entity. An example of such an internal name
would be the name returned from a call to the gss_inquire_cred
routine, when applied to a credential containing credential
elements for multiple authentication mechanisms employing
different namespaces. This gss_name_t object will contain a
distinct name for the entity for each authentication mechanism.
For GSSAPI implementations supporting multiple namespaces, objects
of type gss_name_t must contain sufficient information to
determine the namespace to which each primitive name belongs.
(b) Mechanism-specific contiguous octet-string forms. A format
capable of containing a single name (from a single namespace).
Contiguous string names are always accompanied by an object
identifier specifying the namespace to which the name belongs, and
their format is dependent on the authentication mechanism that
employs the name. Many, but not all, contiguous string names will
be printable, and may therefore be used by GSSAPI applications for
communication with their users.
Routines (gss_import_name and gss_display_name) are provided to convert
names between contiguous string representations and the internal
gss_name_t type. gss_import_name may support multiple syntaxes for each
supported namespace, allowing users the freedom to choose a preferred
name representation. gss_display_name should use an implementation-
chosen printable syntax for each supported name-type.
If an application calls gss_display_name(), passing the internal name
resulting from a call to gss_import_name(), there is no guarantee the
the resulting contiguous string name will be the same as the original
imported string name. Nor do name-space identifiers necessarily survive
unchanged after a journey through the internal name-form. An example of
this might be a mechanism that authenticates X.500 names, but provides
an algorithmic mapping of Internet DNS names into X.500. That
mechanism's implementation of gss_import_name() might, when presented
with a DNS name, generate an internal name that contained both the
original DNS name and the equivalent X.500 name. Alternatively, it might
only store the X.500 name. In the latter case, gss_display_name() would
most likely generate a printable X.500 name, rather than the original
DNS name.
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The process of authentication delivers to the context acceptor an
internal name. Since this name has been authenticated by a single
mechanism, it contains only a single name (even if the internal name of
the context initiator had multiple components). Such names are termed
internal mechanism names, or "MN"s and the names emitted by
gss_accept_sec_context() are always of this type. Since some
applications may require MNs without wanting to incur the overhead of an
authentication operation, a second function, gss_canonicalize_name(), is
provided to convert a general internal name into an MN.
Comparison of internal-form names may be accomplished via the
gss_compare_name() routine, which returns true if the two names being
compared refer to the same entity. This removes the need for the
application program to understand the syntaxes of the various printable
names that a given GSS-API implementation may support. Since GSSAPI
assumes that all primitive names contained within a given internal name
refer to the same entity, gss_compare_name() can return true if the two
names have at least one primitive name in common. If the implementation
embodies knowledge of equivalence relationships between names taken from
different namespaces, this knowledge may also allow successful
comparison of internal names containing no overlapping primitive
elements.
When used in large access control lists, the overhead of invoking
gss_import_name() and gss_compare_name() on each name from the ACL may
be prohibitive. To support this case, GSSAPI defines a special form of
the contiguous string name which may be compared directly (e.g. with
memcmp()). Contigous names suitable for comparison are generated by the
gss_export_name() routine, which requires an MN as input. Exported
names may be re-imported by the gss_import_name() routine, and the
resulting internal name will also be an MN. The gss_OID constant
GSS_C_NT_EXPORT_NAME indentifies the "export name" type, and the value
of this constant is given in Appendix A. Structurally, an exported
name object consists of a header containing an OID identifying the
mechanism that authenticated the name, and a trailer containing the name
itself, where the syntax of the trailer is defined by the individual
mechanism specification. The precise format of an export name is
defined in the language-independent GSSAPI specification [GSSAPI].
The gss_name_t datatype should be implemented as a pointer type. To
allow the compiler to aid the application programmer by performing
type-checking, the use of (void *) is discouraged. A pointer to an
implementation-defined type is the preferred choice.
Storage is allocated by routines that return gss_name_t values. A
procedure, gss_release_name, is provided to free storage associated with
a name.
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5.11. Channel Bindings
GSS-API supports the use of user-specified tags to identify a given
context to the peer application. These tags are intended to be used to
identify the particular communications channel that carries the context.
Channel bindings are communicated to the GSS-API using the following
structure:
typedef struct gss_channel_bindings_struct {
OM_uint32 initiator_addrtype;
gss_buffer_desc initiator_address;
OM_uint32 acceptor_addrtype;
gss_buffer_desc acceptor_address;
gss_buffer_desc application_data;
} *gss_channel_bindings_t;
The initiator_addrtype and acceptor_addrtype fields denote the type of
addresses contained in the initiator_address and acceptor_address
buffers. The address type should be one of the following:
GSS_C_AF_UNSPEC Unspecified address type
GSS_C_AF_LOCAL Host-local address type
GSS_C_AF_INET DARPA Internet address type
GSS_C_AF_IMPLINK ARPAnet IMP address type (eg IP)
GSS_C_AF_PUP pup protocols (eg BSP) address type
GSS_C_AF_CHAOS MIT CHAOS protocol address type
GSS_C_AF_NS XEROX NS address type
GSS_C_AF_NBS nbs address type
GSS_C_AF_ECMA ECMA address type
GSS_C_AF_DATAKIT datakit protocols address type
GSS_C_AF_CCITT CCITT protocols (eg X.25)
GSS_C_AF_SNA IBM SNA address type
GSS_C_AF_DECnet DECnet address type
GSS_C_AF_DLI Direct data link interface address type
GSS_C_AF_LAT LAT address type
GSS_C_AF_HYLINK NSC Hyperchannel address type
GSS_C_AF_APPLETALK AppleTalk address type
GSS_C_AF_BSC BISYNC 2780/3780 address type
GSS_C_AF_DSS Distributed system services address type
GSS_C_AF_OSI OSI TP4 address type
GSS_C_AF_X25 X25
GSS_C_AF_NULLADDR No address specified
Note that these symbols name address families rather than specific
addressing formats. For address families that contain several
alternative address forms, the initiator_address and acceptor_address
fields must contain sufficient information to determine which address
form is used. When not otherwise specified, addresses should be
specified in network byte-order (that is, native byte-ordering for the
address family).
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Conceptually, the GSS-API concatenates the initiator_addrtype,
initiator_address, acceptor_addrtype, acceptor_address and
application_data to form an octet string. The mechanism signs this
octet string, and binds the signature to the context establishment token
emitted by gss_init_sec_context. The same bindings are presented by the
context acceptor to gss_accept_sec_context, and a signature is
calculated in the same way. The calculated signature is compared with
that found in the token, and if the signatures differ,
gss_accept_sec_context will return a GSS_S_BAD_BINDINGS error, and the
context will not be established. Some mechanisms may include the actual
channel binding data in the token (rather than just a signature);
applications should therefore not use confidential data as channel-
binding components. Individual mechanisms may impose additional
constraints on addresses and address types that may appear in channel
bindings. For example, a mechanism may verify that the
initiator_address field of the channel bindings presented to
gss_init_sec_context contains the correct network address of the host
system. Portable applications should therefore ensure that they either
provide correct information for the address fields, or omit addressing
information, specifying GSS_C_AF_NULLADDR as the address-types.
5.12. Optional parameters
Various parameters are described as optional. This means that they
follow a convention whereby a default value may be requested. The
following conventions are used for omitted parameters. These
conventions apply only to those parameters that are explicitly
documented as optional.
5.12.1. gss_buffer_t types
Specify GSS_C_NO_BUFFER as a value. For an input parameter this
signifies that default behavior is requested, while for an output
parameter it indicates that the information that would be returned via
the parameter is not required by the application.
5.12.2. Integer types (input)
Individual parameter documentation lists values to be used to indicate
default actions.
5.12.3. Integer types (output)
Specify NULL as the value for the pointer.
5.12.4. Pointer types
Specify NULL as the value.
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5.12.5. Object IDs
Specify GSS_C_NO_OID as the value.
5.12.6. Object ID Sets
Specify GSS_C_NO_OID_SET as the value.
5.12.7. Channel Bindings
Specify GSS_C_NO_CHANNEL_BINDINGS to indicate that channel bindings are
not to be used.
6. ADDITIONAL CONTROLS
This section discusses the optional services that a context initiator
may request of the GSS-API at context establishment. All these services
are requested by setting flags in the req_flags input parameter to
gss_init_sec_context.
The optional services currently defined are:
Delegation - The (usually temporary) transfer of rights from initiator
to acceptor, enabling the acceptor to authenticate itself as an
agent of the initiator.
Mutual Authentication - In addition to the initiator authenticating its
identity to the context acceptor, the context acceptor should also
authenticate itself to the initiator.
Replay detection - In addition to providing message integrity services,
gss_get_mic and gss_wrap should include message numbering
information to enable gss_verify_mic and gss_unwrap to detect if a
message has been duplicated.
Out-of-sequence detection - In addition to providing message integrity
services, gss_get_mic and gss_wrap should include message
sequencing information to enable gss_verify_mic and gss_unwrap to
detect if a message has been received out of sequence.
Anonymous authentication - The establishment of the security context
should not reveal the initiator's identity to the context
acceptor.
Any currently undefined bits within such flag arguments should be
ignored by GSS-API implementations when presented by an application, and
should be set to zero when returned to the application by the GSS-API
implementation.
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Some mechanisms may not support all optional services, and some
mechanisms may only support some services in conjunction with others.
Both gss_init_sec_context and gss_accept_sec_context inform the
applications which services will be available from the context when the
establishment phase is complete, via the ret_flags output parameter. In
general, if the security mechanism is capable of providing a requested
service, it should do so, even if additional services must be enabled in
order to provide the requested service. If the mechanism is incapable
of providing a requested service, it should proceed without the service,
leaving the application to abort the context establishment process if it
considers the requested service to be mandatory.
Some mechanisms may specify that support for some services is optional,
and that implementors of the mechanism need not provide it. This is
most commonly true of the confidentiality service, often because of
legal restrictions on the use of data-encryption, but may apply to any
of the services. For such mechanisms, at least one token must be sent
from acceptor to initiator during context establishment when the
initiator indicates a desire to use such a service, so that the
initiating GSSAPI can correctly indicate whether the service is
supported by the acceptor's GSSAPI.
6.1. Delegation
The GSS-API allows delegation to be controlled by the initiating
application via a boolean parameter to gss_init_sec_context(), the
routine that establishes a security context. Some mechanisms do not
support delegation, and for such mechanisms attempts by an application
to enable delegation are ignored.
For many mechanisms that support delegation, a simple boolean does not
provide enough control. Examples of additional aspects of delegation
control that a mechanism might provide to an application are duration of
delegation, network addresses from which delegation is valid, and
constraints on the tasks performed by a delegate. Such controls are
presently outside the scope of the GSS-API. GSS-API implementations
supporting mechanisms offering additional controls should provide
extension routines that allow these controls to be exercised (perhaps by
modifying the initiator's GSS-API credential prior to its use in
establishing a context). However, the simple delegation control
provided by GSS-API should always be able to over-ride other mechanism-
specific delegation controls - If the application instructs
gss_init_sec_context() that delegation is not desired, then the
implementation must not permit delegation to occur. This is an
exception to the general rule that a mechanism may enable services even
if they are not requested - delegation may only be provide at the
explicit request of the application.
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6.2. Mutual authentication
Usually, a context acceptor will require that a context initiator
authenticate itself so that the acceptor may make an access-control
decision prior to performing a service for the initiator. In some
cases, the initiator may also request that the acceptor authenticate
itself. GSS-API allows the initiating application to request this
mutual authentication service by setting a flag when calling
gss_init_sec_context.
The initiating application is informed as to whether or not mutual
authentication is being requested of the context acceptor. Note that
some mechanisms may not support mutual authentication, and other
mechanisms may always perform mutual authentication, whether or not the
initiating application requests it. In particular, mutual
authentication my be required by some mechanisms in order to support
replay or out-of-sequence message detection, and for such mechanisms a
request for either of these services will automatically enable mutual
authentication.
6.3. Replay and out-of-sequence detection
The GSS-API may provide detection of mis-ordered message once a security
context has been established. Protection may be applied to messages by
either application, by calling either gss_get_mic or gss_wrap, and
verified by the peer application by calling gss_verify_mic or
gss_unwrap.
gss_get_mic calculates a cryptographic checksum of an application
message, and returns that checksum in a token. The application should
pass both the token and the message to the peer application, which
presents them to gss_verify_mic.
gss_wrap calculates a cryptographic checksum of an application message,
and places both the checksum and the message in a token. The
application should pass the token to the peer application, which
presents it to gss_unwrap to extract the message.
Either pair of routines may be capable of detecting out-of-sequence
message delivery, or duplication of messages. Details of such mis-
ordered messages are indicated through supplementary status bits in the
major status code returned by gss_verify_mic or gss_unwrap. The
relevant supplementary bits are:
GSS_S_DUPLICATE_TOKEN - The token is a duplicate of one that has already
been received and processed. Contexts that do not claim to
provide replay detection may still set this bit if the duplicate
message is processed immediately after the original, with no
intervening messages.
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GSS_S_OLD_TOKEN - The token is too old to determine whether or not it is
a duplicate. Contexts supporting out-of-sequence detection but
not replay detection should always set this bit if
GSS_S_UNSEQ_TOKEN is set; contexts that support replay detection
should only set this bit if the token is so old that it cannot be
checked for duplication.
GSS_S_UNSEQ_TOKEN - A later token has already been processed.
GSS_S_GAP_TOKEN - An earlier token has not yet been received.
A mechanism need not maintain a list of all tokens that have been
processed in order to support these status codes. A typical mechanism
might retain information about only the most recent "N" tokens
processed, allowing it to distinguish duplicates and missing tokens
within the most recent "N" messages; the receipt of a token older than
the most recent "N" would result in a GSS_S_OLD_TOKEN status.
6.4. Anonymous Authentication
In certain situations, an application may wish to initiate the
authentication process to authenticate a peer, without revealing its own
identity. For example, consider an application providing access to a
database containing medical information, and offering unrestricted
access to the service. A client of such a service might wish to
authenticate the service (in order to establish trust in any information
retrieved from it), but might not wish the service to be able to obtain
the client's identity (perhaps due to privacy concerns about the
specific inquiries, or perhaps simply to avoid being placed on mailing-
lists).
In normal use of the GSS-API, the initiator's identity is made available
to the acceptor as a result of the context establishment process.
However, context initiators may request that their identity not be
revealed to the context acceptor. Many mechanisms do not support
anonymous authentication, and for such mechanisms the request will be
refused. An authentication token will be still be generated, but the
application is always informed if a requested service is unavailable,
and has the option to abort context establishment if anonymity is valued
above the other security services that would require a context to be
established.
In addition to informing the application that a context is established
anonymously (via the ret_flags outputs from gss_init_sec_context and
gss_accept_sec_context), the optional src_name output from
gss_accept_sec_context and gss_inquire_context will, for such contexts,
return a reserved internal-form name, defined by the implementation.
When presented to gss_display_name, this reserved internal-form name
will result in a printable name that is syntactically distinguishable
from any valid principal name supported by the implementation,
associated with a name-type object identifier with the value
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GSS_C_NT_ANONYMOUS, whose value us given in Appendix A. The printable
form of an anonymous name should be chosen such that it implies
anonymity, since this name may appear in, for example, audit logs. For
example, the string "<anonymous>" might be a good choice, if no valid
printable names supported by the implementation can begin with "<" and
end with ">".
6.5. Confidentiality
If a context supports the confidentiality service, gss_wrap may be used
to encrypt application messages. Messages are selectively encrypted,
under the control of the conf_req_flag input parameter to gss_wrap.
6.6. Inter-process context transfer
GSSAPI V2 provides routines (gss_export_sec_context and
gss_import_sec_context) which allow a security context to be transferred
between processes on a single machine. The most common use for such a
feature is a client-server design where the server is implemented as a
single process that accepts incoming security contexts, which then
launches child processes to deal with the data on these contexts. In
such a design, the child processes must have access to the security
context cdata structure created within the parent by its call to
gss_accept_sec_context so that they can use per-message protection
services and delete the security context when the communication session
ends.
Since the security context data structure is expected to contain
sequencing information, it is impractical in general to share a context
between processes. Thus GSSAPI provides a call (gss_export_sec_context)
that the process which currently owns the context can call to declare
that it has no intention to use the context subsequently, and to create
an inter-process token containing information needed by the adopting
process to successfully import the context. After successful completion
of this call, the original security context is deleted by GSSAPI, and
any context handles referring to this context are no longer valid. The
originating process transfers the inter-process token to the adopting
process, which passes it to gss_import_sec_context, and a fresh
gss_ctx_id_t is created such that it is functionally identical to the
original context.
The inter-process token may contain sensitive data from the original
security context (including cryptographic keys). Applications using
inter-process tokens to transfer security contexts must take appropriate
steps to protect these tokens in transit.
Implementations are not required to support the inter-process transfer
of security contexts. The ability to transfer a security context is
indicated when the context is created, by gss_init_sec_context or
gss_accept_sec_context setting the GSS_C_TRANS_FLAG bit in their
ret_flags parameter.
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6.7. The use of incomplete contexts
Some mechanisms may allow the per-message services to be used before the
context establishment process is complete. For example, a mechanism may
include sufficient information in its initial context-level token for
the context acceptor to immediately decode messages protected with
gss_wrap or gss_get_mic. For such a mechanism, the initiating
application need not wait until subsequent context-level tokens have
been sent and received before invoking the per-message protection
services.
The ability of a context to provide per-message services in advance of
complete context establishment is indicated by the setting of the
GSS_C_PROT_READY_FLAG bit in the ret_flags parameter from
gss_init_sec_context and gss_accept_sec_context. Applications wishing
to use per-message protection services on patially-established contexts
should check this flag before attempting to invoke gss_wrap or
gss_get_mic.
7. GSS-API routine descriptions
In addition to the explicit major status codes documented here, the code
GSS_S_FAILURE may be returned by any routine, indicating an
implementation-specific or mechanism-specific error condition, further
details of which are reported via the minor_status parameter.
7.1. gss_accept_sec_context
OM_uint32 gss_accept_sec_context (
OM_uint32 * minor_status,
gss_ctx_id_t * context_handle,
GSS_CONST gss_cred_id_t acceptor_cred_handle,
GSS_CONST gss_buffer_t input_token_buffer,
GSS_CONST gss_channel_bindings_t
input_chan_bindings,
GSS_CONST gss_name_t * src_name,
gss_OID * mech_type,
gss_buffer_t output_token,
OM_uint32 * ret_flags,
OM_uint32 * time_rec,
gss_cred_id_t * delegated_cred_handle)
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Purpose:
Allows a remotely initiated security context between the application and
a remote peer to be established. The routine may return a output_token
which should be transferred to the peer application, where the peer
application will present it to gss_init_sec_context. If no token need
be sent, gss_accept_sec_context will indicate this by setting the length
field of the output_token argument to zero. To complete the context
establishment, one or more reply tokens may be required from the peer
application; if so, gss_accept_sec_context will return a status flag of
GSS_S_CONTINUE_NEEDED, in which case it should be called again when the
reply token is received from the peer application, passing the token to
gss_accept_sec_context via the input_token parameters.
Portable applications should be constructed to use the token length and
return status to determine whether token need to be sent or waited for.
Thus a typical portable caller should always invoke
gss_accept_sec_context within a loop:
gss_ctx_id_t context_hdl = GSS_C_NO_CONTEXT;
...
do {
receive_token_from_peer(input_token);
maj_stat = gss_accept_sec_context(&min_stat,
&context_hdl,
cred_hdl,
input_token,
input_bindings,
&client_name,
&mech_type,
output_token,
&ret_flags,
&time_rec,
&deleg_cred);
if (GSS_ERROR(maj_stat)) {
report_error(maj_stat);
break;
};
if (output_token->length != 0) {
send_token_to_peer(output_token);
};
}
while (GSS_SUPPLEMENTARY_INFO(maj_stat) & GSS_S_CONTINUE_NEEDED);
Whenever the routine returns a major status that includes the value
GSS_S_CONTINUE_NEEDED, the context is not fully established and the
following restrictions apply to the output parameters:
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(a) The value returned via the time_rec parameter is undefined
(b) Unless the accompanying ret_flags parameter contains the bit
GSS_C_PROT_READY_FLAG, indicating that per-message services may be
applied in advance of a successful completion status, the value
returned via the mech_type parameter may be undefined until the
routine returns a major status value of GSS_S_COMPLETE.
(c) The values of the GSS_C_DELEG_FLAG, GSS_C_MUTUAL_FLAG,
GSS_C_REPLAY_FLAG, GSS_C_SEQUENCE_FLAG, GSS_C_CONF_FLAG,
GSS_C_INTEG_FLAG and GSS_C_ANON_FLAG bits returned via the
ret_flags parameter should contain the values that the
implementation expects would be valid if context establishment
were to succeed.
The values of the GSS_C_PROT_READY_FLAG and GSS_C_TRANS_FLAG bits
within ret_flags should indicate the actual state at the time
gss_accept_sec_context returns, whether or not the context is
fully established.
Although this requires that GSSAPI implementations set the
GSS_C_PROT_READY_FLAG in the final ret_flags returned to a caller
(i.e. when accompanied by a GSS_S_COMPLETE status code),
applications should not rely on this behavior as the flag was not
defined in Version 1 of the GSSAPI. Instead, applications should
be prepared to use per-message services after a successful context
establishment, according to the GSS_C_INTEG_FLAG and
GSS_C_CONF_FLAG values.
While the routine returns GSS_S_CONTINUE_NEEDED, the values returned via
the ret_flags argument indicate the services that the implementation
expects to be available from the established context.
Parameters:
context_handle gss_ctx_id_t, read/modify
context handle for new context. Supply
GSS_C_NO_CONTEXT for first call; use value
returned in subsequent calls.
acceptor_cred_handle gss_cred_id_t, read
Credential handle claimed by context acceptor.
Specify GSS_C_NO_CREDENTIAL to accept the
context as a default principal. If
GSS_C_NO_CREDENTIAL is specified, but no
default acceptor principal is defined,
GSS_S_NO_CRED will be returned.
input_token_buffer buffer, opaque, read
token obtained from remote application.
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input_chan_bindings channel bindings, read, optional
Application-specified bindings. Allows
application to securely bind channel
identification information to the security
context. If channel bindings are not
used, specify GSS_C_NO_CHANNEL_BINDINGS.
src_name gss_name_t, modify, optional
Authenticated name of context initiator.
After use, this name should be deallocated by
passing it to gss_release_name. If not required,
specify NULL.
mech_type Object ID, modify, optional
Security mechanism used. The returned
OID value will be a pointer into static
storage, and should be treated as read-only
by the caller. If not required, specify
NULL.
output_token buffer, opaque, modify
Token to be passed to peer application. If the
length field of the returned token buffer is 0,
then no token need be passed to the peer
application.
ret_flags bit-mask, modify, optional
Contains various independent flags, each of
which indicates that the context supports a
specific service option. If not needed,
specify NULL. Symbolic names are
provided for each flag, and the symbolic names
corresponding to the required flags
should be logically-ANDed with the ret_flags
value to test whether a given option is
supported by the context. The flags are:
GSS_C_DELEG_FLAG
True - Delegated credentials are available
via the delegated_cred_handle
parameter
False - No credentials were delegated
GSS_C_MUTUAL_FLAG
True - Remote peer asked for mutual
authentication
False - Remote peer did not ask for mutual
authentication
GSS_C_REPLAY_FLAG
True - replay of protected messages
will be detected
False - replayed messages will not be
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detected
GSS_C_SEQUENCE_FLAG
True - out-of-sequence protected
messages will be detected
False - out-of-sequence messages will not
be detected
GSS_C_CONF_FLAG
True - Confidentiality service may be invoked
by calling the gss_wrap routine
False - No confidentiality service (via
gss_wrap) available. gss_wrap will
provide message encapsulation,
data-origin authentication and
integrity services only.
GSS_C_INTEG_FLAG
True - Integrity service may be invoked by
calling either gss_get_mic or gss_wrap
routines.
False - Per-message integrity service
unavailable.
GSS_C_ANON_FLAG
True - The initiator does not wish to
be authenticated; the src_name
parameter (if requested) contains
an anonymous internal name.
False - The initiator has been
authenticated normally.
GSS_C_PROT_READY_FLAG
True - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available
if the accompanying major status return
value is either GSS_S_COMPLETE or
GSS_S_CONTINUE_NEEDED.
False - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available
only if the accompanying major status
return value is GSS_S_COMPLETE.
GSS_C_TRANS_FLAG
True - The resultant security context may
be transferred to other processes via
a call to gss_export_sec_context().
False - The security context is not
transferrable.
time_rec Integer, modify, optional
number of seconds for which the context
will remain valid. Specify NULL if not required.
delegated_cred_handle
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gss_cred_id_t, modify, optional
credential handle for credentials received from
context initiator. Only valid if deleg_flag in
ret_flags is true. If not needed, specify NULL.
minor_status Integer, modify
Mechanism specific status code.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_CONTINUE_NEEDED Indicates that a token from the peer application
is required to complete the context, and that
gss_accept_sec_context must be called again with that
token.
GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed on the
input_token failed.
GSS_S_DEFECTIVE_CREDENTIAL Indicates that consistency checks performed
on the credential failed.
GSS_S_NO_CRED The supplied credentials were not valid for context
acceptance, or the credential handle did not reference
any credentials.
GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired.
GSS_S_BAD_BINDINGS The input_token contains different channel bindings
to those specified via the input_chan_bindings
parameter.
GSS_S_NO_CONTEXT Indicates that the supplied context handle did not
refer to a valid context.
GSS_S_BAD_SIG The input_token contains an invalid signature.
GSS_S_OLD_TOKEN The input_token was too old. This is a fatal error
during context establishment.
GSS_S_DUPLICATE_TOKEN The input_token is valid, but is a duplicate of a
token already processed. This is a fatal error during
context establishment.
GSS_S_BAD_MECH The received token specified a mechanism that is not
supported by the implementation or the provided
credential.
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7.2. gss_acquire_cred
OM_uint32 gss_acquire_cred (
OM_uint32 * minor_status,
GSS_CONST gss_name_t desired_name,
OM_uint32 time_req,
GSS_CONST gss_OID_set desired_mechs,
gss_cred_usage_t cred_usage,
gss_cred_id_t * output_cred_handle,
gss_OID_set * actual_mechs,
OM_uint32 * time_rec)
Purpose:
Allows an application to acquire a handle for a pre-existing credential
by name. GSS-API implementations must impose a local access-control
policy on callers of this routine to prevent unauthorized callers from
acquiring credentials to which they are not entitled. This routine is
not intended to provide a ``login to the network'' function, as such a
function would involve the creation of new credentials rather than
merely acquiring a handle to existing credentials. Such functions, if
required, should be defined in implementation-specific extensions to the
API.
If desired_name is GSS_C_NO_NAME, the call is interpreted as a request
for a credential handle that will invoke default behavior when passed to
gss_init_sec_context() (if cred_usage is GSS_C_INITIATE or GSS_C_BOTH)
or gss_accept_sec_context() (if cred_usage is GSS_C_ACCEPT or
GSS_C_BOTH).
This routine is expected to be used primarily by context acceptors,
since implementations are likely to provide mechanism-specific ways of
obtaining GSS-API initiator credentials from the system login process.
Some implementations may therefore not support the acquisition of
GSS_C_INITIATE or GSS_C_BOTH credentials via gss_acquire_cred for any
name other than an empty name.
If credential acquisition is time-consuming for a mechanism, the
mechanism may chooses to delay the actual acquisition until the
credential is required (e.g. by gss_init_sec_context or
gss_accept_sec_context). Such mechanism-specific implementation
decisions should be invisible to the calling application; thus a call of
gss_inquire_cred immediately following the call of gss_acquire_cred must
return valid credential data, and may therefore incur the overhead of a
deferred credential acquisition.
Parameters:
desired_name gss_name_t, read
Name of principal whose credential
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should be acquired
time_req Integer, read, optional
number of seconds that credentials
should remain valid. Specify GSS_C_INDEFINITE
to request that the credentials have the maximum
permitted lifetime.
desired_mechs Set of Object IDs, read, optional
set of underlying security mechanisms that
may be used. GSS_C_NO_OID_SET may be used
to obtain an implementation-specific default.
cred_usage gss_cred_usage_t, read
GSS_C_BOTH - Credentials may be used
either to initiate or accept
security contexts.
GSS_C_INITIATE - Credentials will only be
used to initiate security
contexts.
GSS_C_ACCEPT - Credentials will only be used to
accept security contexts.
output_cred_handle gss_cred_id_t, modify
The returned credential handle.
actual_mechs Set of Object IDs, modify, optional
The set of mechanisms for which the
credential is valid. Specify NULL
if not required.
time_rec Integer, modify, optional
Actual number of seconds for which the
returned credentials will remain valid. If the
implementation does not support expiration of
credentials, the value GSS_C_INDEFINITE will
be returned. Specify NULL if not required
minor_status Integer, modify
Mechanism specific status code.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_MECH Unavailable mechanism requested
GSS_S_BAD_NAMETYPE Type contained within desired_name parameter is not
supported
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GSS_S_BAD_NAME Value supplied for desired_name parameter is ill-
formed.
7.3. gss_add_cred
OM_uint32 gss_add_cred (
OM_uint32 * minor_status,
GSS_CONST gss_cred_id_t input_cred_handle,
GSS_CONST gss_name_t desired_name,
GSS_CONST gss_OID desired_mech,
gss_cred_usage_t cred_usage,
OM_uint32 initiator_time_req,
OM_uint32 acceptor_time_req,
gss_cred_id_t * output_cred_handle,
gss_OID_set * actual_mechs,
OM_uint32 * initiator_time_rec,
OM_uint32 * acceptor_time_rec)
Purpose:
Adds a credential-element to a credential. The credential-element is
identified by the name of the principal to which it refers. GSSAPI
implementations must impose a local access-control policy on callers of
this routine to prevent unauthorized callers from acquiring credential-
elements to which they are not entitled. This routine is not intended to
provide a ``login to the network'' function, as such a function would
involve the creation of new mechanism-specific authentication data,
rather than merely acquiring a GSSAPI handle to existing data. Such
functions, if required, should be defined in implementation-specific
extensions to the API.
This routine is expected to be used primarily by context acceptors,
since implementations are likely to provide mechanism-specific ways of
obtaining GSS-API initiator credentials from the system login process.
Some implementations may therefore not support the acquisition of
GSS_C_INITIATE or GSS_C_BOTH credentials via gss_acquire_cred.
If credential acquisition is time-consuming for a mechanism, the
mechanism may chooses to delay the actual acquisition until the
credential is required (e.g. by gss_init_sec_context or
gss_accept_sec_context). Such mechanism-specific implementation
decisions should be invisible to the calling application; thus a call of
gss_inquire_cred immediately following the call of gss_acquire_cred must
return valid credential data, and may therefore incur the overhead of a
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deferred credential acquisition.
This routine can be used to either create a new credential containing
all credential-elements of the original in addition to the newly-acquire
credential-element, or to add the new credential-element to an existing
credential. If NULL is specified for the output_cred_handle parameter
argument, the new credential-element will be added to the credential
identified by input_cred_handle; if a valid pointer is specified for the
output_cred_handle parameter, a new credential and handle will be
created.
If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle, the
gss_add_cred will create its output_cred_handle based on default
behavior. That is, the call will have the same effect as if the
application had first made a call to gss_acquire_cred(), specifying the
same usage and passing GSS_C_NO_NAME as the desired_name parameter to
obtain an explicit credential handle embodying default behavior, passed
this credential handle to gss_add_cred(), and finally called
gss_release_cred() on the first credential handle.
If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle parameter,
a non-NULL output_cred_handle must be supplied.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
input_cred_handle gss_cred_id_t, read or modify, optional
The credential to which a credential-element
will be added. If GSS_C_NO_CREDENTIAL is
specified, the routine will create the new
credential based on default behavior (see
description above).
desired_name gss_name_t, read.
Name of principal whose credential
should be acquired.
desired_mech Object ID, read
Underlying security mechanism with which the
credential may be used.
cred_usage gss_cred_usage_t, read
GSS_C_BOTH - Credential may be used
either to initiate or accept
security contexts.
GSS_C_INITIATE - Credential will only be
used to initiate security
contexts.
GSS_C_ACCEPT - Credential will only be used to
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accept security contexts.
initiator_time_req Integer, read, optional
number of seconds that the credential
should remain valid for initiating security
contexts. This argument is ignored if the
created credentials are of type GSS_C_ACCEPT.
Specify GSS_C_INDEFINITE to request that the
credentials have the maximum permitted initiator
lifetime.
acceptor_time_req Integer, read, optional
number of seconds that the credential
should remain valid for accepting security
contexts. This argument is ignored if the
created credentials are of type GSS_C_INITIATE.
Specify GSS_C_INDEFINITE to request that the
credentials have the maximum permitted initiator
lifetime.
output_cred_handle gss_cred_id_t, modify, optional
The returned credential handle, containing
the new credential-element and all the
credential-elements from input_cred_handle.
If a valid pointer to a gss_cred_id_t is
supplied for this parameter, gss_add_cred
creates a new credential handle containing all
credential-elements from the input_cred_handle
and the newly acquired credential-element; if
NULL is specified for this parameter, the newly
acquired credential-element will be added
to the credential identified by input_cred_handle.
actual_mechs Set of Object IDs, modify, optional
The complete set of mechanisms for which
the new credential is valid. Specify NULL
if not required.
initiator_time_rec Integer, modify, optional
Actual number of seconds for which the
returned credentials will remain valid for
initiating contexts using the specified
mechanism. If the implementation or mechanism
does not support expiration of credentials, the
value GSS_C_INDEFINITE will be returned. Specify
NULL if not required
acceptor_time_rec Integer, modify, optional
Actual number of seconds for which the
returned credentials will remain valid for
accepting security contexts using the specified
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mechanism. If the implementation or mechanism
does not support expiration of credentials, the
value GSS_C_INDEFINITE will be returned. Specify
NULL if not required
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_MECH Unavailable mechanism requested
GSS_S_BAD_NAMETYPE Type contained within desired_name parameter is not
supported
GSS_S_BAD_NAME Value supplied for desired_name parameter is ill-
formed.
GSS_S_DUPLICATE_ELEMENT The credential already contains an element for
the requested mechanism with overlapping usage and
validity period.
7.4. gss_add_oid_set_member
OM_uint32 gss_add_oid_set_member (
OM_uint32 * minor_status,
GSS_CONST gss_OID member_oid,
gss_OID_set * oid_set)
Purpose:
Add an Object Identifier to an Object Identifier set. This routine is
intended for use in conjunction with gss_create_empty_oid_set when
constructing a set of mechanism OIDs for input to gss_acquire_cred.
Parameters:
minor_status Integer, modify
Mechanism specific status code
member_oid Object ID, read
The object identifier to copied into
the set.
oid_set Set of Object ID, modify
The set in which the object identifier
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should be inserted.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.5. gss_canonicalize_name
OM_uint32 gss_canonicalize_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t input_name,
CONST gss_OID mech_type,
gss_name_t * output_name)
Purpose:
Generate a canonical mechanism name (MN) from an arbitrary internal
name. The mechanism name is the name that would be returned to a
context acceptor on successful authentication of a context where the
initiator used the input_name in a successful call to gss_acquire_cred,
specifying an OID set containing <mech_type> as its only member,
followed by a call to gss_init_sec_context, specifying <mech_type> as
the authentication mechanism.
Parameters:
minor_status Integer, modify
Mechanism specific status code
input_name gss_name_t, read
The name for which a canonical form is
desired
mech_type Object ID, read
The authentication mechanism for which the
canonical form of the name is desired. The
desired mechanism must be specified explicitly;
no default is provided.
output_name gss_name_t, modify
The resultant canonical name.
Function value: GSS status code
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GSS_S_COMPLETE Successful completion.
GSS_S_BAD_MECH The identified mechanism is not supported.
GSS_S_BAD_NAMETYPE The provided internal name contains no elements that
could be processed by the sepcified mechanism.
GSS_S_BAD_NAME The provided internal name was ill-formed.
7.6. gss_compare_name
OM_uint32 gss_compare_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t name1,
GSS_CONST gss_name_t name2,
int * name_equal)
Purpose:
Allows an application to compare two internal-form names to determine
whether they refer to the same entity.
If either name presented to gss_compare_name denotes an anonymous
principal, the routines should indicate that the two names do not refer
to the same identity.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
name1 gss_name_t, read
internal-form name
name2 gss_name_t, read
internal-form name
name_equal boolean, modify
True - names refer to same entity
False - names refer to different entities
(strictly, the names are not known
to refer to the same identity).
Function value: GSS status code
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GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAMETYPE The two names were of incomparable types.
GSS_S_BAD_NAME One or both of name1 or name2 was ill-formed
7.7. gss_context_time
OM_uint32 gss_context_time (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
OM_uint32 * time_rec)
Purpose:
Determines the number of seconds for which the specified context will
remain valid.
Parameters:
minor_status Integer, modify
Implementation specific status code.
context_handle gss_ctx_id_t, read
Identifies the context to be interrogated.
time_rec Integer, modify
Number of seconds that the context will remain
valid. If the context has already expired,
zero will be returned.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_CONTEXT_EXPIRED The context has already expired
GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid
context
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7.8. gss_create_empty_oid_set
OM_uint32 gss_create_empty_oid_set (
OM_uint32 * minor_status,
gss_OID_set * oid_set)
Purpose:
Create an object-identifier set containing no object identifiers, to
which members may be subsequently added using the gss_add_oid_set_member
routine. These routines are intended to be used to construct sets of
mechanism object identifiers, for input to gss_acquire_cred.
Parameters:
minor_status Integer, modify
Mechanism specific status code
oid_set Set of Object IDs, modify
The empty object identifier set.
The routine will allocate the
gss_OID_set_desc object.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.9. gss_delete_sec_context
OM_uint32 gss_delete_sec_context (
OM_uint32 * minor_status,
gss_ctx_id_t * context_handle,
gss_buffer_t output_token)
Purpose:
Delete a security context. gss_delete_sec_context will delete the local
data structures associated with the specified security context, and may
generate an output_token, which when passed to the peer
gss_process_context_token will instruct it to do likewise. If no token
is required by the mechanism, the GSS-API should set the length field of
the output_token (if provided) to zero. No further security services
may be obtained using the context specified by context_handle.
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The output_token parameter is retained for compatibility with version 1
of the GSS-API. It is recommended that both peer applications invoke
gss_delete_sec_context passing the value GSS_C_NO_BUFFER for the
output_token parameter, indicating that no token is required, and that
gss_delete_sec_context should simply delete local context data
structures. If the application does pass a valid buffer to
gss_delete_sec_context, mechanisms are encouraged to return a zero-
length token, indicating that no peer action is necessary, and that no
token should be transferred by the application.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
context_handle gss_ctx_id_t, modify
context handle identifying context to delete.
output_token buffer, opaque, modify, optional
token to be sent to remote application to
instruct it to also delete the context. It
is recommended that applications specify
GSS_C_NO_BUFFER for this parameter, requesting
local deletion only.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NO_CONTEXT No valid context was supplied
7.10. gss_display_name
OM_uint32 gss_display_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t input_name,
gss_buffer_t output_name_buffer,
gss_OID * output_name_type)
Purpose:
Allows an application to obtain a textual representation of an opaque
internal-form name for display purposes. The syntax of a printable
name is defined by the GSS-API implementation.
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If input_name denotes an anonymous principal, the implementation should
return the gss_OID value GSS_C_NT_ANONYMOUS as the output_name_type, and
a textual name that is syntactically distinct from all valid supported
printable names in output_name_buffer.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
input_name gss_name_t, read
name to be displayed
output_name_buffer buffer, character-string, modify
buffer to receive textual name string
output_name_type Object ID, modify, optional
The type of the returned name. The returned
gss_OID will be a pointer into static storage,
and should be treated as read-only by the caller.
Specify NULL if not required.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAME input_name was ill-formed
7.11. gss_display_status
OM_uint32 gss_display_status (
OM_uint32 * minor_status,
OM_uint32 status_value,
int status_type,
GSS_CONST gss_OID mech_type,
OM_uint32 * message_context,
gss_buffer_t status_string)
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Purpose:
Allows an application to obtain a textual representation of a GSS-API
status code, for display to the user or for logging purposes. Since
some status values may indicate multiple errors, applications may need
to call gss_display_status multiple times, each call generating a single
text string. The message_context parameter is used to indicate which
error message should be extracted from a given status_value;
message_context should be initialized to 0, and gss_display_status will
return a non-zero value if there are further messages to extract.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
status_value Integer, read
Status value to be converted
status_type Integer, read
GSS_C_GSS_CODE - status_value is a GSS status
code
GSS_C_MECH_CODE - status_value is a mechanism
status code
mech_type Object ID, read, optional
Underlying mechanism (used to interpret a
minor status value) Supply GSS_C_NO_OID to
obtain the system default.
message_context Integer, read/modify
Should be initialized to zero by caller
on first call. If further messages are
contained in the status_value parameter,
message_context will be non-zero on return,
and this value should be passed back to
subsequent calls, along with the same
status_value, status_type and mech_type
parameters.
status_string buffer, character string, modify
textual interpretation of the status_value
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_MECH Indicates that translation in accordance with an
unsupported mechanism type was requested
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GSS_S_BAD_STATUS The status value was not recognized, or the status
type was neither GSS_C_GSS_CODE nor GSS_C_MECH_CODE.
7.12. gss_duplicate_name
OM_uint32 gss_duplicate_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t src_name,
gss_name_t * dest_name)
Purpose:
Create an exact duplicate of the existing internal name src_name. The
new dest_name will be independent of src_name (i.e. src_name and
dest_name must both be released, and the release of one shall not affect
the validity of the other).
Parameters:
minor_status Integer, modify
Mechanism specific status code.
src_name gss_name_t, read
internal name to be duplicated.
dest_name gss_name_t, modify
The resultant copy of <src_name>.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAME The src_name parameter was ill-formed.
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7.13. gss_export_name
OM_uint32 gss_export_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t input_name,
gss_buffer_t exported_name)
Purpose:
To produce a canonical contiguous string representation of a mechanism
name (MN), suitable for direct comparison (e.g. with memcmp) for use in
authorization functions (e.g. matching entries in an access-control
list).
The <input_name> parameter must specify a valid MN (i.e. an internal
name generated by gss_accept_sec_context or by gss_canonicalize_name).
Parameters:
minor_status Integer, modify
Mechanism specific status code
input_name gss_name_t, read
The MN to be exported
exported_name gss_buffer_t, octet-string, modify
The canonical contiguous string form of
<input_name>
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NAME_NOT_MN The provided internal name was not a mechanism name.
GSS_S_BAD_NAME The provide internal name was ill-formed.
GSS_S_BAD_NAMETYPE The internal name was of a type not supported by the
GSSAPI implementation.
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7.14. gss_export_sec_context
OM_uint32 gss_export_sec_context (
OM_uint32 * minor_status,
gss_ctx_id_t * context_handle,
gss_buffer_t interprocess_token)
Purpose:
Provided to support the sharing of work between multiple processes.
This routine will typically be used by the context-acceptor, in an
application where a single process receives incoming connection requests
and accepts security contexts over them, then passes the established
context to one or more other processes for message exchange.
gss_export_sec_context() deactivates the security context for the
calling process and creates an interprocess token which, when passed to
gss_import_sec_context in another process, will re-activate the context
in the second process. Only a single instantiation of a given context
may be active at any one time; a subsequent attempt by a context
exporter to access the exported security context will fail.
The implementation may constrain the set of processes by which the
interprocess token may be imported, either as a function of local
security policy, or as a result of implementation decisions. For
example, some implementations may constrain context to be passed only
between processes that run under the same account, or which are part of
the same process group.
The interprocess token may contain security-sensitive information (for
example cryptographic keys). While mechanisms are encouraged to either
avoid placing such sensitive information within interprocess tokens, or
to encrypt the token before returning it to the application, in a
typical object-library GSSAPI implementation this may not be possible.
Thus the application must take care to protect the interprocess token,
and ensure that any process to which the token is transferred is
trustworthy.
Parameters:
minor_status Integer, modify
Mechanism specific status code
context_handle gss_ctx_id_t, modify
context handle identifying the context to transfer.
interprocess_token buffer, opaque, modify
token to be transferred to target process.
Function value: GSS status code
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GSS_S_COMPLETE Successful completion
GSS_S_CONTEXT_EXPIRED The context has expired
GSS_S_NO_CONTEXT The context was invalid
GSS_S_UNAVAILABLE The operation is not supported.
7.15. gss_get_mic
OM_uint32 gss_get_mic (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
gss_qop_t qop_req,
GSS_CONST gss_buffer_t message_buffer,
gss_buffer_t msg_token)
Purpose:
Generates a cryptographic signature for the supplied message, and places
the signature in a token for transfer to the peer application. The
qop_req parameter allows a choice between several cryptographic
algorithms, if supported by the chosen mechanism.
Parameters:
minor_status Integer, modify
Implementation specific status code.
context_handle gss_ctx_id_t, read
identifies the context on which the message
will be sent
qop_req gss_qop_t, read, optional
Specifies requested quality of protection.
Callers are encouraged, on portability grounds,
to accept the default quality of protection
offered by the chosen mechanism, which may be
requested by specifying GSS_C_QOP_DEFAULT for
this parameter. If an unsupported protection
strength is requested, gss_get_mic will return a
major_status of GSS_S_BAD_QOP.
message_buffer buffer, opaque, read
message to be protected
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msg_token buffer, opaque, modify
buffer to receive token
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_CONTEXT_EXPIRED The context has already expired
GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid
context
GSS_S_BAD_QOP The specified QOP is not supported by the mechanism.
7.16. gss_import_name
OM_uint32 gss_import_name (
OM_uint32 * minor_status,
GSS_CONST gss_buffer_t input_name_buffer,
GSS_CONST gss_OID input_name_type,
gss_name_t * output_name)
Purpose:
Convert a contiguous string name to internal form. In general, the
internal name returned (via the <output_name> parameter) will not be an
MN; the exception to this is if the <input_name_type> indicates that the
contiguous string provided via the <input_name_buffer> parameter is of
type GSS_C_NT_EXPORT_NAME, in which case the returned internal name will
be an MN for the mechanism that exported the name.
Parameters:
minor_status Integer, modify
Mechanism specific status code
input_name_buffer buffer, octet-string, read
buffer containing contiguous string name to convert
input_name_type Object ID, read, optional
Object ID specifying type of printable
name. Applications may specify either
GSS_C_NO_OID to use a local system-specific
printable syntax, or an OID registered by the
GSS-API implementation to name a particular
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namespace.
output_name gss_name_t, modify
returned name in internal form
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAMETYPE The input_name_type was unrecognized
GSS_S_BAD_NAME The input_name parameter could not be interpreted as a
name of the specified type
7.17. gss_import_sec_context
OM_uint32 gss_import_sec_context (
OM_uint32 * minor_status,
GSS_CONST gss_buffer_t interprocess_token
gss_ctx_id_t * context_handle)
Purpose:
Allows a process to import a security context established by another
process. See gss_export_sec_context.
Parameters:
minor_status Integer, modify
Mechanism specific status code
interprocess_token buffer, opaque, modify
token received from exporting process
context_handle gss_ctx_id_t, modify
context handle of newly reactivated context.
Function value: GSS status code
GSS_S_COMPLETE Successful completion.
GSS_S_NO_CONTEXT The token did not contain a valid context reference.
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GSS_S_DEFECTIVE_TOKEN The token was invalid.
GSS_S_UNAVAILABLE The operation is unavailable.
GSS_S_UNAUTHORIZED Local policy prevents the import of this context by
the current process..
7.18. gss_indicate_mechs
OM_uint32 gss_indicate_mechs (
OM_uint32 * minor_status,
gss_OID_set * mech_set)
Purpose:
Allows an application to determine which underlying security mechanisms
are available.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
mech_set set of Object IDs, modify
set of implementation-supported mechanisms.
The returned gss_OID_set value will be a
pointer into static storage, and should be
treated as read-only by the caller.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
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7.19. gss_init_sec_context
OM_uint32 gss_init_sec_context (
OM_uint32 * minor_status,
GSS_CONST gss_cred_id_t initiator_cred_handle,
gss_ctx_id_t * context_handle,
GSS_CONST gss_name_t target_name,
GSS_CONST gss_OID mech_type,
OM_uint32 req_flags,
OM_uint32 time_req,
GSS_CONST gss_channel_bindings_t
input_chan_bindings,
GSS_CONST gss_buffer_t input_token
gss_OID * actual_mech_type,
gss_buffer_t output_token,
OM_uint32 * ret_flags,
OM_uint32 * time_rec )
Purpose:
Initiates the establishment of a security context between the
application and a remote peer. Initially, the input_token parameter
should be specified either as GSS_C_NO_BUFFER, or as a pointer to a
gss_buffer_desc object whose length field contains the value zero. The
routine may return a output_token which should be transferred to the
peer application, where the peer application will present it to
gss_accept_sec_context. If no token need be sent, gss_init_sec_context
will indicate this by setting the length field of the output_token
argument to zero. To complete the context establishment, one or more
reply tokens may be required from the peer application; if so,
gss_init_sec_context will return a status containing the supplementary
information bit GSS_S_CONTINUE_NEEDED. In this case,
gss_init_sec_context should be called again when the reply token is
received from the peer application, passing the reply token to
gss_init_sec_context via the input_token parameters.
Portable applications should be constructed to use the token length and
return status to determine whether token need to be sent or waited for.
Thus a typical portable caller should always invoke gss_init_sec_context
within a loop:
int context_established = 0;
gss_ctx_id_t context_hdl = GSS_C_NO_CONTEXT;
...
input_token->length = 0;
while (!context_established) {
maj_stat = gss_init_sec_context(&min_stat,
cred_hdl,
&context_hdl,
target_name,
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desired_mech,
desired_services,
desired_time,
input_bindings,
input_token,
&actual_mech,
output_token,
&actual_services,
&actual_time);
if (GSS_ERROR(maj_stat)) {
report_error(maj_stat);
break;
};
if (output_token->length != 0) {
send_token_to_peer(output_token);
};
if (GSS_SUPPLEMENTARY_INFO(maj_stat) & GSS_S_CONTINUE_NEEDED) {
receive_token_from_peer(input_token);
} else {
context_established = 1;
};
};
Whenever the routine returns a major status that includes the value
GSS_S_CONTINUE_NEEDED, the context is not fully established and the
following restrictions apply to the output parameters:
(a) The value returned via the time_rec parameter is undefined
(b) Unless the accompanying ret_flags parameter contains the bit
GSS_C_PROT_READY_FLAG, indicating that per-message services may be
applied in advance of a successful completion status, the value
returned via the actual_mech_type parameter is undefined until the
routine returns a major status value of GSS_S_COMPLETE.
(c) The values of the GSS_C_DELEG_FLAG, GSS_C_MUTUAL_FLAG,
GSS_C_REPLAY_FLAG, GSS_C_SEQUENCE_FLAG, GSS_C_CONF_FLAG,
GSS_C_INTEG_FLAG and GSS_C_ANON_FLAG bits returned via the
ret_flags parameter should contain the values that the
implementation expects would be valid if context establishment
were to succeed. In particular, if the application has requested
a service such as delegation or anonymous authentication via the
req_flags argument, and such a service is unavailable from the
underlying mechanism, gss_init_sec_context should generate a token
that will not provide the service, and indicate via the ret_flags
argument that the service will not be supported. The application
may choose to abort the context establishment by calling
gss_delete_sec_context (if it cannot continue in the absence of
the service), or it may choose to transmit the token and continue
context establishment (if the service was merely desired but not
mandatory).
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The values of the GSS_C_PROT_READY_FLAG and GSS_C_TRANS_FLAG bits
within ret_flags should indicate the actual state at the time
gss_init_sec_context returns, whether or not the context is fully
established.
Although this requires that GSSAPI implementations set the
GSS_C_PROT_READY_FLAG in the final ret_flags returned to a caller
(i.e. when accompanied by a GSS_S_COMPLETE status code),
applications should not rely on this behavior as the flag was not
defined in Version 1 of the GSSAPI. Instead, applications should
be prepared to use per-message services after a successful context
establishment, according to the GSS_C_INTEG_FLAG and
GSS_C_CONF_FLAG values.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
initiator_cred_handle gss_cred_id_t, read, optional
handle for credentials claimed. Supply
GSS_C_NO_CREDENTIAL to act as a default
initiator principal. If no default
initiator is defined, the function will
return GSS_S_NO_CRED.
context_handle gss_ctx_id_t, read/modify
context handle for new context. Supply
GSS_C_NO_CONTEXT for first call; use value
returned by first call in continuation calls.
target_name gss_name_t, read
Name of target
mech_type OID, read, optional
Object ID of desired mechanism. Supply
GSS_C_NO_OID to obtain an implementation
specific default
req_flags bit-mask, read
Contains various independent flags, each of
which requests that the context support a
specific service option. Symbolic
names are provided for each flag, and the
symbolic names corresponding to the required
flags should be logically-ORed
together to form the bit-mask value. The
flags are:
GSS_C_DELEG_FLAG
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True - Delegate credentials to remote peer
False - Don't delegate
GSS_C_MUTUAL_FLAG
True - Request that remote peer
authenticate itself
False - Authenticate self to remote peer
only
GSS_C_REPLAY_FLAG
True - Enable replay detection for
messages protected with gss_wrap
or gss_get_mic
False - Don't attempt to detect
replayed messages
GSS_C_SEQUENCE_FLAG
True - Enable detection of out-of-sequence
protected messages
False - Don't attempt to detect
out-of-sequence messages
GSS_C_ANON_FLAG
True - Do not reveal the initiator's
identity to the acceptor.
False - Authenticate normally.
time_req Integer, read, optional
Desired number of seconds for which context
should remain valid. Supply 0 to request a
default validity period.
input_chan_bindings channel bindings, read, optional
Application-specified bindings. Allows
application to securely bind channel
identification information to the security
context. Specify GSS_C_NO_CHANNEL_BINDINGS
if channel bindings are not used.
input_token buffer, opaque, read, optional (see text)
Token received from peer application.
Supply GSS_C_NO_BUFFER, or a pointer to
a buffer containing the value GSS_C_EMPTY_BUFFER
on initial call.
actual_mech_type OID, modify, optional
Actual mechanism used. Specify NULL if
not required.
output_token buffer, opaque, modify
token to be sent to peer application. If
the length field of the returned buffer is
zero, no token need be sent to the peer
application.
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ret_flags bit-mask, modify, optional
Contains various independent flags, each of which
indicates that the context supports a specific
service option. Specify NULL if not
required. Symbolic names are provided
for each flag, and the symbolic names
corresponding to the required flags should be
logically-ANDed with the ret_flags value to test
whether a given option is supported by the
context. The flags are:
GSS_C_DELEG_FLAG
True - Credentials were delegated to
the remote peer
False - No credentials were delegated
GSS_C_MUTUAL_FLAG
True - Remote peer has been asked to
authenticated itself
False - Remote peer has not been asked to
authenticate itself
GSS_C_REPLAY_FLAG
True - replay of protected messages
will be detected
False - replayed messages will not be
detected
GSS_C_SEQUENCE_FLAG
True - out-of-sequence protected
messages will be detected
False - out-of-sequence messages will
not be detected
GSS_C_CONF_FLAG
True - Confidentiality service may be
invoked by calling gss_wrap routine
False - No confidentiality service (via
gss_wrap) available. gss_wrap will
provide message encapsulation,
data-origin authentication and
integrity services only.
GSS_C_INTEG_FLAG
True - Integrity service may be invoked by
calling either gss_get_mic or gss_wrap
routines.
False - Per-message integrity service
unavailable.
GSS_C_ANON_FLAG
True - The initiator's identity has not been
revealed, and will not be revealed if
any emitted token is passed to the
acceptor.
False - The initiator's identity has been or
will be authenticated normally.
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GSS_C_PROT_READY_FLAG
True - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available for
use if the accompanying major status
return value is either GSS_S_COMPLETE or
GSS_S_CONTINUE_NEEDED.
False - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available
only if the accompanying major status
return value is GSS_S_COMPLETE.
GSS_C_TRANS_FLAG
True - The resultant security context may
be transferred to other processes via
a call to gss_export_sec_context().
False - The security context is not
transferrable.
time_rec Integer, modify, optional
number of seconds for which the context
will remain valid. If the implementation does
not support context expiration, the value
GSS_C_INDEFINITE will be returned. Specify
NULL if not required.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_CONTINUE_NEEDED Indicates that a token from the peer application
is required to complete the context, and that
gss_init_sec_context must be called again with that
token.
GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed on the
input_token failed
GSS_S_DEFECTIVE_CREDENTIAL Indicates that consistency checks performed
on the credential failed.
GSS_S_NO_CRED The supplied credentials were not valid for context
initiation, or the credential handle did not reference
any credentials.
GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired
GSS_S_BAD_BINDINGS The input_token contains different channel bindings
to those specified via the input_chan_bindings
parameter
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GSS_S_BAD_SIG The input_token contains an invalid signature, or a
signature that could not be verified
GSS_S_OLD_TOKEN The input_token was too old. This is a fatal error
during context establishment
GSS_S_DUPLICATE_TOKEN The input_token is valid, but is a duplicate of a
token already processed. This is a fatal error during
context establishment.
GSS_S_NO_CONTEXT Indicates that the supplied context handle did not
refer to a valid context
GSS_S_BAD_NAMETYPE The provided target_name parameter contained an
invalid or unsupported type of name
GSS_S_BAD_NAME The provided target_name parameter was ill-formed.
GSS_S_BAD_MECH The specified mechanism is not supported by the
provided credential, or is unrecognized by the
implementation.
7.20. gss_inquire_context
OM_uint32 gss_inquire_context (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
gss_name_t * src_name,
gss_name_t * targ_name,
OM_uint32 * lifetime_rec,
gss_OID * mech_type,
OM_uint32 * ctx_flags,
int * locally_initiated,
int * open )
Purpose:
Obtains information about a security context. The caller must already
have obtained a handle that refers to the context, although the context
need not be fully established.
Parameters:
minor_status Integer, modify
Mechanism specific status code
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context_handle gss_ctx_id_t, read
A handle that refers to the security context.
src_name gss_name_t, modify, optional
The name of the context initiator.
If the context was established using anonymous
authentication, and if the application invoking
gss_inquire_context is the context acceptor,
an anonymous name will be returned.
Specify NULL if not required.
targ_name gss_name_t, modify, optional
The name of the context acceptor.
Specify NULL if not required.
lifetime_rec Integer, modify, optional
The number of seconds for which the context
will remain valid. If the context has
expired, this parameter will be set to zero.
If the implementation does not support
context expiration, the value
GSS_C_INDEFINITE will be returned. Specify
NULL if not required.
mech_type gss_OID, modify, optional
The security mechanism providing the
context.
Specify NULL if not required.
ctx_flags bit-mask, modify, optional
Contains various independent flags, each of
which indicates that the context supports
(or is expected to support, if ctx_open is
false) a specific service option. If not
needed, specify NULL. Symbolic names are
provided for each flag, and the symbolic names
corresponding to the required flags
should be logically-ANDed with the ret_flags
value to test whether a given option is
supported by the context. The flags are:
GSS_C_DELEG_FLAG
True - Credentials were delegated from
the initiator to the acceptor.
False - No credentials were delegated
GSS_C_MUTUAL_FLAG
True - The acceptor was authenticated
to the initiator
False - The acceptor did not authenticate
itself.
GSS_C_REPLAY_FLAG
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True - replay of protected messages
will be detected
False - replayed messages will not be
detected
GSS_C_SEQUENCE_FLAG
True - out-of-sequence protected
messages will be detected
False - out-of-sequence messages will not
be detected
GSS_C_CONF_FLAG
True - Confidentiality service may be invoked
by calling gss_wrap routine
False - No confidentiality service (via
gss_wrap) available. gss_wrap will
provide message encapsulation,
data-origin authentication and
integrity services only.
GSS_C_INTEG_FLAG
True - Integrity service may be invoked by
calling either gss_get_mic or gss_wrap
routines.
False - Per-message integrity service
unavailable.
GSS_C_ANON_FLAG
True - The initiator's identity will not
be revealed to the acceptor.
The src_name parameter (if
requested) contains an anonymous
internal name.
False - The initiator has been
authenticated normally.
GSS_C_PROT_READY_FLAG
True - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available
for use.
False - Protection services (as specified
by the states of the GSS_C_CONF_FLAG
and GSS_C_INTEG_FLAG) are available
only if the context is fully
established (i.e. if the open parameter
is non-zero).
GSS_C_TRANS_FLAG
True - The resultant security context may
be transferred to other processes via
a call to gss_export_sec_context().
False - The security context is not
transferrable.
locally_initiated Boolean, modify
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True if the invoking application is the
context initiator.
Specify NULL if not required.
open Boolean, modify
True if the context is fully established;
false if a context-establishment token
is expected from the peer application.
Specify NULL if not required.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NO_CONTEXT The referenced context could not be accessed.
GSS_S_CONTEXT_EXPIRED The context has expired. If the lifetime_rec
parameter was requested, it will be set to 0.
7.21. gss_inquire_cred
OM_uint32 gss_inquire_cred (
OM_uint32 * minor_status,
GSS_CONST gss_cred_id_t cred_handle,
gss_name_t * name,
OM_uint32 * lifetime,
gss_cred_usage_t * cred_usage,
gss_OID_set * mechanisms )
Purpose:
Obtains information about a credential. The caller must already have
obtained a handle that refers to the credential.
Parameters:
minor_status Integer, modify
Mechanism specific status code
cred_handle gss_cred_id_t, read
A handle that refers to the target credential.
Specify GSS_C_NO_CREDENTIAL to inquire about
the default initiator principal.
name gss_name_t, modify, optional
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The name whose identity the credential asserts.
Specify NULL if not required.
lifetime Integer, modify, optional
The number of seconds for which the credential
will remain valid. If the credential has
expired, this parameter will be set to zero.
If the implementation does not support
credential expiration, the value
GSS_C_INDEFINITE will be returned. Specify
NULL if not required.
cred_usage gss_cred_usage_t, modify, optional
How the credential may be used. One of the
following:
GSS_C_INITIATE
GSS_C_ACCEPT
GSS_C_BOTH
Specify NULL if not required.
mechanisms gss_OID_set, modify, optional
Set of mechanisms supported by the credential.
Specify NULL if not required.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NO_CRED The referenced credentials could not be accessed.
GSS_S_DEFECTIVE_CREDENTIAL The referenced credentials were invalid.
GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired. If
the lifetime parameter was not passed as NULL, it will
be set to 0.
7.22. gss_inquire_cred_by_mech
OM_uint32 gss_inquire_cred_by_mech (
OM_uint32 * minor_status,
GSS_CONST gss_cred_id_t cred_handle,
GSS_CONST gss_OID mech_type,
gss_name_t * name,
OM_uint32 * initiator_lifetime,
OM_uint32 * acceptor_lifetime,
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gss_cred_usage_t * cred_usage )
Purpose:
Obtains per-mechanism information about a credential. The caller must
already have obtained a handle that refers to the credential.
Parameters:
minor_status Integer, modify
Mechanism specific status code
cred_handle gss_cred_id_t, read
A handle that refers to the target credential.
Specify GSS_C_NO_CREDENTIAL to inquire about
the default initiator principal.
mech_type gss_OID, read
The mechanism for which information should be
returned.
name gss_name_t, modify, optional
The name whose identity the credential asserts.
Specify NULL if not required.
initiator_lifetime Integer, modify, optional
The number of seconds for which the credential
will remain capable of initiating security contexts
under the specified mechanism. If the credential
can no longer be used to initiate contexts, or if
the credential usage for this mechanism is
GSS_C_ACCEPT,
this parameter will be set to zero. If the
implementation does not support expiration of
initiator credentials, the value GSS_C_INDEFINITE
will be returned. Specify NULL if not required.
acceptor_lifetime Integer, modify, optional
The number of seconds for which the credential
will remain capable of accepting security contexts
under the specified mechanism. If the credential
can no longer be used to accept contexts, or if
the credential usage for this mechanism is
GSS_C_INITIATE, this parameter will be set to zero.
If the implementation does not support expiration
of acceptor credentials, the value GSS_C_INDEFINITE
will be returned. Specify NULL if not required.
cred_usage gss_cred_usage_t, modify, optional
How the credential may be used with the specified
mechanism. One of the following:
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GSS_C_INITIATE
GSS_C_ACCEPT
GSS_C_BOTH
Specify NULL if not required.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NO_CRED The referenced credentials could not be accessed.
GSS_S_DEFECTIVE_CREDENTIAL The referenced credentials were invalid.
GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired. If
the lifetime parameter was not passed as NULL, it will
be set to 0.
7.23. gss_inquire_mechs_for_name
OM_uint32 gss_inquire_mechs_for_name (
OM_uint32 * minor_status,
GSS_CONST gss_name_t input_name,
gss_OID_set * mech_types )
Purpose:
Returns the set of mechanisms supported by the GSSAPI implementation
that may be able to process the specified name.
Each mechanism returned will recognize at least one element within the
name. It is permissible for this routine to be implemented within a
mechanism-independent GSSAPI layer, using the type information contained
within the presented name, and based on registration information
provided by individual mechanism implementations. This means that the
returned mech_types set may indicate that a particular mechanism will
understand the name when in fact it would refuse to accept the name as
input to gss_canonicalize_name, gss_init_sec_context, gss_acquire_cred
or gss_add_cred (due to some property of the specific name, as opposed
to the name type). Thus this routine should be used only as a pre-
filter for a call to a subsequent mechanism-specific routine.
Parameters:
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minor_status Integer, modify
Implementation specific status code.
input_name gss_name_t, read
The name to which the inquiry relates.
mech_types gss_OID_set, modify
Set of mechanisms that may support the
specified name. The returned OID set
must be freed by the caller by a call
to gss_release_oid_set().
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAME The input_name parameter was ill-formed.
GSS_S_BAD_NAMETYPE The input_name parameter contained an invalid or
unsupported type of name
7.24. gss_inquire_names_for_mech
OM_uint32 gss_inquire_names_for_mech (
OM_uint32 * minor_status,
GSS_CONST gss_OID mechanism,
gss_OID_set * name_types)
Purpose:
Returns the set of nametypes supported by the specified mechanism.
Parameters:
minor_status Integer, modify
Implementation specific status code.
mechanism gss_OID, read
The mechanism to be interrogated.
name_types gss_OID_set, modify
Set of name-types supported by the
specified mechanism.
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Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.25. gss_oid_to_str
OM_uint32 gss_oid_to_str (
OM_uint32 * minor_status,
GSS_CONST gss_OID oid,
gss_buffer_t oid_str)
Purpose:
Converts an object identifier value into its printable ASN.1
representation. For example, when passed the OID value
GSS_C_NT_ANONYMOUS, the routine might deliver a buffer object containing
the string "{1 3 6 1 5 6 3}".
If the provided gss_OID value does not contain a validly encoded OID,
the buffer pointedf to by oid_str will contain an empty buffer on
return.
Parameters:
minor_status Integer, modify
Implementation specific status code.
oid gss_OID, read
The OID to be translated.
oid_str buffer, character string, modify
textual interpretation of the OID
Function value: GSS status code
GSS_S_COMPLETE Successful completion
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7.26. gss_process_context_token
OM_uint32 gss_process_context_token (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
GSS_CONST gss_buffer_t token_buffer)
Purpose:
Provides a way to pass a token to the security service. Used with
tokens emitted by gss_delete_sec_context. Note that mechanisms are
encouraged to perform local deletion, and not emit tokens from
gss_delete_sec_context. This routine, therefore, is primarily for
backwards compatibility with V1 applications.
Parameters:
minor_status Integer, modify
Implementation specific status code.
context_handle gss_ctx_id_t, read
context handle of context on which token is to
be processed
token_buffer buffer, opaque, read
token to process
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed on the
token failed
GSS_S_NO_CONTEXT The context_handle did not refer to a valid context
7.27. gss_release_buffer
OM_uint32 gss_release_buffer (
OM_uint32 * minor_status,
gss_buffer_t buffer)
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Purpose:
Free storage associated with a buffer. The storage must have been
allocated by a GSS-API routine. In addition to freeing the associated
storage, the routine will zero the length field in the descriptor to
which the buffer parameter refers.
Parameters:
minor_status Integer, modify
Mechanism specific status code
buffer buffer, modify
The storage associated with the buffer will be
deleted. The gss_buffer_desc object will not
be freed, but its length field will be zeroed.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.28. gss_release_cred
OM_uint32 gss_release_cred (
OM_uint32 * minor_status,
gss_cred_id_t * cred_handle)
Purpose:
Informs GSS-API that the specified credential handle is no longer
required by the process. When all processes have released a credential,
it will be deleted.
Parameters:
cred_handle gss_cred_id_t, modify, optional
Buffer containing opaque credential
handle. If GSS_C_NO_CREDENTIAL is supplied,
the routine will complete successfully, but
will do nothing.
minor_status Integer, modify
Mechanism specific status code.
Function value: GSS status code
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GSS_S_COMPLETE Successful completion
GSS_S_NO_CRED Credentials could not be accessed.
7.29. gss_release_name
OM_uint32 gss_release_name (
OM_uint32 * minor_status,
gss_name_t * name)
Purpose:
Free GSSAPI-allocated storage by associated with an internal form name.
Parameters:
minor_status Integer, modify
Mechanism specific status code
name gss_name_t, modify
The name to be deleted
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_BAD_NAME The name parameter did not contain a valid name
7.30. gss_release_oid
OM_uint32 gss_release_oid (
OM_uint32 * minor_status,
gss_OID * oid)
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Purpose:
Discard an OID. This routine is provided for completeness only. While
some of the GSS-API routines return OIDs, these routines are currently
documented as returning pointers to structures maintained in static
storage. gss_release_oid will recognize any of the GSSAPI's own OID
values, and will silently ignore attempts to free these OIDs; for other
OIDs it will call the C free() routine for both the OID data and the
descriptor. This allows applications to freely mix their own heap-
allocated OID values with OIDs returned by GSS-API.
Parameters:
minor_status Integer, modify
Mechanism specific status code
oid Object ID, modify
The object identifier to be freed.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.31. gss_release_oid_set
OM_uint32 gss_release_oid_set (
OM_uint32 * minor_status,
gss_OID_set * set)
Purpose:
Free storage associated with a gss_OID_set object. Like
gss_release_oid(), gss_release_oid_set() will recognize any static
gss_OID_set objects that the GSSAPI implementation defines, and will
silently ignore attempts to free these sets. For other OID sets, this
routine is functionally equivalent to invoking gss_release_oid() on each
element within the OID set, followed by calling the C free() routine on
the gss_OID_set_desc set descriptor.
Parameters:
minor_status Integer, modify
Mechanism specific status code
set Set of Object IDs, modify
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The storage associated with the gss_OID_set
will be deleted.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
7.32. gss_str_to_oid
OM_uint32 gss_str_to_oid (
OM_uint32 * minor_status,
GSS_CONST gss_buffer_t oid_str,
gss_OID * oid)
Purpose:
Converts an ASN.1 representation of an object identifier into a gss_OID
value. For example, when passed the string "{1 3 6 1 5 6 3}", the
routine would deliver an object identifier whose value is the same as
that of GSS_C_NT_ANONYMOUS.
Note that full support of ASN.1 object identifier value syntax is not
required. At a minimum, strings of the form "{n1 n2 n3 ...}" (where
n1,n2,n3 etc. are integers) should be supported, and it is permissible
to impose reasonable platform-specific limits on the magnitude of
individual components (for example, all components must be less than
LONG_MAX). The implementation must support conversion between gss_OID
values and strings for all object identifier values that the
implementation defines, and all string representations generated by
gss_oid_to_str must also be supported as inputs to gss_str_to_oid.
Parameters:
minor_status Integer, modify
Implementation specific status code.
oid_str buffer, character string, read
textual interpretation of the OID
oid gss_OID, modify
The returned OID value
Function value: GSS status code
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GSS_S_COMPLETE Successful completion
7.33. gss_test_oid_set_member
OM_uint32 gss_test_oid_set_member (
OM_uint32 * minor_status,
GSS_CONST gss_OID member,
GSS_CONST gss_OID_set set,
int * present)
Purpose:
Interrogate an Object Identifier set to determine whether a specified
Object Identifier is a member. This routine is intended to be used with
OID sets returned by gss_indicate_mechs, gss_acquire_cred, and
gss_inquire_cred, but will also work with user-generated sets.
Parameters:
minor_status Integer, modify
Mechanism specific status code
member Object ID, read
The object identifier whose presence
is to be tested.
set Set of Object ID, read
The Object Identifier set.
present Boolean, modify
True if the specified OID is a member
of the set, false if not.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
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7.34. gss_unwrap
OM_uint32 gss_unwrap (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
GSS_CONST gss_buffer_t input_message_buffer,
gss_buffer_t output_message_buffer,
int * conf_state,
gss_qop_t * qop_state)
Purpose:
Converts a message previously protected by gss_wrap back to a usable
form, verifying the embedded signature. The conf_state parameter
indicates whether the message was encrypted; the qop_state parameter
indicates the strength of protection that was used to provide the
confidentiality and integrity services.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
context_handle gss_ctx_id_t, read
Identifies the context on which the message
arrived
input_message_buffer buffer, opaque, read
protected message
output_message_buffer buffer, opaque, modify
Buffer to receive unwrapped message
conf_state boolean, modify, optional
True - Confidentiality and integrity protection
were used
False - Integrity service only was used
Specify NULL if not required
qop_state gss_qop_t, modify, optional
Quality of protection gained from signature
Specify NULL if not required
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_DEFECTIVE_TOKEN The token failed consistency checks
GSS_S_BAD_SIG The signature was incorrect
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GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct
signature for the message, but it had already been
processed
GSS_S_OLD_TOKEN The token was valid, and contained a correct signature
for the message, but it is too old to check for
duplication.
GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct signature
for the message, but has been verified out of
sequence; a later token has already been received.
GSS_S_GAP_TOKEN The token was valid, and contained a correct signature
for the message, but has been verified out of
sequence; an earlier expected token has not yet been
received.
GSS_S_CONTEXT_EXPIRED The context has already expired
GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid
context
7.35. gss_verify_mic
OM_uint32 gss_verify_mic (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
GSS_CONST gss_buffer_t message_buffer,
GSS_CONST gss_buffer_t token_buffer,
gss_qop_t * qop_state)
Purpose:
Verifies that a cryptographic signature, contained in the token
parameter, fits the supplied message. The qop_state parameter allows a
message recipient to determine the strength of protection that was
applied to the message.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
context_handle gss_ctx_id_t, read
Identifies the context on which the message
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arrived
message_buffer buffer, opaque, read
Message to be verified
token_buffer buffer, opaque, read
Token associated with message
qop_state gss_qop_t, modify, optional
quality of protection gained from signature
Specify NULL if not required
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_DEFECTIVE_TOKEN The token failed consistency checks
GSS_S_BAD_SIG The signature was incorrect
GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct
signature for the message, but it had already been
processed
GSS_S_OLD_TOKEN The token was valid, and contained a correct signature
for the message, but it is too old to check for
duplication.
GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct signature
for the message, but has been verified out of
sequence; a later token has already been received.
GSS_S_GAP_TOKEN The token was valid, and contained a correct signature
for the message, but has been verified out of
sequence; an earlier expected token has not yet been
received.
GSS_S_CONTEXT_EXPIRED The context has already expired
GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid
context
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7.36. gss_wrap
OM_uint32 gss_wrap (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req
GSS_CONST gss_buffer_t input_message_buffer,
int * conf_state,
gss_buffer_t output_message_buffer )
Purpose:
Cryptographically signs and optionally encrypts the specified
input_message. The output_message contains both the signature and the
message. The qop_req parameter allows a choice between several
cryptographic algorithms, if supported by the chosen mechanism.
Parameters:
minor_status Integer, modify
Mechanism specific status code.
context_handle gss_ctx_id_t, read
Identifies the context on which the message
will be sent
conf_req_flag boolean, read
True - Both confidentiality and integrity
services are requested
False - Only integrity service is requested
qop_req gss_qop_t, read, optional
Specifies required quality of protection. A
mechanism-specific default may be requested by
setting qop_req to GSS_C_QOP_DEFAULT. If an
unsupported protection strength is requested,
gss_wrap will return a major_status of
GSS_S_BAD_QOP.
input_message_buffer buffer, opaque, read
Message to be protected
conf_state boolean, modify, optional
True - Confidentiality, data origin
authentication and integrity services
have been applied
False - Integrity and data origin services only
has been applied.
Specify NULL if not required
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output_message_buffer buffer, opaque, modify
Buffer to receive protected message
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_CONTEXT_EXPIRED The context has already expired
GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid
context
GSS_S_BAD_QOP The specified QOP is not supported by the mechanism.
7.37. gss_wrap_size_limit
OM_uint32 gss_wrap_size_limit (
OM_uint32 * minor_status,
GSS_CONST gss_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
OM_uint32 req_output_size,
OM_uint32 * max_input_size)
Purpose:
Allows an application to determine the maximum message size that, if
presented to gss_wrap with the same conf_req_flag and qop_req
parameters, will result in an output token containing no more than
req_output_size bytes.
This call is intended for use by applications that communicate over
protocols that impose a maximum message size. It enables the
application to fragment messages prior to applying protection.
Successful completion of this call does not guarantee that gss_wrap will
be able to protect a message of length max_input_size bytes, since this
ability may depend on the availability of system resources at the time
that gss_wrap is called. However, if the implementation itself imposes
an upper limit on the length of messages that may be processed by
gss_wrap, the implementation should not return a value via
max_input_bytes that is greater than this length.
Parameters:
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minor_status Integer, modify
Mechanism specific status code
context_handle gss_ctx_id_t, read
A handle that refers to the security over
which the messages will be sent.
conf_req_flag Boolean, read
Indicates whether gss_wrap will be asked
to apply confidentiality protection in
addition to integrity protection. See
the routine description for gss_wrap
for more details.
qop_req gss_qop_t, read
Indicates the level of protection that
gss_wrap will be asked to provide. See
the routine description for gss_wrap for
more details.
req_output_size Integer, read
The desired maximum size for tokens emitted
by gss_wrap.
max_input_size Integer, modify
The maximum input message size that may
be presented to gss_wrap in order to
guarantee that the emitted token shall
be no larger than req_output_size bytes.
Function value: GSS status code
GSS_S_COMPLETE Successful completion
GSS_S_NO_CONTEXT The referenced context could not be accessed.
GSS_S_CONTEXT_EXPIRED The context has expired.
GSS_S_BAD_QOP The specified QOP is not supported by the mechanism.
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APPENDIX A. GSS-API C header file gssapi.h
C-language GSS-API implementations should include a copy of the
following header-file.
#ifndef GSSAPI_H_
#define GSSAPI_H_
/*
* First, include stddef.h to get size_t defined.
*/
#include <stddef.h>
/*
* If the platform supports the xom.h header file, it should be
* included here.
*/
#include <xom.h>
/*
* define GSS_NO_CONST prior to including this header to tell GSSAPI not
* to declare routine input parameters as "const".
*/
#ifndef GSS_NO_CONST
#define GSS_CONST const
#else
#define GSS_CONST
#endif
/*
* Now define the three platform-dependent pointer types.
*/
typedef <platform-specific> gss_ctx_id_t;
typedef <platform-specific> gss_cred_id_t;
typedef <platform-specific> gss_name_t;
/*
* The following type must be defined as the smallest natural
* unsigned integer supported by the platform that has at least
* 32 bits of precision.
*/
typedef <platform-specific> gss_uint32;
#ifdef OM_STRING
/*
* We have included the xom.h header file. Verify that OM_uint32
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* is defined correctly.
*/
#if sizeof(gss_uint32) != sizeof(OM_uint32)
#error Incompatible definition of OM_uint32 from xom.h
#endif
typedef OM_object_identifier gss_OID_desc, *gss_OID;
#else
/*
* We can't use X/Open definitions, so roll our own.
*/
typedef gss_uint32 OM_uint32;
typedef struct gss_OID_desc_struct {
OM_uint32 length;
void *elements;
} gss_OID_desc, *gss_OID;
#endif
typedef struct gss_OID_set_desc_struct {
size_t count;
gss_OID elements;
} gss_OID_set_desc, *gss_OID_set;
typedef struct gss_buffer_desc_struct {
size_t length;
void *value;
} gss_buffer_desc, *gss_buffer_t;
typedef struct gss_channel_bindings_struct {
OM_uint32 initiator_addrtype;
gss_buffer_desc initiator_address;
OM_uint32 acceptor_addrtype;
gss_buffer_desc acceptor_address;
gss_buffer_desc application_data;
} *gss_channel_bindings_t;
/*
* For now, define a QOP-type as an OM_uint32 (pending resolution
* of ongoing discussions).
*/
typedef OM_uint32 gss_qop_t;
typedef int gss_cred_usage_t;
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/*
* Flag bits for context-level services.
*/
#define GSS_C_DELEG_FLAG 1
#define GSS_C_MUTUAL_FLAG 2
#define GSS_C_REPLAY_FLAG 4
#define GSS_C_SEQUENCE_FLAG 8
#define GSS_C_CONF_FLAG 16
#define GSS_C_INTEG_FLAG 32
#define GSS_C_ANON_FLAG 64
#define GSS_C_PROT_READY_FLAG 128
#define GSS_C_TRANS_FLAG 256
/*
* Credential usage options
*/
#define GSS_C_BOTH 0
#define GSS_C_INITIATE 1
#define GSS_C_ACCEPT 2
/*
* Status code types for gss_display_status
*/
#define GSS_C_GSS_CODE 1
#define GSS_C_MECH_CODE 2
/*
* The constant definitions for channel-bindings address families
*/
#define GSS_C_AF_UNSPEC 0
#define GSS_C_AF_LOCAL 1
#define GSS_C_AF_INET 2
#define GSS_C_AF_IMPLINK 3
#define GSS_C_AF_PUP 4
#define GSS_C_AF_CHAOS 5
#define GSS_C_AF_NS 6
#define GSS_C_AF_NBS 7
#define GSS_C_AF_ECMA 8
#define GSS_C_AF_DATAKIT 9
#define GSS_C_AF_CCITT 10
#define GSS_C_AF_SNA 11
#define GSS_C_AF_DECnet 12
#define GSS_C_AF_DLI 13
#define GSS_C_AF_LAT 14
#define GSS_C_AF_HYLINK 15
#define GSS_C_AF_APPLETALK 16
#define GSS_C_AF_BSC 17
#define GSS_C_AF_DSS 18
#define GSS_C_AF_OSI 19
#define GSS_C_AF_X25 21
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#define GSS_C_AF_NULLADDR 255
/*
* Various Null values
*/
#define GSS_C_NO_NAME ((gss_name_t) 0)
#define GSS_C_NO_BUFFER ((gss_buffer_t) 0)
#define GSS_C_NO_OID ((gss_OID) 0)
#define GSS_C_NO_OID_SET ((gss_OID_set) 0)
#define GSS_C_NO_CONTEXT ((gss_ctx_id_t) 0)
#define GSS_C_NO_CREDENTIAL ((gss_cred_id_t) 0)
#define GSS_C_NO_CHANNEL_BINDINGS ((gss_channel_bindings_t) 0)
#define GSS_C_EMPTY_BUFFER {0, NULL}
/*
* Some alternate names for a couple of the above
* values. These are defined for V1 compatibility.
*/
#define GSS_C_NULL_OID GSS_C_NO_OID
#define GSS_C_NULL_OID_SET GSS_C_NO_OID_SET
/*
* Define the default Quality of Protection for per-message
* services. Note that an implementation that offers multiple
* levels of QOP may either reserve a value (for example zero,
* as assumed here) to mean "default protection", or
* alternatively may simply equate GSS_C_QOP_DEFAULT to a specific
* explicit QOP value. However, a value of 0 should always be
* interpreted by a GSSAPI implementation as a request for the
* default protection level.
*/
#define GSS_C_QOP_DEFAULT 0
/*
* Expiration time of 2^32-1 seconds means infinite lifetime for a
* credential or security context
*/
#define GSS_C_INDEFINITE 0xfffffffful
/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
* "\x01\x02\x01\x01"},
* corresponding to an object-identifier value of
* {iso(1) member-body(2) United States(840) mit(113554)
* infosys(1) gssapi(2) generic(1) user_name(1)}. The constant
* GSS_C_NT_USER_NAME should be initialized to point
* to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_USER_NAME;
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/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
* "\x01\x02\x01\x02"},
* corresponding to an object-identifier value of
* {iso(1) member-body(2) United States(840) mit(113554)
* infosys(1) gssapi(2) generic(1) machine_uid_name(2)}.
* The constant GSS_C_NT_MACHINE_UID_NAME should be
* initialized to point to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_MACHINE_UID_NAME;
/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
* "\x01\x02\x01\x03"},
* corresponding to an object-identifier value of
* {iso(1) member-body(2) United States(840) mit(113554)
* infosys(1) gssapi(2) generic(1) string_uid_name(3)}.
* The constant GSS_C_NT_STRING_UID_NAME should be
* initialized to point to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_STRING_UID_NAME;
/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {6, (void *)"\x2b\x06\x01\x05\x06\x02"},
* corresponding to an object-identifier value of
* {1(iso), 3(org), 6(dod), 1(internet), 5(security),
* 6(nametypes), 2(gss-host-based-services)}. The constant
* GSS_C_NT_HOSTBASED_SERVICE should be initialized to point
* to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_HOSTBASED_SERVICE;
/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {6, (void *)"\x2b\x06\01\x05\x06\x03"},
* corresponding to an object identifier value of
* {1(iso), 3(org), 6(dod), 1(internet), 5(security),
* 6(nametypes), 3(gss-anonymous-name)}. The constant
* and GSS_C_NT_ANONYMOUS should be initialized to point
* to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_ANONYMOUS;
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/*
* The implementation must reserve static storage for a
* gss_OID_desc object containing the value
* {6, (void *)"\x2b\x06\x01\x05\x06\x04"},
* corresponding to an object-identifier value of
* {1(iso), 3(org), 6(dod), 1(internet), 5(security),
* 6(nametypes), 4(gss-api-exported-name)}. The constant
* GSS_C_NT_EXPORT_NAME should be initialized to point
* to that gss_OID_desc.
*/
extern gss_OID GSS_C_NT_EXPORT_NAME;
/* Major status codes */
#define GSS_S_COMPLETE 0
/*
* Some "helper" definitions to make the status code macros obvious.
*/
#define GSS_C_CALLING_ERROR_OFFSET 24
#define GSS_C_ROUTINE_ERROR_OFFSET 16
#define GSS_C_SUPPLEMENTARY_OFFSET 0
#define GSS_C_CALLING_ERROR_MASK 0377ul
#define GSS_C_ROUTINE_ERROR_MASK 0377ul
#define GSS_C_SUPPLEMENTARY_MASK 0177777ul
/*
* The macros that test status codes for error conditions.
* Note that the GSS_ERROR() macro has changed slightly from
* the V1 GSSAPI so that it now evaluates its argument
* only once.
*/
#define GSS_CALLING_ERROR(x) \
(x & (GSS_C_CALLING_ERROR_MASK << GSS_C_CALLING_ERROR_OFFSET))
#define GSS_ROUTINE_ERROR(x) \
(x & (GSS_C_ROUTINE_ERROR_MASK << GSS_C_ROUTINE_ERROR_OFFSET))
#define GSS_SUPPLEMENTARY_INFO(x) \
(x & (GSS_C_SUPPLEMENTARY_MASK << GSS_C_SUPPLEMENTARY_OFFSET))
#define GSS_ERROR(x) \
(x & ((GSS_C_CALLING_ERROR_MASK << GSS_C_CALLING_ERROR_OFFSET) | \
(GSS_C_ROUTINE_ERROR_MASK << GSS_C_ROUTINE_ERROR_OFFSET)))
/*
* Now the actual status code definitions
*/
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/*
* Calling errors:
*/
#define GSS_S_CALL_INACCESSIBLE_READ \
(1ul << GSS_C_CALLING_ERROR_OFFSET)
#define GSS_S_CALL_INACCESSIBLE_WRITE \
(2ul << GSS_C_CALLING_ERROR_OFFSET)
#define GSS_S_CALL_BAD_STRUCTURE \
(3ul << GSS_C_CALLING_ERROR_OFFSET)
/*
* Routine errors:
*/
#define GSS_S_BAD_MECH (1ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_NAME (2ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_NAMETYPE (3ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_BINDINGS (4ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_STATUS (5ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_SIG (6ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_NO_CRED (7ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_NO_CONTEXT (8ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_DEFECTIVE_TOKEN (9ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_DEFECTIVE_CREDENTIAL (10ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_CREDENTIALS_EXPIRED (11ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_CONTEXT_EXPIRED (12ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_FAILURE (13ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_BAD_QOP (14ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_UNAUTHORIZED (15ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_UNAVAILABLE (16ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_DUPLICATE_ELEMENT (17ul << GSS_C_ROUTINE_ERROR_OFFSET)
#define GSS_S_NAME_NOT_MN (18ul << GSS_C_ROUTINE_ERROR_OFFSET)
/*
* Supplementary info bits:
*/
#define GSS_S_CONTINUE_NEEDED (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 0))
#define GSS_S_DUPLICATE_TOKEN (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 1))
#define GSS_S_OLD_TOKEN (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 2))
#define GSS_S_UNSEQ_TOKEN (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 3))
#define GSS_S_GAP_TOKEN (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 4))
/*
* Finally, function prototypes for the GSS-API routines.
*/
OM_uint32 gss_acquire_cred
(OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* desired_name */
OM_uint32, /* time_req */
GSS_CONST gss_OID_set, /* desired_mechs */
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gss_cred_usage_t, /* cred_usage */
gss_cred_id_t *, /* output_cred_handle */
gss_OID_set *, /* actual_mechs */
OM_uint32 * /* time_rec */
);
OM_uint32 gss_release_cred
(OM_uint32 *, /* minor_status */
gss_cred_id_t * /* cred_handle */
);
OM_uint32 gss_init_sec_context
(OM_uint32 *, /* minor_status */
GSS_CONST gss_cred_id_t, /* initiator_cred_handle */
gss_ctx_id_t *, /* context_handle */
GSS_CONST gss_name_t, /* target_name */
GSS_CONST gss_OID, /* mech_type */
OM_uint32, /* req_flags */
OM_uint32, /* time_req */
GSS_CONST gss_channel_bindings_t,
/* input_chan_bindings */
GSS_CONST gss_buffer_t, /* input_token */
gss_OID *, /* actual_mech_type */
gss_buffer_t, /* output_token */
OM_uint32 *, /* ret_flags */
OM_uint32 * /* time_rec */
);
OM_uint32 gss_accept_sec_context
(OM_uint32 *, /* minor_status */
gss_ctx_id_t *, /* context_handle */
GSS_CONST gss_cred_id_t, /* acceptor_cred_handle */
GSS_CONST gss_buffer_t, /* input_token_buffer */
GSS_CONST gss_channel_bindings_t,
/* input_chan_bindings */
gss_name_t *, /* src_name */
gss_OID *, /* mech_type */
gss_buffer_t, /* output_token */
OM_uint32 *, /* ret_flags */
OM_uint32 *, /* time_rec */
gss_cred_id_t * /* delegated_cred_handle */
);
OM_uint32 gss_process_context_token
(OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
GSS_CONST gss_buffer_t /* token_buffer */
);
OM_uint32 gss_delete_sec_context
(OM_uint32 *, /* minor_status */
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gss_ctx_id_t *, /* context_handle */
gss_buffer_t /* output_token */
);
OM_uint32 gss_context_time
(OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
OM_uint32 * /* time_rec */
);
OM_uint32 gss_get_mic
(OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
gss_qop_t, /* qop_req */
GSS_CONST gss_buffer_t, /* message_buffer */
gss_buffer_t /* message_token */
);
OM_uint32 gss_verify_mic
(OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
GSS_CONST gss_buffer_t, /* message_buffer */
GSS_CONST gss_buffer_t, /* token_buffer */
gss_qop_t * /* qop_state */
);
OM_uint32 gss_wrap
(OM_uint32 *, /* minor_status */
GSS_COINST gss_ctx_id_t, /* context_handle */
int, /* conf_req_flag */
gss_qop_t, /* qop_req */
GSS_CONST gss_buffer_t, /* input_message_buffer */
int *, /* conf_state */
gss_buffer_t /* output_message_buffer */
);
OM_uint32 gss_unwrap
(OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
GSS_CONST gss_buffer_t, /* input_message_buffer */
gss_buffer_t, /* output_message_buffer */
int *, /* conf_state */
gss_qop_t * /* qop_state */
);
OM_uint32 gss_display_status
(OM_uint32 *, /* minor_status */
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OM_uint32, /* status_value */
int, /* status_type */
GSS_CONST gss_OID, /* mech_type */
OM_uint32 *, /* message_context */
gss_buffer_t /* status_string */
);
OM_uint32 gss_indicate_mechs
(OM_uint32 *, /* minor_status */
gss_OID_set * /* mech_set */
);
OM_uint32 gss_compare_name
(OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* name1 */
GSS_CONST gss_name_t, /* name2 */
int * /* name_equal */
);
OM_uint32 gss_display_name
(OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* input_name */
gss_buffer_t, /* output_name_buffer */
gss_OID * /* output_name_type */
);
OM_uint32 gss_import_name
(OM_uint32 *, /* minor_status */
GSS_CONST gss_buffer_t, /* input_name_buffer */
GSS_CONST gss_OID, /* input_name_type */
gss_name_t * /* output_name */
);
OM_uint32 gss_export_name
(OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* input_name */
gss_buffer_t /* exported_name */
);
OM_uint32 gss_release_name
(OM_uint32 *, /* minor_status */
gss_name_t * /* input_name */
);
OM_uint32 gss_release_buffer
(OM_uint32 *, /* minor_status */
gss_buffer_t /* buffer */
);
OM_uint32 gss_release_oid_set
(OM_uint32 *, /* minor_status */
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gss_OID_set * /* set */
);
OM_uint32 gss_inquire_cred
(OM_uint32 *, /* minor_status */
GSS_CONST gss_cred_id_t, /* cred_handle */
gss_name_t *, /* name */
OM_uint32 *, /* lifetime */
gss_cred_usage_t *, /* cred_usage */
gss_OID_set * /* mechanisms */
);
OM_uint32 gss_inquire_context (
OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
gss_name_t *, /* src_name */
gss_name_t *, /* targ_name */
OM_uint32 *, /* lifetime_rec */
gss_OID *, /* mech_type */
OM_uint32 *, /* ctx_flags */
int *, /* locally_initiated */
int * /* open */
);
OM_uint32 gss_wrap_size_limit (
OM_uint32 *, /* minor_status */
GSS_CONST gss_ctx_id_t, /* context_handle */
int, /* conf_req_flag */
gss_qop_t, /* qop_req */
OM_uint32, /* req_output_size */
OM_uint32 * /* max_input_size */
);
OM_uint32 gss_add_cred (
OM_uint32 *, /* minor_status */
GSS_CONST gss_cred_id_t, /* input_cred_handle */
GSS_CONST gss_name_t, /* desired_name */
GSS_CONST gss_OID, /* desired_mech */
gss_cred_usage_t, /* cred_usage */
OM_uint32, /* initiator_time_req */
OM_uint32, /* acceptor_time_req */
gss_cred_id_t *, /* output_cred_handle */
gss_OID_set *, /* actual_mechs */
OM_uint32 *, /* initiator_time_rec */
OM_uint32 * /* acceptor_time_rec */
);
OM_uint32 gss_inquire_cred_by_mech (
OM_uint32 *, /* minor_status */
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GSS_CONST gss_cred_id_t, /* cred_handle */
GSS_CONST gss_OID, /* mech_type */
gss_name_t *, /* name */
OM_uint32 *, /* initiator_lifetime */
OM_uint32 *, /* acceptor_lifetime */
gss_cred_usage_t * /* cred_usage */
);
OM_uint32 gss_export_sec_context (
OM_uint32 *, /* minor_status */
gss_ctx_id_t *, /* context_handle */
gss_buffer_t /* interprocess_token */
);
OM_uint32 gss_import_sec_context (
OM_uint32 *, /* minor_status */
GSS_CONST gss_buffer_t, /* interprocess_token */
gss_ctx_id_t * /* context_handle */
);
OM_uint32 gss_release_oid (
OM_uint32 *, /* minor_status */
gss_OID * /* oid */
);
OM_uint32 gss_create_empty_oid_set (
OM_uint32 *, /* minor_status */
gss_OID_set * /* oid_set */
);
OM_uint32 gss_add_oid_set_member (
OM_uint32 *, /* minor_status */
GSS_CONST gss_OID, /* member_oid */
gss_OID_set * /* oid_set */
);
OM_uint32 gss_test_oid_set_member (
OM_uint32 *, /* minor_status */
GSS_CONST gss_OID, /* member */
GSS_CONST gss_OID_set, /* set */
int * /* present */
);
OM_uint32 gss_str_to_oid (
OM_uint32 *, /* minor_status */
GSS_CONST gss_buffer_t, /* oid_str */
gss_OID * /* oid */
);
OM_uint32 gss_oid_to_str (
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OM_uint32 *, /* minor_status */
GSS_CONST gss_OID, /* oid */
gss_buffer_t /* oid_str */
);
OM_uint32 gss_inquire_names_for_mech (
OM_uint32 *, /* minor_status */
GSS_CONST gss_OID, /* mechanism */
gss_OID_set * /* name_types */
);
OM_uint32 gss_inquire_mechs_for_name (
OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* input_name */
gss_OID_set * /* mech_types */
);
OM_uint32 gss_canonicalize_name (
OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* input_name */
GSS_CONST gss_OID, /* mech_type */
gss_name_t * /* output_name */
);
OM_uint32 gss_duplicate_name (
OM_uint32 *, /* minor_status */
GSS_CONST gss_name_t, /* src_name */
gss_name_t * /* dest_name */
);
/*
* The following routines are obsolete variants of gss_get_mic,
* gss_wrap, gss_verify_mic and gss_unwrap. They should be
* provided by GSSAPI V2 implementations for backwards
* compatibility with V1 applications. Distinct entrypoints
* (as opposed to #defines) should be provided, both toallow
* GSSAPI V1 applications to link against GSSAPI V2 implementations,
* and to retain the slight parameter type differences between the
* obsolete versions of these routines and their current forms.
*/
OM_uint32 gss_sign
(OM_uint32 *, /* minor_status */
gss_ctx_id_t, /* context_handle */
int, /* qop_req */
gss_buffer_t, /* message_buffer */
gss_buffer_t /* message_token */
);
OM_uint32 gss_verify
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(OM_uint32 *, /* minor_status */
gss_ctx_id_t, /* context_handle */
gss_buffer_t, /* message_buffer */
gss_buffer_t, /* token_buffer */
int * /* qop_state */
);
OM_uint32 gss_seal
(OM_uint32 *, /* minor_status */
gss_ctx_id_t, /* context_handle */
int, /* conf_req_flag */
int, /* qop_req */
gss_buffer_t, /* input_message_buffer */
int *, /* conf_state */
gss_buffer_t /* output_message_buffer */
);
OM_uint32 gss_unseal
(OM_uint32 *, /* minor_status */
gss_ctx_id_t, /* context_handle */
gss_buffer_t, /* input_message_buffer */
gss_buffer_t, /* output_message_buffer */
int *, /* conf_state */
int * /* qop_state */
);
#endif /* GSSAPI_H_ */
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APPENDIX B. Additional constraints for application binary portability
The purpose of this C-bindings document is to encourage source-level
portability of applications across GSS-API implementations on different
platforms and atop different mechanisms. Additional goals that have not
been explicitly addressed by this document are link-time and run-time
portability.
Link-time portability provides the ability to compile an application
against one implementation of GSS-API, and then link it against a
different implementation on the same platform. It is a stricter
requirement than source-level portability.
Run-time portability differs from link-time portability only on those
platforms that implement dynamically loadable GSS-API implementations,
but do not offer load-time symbol resolution. On such platforms, run-
time portability is a stricter requirement than link-time portability,
and will typically include the precise placement of the various GSS-API
routines within library entrypoint vectors.
Individual platforms will impose their own rules that must be followed
to achieve link-time (and run-time, if different) portability. In order
to ensure either form of binary portability, an ABI specification must
be written for GSS-API implementations on that platform. However, it is
recognized that there are some issues that are likely to be common to
all such ABI specifications. This appendix is intended to be a
repository for such common issues, and contains some suggestions that
individual ABI specifications may choose to reference. Since machine
architectures vary greatly, it may not be possible or desirable to
follow these suggestions on all platforms.
B.1. Pointers
While ANSI-C provides a single pointer type for each declared type, plus
a single (void *) type, some platforms (notably those using segmented
memory architectures) augment this with various modified pointer types
(e.g. far pointers, near pointers). These language bindings assume
ANSI-C, and thus do not address such non-standard implementations.
GSS-API implementations for such platforms must choose an appropriate
memory model, and should use it consistently throughout. For example,
if a memory model is chosen that requires the use of far pointers when
passing routine parameters, then far pointers should also be used within
the structures defined by GSS-API.
B.2. Internal structure alignment
GSS-API defines several data-structures containing differently-sized
fields. An ABI specification should include a detailed description of
how the fields of such structures are aligned, and if there is any
internal padding in these data structures. The use of compiler defaults
for the platform is recommended.
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B.3. Handle types
The C bindings specify that the gss_cred_id_t and gss_ctx_id_t types
should be implemented as either pointer or arithmetic types, and that if
pointer types are used, care should be taken to ensure that two handles
may be compared with the == operator. Note that ANSI-C does not
guarantee that two pointer values may be compared with the == operator
unless either the two pointers point to members of a single array, or at
least one of the pointers contains a NULL value.
For binary portability, additional constraints are required. The
following is an attempt at defining platform-independent constraints.
(a) The size of the handle type must be the same as sizeof(void *),
using the appropriate memory model.
(b) The == operator for the chosen type must be a simple bit-wise
comparison. That is, for two in-memory handle objects h1 and h2,
the boolean value of the expression
(h1 == h2)
should always be the same as the boolean value of the expression
(memcmp(&h1, &h2, sizeof(h1)) == 0)
(c) The actual use of the type (void *) for handle types is
discouraged, not for binary portability reasons, but since it
effectively disables much of the compile-time type-checking that
the compiler can otherwise perform, and is therefore not
"programmer-friendly". If a pointer implementation is desired,
and if the platform's implementation of pointers permits, the
handles should be implemented as pointers to distinct
implementation-defined types.
B.4. The gss_name_t type
The gss_name_t type, representing the internal name object, should be
implemented as a pointer type. The use of the (void *) type is
discouraged as it does not allow the compiler to perform strong type-
checking. However, the pointer type chosen should be of the same size
as the (void *) type. Provided this rule is obeyed, ABI specifications
need not further constrain the implementation of gss_name_t objects.
B.5. The int and size_t types
Some platforms may support differently sized implementations of the
"int" and "size_t" types, perhaps chosen through compiler switches, and
perhaps dependent on memory model. An ABI specification for such a
platform should include required implementations for these types. It is
recommended that the default implementation (for the chosen memory
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model, if appropriate) is chosen.
B.6. Procedure-calling conventions
Some platforms support a variety of different binary conventions for
calling procedures. Such conventions cover things like the format of
the stack frame, the order in which the routine parameters are pushed
onto the stack, whether or not a parameter count is pushed onto the
stack, whether some argument(s) or return values are to be passed in
registers, and whether the called routine or the caller is responsible
for removing the stack frame on return. For such platforms, an ABI
specification should specify which calling convention is to be used for
GSSAPI implementations.
REFERENCES
[GSSAPI] J. Linn, "Generic Security Service Application Program
Interface, Version 2", Internet-Draft draft-ietf-cat-gssv2-
08, 26 August 1996. (This Internet-Draft, like all other
Internet-Drafts, is not an archival document and is subject
to change or deletion. It is available at the time of this
writing by anonymous ftp from ds.internic.net, directory
internet-drafts. Would-be readers should check for successor
Internet-Draft versions or Internet RFCs before relying on
this document.)
[XOM] "OSI Object Management API Specification, Version 2.0",
X.400 API Association & X/Open Company Limited, August 24,
1990. Specification of datatypes and routines for
manipulating information objects.
AUTHOR'S ADDRESS
John Wray Internet email: Wray@tuxedo.enet.dec.com
Digital Equipment Corporation Telephone: +1-508-486-5210
550 King Street, LKG2-2/Z7
Littleton, MA 01460
USA
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