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Projects/GS2

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This is an early stage project for MIT Kerberos. It is being fleshed out by its proponents. Feel free to help flesh out the details of this project. After the project is ready, it will be presented for review and approval.


This project is targeted at release 1.9.


Background

Some additional features in the GSS mechanism glue are useful for implementors of SASL GS2.

  • RFC 5801: GSS_Inquire_SASLname_for_mech and GSS_Inquire_mech_for_SASLname
  • RFC 5587: gss_inquire_attrs_for_mech &c

These allow a SASL library to dynamically bridge GSS mechanisms without mechanism-specific knowledge.

Architecture

The functionality of the aforementioned APIs is as follows:

  • a bidirectional mapping between GSS OIDs and SASL mechanism names. (In the case of no mapping, the mechanism glue synthesises a SASL name using a base-32 encoded SHA-1 of the OID.)
  • a means to determine which features, denoted by OIDs, are supported by mechanisms

For example, a GS2 implementation that wished to ignore negotiate mechanisms whilst selecting mechanisms that supported mutual authentication, might do: 

static int gs2_indicate_mechs(void)
{
    OM_uint32 major, minor;
    gss_OID_desc desired_oids[2];
    gss_OID_set_desc desired_attrs;
    gss_OID_desc except_oids[3];
    gss_OID_set_desc except_attrs;

    desired_oids[0] = *GSS_C_MA_AUTH_INIT;
    desired_oids[1] = *GSS_C_MA_AUTH_TARG;
    desired_attrs.count = sizeof(desired_oids)/sizeof(desired_oids[0]);
    desired_attrs.elements = desired_oids;

    except_oids[0] = *GSS_C_MA_MECH_NEGO;
    except_oids[1] = *GSS_C_MA_NOT_MECH;
    except_oids[2] = *GSS_C_MA_DEPRECATED;

    except_attrs.count = sizeof(except_oids)/sizeof(except_oids[0]);
    except_attrs.elements = except_oids;

    major = gss_indicate_mechs_by_attrs(&minor,
                                        &desired_attrs,
                                        &except_attrs,
                                        GSS_C_NO_OID_SET,
                                        &gs2_mechs);
    if (GSS_ERROR(major)) {
        return SASL_FAIL;
    }

    return SASL_OK;

Implementation

The implementations live in src/lib/gssapi/mechglue/g_saslname.c and src/lib/gssapi/mechglue/g_mechattr.c, respectively. 

OM_uint32 KRB5_CALLCONV gss_inquire_saslname_for_mech(
    OM_uint32     *minor_status,
    const gss_OID  desired_mech,
    gss_buffer_t   sasl_mech_name,
    gss_buffer_t   mech_name,
    gss_buffer_t   mech_description);

OM_uint32 KRB5_CALLCONV gss_inquire_mech_for_saslname(
    OM_uint32           *minor_status,
    const gss_buffer_t   sasl_mech_name,
    gss_OID             *mech_type);

OM_uint32 KRB5_CALLCONV
gss_indicate_mechs_by_attrs(
    OM_uint32 *,        /* minor_status */
    gss_const_OID_set,  /* desired_mech_attrs */
    gss_const_OID_set,  /* except_mech_attrs */
    gss_const_OID_set,  /* critical_mech_attrs */
    gss_OID_set *);     /* mechs */

OM_uint32 KRB5_CALLCONV
gss_inquire_attrs_for_mech(
    OM_uint32 *,        /* minor_status */
    gss_const_OID,      /* mech */
    gss_OID_set *,      /* mech_attrs */
    gss_OID_set *);     /* known_mech_attrs */

OM_uint32 KRB5_CALLCONV
gss_display_mech_attr(
    OM_uint32 *,        /* minor_status */
    gss_const_OID,      /* mech_attr */
    gss_buffer_t,       /* name */
    gss_buffer_t,       /* short_desc */
    gss_buffer_t);      /* long_desc */

If a mechanism does not provide the entry point or returns GSS_S_BAD_MECH, then the name is mapped as described above.

The Kerberos and SPNEGO mechanisms have been updated to return GS2-KRB5 and SPNEGO, respectively, as their SASL names.

Status

Implemented and tested with a prototype GS2 implementation, as well as a mechanism plugin. Code is in the users/lhoward/sasl-gs2 branch (note that this is branched off import-cred; pick up only the changes you need).

A test program is in src/tests/gssapi/t_saslname.c.

Examples

A list of GS2 mechanisms and their attributes. 

------------------------------------------------------------------------------
OID        : { 1 2 840 113554 1 2 2 }
SASL mech  : GS2-KRB5
Mech name  : krb5
Mech desc  : Kerberos 5 GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 5 1 5 2 }
SASL mech  : GS2-KRB5
Mech name  : krb5
Mech desc  : Kerberos 5 GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
Got different OID { 1 2 840 113554 1 2 2 } for mechanism GS2-KRB5
------------------------------------------------------------------------------
OID        : { 1 2 840 48018 1 2 2 }
SASL mech  : GS2-KRB5
Mech name  : krb5
Mech desc  : Kerberos 5 GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 6 1 5 2 5 }
SASL mech  : GS2-KRB5
Mech name  : krb5
Mech desc  : Kerberos 5 GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
Got different OID { 1 2 840 113554 1 2 2 } for mechanism GS2-KRB5
------------------------------------------------------------------------------
OID        : { 1 3 6 1 5 5 2 }
SASL mech  : SPNEGO
Mech name  : spnego
Mech desc  : Simple and Protected GSS-API Negotiation Mechanism
Mech attrs:  GSS_C_MA_MECH_NEGO GSS_C_MA_ITOK_FRAMED GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 6 1 4 1 5322 21 1 16 }
SASL mech  : GS2-ZGMBGB5SLBQ
Mech name  : eap-des3-cbc-sha1
Mech desc  : Extensible Authentication Protocol GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 6 1 4 1 5322 21 1 17 }
SASL mech  : GS2-EAP-AES128
Mech name  : eap-aes128-cts-hmac-sha1-96
Mech desc  : Extensible Authentication Protocol GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 6 1 4 1 5322 21 1 18 }
SASL mech  : GS2-EAP-AES256
Mech name  : eap-aes256-cts-hmac-sha1-96
Mech desc  : Extensible Authentication Protocol GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS 
------------------------------------------------------------------------------
------------------------------------------------------------------------------
OID        : { 1 3 6 1 4 1 5322 21 1 23 }
SASL mech  : GS2-6PUERUGDUSC
Mech name  : eap-arcfour-hmac
Mech desc  : Extensible Authentication Protocol GSS-API Mechanism
Mech attrs:  GSS_C_MA_MECH_CONCRETE GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_CTX_TRANS GSS_C_MA_NOT_DFLT_MECH 
Known attrs: GSS_C_MA_MECH_CONCRETE GSS_C_MA_MECH_PSEUDO GSS_C_MA_MECH_COMPOSITE GSS_C_MA_MECH_NEGO GSS_C_MA_MECH_GLUE GSS_C_MA_NOT_MECH GSS_C_MA_DEPRECATED GSS_C_MA_NOT_DFLT_MECH GSS_C_MA_ITOK_FRAMED GSS_C_MA_AUTH_INIT GSS_C_MA_AUTH_TARG GSS_C_MA_AUTH_INIT_INIT GSS_C_MA_AUTH_TARG_INIT GSS_C_MA_AUTH_INIT_ANON GSS_C_MA_AUTH_TARG_ANON GSS_C_MA_DELEG_CRED GSS_C_MA_INTEG_PROT GSS_C_MA_CONF_PROT GSS_C_MA_MIC GSS_C_MA_WRAP GSS_C_MA_PROT_READY GSS_C_MA_REPLAY_DET GSS_C_MA_OOS_DET GSS_C_MA_CBINDINGS GSS_C_MA_PFS GSS_C_MA_COMPRESS GSS_C_MA_CTX_TRANS
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