GS2 helpers
[mech_eap.git] / util_reauth.c
index 63b12d9..abfe90c 100644 (file)
@@ -44,6 +44,18 @@ krb5_encrypt_tkt_part(krb5_context, const krb5_keyblock *, krb5_ticket *);
 krb5_error_code
 encode_krb5_ticket(const krb5_ticket *rep, krb5_data **code);
 
+static OM_uint32
+gssDisplayName(OM_uint32 *minor,
+               gss_name_t name,
+               gss_buffer_t buffer,
+               gss_OID *name_type);
+
+static OM_uint32
+gssImportName(OM_uint32 *minor,
+              gss_buffer_t buffer,
+              gss_OID name_type,
+              gss_name_t *name);
+
 static krb5_error_code
 getAcceptorKey(krb5_context krbContext,
                gss_ctx_id_t ctx,
@@ -53,12 +65,11 @@ getAcceptorKey(krb5_context krbContext,
 {
     krb5_error_code code;
     krb5_keytab keytab = NULL;
-    krb5_keytab_entry ktent;
+    krb5_keytab_entry ktent = { 0 };
     krb5_kt_cursor cursor = NULL;
 
     *princ = NULL;
     memset(key, 0, sizeof(*key));
-    memset(&ktent, 0, sizeof(ktent));
 
     code = krb5_kt_default(krbContext, &keytab);
     if (code != 0)
@@ -71,17 +82,20 @@ getAcceptorKey(krb5_context krbContext,
         if (code != 0)
             goto cleanup;
     } else {
+        /*
+         * It's not clear that looking encrypting the ticket in the
+         * requested EAP enctype provides any value.
+         */
         code = krb5_kt_start_seq_get(krbContext, keytab, &cursor);
         if (code != 0)
             goto cleanup;
 
         while ((code = krb5_kt_next_entry(krbContext, keytab,
                                           &ktent, &cursor)) == 0) {
-            if (ktent.key.enctype == ctx->encryptionType) {
+            if (ktent.key.enctype == ctx->encryptionType)
                 break;
-            } else {
+            else
                 krb5_free_keytab_entry_contents(krbContext, &ktent);
-            }
         }
     }
 
@@ -95,18 +109,54 @@ cleanup:
         krb5_kt_end_seq_get(krbContext, keytab, &cursor);
     krb5_kt_close(krbContext, keytab);
 
+    if (code != 0)
+        krb5_free_keytab_entry_contents(krbContext, &ktent);
+
+    return code;
+}
+
+static OM_uint32
+freezeAttrContext(OM_uint32 *minor,
+                  gss_name_t initiatorName,
+                  krb5_const_principal acceptorPrinc,
+                  krb5_keyblock *session,
+                  krb5_authdata ***authdata)
+{
+    OM_uint32 major, tmpMinor;
+    krb5_error_code code;
+    gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
+    krb5_authdata *authData[2], authDatum = { 0 };
+    krb5_context krbContext;
+
+    GSSEAP_KRB_INIT(&krbContext);
+
+    major = gssEapExportAttrContext(minor, initiatorName, &attrBuf);
+    if (GSS_ERROR(major))
+        return major;
+
+    authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
+    authDatum.length = attrBuf.length;
+    authDatum.contents = attrBuf.value;
+    authData[0] = &authDatum;
+    authData[1] = NULL;
+
+    code = krb5_make_authdata_kdc_issued(krbContext, session, acceptorPrinc,
+                                         authData, authdata);
     if (code != 0) {
-        if (*princ != NULL) {
-            krb5_free_principal(krbContext, *princ);
-            *princ = NULL;
-        }
-        krb5_free_keyblock_contents(krbContext, key),
-        memset(key, 0, sizeof(key));
+        major = GSS_S_FAILURE;
+        *minor = code;
+    } else {
+        major = GSS_S_COMPLETE;
     }
 
-    return code;
+    gss_release_buffer(&tmpMinor, &attrBuf);
+
+    return major;
 }
 
+/*
+ * Fabricate a ticket to ourselves given a GSS EAP context.
+ */
 OM_uint32
 gssEapMakeReauthCreds(OM_uint32 *minor,
                       gss_ctx_id_t ctx,
@@ -119,8 +169,6 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     krb5_ticket ticket = { 0 };
     krb5_keyblock session = { 0 }, acceptorKey = { 0 };
     krb5_enc_tkt_part enc_part = { 0 };
-    gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
-    krb5_authdata *authData[2], authDatum = { 0 };
     krb5_data *ticketData = NULL, *credsData = NULL;
     krb5_creds creds = { 0 };
     krb5_auth_context authContext = NULL;
@@ -146,6 +194,10 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
 
     enc_part.flags = TKT_FLG_INITIAL;
 
+    /*
+     * Generate a random session key to place in the ticket and
+     * sign the "KDC-Issued" authorization data element.
+     */
     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
                                   &session);
     if (code != 0)
@@ -160,23 +212,11 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
                              : KRB5_INT32_MAX;
     enc_part.times.renew_till = 0;
 
-    major = gssEapExportAttrContext(minor, ctx->initiatorName,
-                                    &attrBuf);
+    major = freezeAttrContext(minor, ctx->initiatorName, ticket.server,
+                              &session, &enc_part.authorization_data);
     if (GSS_ERROR(major))
         goto cleanup;
 
-    authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
-    authDatum.length = attrBuf.length;
-    authDatum.contents = attrBuf.value;
-    authData[0] = &authDatum;
-    authData[1] = NULL;
-
-    code = krb5_make_authdata_kdc_issued(krbContext, &session,
-                                         ticket.server, authData,
-                                         &enc_part.authorization_data);
-    if (code != 0)
-        goto cleanup;
-
     ticket.enc_part2 = &enc_part;
 
     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
@@ -193,7 +233,7 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     creds.times = enc_part.times;
     creds.ticket_flags = enc_part.flags;
     creds.ticket = *ticketData;
-    creds.authdata = authData;
+    creds.authdata = enc_part.authorization_data;
 
     code = krb5_auth_con_init(krbContext, &authContext);
     if (code != 0)
@@ -219,7 +259,6 @@ cleanup:
         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
     krb5_free_keyblock_contents(krbContext, &session);
     krb5_free_keyblock_contents(krbContext, &acceptorKey);
-    gss_release_buffer(minor, &attrBuf);
     krb5_free_data(krbContext, ticketData);
     krb5_auth_con_free(krbContext, authContext);
     krb5_free_authdata(krbContext, enc_part.authorization_data);
@@ -240,12 +279,16 @@ isTicketGrantingServiceP(krb5_context krbContext,
 {
     if (krb5_princ_size(krbContext, principal) == 2 &&
         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
-        memcmp(krb5_princ_component(krbContext, principal, 0)->data, "krbtgt", 6) == 0)
+        memcmp(krb5_princ_component(krbContext,
+                                    principal, 0)->data, "krbtgt", 6) == 0)
         return TRUE;
 
     return FALSE;
 }
 
+/*
+ * Store re-authentication (Kerberos) credentials in a credential handle.
+ */
 OM_uint32
 gssEapStoreReauthCreds(OM_uint32 *minor,
                        gss_ctx_id_t ctx,
@@ -310,7 +353,9 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
 
         /*
          * Swap in the acceptor name the client asked for so
-         * get_credentials() works
+         * get_credentials() works. We're making the assumption that
+         * any service tickets returned are for us. We'll need to
+         * reflect some more on whether that is a safe assumption.
          */
         if (!isTicketGrantingServiceP(krbContext, kcred.server))
             kcred.server = ctx->acceptorName->krbPrincipal;
@@ -320,6 +365,11 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
             goto cleanup;
     }
 
+    /*
+     * To turn a credentials cache into a GSS credentials handle, we
+     * require the gss_krb5_import_cred() API (present in Heimdal, but
+     * not shipped in MIT yet).
+     */
     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
                                  &cred->krbCred);
     if (GSS_ERROR(major))
@@ -339,274 +389,6 @@ cleanup:
     return major;
 }
 
-static OM_uint32 (*gssInitSecContextNext)(
-    OM_uint32 *minor,
-    gss_cred_id_t cred,
-    gss_ctx_id_t *context_handle,
-    gss_name_t target_name,
-    gss_OID mech_type,
-    OM_uint32 req_flags,
-    OM_uint32 time_req,
-    gss_channel_bindings_t input_chan_bindings,
-    gss_buffer_t input_token,
-    gss_OID *actual_mech_type,
-    gss_buffer_t output_token,
-    OM_uint32 *ret_flags,
-    OM_uint32 *time_rec);
-
-static OM_uint32 (*gssAcceptSecContextNext)(
-    OM_uint32 *minor,
-    gss_ctx_id_t *context_handle,
-    gss_cred_id_t cred,
-    gss_buffer_t input_token,
-    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);
-
-static OM_uint32 (*gssReleaseCredNext)(
-    OM_uint32 *minor,
-    gss_cred_id_t *cred_handle);
-
-static OM_uint32 (*gssReleaseNameNext)(
-    OM_uint32 *minor,
-    gss_name_t *name);
-
-static OM_uint32 (*gssInquireSecContextByOidNext)(
-    OM_uint32 *minor,
-    const gss_ctx_id_t context_handle,
-    const gss_OID desired_object,
-    gss_buffer_set_t *data_set);
-
-static OM_uint32 (*gssDeleteSecContextNext)(
-    OM_uint32 *minor,
-    gss_ctx_id_t *context_handle,
-    gss_buffer_t output_token);
-
-static OM_uint32 (*gssDisplayNameNext)(
-    OM_uint32 *minor,
-    gss_name_t name,
-    gss_buffer_t output_name_buffer,
-    gss_OID *output_name_type);
-
-static OM_uint32 (*gssImportNameNext)(
-    OM_uint32 *minor,
-    gss_buffer_t buffer,
-    gss_OID nameType,
-    gss_name_t *outputName);
-
-static OM_uint32 (*gssKrbExtractAuthzDataFromSecContextNext)(
-    OM_uint32 *minor,
-    const gss_ctx_id_t context_handle,
-    int ad_type,
-    gss_buffer_t ad_data);
-
-static OM_uint32 (*gssStoreCredNext)(
-    OM_uint32 *minor,
-    const gss_cred_id_t input_cred_handle,
-    gss_cred_usage_t input_usage,
-    const gss_OID desired_mech,
-    OM_uint32 overwrite_cred,
-    OM_uint32 default_cred,
-    gss_OID_set *elements_stored,
-    gss_cred_usage_t *cred_usage_stored);
-
-static OM_uint32 (*gssGetNameAttributeNext)(
-    OM_uint32 *minor,
-    gss_name_t name,
-    gss_buffer_t attr,
-    int *authenticated,
-    int *complete,
-    gss_buffer_t value,
-    gss_buffer_t display_value,
-    int *more);
-
-#define NEXT_SYMBOL(local, global)  ((local) = dlsym(RTLD_NEXT, (global)))
-
-OM_uint32
-gssEapReauthInitialize(OM_uint32 *minor)
-{
-    NEXT_SYMBOL(gssInitSecContextNext,                    "gss_init_sec_context");
-    NEXT_SYMBOL(gssAcceptSecContextNext,                  "gss_accept_sec_context");
-    NEXT_SYMBOL(gssReleaseCredNext,                       "gss_release_cred");
-    NEXT_SYMBOL(gssReleaseNameNext,                       "gss_release_name");
-    NEXT_SYMBOL(gssInquireSecContextByOidNext,            "gss_inquire_sec_context_by_oid");
-    NEXT_SYMBOL(gssDeleteSecContextNext,                  "gss_delete_sec_context");
-    NEXT_SYMBOL(gssDisplayNameNext,                       "gss_display_name");
-    NEXT_SYMBOL(gssImportNameNext,                        "gss_import_name");
-    NEXT_SYMBOL(gssKrbExtractAuthzDataFromSecContextNext, "gsskrb5_extract_authz_data_from_sec_context");
-    NEXT_SYMBOL(gssStoreCredNext,                         "gss_store_cred");
-    NEXT_SYMBOL(gssGetNameAttributeNext,                  "gss_get_name_attribute");
-
-    return GSS_S_COMPLETE;
-}
-
-OM_uint32
-gssInitSecContext(OM_uint32 *minor,
-                  gss_cred_id_t cred,
-                  gss_ctx_id_t *context_handle,
-                  gss_name_t target_name,
-                  gss_OID mech_type,
-                  OM_uint32 req_flags,
-                  OM_uint32 time_req,
-                  gss_channel_bindings_t input_chan_bindings,
-                  gss_buffer_t input_token,
-                  gss_OID *actual_mech_type,
-                  gss_buffer_t output_token,
-                  OM_uint32 *ret_flags,
-                  OM_uint32 *time_rec)
-{
-    if (gssInitSecContextNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssInitSecContextNext(minor, cred, context_handle,
-                                 target_name, mech_type, req_flags,
-                                 time_req, input_chan_bindings,
-                                 input_token, actual_mech_type,
-                                 output_token, ret_flags, time_rec);
-}
-
-OM_uint32
-gssAcceptSecContext(OM_uint32 *minor,
-                    gss_ctx_id_t *context_handle,
-                    gss_cred_id_t cred,
-                    gss_buffer_t input_token,
-                    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)
-{
-    if (gssAcceptSecContextNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssAcceptSecContextNext(minor, context_handle, cred,
-                                   input_token, input_chan_bindings,
-                                   src_name, mech_type, output_token,
-                                   ret_flags, time_rec, delegated_cred_handle);
-}
-
-OM_uint32
-gssReleaseCred(OM_uint32 *minor,
-               gss_cred_id_t *cred_handle)
-{
-    if (gssReleaseCredNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssReleaseCredNext(minor, cred_handle);
-}
-
-OM_uint32
-gssReleaseName(OM_uint32 *minor,
-               gss_name_t *name)
-{
-    if (gssReleaseName == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssReleaseNameNext(minor, name);
-}
-
-OM_uint32
-gssDeleteSecContext(OM_uint32 *minor,
-                    gss_ctx_id_t *context_handle,
-                    gss_buffer_t output_token)
-{
-    if (gssDeleteSecContextNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssDeleteSecContextNext(minor, context_handle, output_token);
-}
-
-static OM_uint32
-gssDisplayName(OM_uint32 *minor,
-               gss_name_t name,
-               gss_buffer_t buffer,
-               gss_OID *name_type)
-{
-    if (gssDisplayNameNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssDisplayNameNext(minor, name, buffer, name_type);
-}
-
-static OM_uint32
-gssImportName(OM_uint32 *minor,
-              gss_buffer_t buffer,
-              gss_OID name_type,
-              gss_name_t *name)
-{
-    if (gssImportNameNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssImportNameNext(minor, buffer, name_type, name);
-}
-
-OM_uint32
-gssInquireSecContextByOid(OM_uint32 *minor,
-                          const gss_ctx_id_t context_handle,
-                          const gss_OID desired_object,
-                          gss_buffer_set_t *data_set)
-{
-    if (gssInquireSecContextByOidNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssInquireSecContextByOidNext(minor, context_handle,
-                                         desired_object, data_set);
-}
-
-OM_uint32
-gssKrbExtractAuthzDataFromSecContext(OM_uint32 *minor,
-                                     const gss_ctx_id_t ctx,
-                                     int ad_type,
-                                     gss_buffer_t ad_data)
-{
-    if (gssKrbExtractAuthzDataFromSecContextNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssKrbExtractAuthzDataFromSecContextNext(minor, ctx,
-                                                    ad_type, ad_data);
-}
-
-OM_uint32
-gssStoreCred(OM_uint32 *minor,
-             const gss_cred_id_t input_cred_handle,
-             gss_cred_usage_t input_usage,
-             const gss_OID desired_mech,
-             OM_uint32 overwrite_cred,
-             OM_uint32 default_cred,
-             gss_OID_set *elements_stored,
-             gss_cred_usage_t *cred_usage_stored)
-{
-    if (gssStoreCredNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssStoreCredNext(minor, input_cred_handle, input_usage,
-                            desired_mech, overwrite_cred, default_cred,
-                            elements_stored, cred_usage_stored);
-}
-
-OM_uint32
-gssGetNameAttribute(OM_uint32 *minor,
-                    gss_name_t name,
-                    gss_buffer_t attr,
-                    int *authenticated,
-                    int *complete,
-                    gss_buffer_t value,
-                    gss_buffer_t display_value,
-                    int *more)
-{
-    if (gssGetNameAttributeNext == NULL)
-        return GSS_S_UNAVAILABLE;
-
-    return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
-                                   value, display_value, more);
-}
-
 static gss_buffer_desc radiusAvpKrbAttr = {
     sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
 };
@@ -622,8 +404,12 @@ static gss_buffer_desc radiusAvpKrbAttr = {
  * be to sign the authorization data with our long-term key, but it
  * seems a pity to compromise the design because of current implementation
  * limitations.
+ *
+ * (Specifically, the hoops involve a libkrb5 authorisation data plugin
+ * that exposes the verified and serialised attribute context through
+ * the Kerberos GSS mechanism's naming extensions API.)
  */
-OM_uint32
+static OM_uint32
 defrostAttrContext(OM_uint32 *minor,
                    gss_name_t glueName,
                    gss_name_t mechName)
@@ -652,6 +438,10 @@ defrostAttrContext(OM_uint32 *minor,
     return major;
 }
 
+/*
+ * Convert a mechanism glue to an EAP mechanism name by displaying and
+ * importing it. This also handles the RADIUS attributes.
+ */
 OM_uint32
 gssEapGlueToMechName(OM_uint32 *minor,
                      gss_name_t glueName,
@@ -686,6 +476,10 @@ cleanup:
     return major;
 }
 
+/*
+ * Convert an EAP mechanism name to a mechanism glue name by displaying
+ * and importing it.
+ */
 OM_uint32
 gssEapMechToGlueName(OM_uint32 *minor,
                      gss_name_t mechName,
@@ -711,6 +505,10 @@ cleanup:
     return major;
 }
 
+/*
+ * Suck out the analgous elements of a Kerberos GSS context into an EAP
+ * one so that the application doesn't know the difference.
+ */
 OM_uint32
 gssEapReauthComplete(OM_uint32 *minor,
                     gss_ctx_id_t ctx,
@@ -726,6 +524,7 @@ gssEapReauthComplete(OM_uint32 *minor,
         goto cleanup;
     }
 
+    /* Get the raw subsession key and encryption type*/
     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
     if (GSS_ERROR(major))
@@ -774,6 +573,7 @@ gssEapReauthComplete(OM_uint32 *minor,
     if (timeRec != GSS_C_INDEFINITE)
         ctx->expiryTime = time(NULL) + timeRec;
 
+    /* Initialize our sequence state */
     major = sequenceInit(minor,
                          &ctx->seqState, ctx->recvSeq,
                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
@@ -790,3 +590,252 @@ cleanup:
     return major;
 }
 
+/*
+ * The remainder of this file consists of wrappers so we can call into the
+ * mechanism glue without calling ourselves.
+ */
+static OM_uint32
+(*gssInitSecContextNext)(OM_uint32 *,
+                         gss_cred_id_t,
+                         gss_ctx_id_t *,
+                         gss_name_t,
+                         gss_OID,
+                         OM_uint32,
+                         OM_uint32,
+                         gss_channel_bindings_t,
+                         gss_buffer_t,
+                         gss_OID *,
+                         gss_buffer_t,
+                         OM_uint32 *,
+                         OM_uint32 *);
+
+static OM_uint32
+(*gssAcceptSecContextNext)(OM_uint32 *,
+                           gss_ctx_id_t *,
+                           gss_cred_id_t,
+                           gss_buffer_t,
+                           gss_channel_bindings_t,
+                           gss_name_t *,
+                           gss_OID *,
+                           gss_buffer_t,
+                           OM_uint32 *,
+                           OM_uint32 *,
+                           gss_cred_id_t *);
+
+static OM_uint32
+(*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
+
+static OM_uint32
+(*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
+
+static OM_uint32
+(*gssInquireSecContextByOidNext)(OM_uint32 *,
+                                 const gss_ctx_id_t,
+                                 const gss_OID,
+                                 gss_buffer_set_t *);
+
+static OM_uint32
+(*gssDeleteSecContextNext)(OM_uint32 *,
+                          gss_ctx_id_t *,
+                          gss_buffer_t);
+
+static OM_uint32
+(*gssDisplayNameNext)(OM_uint32 *,
+                      gss_name_t,
+                      gss_buffer_t,
+                      gss_OID *);
+
+static OM_uint32
+(*gssImportNameNext)(OM_uint32 *,
+                     gss_buffer_t,
+                     gss_OID,
+                     gss_name_t *);
+
+static OM_uint32
+(*gssStoreCredNext)(OM_uint32 *,
+                    const gss_cred_id_t,
+                    gss_cred_usage_t,
+                    const gss_OID,
+                    OM_uint32,
+                    OM_uint32,
+                    gss_OID_set *,
+                    gss_cred_usage_t *);
+
+static OM_uint32
+(*gssGetNameAttributeNext)(OM_uint32 *,
+                          gss_name_t,
+                          gss_buffer_t,
+                          int *,
+                          int *,
+                          gss_buffer_t,
+                          gss_buffer_t,
+                          int *);
+
+#define NEXT_SYMBOL(local, global)  ((local) = dlsym(RTLD_NEXT, (global)))
+
+OM_uint32
+gssEapReauthInitialize(OM_uint32 *minor)
+{
+    NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
+    NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
+    NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
+    NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
+    NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
+    NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
+    NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
+    NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
+    NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
+    NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
+
+    return GSS_S_COMPLETE;
+}
+
+OM_uint32
+gssInitSecContext(OM_uint32 *minor,
+                  gss_cred_id_t cred,
+                  gss_ctx_id_t *context_handle,
+                  gss_name_t target_name,
+                  gss_OID mech_type,
+                  OM_uint32 req_flags,
+                  OM_uint32 time_req,
+                  gss_channel_bindings_t input_chan_bindings,
+                  gss_buffer_t input_token,
+                  gss_OID *actual_mech_type,
+                  gss_buffer_t output_token,
+                  OM_uint32 *ret_flags,
+                  OM_uint32 *time_rec)
+{
+    if (gssInitSecContextNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssInitSecContextNext(minor, cred, context_handle,
+                                 target_name, mech_type, req_flags,
+                                 time_req, input_chan_bindings,
+                                 input_token, actual_mech_type,
+                                 output_token, ret_flags, time_rec);
+}
+
+OM_uint32
+gssAcceptSecContext(OM_uint32 *minor,
+                    gss_ctx_id_t *context_handle,
+                    gss_cred_id_t cred,
+                    gss_buffer_t input_token,
+                    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)
+{
+    if (gssAcceptSecContextNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssAcceptSecContextNext(minor, context_handle, cred,
+                                   input_token, input_chan_bindings,
+                                   src_name, mech_type, output_token,
+                                   ret_flags, time_rec, delegated_cred_handle);
+}
+
+OM_uint32
+gssReleaseCred(OM_uint32 *minor,
+               gss_cred_id_t *cred_handle)
+{
+    if (gssReleaseCredNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssReleaseCredNext(minor, cred_handle);
+}
+
+OM_uint32
+gssReleaseName(OM_uint32 *minor,
+               gss_name_t *name)
+{
+    if (gssReleaseName == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssReleaseNameNext(minor, name);
+}
+
+OM_uint32
+gssDeleteSecContext(OM_uint32 *minor,
+                    gss_ctx_id_t *context_handle,
+                    gss_buffer_t output_token)
+{
+    if (gssDeleteSecContextNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssDeleteSecContextNext(minor, context_handle, output_token);
+}
+
+static OM_uint32
+gssDisplayName(OM_uint32 *minor,
+               gss_name_t name,
+               gss_buffer_t buffer,
+               gss_OID *name_type)
+{
+    if (gssDisplayNameNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssDisplayNameNext(minor, name, buffer, name_type);
+}
+
+static OM_uint32
+gssImportName(OM_uint32 *minor,
+              gss_buffer_t buffer,
+              gss_OID name_type,
+              gss_name_t *name)
+{
+    if (gssImportNameNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssImportNameNext(minor, buffer, name_type, name);
+}
+
+OM_uint32
+gssInquireSecContextByOid(OM_uint32 *minor,
+                          const gss_ctx_id_t context_handle,
+                          const gss_OID desired_object,
+                          gss_buffer_set_t *data_set)
+{
+    if (gssInquireSecContextByOidNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssInquireSecContextByOidNext(minor, context_handle,
+                                         desired_object, data_set);
+}
+
+OM_uint32
+gssStoreCred(OM_uint32 *minor,
+             const gss_cred_id_t input_cred_handle,
+             gss_cred_usage_t input_usage,
+             const gss_OID desired_mech,
+             OM_uint32 overwrite_cred,
+             OM_uint32 default_cred,
+             gss_OID_set *elements_stored,
+             gss_cred_usage_t *cred_usage_stored)
+{
+    if (gssStoreCredNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssStoreCredNext(minor, input_cred_handle, input_usage,
+                            desired_mech, overwrite_cred, default_cred,
+                            elements_stored, cred_usage_stored);
+}
+
+OM_uint32
+gssGetNameAttribute(OM_uint32 *minor,
+                    gss_name_t name,
+                    gss_buffer_t attr,
+                    int *authenticated,
+                    int *complete,
+                    gss_buffer_t value,
+                    gss_buffer_t display_value,
+                    int *more)
+{
+    if (gssGetNameAttributeNext == NULL)
+        return GSS_S_UNAVAILABLE;
+
+    return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
+                                   value, display_value, more);
+}