cleanup unused parameter warnings
[mech_eap.git] / util_reauth.c
index b4407b7..820f6e6 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, JANET(UK)
+ * Copyright (c) 2011, JANET(UK)
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * SUCH DAMAGE.
  */
 
+/*
+ * Fast reauthentication support.
+ */
+
 #include "gssapiP_eap.h"
 
 #include <dlfcn.h>
@@ -44,6 +48,18 @@ 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 +69,12 @@ getAcceptorKey(krb5_context krbContext,
 {
     krb5_error_code code;
     krb5_keytab keytab = NULL;
-    krb5_keytab_entry ktent;
-    krb5_kt_cursor cursor = NULL;
+    krb5_keytab_entry ktent = { 0 };
+    krb5_kt_cursor cursor;
 
     *princ = NULL;
     memset(key, 0, sizeof(*key));
-    memset(&ktent, 0, sizeof(ktent));
+    memset(&cursor, 0, sizeof(cursor));
 
     code = krb5_kt_default(krbContext, &keytab);
     if (code != 0)
@@ -71,42 +87,99 @@ 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 (KRB_KEY_TYPE(KRB_KT_ENT_KEYBLOCK(&ktent)) == ctx->encryptionType)
                 break;
-            } else {
-                krb5_free_keytab_entry_contents(krbContext, &ktent);
-            }
+            else
+                KRB_KT_ENT_FREE(krbContext, &ktent);
         }
     }
 
     if (code == 0) {
         *princ = ktent.principal;
-        *key = ktent.key;
+        *key = *KRB_KT_ENT_KEYBLOCK(&ktent);
     }
 
 cleanup:
     if (cred == GSS_C_NO_CREDENTIAL || cred->name == GSS_C_NO_NAME)
         krb5_kt_end_seq_get(krbContext, keytab, &cursor);
     krb5_kt_close(krbContext, keytab);
+    if (code != 0)
+        KRB_KT_ENT_FREE(krbContext, &ktent);
+
+    return code;
+}
+
+static OM_uint32
+freezeAttrContext(OM_uint32 *minor,
+                  gss_name_t initiatorName,
+                  krb5_const_principal acceptorPrinc,
+                  krb5_keyblock *session,
+#ifdef HAVE_HEIMDAL_VERSION
+                  krb5_authdata *kdcIssuedAuthData
+#else
+                  krb5_authdata ***kdcIssuedAuthData
+#endif
+                  )
+{
+    OM_uint32 major, tmpMinor;
+    krb5_error_code code;
+    krb5_context krbContext;
+    gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
+#ifdef HAVE_HEIMDAL_VERSION
+    krb5_authdata authDataBuf, *authData = &authDataBuf;
+    AuthorizationDataElement authDatum = { 0 };
+#else
+    krb5_authdata *authData[2], authDatum = { 0 };
+#endif
+
+    memset(kdcIssuedAuthData, 0, sizeof(*kdcIssuedAuthData));
+
+    GSSEAP_KRB_INIT(&krbContext);
+
+    major = gssEapExportAttrContext(minor, initiatorName, &attrBuf);
+    if (GSS_ERROR(major))
+        return major;
+
+    authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
+#ifdef HAVE_HEIMDAL_VERSION
+    authDatum.ad_data.length = attrBuf.length;
+    authDatum.ad_data.data = attrBuf.value;
+    authData->len = 1;
+    authData->val = &authDatum;
+#else
+    authDatum.length = attrBuf.length;
+    authDatum.contents = attrBuf.value;
+    authData[0] = &authDatum;
+    authData[1] = NULL;
+#endif
 
+    code = krbMakeAuthDataKdcIssued(krbContext, session, acceptorPrinc,
+                                    authData, kdcIssuedAuthData);
     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,
@@ -116,67 +189,115 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     OM_uint32 major = GSS_S_COMPLETE;
     krb5_error_code code;
     krb5_context krbContext = NULL;
-    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_principal server = NULL;
+#ifdef HAVE_HEIMDAL_VERSION
+    Ticket ticket;
+    EncTicketPart enc_part;
+    AuthorizationData authData = { 0 };
+    krb5_crypto krbCrypto = NULL;
+    krb5_data ticketData = { 0 };
+    krb5_data encPartData = { 0 };
+    size_t len;
+#else
+    krb5_ticket ticket;
+    krb5_enc_tkt_part enc_part;
+    krb5_data *ticketData = NULL;
+#endif
+    krb5_data credsData = { 0 };
     krb5_creds creds = { 0 };
     krb5_auth_context authContext = NULL;
 
+    memset(&ticket, 0, sizeof(ticket));
+    memset(&enc_part, 0, sizeof(enc_part));
+
     credBuf->length = 0;
     credBuf->value = NULL;
 
     GSSEAP_KRB_INIT(&krbContext);
 
-    code = getAcceptorKey(krbContext, ctx, cred,
-                          &ticket.server, &acceptorKey);
+    code = getAcceptorKey(krbContext, ctx, cred, &server, &acceptorKey);
     if (code == KRB5_KT_NOTFOUND) {
-        gss_buffer_desc emptyToken = { 0, "" };
-
-        /*
-         * If we can't produce the KRB-CRED message, we need to
-         * return an empty (not NULL) token to the caller so we
-         * don't change the number of authentication legs.
-         */
-        return duplicateBuffer(minor, &emptyToken, credBuf);
+        *minor = code;
+        return GSS_S_UNAVAILABLE;
     } else if (code != 0)
         goto cleanup;
 
-    enc_part.flags = TKT_FLG_INITIAL;
+    /*
+     * Generate a random session key to place in the ticket and
+     * sign the "KDC-Issued" authorization data element.
+     */
+#ifdef HAVE_HEIMDAL_VERSION
+    ticket.realm = server->realm;
+    ticket.sname = server->name;
+
+    code = krb5_generate_random_keyblock(krbContext, ctx->encryptionType,
+                                         &session);
+    if (code != 0)
+        goto cleanup;
+
+    enc_part.flags.initial = 1;
+    enc_part.key = session;
+    enc_part.crealm = ctx->initiatorName->krbPrincipal->realm;
+    enc_part.cname = ctx->initiatorName->krbPrincipal->name;
+    enc_part.authtime = time(NULL);
+    enc_part.starttime = &enc_part.authtime;
+    enc_part.endtime = (ctx->expiryTime != 0)
+                       ? ctx->expiryTime : KRB_TIME_FOREVER;
+    enc_part.renew_till = NULL;
+    enc_part.authorization_data = &authData;
+
+    major = freezeAttrContext(minor, ctx->initiatorName, server,
+                              &session, &authData);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    ASN1_MALLOC_ENCODE(EncTicketPart, encPartData.data, encPartData.length,
+                       &enc_part, &len, code);
+    if (code != 0)
+        goto cleanup;
+
+    code = krb5_crypto_init(krbContext, &acceptorKey, 0, &krbCrypto);
+    if (code != 0)
+        goto cleanup;
+
+    code = krb5_encrypt_EncryptedData(krbContext,
+                                      krbCrypto,
+                                      KRB5_KU_TICKET,
+                                      encPartData.data,
+                                      encPartData.length,
+                                      0,
+                                      &ticket.enc_part);
+    if (code != 0)
+        goto cleanup;
+
+    ASN1_MALLOC_ENCODE(Ticket, ticketData.data, ticketData.length,
+                       &ticket, &len, code);
+    if (code != 0)
+        goto cleanup;
+#else
+    ticket.server = server;
 
     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
                                   &session);
     if (code != 0)
         goto cleanup;
 
+    enc_part.flags = TKT_FLG_INITIAL;
     enc_part.session = &session;
     enc_part.client = ctx->initiatorName->krbPrincipal;
     enc_part.times.authtime = time(NULL);
     enc_part.times.starttime = enc_part.times.authtime;
-    enc_part.times.endtime = ctx->expiryTime
+    enc_part.times.endtime = (ctx->expiryTime != 0)
                              ? ctx->expiryTime
-                             : KRB5_INT32_MAX;
+                             : KRB_TIME_FOREVER;
     enc_part.times.renew_till = 0;
 
-    major = gssEapExportAttrContext(minor, ctx->initiatorName,
-                                    &attrBuf);
+    major = freezeAttrContext(minor, ctx->initiatorName, 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);
@@ -186,14 +307,26 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     code = encode_krb5_ticket(&ticket, &ticketData);
     if (code != 0)
         goto cleanup;
-
-    creds.client = enc_part.client;
-    creds.server = ticket.server;
+#endif /* HAVE_HEIMDAL_VERSION */
+
+    creds.client = ctx->initiatorName->krbPrincipal;
+    creds.server = server;
+#ifdef HAVE_HEIMDAL_VERSION
+    creds.session = session;
+    creds.times.authtime = enc_part.authtime;
+    creds.times.starttime = *enc_part.starttime;
+    creds.times.endtime = enc_part.endtime;
+    creds.times.renew_till = 0;
+    creds.flags.b = enc_part.flags;
+    creds.ticket = ticketData;
+    creds.authdata = authData;
+#else
     creds.keyblock = session;
     creds.times = enc_part.times;
     creds.ticket_flags = enc_part.flags;
     creds.ticket = *ticketData;
-    creds.authdata = authData;
+    creds.authdata = enc_part.authorization_data;
+#endif
 
     code = krb5_auth_con_init(krbContext, &authContext);
     if (code != 0)
@@ -208,56 +341,181 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     if (code != 0)
         goto cleanup;
 
-    code = krb5_mk_1cred(krbContext, authContext, &creds, &credsData, NULL);
+    code = krbMakeCred(krbContext, authContext, &creds, &credsData);
     if (code != 0)
         goto cleanup;
 
-    krbDataToGssBuffer(credsData, credBuf);
+    krbDataToGssBuffer(&credsData, credBuf);
 
 cleanup:
+#ifdef HAVE_HEIMDAL_VERSION
+    if (krbCrypto != NULL)
+        krb5_crypto_destroy(krbContext, krbCrypto);
+    free_AuthorizationData(&authData);
+    free_EncryptedData(&ticket.enc_part);
+    krb5_data_free(&ticketData);
+    krb5_data_free(&encPartData);
+#else
+    krb5_free_authdata(krbContext, enc_part.authorization_data);
     if (ticket.enc_part.ciphertext.data != NULL)
         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
+    krb5_free_data(krbContext, ticketData);
+#endif
     krb5_free_keyblock_contents(krbContext, &session);
+    krb5_free_principal(krbContext, server);
     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);
-    if (credsData != NULL)
-        GSSEAP_FREE(credsData);
 
     if (major == GSS_S_COMPLETE) {
         *minor = code;
-        major = code != 0 ? GSS_S_FAILURE : GSS_S_COMPLETE;
+        major = (code != 0) ? GSS_S_FAILURE : GSS_S_COMPLETE;
     }
 
     return major;
 }
 
 static int
-isTicketGrantingServiceP(krb5_context krbContext,
+isTicketGrantingServiceP(krb5_context krbContext GSSEAP_UNUSED,
                          krb5_const_principal principal)
 {
-    if (krb5_princ_size(krbContext, principal) == 2 &&
+    if (KRB_PRINC_LENGTH(principal) == 2 &&
+#ifdef HAVE_HEIMDAL_VERSION
+        strcmp(KRB_PRINC_NAME(principal)[0], "krbtgt") == 0
+#else
         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
+#endif
+        )
+        return TRUE;
+
+    return FALSE;
+}
+
+/*
+ * Returns TRUE if the configuration variable reauth_use_ccache is
+ * set in krb5.conf for the eap_gss application and the client realm.
+ */
+static int
+reauthUseCredsCache(krb5_context krbContext,
+                    krb5_principal principal)
+{
+    int reauthUseCCache;
+
+    /* if reauth_use_ccache, use default credentials cache if ticket is for us */
+    krb5_appdefault_boolean(krbContext, "eap_gss",
+                            KRB_PRINC_REALM(principal),
+                            "reauth_use_ccache", 0, &reauthUseCCache);
+
+    return reauthUseCCache;
+}
+
+/*
+ * Look in default credentials cache for reauthentication credentials,
+ * if policy allows.
+ */
+static OM_uint32
+getDefaultReauthCredentials(OM_uint32 *minor,
+                            gss_cred_id_t cred,
+                            gss_name_t target,
+                            time_t now,
+                            OM_uint32 timeReq)
+{
+    OM_uint32 major = GSS_S_CRED_UNAVAIL;
+    krb5_context krbContext = NULL;
+    krb5_error_code code = 0;
+    krb5_ccache ccache = NULL;
+    krb5_creds match = { 0 };
+    krb5_creds creds = { 0 };
+
+    GSSEAP_KRB_INIT(&krbContext);
+
+    assert(cred != GSS_C_NO_CREDENTIAL);
+    assert(target != GSS_C_NO_NAME);
+
+    if (cred->name == GSS_C_NO_NAME ||
+        !reauthUseCredsCache(krbContext, cred->name->krbPrincipal))
+        goto cleanup;
+
+    match.client = cred->name->krbPrincipal;
+    match.server = target->krbPrincipal;
+    if (timeReq != 0 && timeReq != GSS_C_INDEFINITE)
+        match.times.endtime = now + timeReq;
+
+    code = krb5_cc_default(krbContext, &ccache);
+    if (code != 0)
+        goto cleanup;
+
+    code = krb5_cc_retrieve_cred(krbContext, ccache, 0, &match, &creds);
+    if (code != 0)
+        goto cleanup;
+
+    cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
+    cred->krbCredCache = ccache;
+    ccache = NULL;
+
+    major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
+                                 &cred->krbCred);
+
+cleanup:
+    if (major == GSS_S_CRED_UNAVAIL)
+        *minor = code;
+
+    if (ccache != NULL)
+        krb5_cc_close(krbContext, ccache);
+    krb5_free_cred_contents(krbContext, &creds);
+
+    return major;
+}
+
+/*
+ * Returns TRUE if the credential handle's reauth credentials are
+ * valid or if we can use the default credentials cache. Credentials
+ * handle must be locked.
+ */
+int
+gssEapCanReauthP(gss_cred_id_t cred,
+                 gss_name_t target,
+                 OM_uint32 timeReq)
+{
+    time_t now, expiryReq;
+    OM_uint32 minor;
+
+    assert(cred != GSS_C_NO_CREDENTIAL);
+
+    now = time(NULL);
+    expiryReq = now;
+    if (timeReq != GSS_C_INDEFINITE)
+        expiryReq += timeReq;
+
+    if (cred->krbCredCache != NULL && cred->expiryTime > expiryReq)
+        return TRUE;
+
+    if (getDefaultReauthCredentials(&minor, cred, target,
+                                    now, timeReq) == GSS_S_COMPLETE)
         return TRUE;
 
     return FALSE;
 }
 
+/*
+ * Store re-authentication (Kerberos) credentials in a credential handle.
+ * Credentials handle must be locked.
+ */
 OM_uint32
 gssEapStoreReauthCreds(OM_uint32 *minor,
                        gss_ctx_id_t ctx,
                        gss_cred_id_t cred,
                        gss_buffer_t credBuf)
 {
-    OM_uint32 major = GSS_S_COMPLETE, code;
+    OM_uint32 major = GSS_S_COMPLETE;
+    krb5_error_code code;
     krb5_context krbContext = NULL;
     krb5_auth_context authContext = NULL;
     krb5_data credData = { 0 };
     krb5_creds **creds = NULL;
     krb5_principal canonPrinc;
+    krb5_principal ccPrinc = NULL;
     int i;
 
     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
@@ -294,23 +552,52 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
     krb5_free_principal(krbContext, cred->name->krbPrincipal);
     cred->name->krbPrincipal = canonPrinc;
 
-    cred->expiryTime = creds[0]->times.endtime;
+    if (creds[0]->times.endtime == KRB_TIME_FOREVER)
+        cred->expiryTime = 0;
+    else
+        cred->expiryTime = creds[0]->times.endtime;
 
-    code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
-    if (code != 0)
-        goto cleanup;
+    if (cred->krbCredCache == NULL) {
+        if (reauthUseCredsCache(krbContext, creds[0]->client) &&
+            krb5_cc_default(krbContext, &cred->krbCredCache) == 0)
+            cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
+    } else {
+        /*
+         * If we already have an associated credentials cache, possibly from
+         * the last time we stored a reauthentication credential, then we
+         * need to clear it out and release the associated GSS credential.
+         */
+        if (cred->flags & CRED_FLAG_DEFAULT_CCACHE) {
+            krb5_cc_remove_cred(krbContext, cred->krbCredCache, 0, creds[0]);
+        } else {
+            krb5_cc_destroy(krbContext, cred->krbCredCache);
+            cred->krbCredCache = NULL;
+        }
+        gssReleaseCred(minor, &cred->krbCred);
+    }
 
-    code = krb5_cc_initialize(krbContext, cred->krbCredCache,
-                              creds[0]->client);
-    if (code != 0)
-        goto cleanup;
+    if (cred->krbCredCache == NULL) {
+        code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
+        if (code != 0)
+            goto cleanup;
+    }
+
+    if ((cred->flags & CRED_FLAG_DEFAULT_CCACHE) == 0 ||
+        krb5_cc_get_principal(krbContext, cred->krbCredCache, &ccPrinc) != 0) {
+        code = krb5_cc_initialize(krbContext, cred->krbCredCache,
+                                  creds[0]->client);
+        if (code != 0)
+            goto cleanup;
+    }
 
     for (i = 0; creds[i] != NULL; i++) {
         krb5_creds kcred = *(creds[i]);
 
         /*
          * 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;
@@ -328,10 +615,12 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
 cleanup:
     *minor = code;
 
+    krb5_free_principal(krbContext, ccPrinc);
     krb5_auth_con_free(krbContext, authContext);
     if (creds != NULL) {
         for (i = 0; creds[i] != NULL; i++)
             krb5_free_creds(krbContext, creds[i]);
+        GSSEAP_FREE(creds);
     }
     if (major == GSS_S_COMPLETE)
         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
@@ -339,325 +628,100 @@ 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)))
+#ifndef HAVE_HEIMDAL_VERSION
+static gss_buffer_desc radiusAvpKrbAttr = {
+    sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
+};
+#endif
 
-OM_uint32
-gssEapReauthInitialize(OM_uint32 *minor)
+/*
+ * Unfortunately extracting an AD-KDCIssued authorization data element
+ * is pretty implementation-dependent. It's not possible to verify the
+ * signature ourselves because the ticket session key is not exposed
+ * outside GSS. In an ideal world, all AD-KDCIssued elements would be
+ * verified by the Kerberos library and authentication would fail if
+ * verification failed. We're not quite there yet and as a result have
+ * to go through some hoops to get this to work. The alternative would
+ * 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.)
+ */
+static OM_uint32
+defrostAttrContext(OM_uint32 *minor,
+#ifdef HAVE_HEIMDAL_VERSION
+                   gss_ctx_id_t glueContext,
+#else
+                   gss_ctx_id_t glueContext GSSEAP_UNUSED,
+#endif
+                   gss_name_t glueName,
+                   gss_name_t mechName)
 {
-    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 major, tmpMinor;
+#ifdef HAVE_HEIMDAL_VERSION
+    gss_OID_desc oid = { 0 };
+    gss_buffer_set_t authData = GSS_C_NO_BUFFER_SET;
+#else
+    gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
+    gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
+    int more = -1;
+    int authenticated, complete;
+#endif
 
-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;
+#ifdef HAVE_HEIMDAL_VERSION
+    major = composeOid(minor,
+                       GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->elements,
+                       GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->length,
+                       KRB5_AUTHDATA_RADIUS_AVP, &oid);
+    if (GSS_ERROR(major))
+        return major;
 
-    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);
-}
+    /* XXX we are assuming that this verifies AD-KDCIssued signature */
+    major = gssInquireSecContextByOid(minor, glueContext,
+                                      &oid, &authData);
+    if (major == GSS_S_COMPLETE) {
+        if (authData == GSS_C_NO_BUFFER_SET || authData->count != 1)
+            major = GSS_S_FAILURE;
+        else
+            major = gssEapImportAttrContext(minor, authData->elements, mechName);
+    } else if (major == GSS_S_FAILURE && *minor == ENOENT) {
+        /* This is the equivalent of GSS_S_UNAVAILABLE for MIT attr APIs */
+        *minor = 0;
+        major = GSS_S_COMPLETE;
+    }
 
-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;
+    gss_release_buffer_set(&tmpMinor, &authData);
+    GSSEAP_FREE(oid.elements);
+#else
+    major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
+                                &authenticated, &complete,
+                                &authData, &authDataDisplay, &more);
+    if (major == GSS_S_COMPLETE) {
+        if (authenticated == 0)
+            major = GSS_S_BAD_NAME;
+        else
+            major = gssEapImportAttrContext(minor, &authData, mechName);
+    } else if (major == GSS_S_UNAVAILABLE) {
+        major = GSS_S_COMPLETE;
+    }
 
-    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"
-};
-
-/*
- * Unfortunately extracting an AD-KDCIssued authorization data element
- * is pretty implementation-dependent. It's not possible to verify the
- * signature ourselves because the ticket session key is not exposed
- * outside GSS. In an ideal world, all AD-KDCIssued elements would be
- * verified by the Kerberos library and authentication would fail if
- * verification failed. We're not quite there yet and as a result have
- * to go through some hoops to get this to work. The alternative would
- * 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.)
- */
-static OM_uint32
-defrostAttrContext(OM_uint32 *minor,
-                   gss_name_t glueName,
-                   gss_name_t mechName)
-{
-    OM_uint32 major, tmpMinor;
-    gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
-    gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
-    int more = -1;
-    int authenticated, complete;
-
-    major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
-                                &authenticated, &complete,
-                                &authData, &authDataDisplay, &more);
-    if (major == GSS_S_COMPLETE) {
-        if (authenticated == 0)
-            major = GSS_S_BAD_NAME;
-        else
-            major = gssEapImportAttrContext(minor, &authData, mechName);
-    } else if (major == GSS_S_UNAVAILABLE) {
-        major = GSS_S_COMPLETE;
-    }
-
-    gss_release_buffer(&tmpMinor, &authData);
-    gss_release_buffer(&tmpMinor, &authDataDisplay);
-
-    return major;
+    gss_release_buffer(&tmpMinor, &authData);
+    gss_release_buffer(&tmpMinor, &authDataDisplay);
+#endif /* HAVE_HEIMDAL_VERSION */
+
+    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_ctx_id_t glueContext,
                      gss_name_t glueName,
                      gss_name_t *pMechName)
 {
@@ -675,7 +739,7 @@ gssEapGlueToMechName(OM_uint32 *minor,
     if (GSS_ERROR(major))
         goto cleanup;
 
-    major = defrostAttrContext(minor, glueName, *pMechName);
+    major = defrostAttrContext(minor, glueContext, glueName, *pMechName);
     if (GSS_ERROR(major))
         goto cleanup;
 
@@ -690,6 +754,10 @@ 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,
@@ -715,26 +783,65 @@ 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,
-                    gss_cred_id_t cred,
-                    const gss_OID mech,
-                    OM_uint32 timeRec)
+                     gss_ctx_id_t ctx,
+                     gss_cred_id_t cred GSSEAP_UNUSED,
+                     const gss_OID mech,
+                     OM_uint32 timeRec)
 {
     OM_uint32 major, tmpMinor;
     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
+    krb5_context krbContext = NULL;
+#ifdef HAVE_HEIMDAL_VERSION
+    krb5_storage *sp = NULL;
+#endif
+
+    GSSEAP_KRB_INIT(&krbContext);
 
     if (!oidEqual(mech, gss_mech_krb5)) {
         major = GSS_S_BAD_MECH;
         goto cleanup;
     }
 
+    /* Get the raw subsession key and encryption type */
+#ifdef HAVE_HEIMDAL_VERSION
+#define KRB_GSS_SUBKEY_COUNT    1 /* encoded session key */
+    major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
+                                      GSS_KRB5_GET_SUBKEY_X, &keyData);
+#else
+#define KRB_GSS_SUBKEY_COUNT    2 /* raw session key, enctype OID */
     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
+#endif
     if (GSS_ERROR(major))
         goto cleanup;
 
+    if (keyData == GSS_C_NO_BUFFER_SET || keyData->count < KRB_GSS_SUBKEY_COUNT) {
+        *minor = GSSEAP_KEY_UNAVAILABLE;
+        major = GSS_S_FAILURE;
+        goto cleanup;
+    }
+
+#ifdef HAVE_HEIMDAL_VERSION
+    sp = krb5_storage_from_mem(keyData->elements[0].value,
+                               keyData->elements[0].length);
+    if (sp == NULL) {
+        *minor = ENOMEM;
+        major = GSS_S_FAILURE;
+        goto cleanup;
+    }
+
+    *minor = krb5_ret_keyblock(sp, &ctx->rfc3961Key);
+    if (*minor != 0) {
+        major = GSS_S_FAILURE;
+        goto cleanup;
+    }
+#else
     {
         gss_OID_desc oid;
         int suffix;
@@ -753,11 +860,8 @@ gssEapReauthComplete(OM_uint32 *minor,
     }
 
     {
-        krb5_context krbContext = NULL;
         krb5_keyblock key;
 
-        GSSEAP_KRB_INIT(&krbContext);
-
         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
@@ -769,6 +873,7 @@ gssEapReauthComplete(OM_uint32 *minor,
             goto cleanup;
         }
     }
+#endif /* HAVE_HEIMDAL_VERSION */
 
     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
                                       &ctx->checksumType);
@@ -778,6 +883,7 @@ 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),
@@ -789,8 +895,292 @@ gssEapReauthComplete(OM_uint32 *minor,
     major = GSS_S_COMPLETE;
 
 cleanup:
+#ifdef HAVE_HEIMDAL_VERSION
+    if (sp != NULL)
+        krb5_storage_free(sp);
+#endif
     gss_release_buffer_set(&tmpMinor, &keyData);
 
     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)  do {        \
+        ((local) = dlsym(RTLD_NEXT, (global))); \
+        if ((local) == NULL) {                  \
+            *minor = GSSEAP_NO_MECHGLUE_SYMBOL; \
+            major = GSS_S_UNAVAILABLE;          \
+            /* but continue */                  \
+        }                                       \
+    } while (0)
+
+OM_uint32
+gssEapReauthInitialize(OM_uint32 *minor)
+{
+    OM_uint32 major = GSS_S_COMPLETE;
+
+    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");
+#ifndef HAVE_HEIMDAL_VERSION
+    NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
+#endif
+
+    return major;
+}
+
+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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        return GSS_S_UNAVAILABLE;
+    }
+
+    return gssReleaseCredNext(minor, cred_handle);
+}
+
+OM_uint32
+gssReleaseName(OM_uint32 *minor,
+               gss_name_t *name)
+{
+    if (gssReleaseName == NULL) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        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) {
+        *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
+        return GSS_S_UNAVAILABLE;
+    }
+
+    return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
+                                   value, display_value, more);
+}