check for gss_krb5_import_cred
[mech_eap.git] / util_reauth.c
index c442038..7015451 100644 (file)
  * Fast reauthentication support for EAP GSS.
  */
 
-#define KRB5_AUTHDATA_RADIUS_AVP        513
-
 krb5_error_code
 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,
@@ -55,12 +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)
@@ -68,22 +77,25 @@ getAcceptorKey(krb5_context krbContext,
 
     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
         code = krb5_kt_get_entry(krbContext, keytab,
-                                 cred->name->krbPrincipal, 0, 
+                                 cred->name->krbPrincipal, 0,
                                  ctx->encryptionType, &ktent);
         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);
-            }
         }
     }
 
@@ -97,47 +109,95 @@ 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,
                       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_ticket ticket = { 0 };
-    krb5_keyblock session, acceptorKey = { 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;
+
     credBuf->length = 0;
     credBuf->value = NULL;
+
     GSSEAP_KRB_INIT(&krbContext);
 
     code = getAcceptorKey(krbContext, ctx, cred,
                           &ticket.server, &acceptorKey);
-    if (code != 0)
+    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);
+    } 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.
+     */
     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
                                   &session);
     if (code != 0)
@@ -152,25 +212,18 @@ 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;
-    enc_part.authorization_data = authData;
-
     ticket.enc_part2 = &enc_part;
 
-    code = encode_krb5_ticket(&ticket, &ticketData);
+    code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
     if (code != 0)
         goto cleanup;
 
-    code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
+    code = encode_krb5_ticket(&ticket, &ticketData);
     if (code != 0)
         goto cleanup;
 
@@ -180,7 +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)
@@ -190,7 +243,8 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     if (code != 0)
         goto cleanup;
 
-    code = krb5_auth_con_setsendsubkey(krbContext, authContext, &ctx->rfc3961Key);
+    code = krb5_auth_con_setsendsubkey(krbContext, authContext,
+                                       &ctx->rfc3961Key);
     if (code != 0)
         goto cleanup;
 
@@ -201,25 +255,40 @@ gssEapMakeReauthCreds(OM_uint32 *minor,
     krbDataToGssBuffer(credsData, credBuf);
 
 cleanup:
-    *minor = code;
-
     if (ticket.enc_part.ciphertext.data != NULL)
         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
-
     krb5_free_keyblock_contents(krbContext, &session);
     krb5_free_keyblock_contents(krbContext, &acceptorKey);
-    gss_release_buffer(&code, &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)
-        major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
+    if (major == GSS_S_COMPLETE) {
+        *minor = code;
+        major = code != 0 ? GSS_S_FAILURE : GSS_S_COMPLETE;
+    }
 
     return major;
 }
 
+static int
+isTicketGrantingServiceP(krb5_context krbContext,
+                         krb5_const_principal principal)
+{
+    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)
+        return TRUE;
+
+    return FALSE;
+}
+
+/*
+ * Store re-authentication (Kerberos) credentials in a credential handle.
+ */
 OM_uint32
 gssEapStoreReauthCreds(OM_uint32 *minor,
                        gss_ctx_id_t ctx,
@@ -231,6 +300,7 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
     krb5_auth_context authContext = NULL;
     krb5_data credData = { 0 };
     krb5_creds **creds = NULL;
+    krb5_principal canonPrinc;
     int i;
 
     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
@@ -260,17 +330,54 @@ gssEapStoreReauthCreds(OM_uint32 *minor,
     if (creds == NULL || creds[0] == NULL)
         goto cleanup;
 
+    code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
+    if (code != 0)
+        goto cleanup;
+
+    krb5_free_principal(krbContext, cred->name->krbPrincipal);
+    cred->name->krbPrincipal = canonPrinc;
+
+    cred->expiryTime = creds[0]->times.endtime;
+
     code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
     if (code != 0)
         goto cleanup;
 
-    code = krb5_cc_store_cred(krbContext, cred->krbCredCache, creds[0]);
+    code = krb5_cc_initialize(krbContext, cred->krbCredCache,
+                              creds[0]->client);
     if (code != 0)
         goto cleanup;
 
-    major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL, &cred->krbCred);
+    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. 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;
+
+        code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
+        if (code != 0)
+            goto cleanup;
+    }
+
+#ifdef HAVE_GSS_KRB5_IMPORT_CRED
+    /*
+     * 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))
         goto cleanup;
+#else
+#warning Missing gss_krb5_import_cred() implementation
+#endif
 
 cleanup:
     *minor = code;
@@ -286,68 +393,303 @@ 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 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;
+}
+
+/*
+ * 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,
+                     gss_name_t *pMechName)
+{
+    OM_uint32 major, tmpMinor;
+    gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
+
+    *pMechName = GSS_C_NO_NAME;
+
+    major = gssDisplayName(minor, glueName, &nameBuf, NULL);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
+                             pMechName);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    major = defrostAttrContext(minor, glueName, *pMechName);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+cleanup:
+    if (GSS_ERROR(major)) {
+        gssReleaseName(&tmpMinor, pMechName);
+        *pMechName = GSS_C_NO_NAME;
+    }
+
+    gss_release_buffer(&tmpMinor, &nameBuf);
+
+    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,
+                     gss_name_t *pGlueName)
+{
+    OM_uint32 major, tmpMinor;
+    gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
+
+    *pGlueName = GSS_C_NO_NAME;
+
+    major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
+                          pGlueName);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+cleanup:
+    gss_release_buffer(&tmpMinor, &nameBuf);
+
+    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)
+{
+    OM_uint32 major, tmpMinor;
+    gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
+
+    if (!oidEqual(mech, gss_mech_krb5)) {
+        major = GSS_S_BAD_MECH;
+        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))
+        goto cleanup;
+
+    {
+        gss_OID_desc oid;
+        int suffix;
+
+        oid.length = keyData->elements[1].length;
+        oid.elements = keyData->elements[1].value;
+
+        /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
+        major = decomposeOid(minor,
+                             "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
+                             10, &oid, &suffix);
+        if (GSS_ERROR(major))
+            goto cleanup;
+
+        ctx->encryptionType = suffix;
+    }
+
+    {
+        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;
+
+        *minor = krb5_copy_keyblock_contents(krbContext,
+                                             &key, &ctx->rfc3961Key);
+        if (*minor != 0) {
+            major = GSS_S_FAILURE;
+            goto cleanup;
+        }
+    }
+
+    major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
+                                      &ctx->checksumType);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    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),
+                         ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
+                         TRUE);
+    if (GSS_ERROR(major))
+        goto cleanup;
+
+    major = GSS_S_COMPLETE;
+
+cleanup:
+    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)  ((local) = dlsym(RTLD_NEXT, (global)))
 
 OM_uint32
 gssEapReauthInitialize(OM_uint32 *minor)
 {
-    gssInitSecContextNext = dlsym(RTLD_NEXT, "gss_init_sec_context");
-    gssAcceptSecContextNext = dlsym(RTLD_NEXT, "gss_accept_sec_context");
-    gssReleaseCredNext = dlsym(RTLD_NEXT, "gss_release_cred");
-    gssReleaseNameNext = dlsym(RTLD_NEXT, "gss_release_name");
-    gssInquireSecContextByOidNext = dlsym(RTLD_NEXT, "gss_inquire_sec_context_by_oid");
-    gssDeleteSecContextNext = dlsym(RTLD_NEXT, "gss_delete_sec_context");
+    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;
 }
@@ -430,7 +772,7 @@ gssDeleteSecContext(OM_uint32 *minor,
     return gssDeleteSecContextNext(minor, context_handle, output_token);
 }
 
-OM_uint32
+static OM_uint32
 gssDisplayName(OM_uint32 *minor,
                gss_name_t name,
                gss_buffer_t buffer,
@@ -442,6 +784,18 @@ gssDisplayName(OM_uint32 *minor,
     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,
@@ -454,3 +808,38 @@ gssInquireSecContextByOid(OM_uint32 *minor,
     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);
+}