heimdal: handle referrals for 3 part DRSUAPI SPNs

This handles referrals for SPNs of the form
E3514235-4B06-11D1-AB04-00C04FC2DCD2/NTDSGUID/REALM, which are
used during DRS replication when we don't know the dnsHostName of the
target DC (which we don't know until the first replication from that
DC completes).

We use the 3rd part of the SPN directly as the realm name in the
referral.

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>

diff --git a/kdc/krb5tgs.c b/kdc/krb5tgs.c
index 347a4221dca5d5c0f1db9790efd18ad3881a3ca8..369292b75ed03fff8faccce6a2a66be2290d0545 100644 (file)
--- a/kdc/krb5tgs.c
+++ b/kdc/krb5tgs.c
@@ -1122,7 +1122,24 @@ need_referral(krb5_context context, krb5_kdc_configuration *config,
 
     if (server->name.name_string.len == 1)
        name = server->name.name_string.val[0];
-    else if (server->name.name_string.len > 1)
+    else if (server->name.name_string.len == 3 &&
+            strcasecmp("E3514235-4B06-11D1-AB04-00C04FC2DCD2", server->name.name_string.val[0]) == 0) {
+       /*
+         This is used to give referrals for the
+         E3514235-4B06-11D1-AB04-00C04FC2DCD2/NTDSGUID/DNSDOMAIN
+         SPN form, which is used for inter-domain communication in AD
+        */
+       name = server->name.name_string.val[2];
+       kdc_log(context, config, 0, "Giving 3 part DRSUAPI referral for %s", name);
+       *realms = malloc(sizeof(char *)*2);
+       if (*realms == NULL) {
+           krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
+           return FALSE;
+       }
+       (*realms)[0] = strdup(name);
+       (*realms)[1] = NULL;
+       return TRUE;
+    } else if (server->name.name_string.len > 1)
        name = server->name.name_string.val[1];
     else
        return FALSE;