From 2e4bf8bfcdf7dea3beb754125c45e337a4afb228 Mon Sep 17 00:00:00 2001 From: Amitay Isaacs Date: Mon, 28 Nov 2011 10:33:53 +1100 Subject: s4-repl: Check if GC SPN exists before using it for replication Sometimes windows DC will set up dNSHostname before setting up GC SPN and that causes replication errors since samba tries to use GC SPN, which does not yet exist locally. Pair-Programmed-With: Andrew Tridgell --- source4/dsdb/repl/drepl_partitions.c | 57 ++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 3 deletions(-) (limited to 'source4') diff --git a/source4/dsdb/repl/drepl_partitions.c b/source4/dsdb/repl/drepl_partitions.c index 70f9971a7c..927dc68766 100644 --- a/source4/dsdb/repl/drepl_partitions.c +++ b/source4/dsdb/repl/drepl_partitions.c @@ -125,6 +125,47 @@ WERROR dreplsrv_load_partitions(struct dreplsrv_service *s) return WERR_OK; } +/* + Check if particular SPN exists for an account + */ +static bool dreplsrv_spn_exists(struct ldb_context *samdb, struct ldb_dn *ntds_dn, + const char *principal_name) +{ + TALLOC_CTX *tmp_ctx; + const char *attrs[] = { "serverReference", NULL }; + const char *attrs_empty[] = { NULL }; + int ret; + struct ldb_result *res; + struct ldb_dn *account_dn; + + tmp_ctx = talloc_new(samdb); + + ret = dsdb_search_dn(samdb, tmp_ctx, &res, ntds_dn, attrs, 0); + if (ret != LDB_SUCCESS) { + talloc_free(tmp_ctx); + return false; + } + + account_dn = ldb_msg_find_attr_as_dn(samdb, tmp_ctx, res->msgs[0], "serverReference"); + if (account_dn == NULL) { + talloc_free(tmp_ctx); + return false; + } + + talloc_free(res); + + ret = dsdb_search(samdb, tmp_ctx, &res, account_dn, LDB_SCOPE_BASE, attrs_empty, + 0, "servicePrincipalName=%s", + ldb_binary_encode_string(tmp_ctx, principal_name)); + if (ret != LDB_SUCCESS || res->count != 1) { + talloc_free(tmp_ctx); + return false; + } + + talloc_free(tmp_ctx); + return true; +} + /* work out the principal to use for DRS replication connections */ @@ -181,15 +222,25 @@ NTSTATUS dreplsrv_get_target_principal(struct dreplsrv_service *s, hostname = ldb_msg_find_attr_as_string(res->msgs[0], "dNSHostName", NULL); if (hostname != NULL) { + char *local_principal; + /* if we have the dNSHostName attribute then we can use the GC/hostname/realm SPN. All DCs should have this SPN + + Windows DC may set up it's dNSHostName before setting up + GC/xx/xx SPN. So make sure it exists, before using it. */ - *target_principal = talloc_asprintf(mem_ctx, "GC/%s/%s", + local_principal = talloc_asprintf(mem_ctx, "GC/%s/%s", hostname, samdb_dn_to_dns_domain(tmp_ctx, forest_dn)); - talloc_free(tmp_ctx); - return NT_STATUS_OK; + if (dreplsrv_spn_exists(s->samdb, ntds_dn, local_principal)) { + *target_principal = local_principal; + talloc_free(tmp_ctx); + return NT_STATUS_OK; + } + + talloc_free(local_principal); } /* -- cgit