[SCM] Samba Shared Repository - branch master updated
Andrew Tridgell
tridge at samba.org
Mon Nov 8 01:46:01 MST 2010
The branch, master has been updated
via b38a9a8 s4-drs: allow bypass of writespn checking for some SPNs
from cb3d6c4 heimdal Add clock-skew handling to DCE-style GSSAPI
http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master
- Log -----------------------------------------------------------------
commit b38a9a8999949733e98be52fafd1b3a7a2317116
Author: Andrew Tridgell <tridge at samba.org>
Date: Mon Nov 8 19:01:36 2010 +1100
s4-drs: allow bypass of writespn checking for some SPNs
this allows accounts (and in particular RODCs) to make SPN updates on
their own account if they take the form SERVICE/hostname
we may be able to remove this in the future after some changes in our
ACL checking for userPrincipalName
Pair-Programmed-With: Andrew Bartlett <abartlet at samba.org>
Autobuild-User: Andrew Tridgell <tridge at samba.org>
Autobuild-Date: Mon Nov 8 08:45:16 UTC 2010 on sn-devel-104
-----------------------------------------------------------------------
Summary of changes:
source4/rpc_server/drsuapi/writespn.c | 112 ++++++++++++++++++++++++++++++++-
1 files changed, 111 insertions(+), 1 deletions(-)
Changeset truncated at 500 lines:
diff --git a/source4/rpc_server/drsuapi/writespn.c b/source4/rpc_server/drsuapi/writespn.c
index 2e7bd76..d9338f7 100644
--- a/source4/rpc_server/drsuapi/writespn.c
+++ b/source4/rpc_server/drsuapi/writespn.c
@@ -25,6 +25,106 @@
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "rpc_server/drsuapi/dcesrv_drsuapi.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "libcli/security/session.h"
+#include "libcli/security/security.h"
+#include "auth/session.h"
+
+/*
+ check that the SPN update should be allowed as an override
+ via sam_ctx_system
+
+ This is only called if the client is not a domain controller or
+ administrator
+ */
+static bool writespn_check_spn(struct drsuapi_bind_state *b_state,
+ struct dcesrv_call_state *dce_call,
+ struct ldb_dn *dn,
+ const char *spn)
+{
+ /*
+ we only allow SPN updates if:
+
+ 1) they are on the clients own account object
+ 2) they are of the form SERVICE/dnshostname
+ */
+ struct dom_sid *user_sid, *sid;
+ TALLOC_CTX *tmp_ctx = talloc_new(dce_call);
+ struct ldb_result *res;
+ const char *attrs[] = { "objectSID", "dnsHostName", NULL };
+ int ret;
+ krb5_context krb_ctx;
+ krb5_error_code kerr;
+ krb5_principal principal;
+ const char *dns_name, *dnsHostName;
+
+ /*
+ get the objectSid of the DN that is being modified, and
+ check it matches the user_sid in their token
+ */
+
+ ret = dsdb_search_dn(b_state->sam_ctx, tmp_ctx, &res, dn, attrs, DSDB_SEARCH_ONE_ONLY);
+ if (ret != LDB_SUCCESS) {
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ user_sid = &dce_call->conn->auth_state.session_info->security_token->sids[PRIMARY_USER_SID_INDEX];
+ sid = samdb_result_dom_sid(tmp_ctx, res->msgs[0], "objectSid");
+ if (sid == NULL) {
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ dnsHostName = ldb_msg_find_attr_as_string(res->msgs[0], "dnsHostName", NULL);
+ if (dnsHostName == NULL) {
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ if (!dom_sid_equal(sid, user_sid)) {
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ kerr = smb_krb5_init_context_basic(tmp_ctx, dce_call->conn->dce_ctx->lp_ctx, &krb_ctx);
+ if (kerr != 0) {
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ ret = krb5_parse_name_flags(krb_ctx, spn, KRB5_PRINCIPAL_PARSE_NO_REALM, &principal);
+ if (kerr != 0) {
+ krb5_free_context(krb_ctx);
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ if (principal->name.name_string.len != 2) {
+ krb5_free_principal(krb_ctx, principal);
+ krb5_free_context(krb_ctx);
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ dns_name = principal->name.name_string.val[1];
+
+ if (strcasecmp(dns_name, dnsHostName) != 0) {
+ krb5_free_principal(krb_ctx, principal);
+ krb5_free_context(krb_ctx);
+ talloc_free(tmp_ctx);
+ return false;
+ }
+
+ /* its a simple update on their own account - allow it with
+ * permissions override */
+ krb5_free_principal(krb_ctx, principal);
+ krb5_free_context(krb_ctx);
+ talloc_free(tmp_ctx);
+
+ return true;
+}
/*
drsuapi_DsWriteAccountSpn
@@ -34,6 +134,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL
{
struct drsuapi_bind_state *b_state;
struct dcesrv_handle *h;
+ enum security_user_level level;
*r->out.level_out = r->in.level;
@@ -43,6 +144,8 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL
r->out.res = talloc(mem_ctx, union drsuapi_DsWriteAccountSpnResult);
W_ERROR_HAVE_NO_MEMORY(r->out.res);
+ level = security_session_user_level(dce_call->conn->auth_state.session_info, NULL);
+
switch (r->in.level) {
case 1: {
struct drsuapi_DsWriteAccountSpnRequest1 *req;
@@ -51,6 +154,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL
unsigned int i;
int ret;
unsigned spn_count=0;
+ bool passed_checks = true;
req = &r->in.req->req1;
count = req->count;
@@ -68,6 +172,12 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL
/* construct mods */
for (i = 0; i < count; i++) {
+ if (!writespn_check_spn(b_state,
+ dce_call,
+ msg->dn,
+ req->spn_names[i].str)) {
+ passed_checks = false;
+ }
ret = samdb_msg_add_string(b_state->sam_ctx,
msg, msg, "servicePrincipalName",
req->spn_names[i].str);
@@ -98,7 +208,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL
}
/* Apply to database */
- ret = dsdb_modify(b_state->sam_ctx, msg,
+ ret = dsdb_modify(passed_checks?b_state->sam_ctx_system:b_state->sam_ctx, msg,
DSDB_MODIFY_PERMISSIVE);
if (ret != LDB_SUCCESS) {
DEBUG(0,("Failed to modify SPNs on %s: %s\n",
--
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