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-rw-r--r--source4/heimdal/kdc/krb5tgs.c40
1 files changed, 36 insertions, 4 deletions
diff --git a/source4/heimdal/kdc/krb5tgs.c b/source4/heimdal/kdc/krb5tgs.c
index 53c0a589ba..ca650645de 100644
--- a/source4/heimdal/kdc/krb5tgs.c
+++ b/source4/heimdal/kdc/krb5tgs.c
@@ -486,7 +486,7 @@ check_tgs_flags(krb5_context context,
}
/*
- *
+ * Determine if constrained delegation is allowed from this client to this server
*/
static krb5_error_code
@@ -529,6 +529,38 @@ check_constrained_delegation(krb5_context context,
}
/*
+ * Determine if s4u2self is allowed from this client to this server
+ *
+ * For example, regardless of the principal being impersonated, if the
+ * 'client' and 'server' are the same, then it's safe.
+ */
+
+static krb5_error_code
+check_s4u2self(krb5_context context,
+ krb5_kdc_configuration *config,
+ HDB *clientdb,
+ hdb_entry_ex *client,
+ krb5_const_principal server)
+{
+ const HDB_Ext_Constrained_delegation_acl *acl;
+ krb5_error_code ret;
+ int i;
+
+ /* if client does a s4u2self to itself, that ok */
+ if (krb5_principal_compare(context, client->entry.principal, server) == TRUE)
+ return 0;
+
+ if (clientdb->hdb_check_s4u2self) {
+ ret = clientdb->hdb_check_s4u2self(context, clientdb, client, server);
+ if (ret == 0)
+ return 0;
+ } else {
+ ret = KRB5KDC_ERR_BADOPTION;
+ }
+ return ret;
+}
+
+/*
*
*/
@@ -1783,13 +1815,13 @@ server_lookup:
* Check that service doing the impersonating is
* requesting a ticket to it-self.
*/
- if (krb5_principal_compare(context, cp, sp) != TRUE) {
+ ret = check_s4u2self(context, config, clientdb, client, sp);
+ if (ret) {
kdc_log(context, config, 0, "S4U2Self: %s is not allowed "
- "to impersonate some other user "
+ "to impersonate to service "
"(tried for user %s to service %s)",
cpn, selfcpn, spn);
free(selfcpn);
- ret = KRB5KDC_ERR_BADOPTION; /* ? */
goto out;
}