CVE-2026-4408: s3:samr-server: only allow _samr_ValidatePassword as DC

This is only supported with 'rpc start on demand helpers = no',
as it needs ncacn_ip_tcp, but we better also restrict it to DCs.

Maybe only FreeIPA needs it as NT4 didn't support ncacn_ip_tcp.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=16034

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>

diff --git a/source3/rpc_server/samr/srv_samr_nt.c b/source3/rpc_server/samr/srv_samr_nt.c
index 05f73829ebc03340ae2b209840e74b2689826457..885ff8e2c60a24c6da18f45934f9f5158441a6b3 100644 (file)
--- a/source3/rpc_server/samr/srv_samr_nt.c
+++ b/source3/rpc_server/samr/srv_samr_nt.c
@@ -7485,6 +7485,14 @@ NTSTATUS _samr_ValidatePassword(struct pipes_struct *p,
                return NT_STATUS_ACCESS_DENIED;
        }
 
+       if (lp_server_role() <= ROLE_DOMAIN_MEMBER) {
+               /*
+                * We only want this on DCs
+                */
+               p->fault_state = DCERPC_FAULT_ACCESS_DENIED;
+               return NT_STATUS_ACCESS_DENIED;
+       }
+
        if (r->in.level < 1 || r->in.level > 3) {
                return NT_STATUS_INVALID_INFO_CLASS;
        }