auth/ntlmssp: do map to guest checking after the authentication

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11847

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>

2 files changed, 41 insertions, 15 deletions

diff --git a/auth/ntlmssp/gensec_ntlmssp_server.c b/auth/ntlmssp/gensec_ntlmssp_server.c
index ca19863eadd..120c6e03315 100644
--- a/auth/ntlmssp/gensec_ntlmssp_server.c
+++ b/auth/ntlmssp/gensec_ntlmssp_server.c
@@ -131,21 +131,7 @@ NTSTATUS gensec_ntlmssp_server_start(struct gensec_security *gensec_security)
 		ntlmssp_state->allow_lm_key = true;
 	}
 
-	if (lpcfg_map_to_guest(gensec_security->settings->lp_ctx) != NEVER_MAP_TO_GUEST) {
-		/*
-		 * map to guest is not secure anyway, so
-		 * try to make it work and don't try to
-		 * negotiate new_spnego and MIC checking
-		 */
-		ntlmssp_state->force_old_spnego = true;
-	}
-
-	if (role == ROLE_ACTIVE_DIRECTORY_DC) {
-		/*
-		 * map to guest is not supported on an AD DC.
-		 */
-		ntlmssp_state->force_old_spnego = false;
-	}
+	ntlmssp_state->force_old_spnego = false;
 
 	ntlmssp_state->neg_flags =
 		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_VERSION;
diff --git a/auth/ntlmssp/ntlmssp_server.c b/auth/ntlmssp/ntlmssp_server.c
index 17d5adeaeb5..ddee8756bfe 100644
--- a/auth/ntlmssp/ntlmssp_server.c
+++ b/auth/ntlmssp/ntlmssp_server.c
@@ -31,6 +31,9 @@
 #include "auth/gensec/gensec.h"
 #include "auth/gensec/gensec_internal.h"
 #include "auth/common_auth.h"
+#include "param/param.h"
+#include "param/loadparm.h"
+#include "libcli/security/session.h"
 
 /**
  * Determine correct target name flags for reply, given server role
@@ -700,6 +703,7 @@ static NTSTATUS ntlmssp_server_check_password(struct gensec_security *gensec_sec
 	struct ntlmssp_state *ntlmssp_state = gensec_ntlmssp->ntlmssp_state;
 	struct auth4_context *auth_context = gensec_security->auth_context;
 	NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
+	struct auth_session_info *session_info = NULL;
 	struct auth_usersupplied_info *user_info;
 
 	user_info = talloc_zero(ntlmssp_state, struct auth_usersupplied_info);
@@ -736,6 +740,42 @@ static NTSTATUS ntlmssp_server_check_password(struct gensec_security *gensec_sec
 
 	NT_STATUS_NOT_OK_RETURN(nt_status);
 
+	if (lpcfg_map_to_guest(gensec_security->settings->lp_ctx) != NEVER_MAP_TO_GUEST
+	    && auth_context->generate_session_info != NULL)
+	{
+		NTSTATUS tmp_status;
+
+		/*
+		 * We need to check if the auth is anonymous or mapped to guest
+		 */
+		tmp_status = auth_context->generate_session_info(auth_context, mem_ctx,
+								 gensec_ntlmssp->server_returned_info,
+								 gensec_ntlmssp->ntlmssp_state->user,
+								 AUTH_SESSION_INFO_SIMPLE_PRIVILEGES,
+								 &session_info);
+		if (!NT_STATUS_IS_OK(tmp_status)) {
+			/*
+			 * We don't care about failures,
+			 * the worst result is that we try MIC checking
+			 * for a map to guest authentication.
+			 */
+			TALLOC_FREE(session_info);
+		}
+	}
+
+	if (session_info != NULL) {
+		if (security_session_user_level(session_info, NULL) < SECURITY_USER) {
+			/*
+			 * Anonymous and GUEST are not secure anyway.
+			 * avoid new_spnego and MIC checking.
+			 */
+			ntlmssp_state->new_spnego = false;
+			ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_SIGN;
+			ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_SEAL;
+		}
+		TALLOC_FREE(session_info);
+	}
+
 	talloc_steal(mem_ctx, user_session_key->data);
 	talloc_steal(mem_ctx, lm_session_key->data);