fs/cifs: correctly to anonymous authentication for the NTLM(v1) authentication

Only server which map unknown users to guest will allow
access using a non-null NTChallengeResponse.

For Samba it's the "map to guest = bad user" option.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11913Signed-off-by: Stefan Metzmacher <metze@samba.org>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/sess.c

@@ -781,6 +781,7 @@ sess_auth_ntlm(struct sess_data *sess_data)
 	capabilities = cifs_ssetup_hdr(ses, pSMB);
 
 	pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
+	if (ses->user_name != NULL) {
 		pSMB->req_no_secext.CaseInsensitivePasswordLength =
 				cpu_to_le16(CIFS_AUTH_RESP_SIZE);
 		pSMB->req_no_secext.CaseSensitivePasswordLength =
@@ -801,6 +802,10 @@ sess_auth_ntlm(struct sess_data *sess_data)
 		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
 				CIFS_AUTH_RESP_SIZE);
 		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
+		pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+	}
 
 	if (ses->capabilities & CAP_UNICODE) {
 		/* unicode strings must be word aligned */