Code: uint8_t smb2cli_session_security_mode(struct smbXcli_session *session)
{
	struct smbXcli_conn *conn = session->conn;
	uint8_t security_mode = 0;

	if (conn == NULL) {
		return security_mode;
	}

	security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED;
        if (conn->mandatory_signing) {
                security_mode |= SMB2_NEGOTIATE_SIGNING_REQUIRED;
        }
 
        return security_mode;
 }

Vulnerability Type: 
CWE ID: CWE-20
Summary: Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 supports connections that are encrypted but unsigned, which allows man-in-the-middle attackers to conduct encrypted-to-unencrypted downgrade attacks by modifying the client-server data stream, related to clidfs.c, libsmb_server.c, and smbXcli_base.c.
Commit Message: 