From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51328) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dYESh-0004rz-IW for qemu-devel@nongnu.org; Thu, 20 Jul 2017 12:38:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dYESe-0002ar-D6 for qemu-devel@nongnu.org; Thu, 20 Jul 2017 12:38:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37356) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dYESe-0002aQ-6u for qemu-devel@nongnu.org; Thu, 20 Jul 2017 12:38:00 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A1E536574B for ; Thu, 20 Jul 2017 16:29:16 +0000 (UTC) From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Doktor?= Date: Thu, 20 Jul 2017 18:28:06 +0200 Message-Id: <20170720162815.19802-3-ldoktor@redhat.com> In-Reply-To: <20170720162815.19802-1-ldoktor@redhat.com> References: <20170720162815.19802-1-ldoktor@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH 02/11] qemu.py: Avoid dangerous arguments List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: ldoktor@redhat.com, apahim@redhat.com, qemu-devel@nongnu.org, famz@redhat.com, armbru@redhat.com, mreitz@redhat.com, ehabkost@redhat.com The list object is mutable in python and potentially might modify other object's arguments when used as default argument. Reproducer: >>> vm1 =3D QEMUMachine("qemu") >>> vm2 =3D QEMUMachine("qemu") >>> vm1._wrapper.append("foo") >>> print vm2._wrapper ['foo'] In this case the `args` is actually copied so it would be safe to keep it, but it's not a good practice to keep it. Signed-off-by: Luk=C3=A1=C5=A1 Doktor --- scripts/qemu.py | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/scripts/qemu.py b/scripts/qemu.py index 191c916..66fd863 100644 --- a/scripts/qemu.py +++ b/scripts/qemu.py @@ -23,7 +23,7 @@ import qmp.qmp class QEMUMachine(object): '''A QEMU VM''' =20 - def __init__(self, binary, args=3D[], wrapper=3D[], name=3DNone, + def __init__(self, binary, args=3DNone, wrapper=3DNone, name=3DNone, test_dir=3D"/var/tmp", monitor_address=3DNone, socket_scm_helper=3DNone, debug=3DFalse): ''' @@ -39,6 +39,10 @@ class QEMUMachine(object): @param debug: enable debug mode (forwarded to QMP helper and suc= h) @note: Qemu process is not started until launch() is used. ''' + if args is None: + args =3D [] + if wrapper is None: + wrapper =3D [] if name is None: name =3D "qemu-%d" % os.getpid() if monitor_address is None: --=20 2.9.4