From patchwork Fri Apr 8 16:12:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 608099 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qhPhv4v9Tz9t5c for ; Sat, 9 Apr 2016 02:16:15 +1000 (AEST) Received: from localhost ([::1]:57035 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoZ4v-0005Co-MG for incoming@patchwork.ozlabs.org; Fri, 08 Apr 2016 12:16:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36935) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoZ28-0007gI-7j for qemu-devel@nongnu.org; Fri, 08 Apr 2016 12:13:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aoZ24-0002Kl-PF for qemu-devel@nongnu.org; Fri, 08 Apr 2016 12:13:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49534) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoZ24-0002KX-IY for qemu-devel@nongnu.org; Fri, 08 Apr 2016 12:13:16 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4CDFB6368; Fri, 8 Apr 2016 16:13:16 +0000 (UTC) Received: from red.redhat.com (ovpn-113-199.phx2.redhat.com [10.3.113.199]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u38GDEGF012676; Fri, 8 Apr 2016 12:13:15 -0400 From: Eric Blake To: qemu-devel@nongnu.org Date: Fri, 8 Apr 2016 10:12:56 -0600 Message-Id: <1460131992-32278-4-git-send-email-eblake@redhat.com> In-Reply-To: <1460131992-32278-1-git-send-email-eblake@redhat.com> References: <1460131992-32278-1-git-send-email-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 08 Apr 2016 16:13:16 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v14 03/19] qapi: Guarantee NULL obj on input visitor callback error X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: armbru@redhat.com, Michael Roth Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Our existing input visitors were not very consistent on errors in a function taking 'TYPE **obj'. While all of them set '*obj' to allocated storage on success, it was not obvious whether '*obj' was guaranteed safe on failure, or whether it was left uninitialized. But a future patch wants to guarantee that visit_type_FOO() does not leak a partially-constructed obj back to the caller; it is easier to implement this if we can reliably state that '*obj' is assigned on exit, even on failures. The opts-visitor start_struct() doesn't set an error, but it also was doing a weird check for 0 size; all callers pass in non-zero size if obj is non-NULL. Signed-off-by: Eric Blake --- v14: no change v13: no change v12: new patch --- qapi/opts-visitor.c | 3 ++- qapi/qmp-input-visitor.c | 4 ++++ qapi/string-input-visitor.c | 1 + 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c index f98cf2e..cdb6e42 100644 --- a/qapi/opts-visitor.c +++ b/qapi/opts-visitor.c @@ -133,7 +133,7 @@ opts_start_struct(Visitor *v, const char *name, void **obj, const QemuOpt *opt; if (obj) { - *obj = g_malloc0(size > 0 ? size : 1); + *obj = g_malloc0(size); } if (ov->depth++ > 0) { return; @@ -314,6 +314,7 @@ opts_type_str(Visitor *v, const char *name, char **obj, Error **errp) opt = lookup_scalar(ov, name, errp); if (!opt) { + *obj = NULL; return; } *obj = g_strdup(opt->str ? opt->str : ""); diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 02d4233..77cce8b 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -120,6 +120,9 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, QObject *qobj = qmp_input_get_object(qiv, name, true); Error *err = NULL; + if (obj) { + *obj = NULL; + } if (!qobj || qobject_type(qobj) != QTYPE_QDICT) { error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "QDict"); @@ -267,6 +270,7 @@ static void qmp_input_type_str(Visitor *v, const char *name, char **obj, QString *qstr = qobject_to_qstring(qmp_input_get_object(qiv, name, true)); if (!qstr) { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); return; diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c index d604575..797973a 100644 --- a/qapi/string-input-visitor.c +++ b/qapi/string-input-visitor.c @@ -293,6 +293,7 @@ static void parse_type_str(Visitor *v, const char *name, char **obj, if (siv->string) { *obj = g_strdup(siv->string); } else { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); }