From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00276C07E96 for ; Thu, 8 Jul 2021 09:25:48 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 77EBF61983 for ; Thu, 8 Jul 2021 09:25:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77EBF61983 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59868 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m1QHz-0006in-II for qemu-devel@archiver.kernel.org; Thu, 08 Jul 2021 05:25:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52794) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1QH9-00062i-Te for qemu-devel@nongnu.org; Thu, 08 Jul 2021 05:24:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56625) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1QH8-0004PY-9T for qemu-devel@nongnu.org; Thu, 08 Jul 2021 05:24:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625736293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=InbTtbhjUOAuNIt0cbXzASaS2gaEn03cQbtk/doY6I8=; b=VyTRpqsjFiNLDN+OwRszNNZNWmh72xZ7WCR1liItvyOLbgFdRMHFMUEpfrQAASLlGa8qS1 hqnbjcNmyM3556Yyn3JAy1JxO4boO0MTYZY2mU9kY1PQFL38OpBCmyFo09/RDw6P2SEZjT zT7CtJySXZvwA+TpynMyZyF7y4K669Q= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-48-OGPTNzC8NM-aPtWHXjHXwg-1; Thu, 08 Jul 2021 05:24:50 -0400 X-MC-Unique: OGPTNzC8NM-aPtWHXjHXwg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 740388015F5; Thu, 8 Jul 2021 09:24:49 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-104.ams2.redhat.com [10.36.112.104]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1E4F55C1C2; Thu, 8 Jul 2021 09:24:49 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 926AB1132B52; Thu, 8 Jul 2021 11:24:47 +0200 (CEST) From: Markus Armbruster To: Paolo Bonzini Subject: Re: [PATCH] qemu-config: never call the callback after an error, fix leak References: <20210707121545.361829-2-pbonzini@redhat.com> Date: Thu, 08 Jul 2021 11:24:47 +0200 In-Reply-To: <20210707121545.361829-2-pbonzini@redhat.com> (Paolo Bonzini's message of "Wed, 7 Jul 2021 14:15:45 +0200") Message-ID: <87eec99mzk.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.439, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Paolo Bonzini writes: > Ensure that the callback to qemu_config_foreach is never called upon > an error, by moving the invocation before the "out" label and ensuring > all error cases jump to the label. The qobject_unref however needs > to be done in all cases (which Coverity is already complaining about). > > The leak is basically impossible to reach, since the only common way > to get ferror(fp) is by passing a directory to -readconfig. In that > case, the error occurs before qdict is set to anything non-NULL. > However, it's theoretically possible to get there after an EIO. > > Cc: armbru@redhat.com > Reported-by: Peter Maydell > Signed-off-by: Paolo Bonzini > --- > util/qemu-config.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/util/qemu-config.c b/util/qemu-config.c > index 84ee6dc4ea..6c4373e8fb 100644 > --- a/util/qemu-config.c > +++ b/util/qemu-config.c > @@ -412,16 +412,15 @@ static int qemu_config_foreach(FILE *fp, QEMUConfigCB *cb, void *opaque, > goto out; > } > if (ferror(fp)) { > - loc_pop(&loc); > error_setg_errno(errp, errno, "Cannot read config file"); I'm afraid we now report the error with the wrong location when @errp is &error-fatal. > - return res; > + goto out; > } > res = count; > -out: > if (qdict) { > cb(group, qdict, opaque, errp); > - qobject_unref(qdict); > } > +out: > + qobject_unref(qdict); > loc_pop(&loc); > return res; > } Looks like the patch fixes two separate issues: 1. Memory leak on ferror() Fixes: f7544edcd32e602af1aae86714dc7c32350d5d7c 2. Callback can run on error. Fixes: 37701411397c7b7d709ae92abd347cc593940ee5 I *think* this happens when the cb() further up fails, and when a line following the [...] section header cannot be parsed. Worth fixing the separate bugs in separate patches?