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=-10.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 5EBFDC432BE for ; Tue, 31 Aug 2021 17:26:55 +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 E94BF610A4 for ; Tue, 31 Aug 2021 17:26:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E94BF610A4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:36244 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mL7XC-0004Vo-5u for qemu-devel@archiver.kernel.org; Tue, 31 Aug 2021 13:26:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53814) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mL7Sx-0008Ot-G9 for qemu-devel@nongnu.org; Tue, 31 Aug 2021 13:22:31 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:36801) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mL7Sv-0006Cn-Nq for qemu-devel@nongnu.org; Tue, 31 Aug 2021 13:22:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630430548; 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=2IKPzZVh2vUSM0lXoWaU94FE+1ThRkyEvfpsdfcrEO8=; b=EkiSb/yMVIZROvPpYawA8iHhUDtBFXVX8nKM1HJyYKuBc7hT9SQ7/xOIPxWVTwoysDoaqt TujUiJxsoEItB17n9f51pxQ9dRE47XaEmVK+If7RSxRnKkauPRBvhOBnuUg46YpwS3t5W4 UBRqRA4rl8puTcdybdYQpCy4/QUrVIc= Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-234-gzh54I_nObyFTAQm3bQq_g-1; Tue, 31 Aug 2021 13:22:13 -0400 X-MC-Unique: gzh54I_nObyFTAQm3bQq_g-1 Received: by mail-pf1-f197.google.com with SMTP id v65-20020a627a44000000b003f286b054cbso1891583pfc.11 for ; Tue, 31 Aug 2021 10:22:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2IKPzZVh2vUSM0lXoWaU94FE+1ThRkyEvfpsdfcrEO8=; b=MwUaQfb/fB4oYGuZku+/YqDUZMsFm0a3oTxG+Ezs7jQpRfzEVvdthNht4kn4kbZEsN KxMS/16nHYwG/sBQlGXYnuvzbat/zCbeYgiv0WKAp+z+Pw5RuyPL8upo0ON2E5DvbH4c oMMvTFww/51XXqlTDAD+TFDxekAl7qXnvO0iqMT0TshPlu8q3SJz7gscGDxnQ/UVbFui DLfwyW1ju48ZpfLni3rgMYQzH4PlbtfOEVht7apk1k+lU7olNHXyXUkQG8KbAOyxdaVd 1y/rAnFhYb+gEgApkJElv7lOtUYPrD3nC0Nt719p6FtwOAsqUAJ6SsZGH3hCGzhDHzuD CpDw== X-Gm-Message-State: AOAM531YMNeuZUHb2LyCpFkOw05xLb2UdLuuWuxUqfvkTD9jcWclz0iu KyDZheDvaZq4ByV+OtTP4yJuBUAO102opGKym45CNWwpVMmglOM1sctmfvMsR7Zqqc5tiqybsZs n6a1KK+ZoWkwJT+FejfPyv7aaPj1BRRE= X-Received: by 2002:a17:90a:c798:: with SMTP id gn24mr6453130pjb.97.1630430532400; Tue, 31 Aug 2021 10:22:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzBXQbuAeNj37UjTiDFPQJnsfmnCuiJg4pFRyA0lvbW+9mbmzMXN9sRyPkpeZPbjLPmXhCB5T1FGPsSn96lq8s= X-Received: by 2002:a17:90a:c798:: with SMTP id gn24mr6453110pjb.97.1630430532120; Tue, 31 Aug 2021 10:22:12 -0700 (PDT) MIME-Version: 1.0 References: <20210830225449.1509719-1-mjt@msgid.tls.msk.ru> In-Reply-To: From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Tue, 31 Aug 2021 21:22:01 +0400 Message-ID: Subject: Re: qemu-sockets: account for trailing \0 byte in unix socket pathname To: Michael Tokarev Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlureau@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/alternative; boundary="000000000000b2ca2e05cade3041" Received-SPF: pass client-ip=170.10.133.124; envelope-from=mlureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.391, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= , qemu-devel , qemu-stable Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --000000000000b2ca2e05cade3041 Content-Type: text/plain; charset="UTF-8" Hi On Tue, Aug 31, 2021 at 9:17 PM Michael Tokarev wrote: > 31.08.2021 01:54, Michael Tokarev wrote: > > Linux kernel can return size of af_unix socket to be > > one byte larger than sockaddr_un structure - adding > > the trailing zero byte. > > > > Signed-off-by: Michael Tokarev > > Fixes: 4cfd970ec188558daa6214f26203fe553fb1e01f (first in 6.1.0) > > Cc: qemu-stable@nongnu.org > > > > diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c > > index f2f3676d1f..83926dc2bc 100644 > > --- a/util/qemu-sockets.c > > +++ b/util/qemu-sockets.c > > @@ -1345,8 +1345,9 @@ socket_sockaddr_to_address_unix(struct > sockaddr_storage *sa, > > SocketAddress *addr; > > struct sockaddr_un *su = (struct sockaddr_un *)sa; > > > > + /* kernel might have added \0 terminator to non-abstract socket */ > > assert(salen >= sizeof(su->sun_family) + 1 && > > - salen <= sizeof(struct sockaddr_un)); > > + salen <= sizeof(struct sockaddr_un) + su->sun_path[0] ? 1 : > 0); > > > > addr = g_new0(SocketAddress, 1); > > addr->type = SOCKET_ADDRESS_TYPE_UNIX; > > Actually, this is not sufficient. > > While this change fixes one issue (the famous trailing null byte \0), > the actual assertion failure occurs because salen = 2, ie, too SMALL, > not too large. > > So it looks like libvirt provides an unnamed socket there, -- > maybe from a socketpair(2)? > Yes Ok, I guess it should still check for salen >= sizeof(su->sun_family) and then modify if (salen > sizeof(su->sun_family) && !su->sun_path[0]) { > Hwell.. > hmm, too bad we didn't catch it during RC! (strange that it seems to hit Debian libvirt/virt-manager users and apparently not on Fedora) --000000000000b2ca2e05cade3041 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi

On Tue, Aug 31, 2021 at 9:17 PM Mic= hael Tokarev <mjt@tls.msk.ru> w= rote:
31.08.2021= 01:54, Michael Tokarev wrote:
> Linux kernel can return size of af_unix socket to be
> one byte larger than sockaddr_un structure - adding
> the trailing zero byte.
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> Fixes: 4cfd970ec188558daa6214f26203fe553fb1e01f (first in 6.1.0)
> Cc: qemu-s= table@nongnu.org
>
> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
> index f2f3676d1f..83926dc2bc 100644
> --- a/util/qemu-sockets.c
> +++ b/util/qemu-sockets.c
> @@ -1345,8 +1345,9 @@ socket_sockaddr_to_address_unix(struct sockaddr_= storage *sa,
>=C2=A0 =C2=A0 =C2=A0 =C2=A0SocketAddress *addr;
>=C2=A0 =C2=A0 =C2=A0 =C2=A0struct sockaddr_un *su =3D (struct sockaddr_= un *)sa;
>=C2=A0 =C2=A0
> +=C2=A0 =C2=A0 /* kernel might have added \0 terminator to non-abstrac= t socket */
>=C2=A0 =C2=A0 =C2=A0 =C2=A0assert(salen >=3D sizeof(su->sun_famil= y) + 1 &&
> -=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0salen <=3D sizeof(struct = sockaddr_un));
> +=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0salen <=3D sizeof(struct = sockaddr_un) + su->sun_path[0] ? 1 : 0);
>=C2=A0 =C2=A0
>=C2=A0 =C2=A0 =C2=A0 =C2=A0addr =3D g_new0(SocketAddress, 1);
>=C2=A0 =C2=A0 =C2=A0 =C2=A0addr->type =3D SOCKET_ADDRESS_TYPE_UNIX;<= br>
Actually, this is not sufficient.

While this change fixes one issue (the famous trailing null byte \0),
the actual assertion failure occurs because salen =3D 2, ie, too SMALL,
not too large.

So it looks like libvirt provides an unnamed socket there, --
maybe from a socketpair(2)?

Yes

Ok, I guess it should still check for salen >=3D s= izeof(su->sun_family)

and then modify if (salen= > sizeof(su->sun_family) && !su->sun_path[0]) {


Hwell..

hmm, too bad we didn't catc= h it during RC!

(strange that it seems to hit= Debian libvirt/virt-manager users and apparently not on Fedora)
<= /div>
--000000000000b2ca2e05cade3041--