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=-15.1 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,USER_AGENT_SANE_1 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 3E4DCC432BE for ; Wed, 1 Sep 2021 13:10:59 +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 D828C601FF for ; Wed, 1 Sep 2021 13:10:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D828C601FF 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]:44078 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mLQ13-0006M4-Ty for qemu-devel@archiver.kernel.org; Wed, 01 Sep 2021 09:10:57 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43326) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mLPsf-0008Hr-QR for qemu-devel@nongnu.org; Wed, 01 Sep 2021 09:02:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:54739) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mLPsW-0001u2-BP for qemu-devel@nongnu.org; Wed, 01 Sep 2021 09:02:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630501327; h=from:from:reply-to: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=36d7twqxIVPd10QfZ3xm4NjpdJXlzz3fh64p4Fuj2BU=; b=Lerfh7F3O8qNO7nxqo+gtGNmcvwDPI19IR4/9CYqtcEfoADBPKG3ArGmXIVUlXs+sWi9fQ qbEFZ5tSf5ZvOsk6y94VUQekLcsml3ZiT3YVR3c3NPv3jb70axJMa6Sj8bT3yskFubpppK j3bGO4zLjbF+LHK7FNd9XTFePPMYm18= 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-33-rrDNtaAMMh26A_o6kuJvQQ-1; Wed, 01 Sep 2021 09:02:04 -0400 X-MC-Unique: rrDNtaAMMh26A_o6kuJvQQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0136F1B2C983; Wed, 1 Sep 2021 13:02:03 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.162]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 350386ACED; Wed, 1 Sep 2021 13:01:56 +0000 (UTC) Date: Wed, 1 Sep 2021 14:01:53 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Michael Tokarev Subject: Re: [PATCH v2] qemu-sockets: fix unix socket path copy (again) Message-ID: References: <20210901125055.41915-1-mjt@msgid.tls.msk.ru> MIME-Version: 1.0 In-Reply-To: <20210901125055.41915-1-mjt@msgid.tls.msk.ru> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) DKIMWL_WL_HIGH=-0.392, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Peter Maydell Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Sep 01, 2021 at 03:50:55PM +0300, Michael Tokarev wrote: > Commit 4cfd970ec188558daa6214f26203fe553fb1e01f added an > assert which ensures the path within an address of a unix > socket returned from the kernel is at least one byte and > does not exceed sun_path buffer. Both of this constraints > are wrong: > > A unix socket can be unnamed, in this case the path is > completely empty (not even \0) > > And some implementations (notable linux) can add extra > trailing byte (\0) _after_ the sun_path buffer if we > passed buffer larger than it (and we do). > > So remove the assertion (since it causes real-life breakage) > but at the same time fix the usage of sun_path. Namely, > we should not access sun_path[0] if kernel did not return > it at all (this is the case for unnamed sockets), > and use the returned salen when copyig actual path as an > upper constraint for the amount of bytes to copy - this > will ensure we wont exceed the information provided by > the kernel, regardless whenever there is a trailing \0 > or not. This also helps with unnamed sockets. > > Note the case of abstract socket, the sun_path is actually > a blob and can contain \0 characters, - it should not be > passed to g_strndup and the like, it should be accessed by > memcpy-like functions. > > Fixes: 4cfd970ec188558daa6214f26203fe553fb1e01f > Fixes: http://bugs.debian.org/993145 > Signed-off-by: Michael Tokarev > CC: qemu-stable@nongnu.org > --- > util/qemu-sockets.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c > index f2f3676d1f..842bd707ac 100644 > --- a/util/qemu-sockets.c > +++ b/util/qemu-sockets.c > @@ -1345,13 +1345,11 @@ socket_sockaddr_to_address_unix(struct sockaddr_storage *sa, > SocketAddress *addr; > struct sockaddr_un *su = (struct sockaddr_un *)sa; > > - assert(salen >= sizeof(su->sun_family) + 1 && > - salen <= sizeof(struct sockaddr_un)); > - > addr = g_new0(SocketAddress, 1); > addr->type = SOCKET_ADDRESS_TYPE_UNIX; > + salen -= offsetof(struct sockaddr_un, sun_path); Adjusted salen value.... > #ifdef CONFIG_LINUX > - if (!su->sun_path[0]) { > + if (salen > 0 && !su->sun_path[0]) { > /* Linux abstract socket */ > addr->u.q_unix.path = g_strndup(su->sun_path + 1, > salen - sizeof(su->sun_family) - 1); ....still assuming the original salen value. > @@ -1363,7 +1361,7 @@ socket_sockaddr_to_address_unix(struct sockaddr_storage *sa, > } > #endif > > - addr->u.q_unix.path = g_strndup(su->sun_path, sizeof(su->sun_path)); > + addr->u.q_unix.path = g_strndup(su->sun_path, salen); > return addr; > } > #endif /* WIN32 */ Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|