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=-7.8 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,URIBL_SBL,URIBL_SBL_A,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 2150CC0650E for ; Mon, 1 Jul 2019 09:41:10 +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 E1F9F208C4 for ; Mon, 1 Jul 2019 09:41:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E1F9F208C4 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]:56520 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hhso8-0002kd-PN for qemu-devel@archiver.kernel.org; Mon, 01 Jul 2019 05:41:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51179) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hhsli-0008LC-8P for qemu-devel@nongnu.org; Mon, 01 Jul 2019 05:38:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hhslg-0006hf-Qv for qemu-devel@nongnu.org; Mon, 01 Jul 2019 05:38:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37091) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hhslg-00068X-KU for qemu-devel@nongnu.org; Mon, 01 Jul 2019 05:38:36 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4D3AB30872EE; Mon, 1 Jul 2019 09:37:54 +0000 (UTC) Received: from redhat.com (ovpn-112-60.ams2.redhat.com [10.36.112.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 750CD19C77; Mon, 1 Jul 2019 09:37:52 +0000 (UTC) Date: Mon, 1 Jul 2019 10:37:49 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: P J P Message-ID: <20190701093749.GE3573@redhat.com> References: <20190701090904.31312-1-ppandit@redhat.com> <20190701090904.31312-4-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190701090904.31312-4-ppandit@redhat.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Mon, 01 Jul 2019 09:37:54 +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: Re: [Qemu-devel] [PATCH v2 3/3] net: tap: restrict bridge name to IFNAMSIZ 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: Riccardo Schirone , Jason Wang , Li Qiang , Qemu Developers , Prasad J Pandit Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jul 01, 2019 at 02:39:04PM +0530, P J P wrote: > From: Prasad J Pandit > > The interface name in Linux interface request struct 'ifreq' > OR in qemu-bridge-helper is defined to be of size IFNAMSIZ(=16), > including the terminating null('\0') byte. > > QEMU tap device, while invoking qemu-bridge-helper, supplies bridge > name of 16 characters, restrict it to IFNAMESIZ-1 to accommodate > terminating null('\0') byte. > > Signed-off-by: Prasad J Pandit > --- > net/tap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/tap.c b/net/tap.c > index e8aadd8d4b..ca8536624c 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -499,7 +499,7 @@ static int net_bridge_run_helper(const char *helper, const char *bridge, > if (pid == 0) { > int open_max = sysconf(_SC_OPEN_MAX), i; > char fd_buf[6+10]; > - char br_buf[6+IFNAMSIZ] = {0}; > + char br_buf[5+IFNAMSIZ] = {0}; > char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15]; > > for (i = 3; i < open_max; i++) { Playing games with multiple "perfectly" sized static buffers & snprintf is madness. How about re-writing this method so that it just uses g_strdup_printf() to dynamically format the helper_cmd string. Alternatively we could get rid of the use of shell and directly exec the helper program. This would let us just pass argv[] and avoid the printf'ing entirely. 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 :|