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[209.51.188.17]) by mx.google.com with ESMTPS id tn1-20020a05620a3c0100b007725a68ea34si5540633qkn.89.2023.09.18.01.35.40 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Sep 2023 01:35:40 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=DWxBeGIc; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qi9hO-0007z8-11; Mon, 18 Sep 2023 04:33:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qi9gK-0006ML-7H for qemu-devel@nongnu.org; Mon, 18 Sep 2023 04:32:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qi9gF-0004Ev-BQ for qemu-devel@nongnu.org; Mon, 18 Sep 2023 04:32:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695025949; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r4OySs/MlLnhS4aHMYzmzTaVrGn4YZ/1dItiYGgCXgg=; b=DWxBeGIcLpduop4V8vC2A4CDQjRBnYyy3ZE1UnSuzS4PeUdnsaBjbAiZgGcSo5tW611c6i QMvwR3O5+L5Xvt86+aAPzbB8wnWPsK7YnwLHb/gikibBXsICxK0ISMfb8QyM8eyHNVVd90 EE22eO9qLINKF+ImvZJC0KsB6ilBx0M= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-94-7YkuCCHPP2CSqpJKk4sd0A-1; Mon, 18 Sep 2023 04:32:25 -0400 X-MC-Unique: 7YkuCCHPP2CSqpJKk4sd0A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7B4C23806706; Mon, 18 Sep 2023 08:32:25 +0000 (UTC) Received: from localhost.localdomain (unknown [10.72.113.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id 78D8C2156701; Mon, 18 Sep 2023 08:32:23 +0000 (UTC) From: Jason Wang To: qemu-devel@nongnu.org Cc: Peter Maydell , Francisco Iglesias , Jason Wang Subject: [PULL V2 17/17] net/tap: Avoid variable-length array Date: Mon, 18 Sep 2023 16:31:32 +0800 Message-Id: <20230918083132.55423-18-jasowang@redhat.com> In-Reply-To: <20230918083132.55423-1-jasowang@redhat.com> References: <20230918083132.55423-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org From: Peter Maydell Use a heap allocation instead of a variable length array in tap_receive_iov(). The codebase has very few VLAs, and if we can get rid of them all we can make the compiler error on new additions. This is a defensive measure against security bugs where an on-stack dynamic allocation isn't correctly size-checked (e.g. CVE-2021-3527). Signed-off-by: Peter Maydell Reviewed-by: Francisco Iglesias Signed-off-by: Jason Wang --- net/tap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/tap.c b/net/tap.c index bcea8d0..c23d032 100644 --- a/net/tap.c +++ b/net/tap.c @@ -118,10 +118,11 @@ static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov, { TAPState *s = DO_UPCAST(TAPState, nc, nc); const struct iovec *iovp = iov; - struct iovec iov_copy[iovcnt + 1]; + g_autofree struct iovec *iov_copy = NULL; struct virtio_net_hdr_mrg_rxbuf hdr = { }; if (s->host_vnet_hdr_len && !s->using_vnet_hdr) { + iov_copy = g_new(struct iovec, iovcnt + 1); iov_copy[0].iov_base = &hdr; iov_copy[0].iov_len = s->host_vnet_hdr_len; memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));