From patchwork Tue Dec 4 03:53:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 1007419 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4387LQ6ychz9s55 for ; Tue, 4 Dec 2018 14:55:26 +1100 (AEDT) Received: from localhost ([::1]:53867 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gU1nw-0006sD-J9 for incoming@patchwork.ozlabs.org; Mon, 03 Dec 2018 22:55:24 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41250) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gU1n7-0006q9-VE for qemu-devel@nongnu.org; Mon, 03 Dec 2018 22:54:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gU1n5-0005gr-EZ for qemu-devel@nongnu.org; Mon, 03 Dec 2018 22:54:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50282) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gU1n4-0005TV-I3; Mon, 03 Dec 2018 22:54:31 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1B9173082130; Tue, 4 Dec 2018 03:54:12 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-125.pek2.redhat.com [10.72.12.125]) by smtp.corp.redhat.com (Postfix) with ESMTP id D8A7B6013F; Tue, 4 Dec 2018 03:54:06 +0000 (UTC) From: Jason Wang To: qemu-devel@nongnu.org, peter.maydell@linaro.org Date: Tue, 4 Dec 2018 11:53:43 +0800 Message-Id: <20181204035347.6148-2-jasowang@redhat.com> In-Reply-To: <20181204035347.6148-1-jasowang@redhat.com> References: <20181204035347.6148-1-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 04 Dec 2018 03:54:12 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH V5 for 3.1 1/5] net: drop too large packet early X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thuth@redhat.com, mst@redhat.com, liq3ea@163.com, Jason Wang , liq3ea@gmail.com, qemu-stable@nongnu.org, ppandit@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" We try to detect and drop too large packet (>INT_MAX) in 1592a9947036 ("net: ignore packet size greater than INT_MAX") during packet delivering. Unfortunately, this is not sufficient as we may hit another integer overflow when trying to queue such large packet in qemu_net_queue_append_iov(): - size of the allocation may overflow on 32bit - packet->size is integer which may overflow even on 64bit Fixing this by moving the check to qemu_sendv_packet_async() which is the entrance of all networking codes and reduce the limit to NET_BUFSIZE to be more conservative. This works since: - For the callers that call qemu_sendv_packet_async() directly, they only care about if zero is returned to determine whether to prevent the source from producing more packets. A callback will be triggered if peer can accept more then source could be enabled. This is usually used by high speed networking implementation like virtio-net or netmap. - For the callers that call qemu_sendv_packet() that calls qemu_sendv_packet_async() indirectly, they often ignore the return value. In this case qemu will just the drop packets if peer can't receive. Qemu will copy the packet if it was queued. So it was safe for both kinds of the callers to assume the packet was sent. Since we move the check from qemu_deliver_packet_iov() to qemu_sendv_packet_async(), it would be safer to make qemu_deliver_packet_iov() static to prevent any external user in the future. This is a revised patch of CVE-2018-17963. Cc: qemu-stable@nongnu.org Cc: Li Qiang Fixes: 1592a9947036 ("net: ignore packet size greater than INT_MAX") Reported-by: Li Qiang Reviewed-by: Li Qiang Signed-off-by: Jason Wang Reviewed-by: Thomas Huth --- include/net/net.h | 6 ------ net/net.c | 28 +++++++++++++++++----------- 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/include/net/net.h b/include/net/net.h index 7936d53d2f..ec13702dbf 100644 --- a/include/net/net.h +++ b/include/net/net.h @@ -169,12 +169,6 @@ void qemu_check_nic_model(NICInfo *nd, const char *model); int qemu_find_nic_model(NICInfo *nd, const char * const *models, const char *default_model); -ssize_t qemu_deliver_packet_iov(NetClientState *sender, - unsigned flags, - const struct iovec *iov, - int iovcnt, - void *opaque); - void print_net_client(Monitor *mon, NetClientState *nc); void hmp_info_network(Monitor *mon, const QDict *qdict); void net_socket_rs_init(SocketReadState *rs, diff --git a/net/net.c b/net/net.c index 07c194a8f6..1f7d626197 100644 --- a/net/net.c +++ b/net/net.c @@ -231,6 +231,11 @@ static void qemu_net_client_destructor(NetClientState *nc) { g_free(nc); } +static ssize_t qemu_deliver_packet_iov(NetClientState *sender, + unsigned flags, + const struct iovec *iov, + int iovcnt, + void *opaque); static void qemu_net_client_setup(NetClientState *nc, NetClientInfo *info, @@ -705,22 +710,18 @@ static ssize_t nc_sendv_compat(NetClientState *nc, const struct iovec *iov, return ret; } -ssize_t qemu_deliver_packet_iov(NetClientState *sender, - unsigned flags, - const struct iovec *iov, - int iovcnt, - void *opaque) +static ssize_t qemu_deliver_packet_iov(NetClientState *sender, + unsigned flags, + const struct iovec *iov, + int iovcnt, + void *opaque) { NetClientState *nc = opaque; - size_t size = iov_size(iov, iovcnt); int ret; - if (size > INT_MAX) { - return size; - } if (nc->link_down) { - return size; + return iov_size(iov, iovcnt); } if (nc->receive_disabled) { @@ -745,10 +746,15 @@ ssize_t qemu_sendv_packet_async(NetClientState *sender, NetPacketSent *sent_cb) { NetQueue *queue; + size_t size = iov_size(iov, iovcnt); int ret; + if (size > NET_BUFSIZE) { + return size; + } + if (sender->link_down || !sender->peer) { - return iov_size(iov, iovcnt); + return size; } /* Let filters handle the packet first */