From patchwork Thu Feb 4 08:31:33 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 578712 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id BFDEA140AD9 for ; Thu, 4 Feb 2016 19:33:55 +1100 (AEDT) Received: from localhost ([::1]:40234 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRFMP-00024l-Rk for incoming@patchwork.ozlabs.org; Thu, 04 Feb 2016 03:33:53 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34986) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRFL8-0007Zi-Tj for qemu-devel@nongnu.org; Thu, 04 Feb 2016 03:32:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aRFKq-0007Yv-Ua for qemu-devel@nongnu.org; Thu, 04 Feb 2016 03:32:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51841) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRFKq-0007Yd-MZ for qemu-devel@nongnu.org; Thu, 04 Feb 2016 03:32:16 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 5871F859F8; Thu, 4 Feb 2016 08:32:16 +0000 (UTC) Received: from jason-ThinkPad-T430s.redhat.com (vpn1-7-60.pek2.redhat.com [10.72.7.60]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u148VnLG022765; Thu, 4 Feb 2016 03:32:12 -0500 From: Jason Wang To: peter.maydell@linaro.org, qemu-devel@nongnu.org Date: Thu, 4 Feb 2016 16:31:33 +0800 Message-Id: <1454574706-5681-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1454574706-5681-1-git-send-email-jasowang@redhat.com> References: <1454574706-5681-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Jason Wang , "Michael S. Tsirkin" Subject: [Qemu-devel] [PULL V2 04/17] cadence_gem: fix buffer overflow X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: "Michael S. Tsirkin" gem_transmit copies a packet from guest into an tx_packet[2048] array on stack, with size limited by descriptor length set by guest. If guest is malicious and specifies a descriptor length that is too large, and should packet size exceed array size, this results in a buffer overflow. Reported-by: 刘令 Signed-off-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/net/cadence_gem.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c index e513d9d..0346f3e 100644 --- a/hw/net/cadence_gem.c +++ b/hw/net/cadence_gem.c @@ -867,6 +867,14 @@ static void gem_transmit(CadenceGEMState *s) break; } + if (tx_desc_get_length(desc) > sizeof(tx_packet) - (p - tx_packet)) { + DB_PRINT("TX descriptor @ 0x%x too large: size 0x%x space 0x%x\n", + (unsigned)packet_desc_addr, + (unsigned)tx_desc_get_length(desc), + sizeof(tx_packet) - (p - tx_packet)); + break; + } + /* Gather this fragment of the packet from "dma memory" to our contig. * buffer. */