From patchwork Mon May 30 07:09:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 9140335 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B64AC60759 for ; Mon, 30 May 2016 07:16:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A89F9280B2 for ; Mon, 30 May 2016 07:16:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9D904281FE; Mon, 30 May 2016 07:16:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.9 required=2.0 tests=BAYES_00,FSL_HELO_HOME, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2A188280B2 for ; Mon, 30 May 2016 07:16:45 +0000 (UTC) Received: from localhost ([::1]:58262 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7HRM-0005YY-9N for patchwork-qemu-devel@patchwork.kernel.org; Mon, 30 May 2016 03:16:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50035) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7HKX-0008BG-Jq for qemu-devel@nongnu.org; Mon, 30 May 2016 03:09:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b7HKR-0001lw-1Y for qemu-devel@nongnu.org; Mon, 30 May 2016 03:09:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50353) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b7HKQ-0001la-SN for qemu-devel@nongnu.org; Mon, 30 May 2016 03:09:34 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AE389C0467F2; Mon, 30 May 2016 07:09:32 +0000 (UTC) Received: from nilsson.home.kraxel.org (ovpn-116-35.ams2.redhat.com [10.36.116.35]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u4U79VeD007170; Mon, 30 May 2016 03:09:32 -0400 Received: by nilsson.home.kraxel.org (Postfix, from userid 500) id CCED58194C; Mon, 30 May 2016 09:09:30 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Mon, 30 May 2016 09:09:18 +0200 Message-Id: <1464592161-18348-2-git-send-email-kraxel@redhat.com> In-Reply-To: <1464592161-18348-1-git-send-email-kraxel@redhat.com> References: <1464592161-18348-1-git-send-email-kraxel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 30 May 2016 07:09:34 +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: [Qemu-devel] [PATCH 1/4] vmsvga: move fifo sanity checks to vmsvga_fifo_length 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: =?UTF-8?q?=E6=9D=8E=E5=BC=BA?= , Gerd Hoffmann , P J P Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Sanity checks are applied when the fifo is enabled by the guest (SVGA_REG_CONFIG_DONE write). Which doesn't help much if the guest changes the fifo registers afterwards. Move the checks to vmsvga_fifo_length so they are done each time qemu is about to read from the fifo. Fixes: CVE-2016-4454 Cc: P J P Reported-by: 李强 Signed-off-by: Gerd Hoffmann --- hw/display/vmware_vga.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/hw/display/vmware_vga.c b/hw/display/vmware_vga.c index 0c63fa8..63a7c05 100644 --- a/hw/display/vmware_vga.c +++ b/hw/display/vmware_vga.c @@ -555,6 +555,21 @@ static inline int vmsvga_fifo_length(struct vmsvga_state_s *s) if (!s->config || !s->enable) { return 0; } + + /* Check range and alignment. */ + if ((CMD(min) | CMD(max) | CMD(next_cmd) | CMD(stop)) & 3) { + return 0; + } + if (CMD(min) < (uint8_t *) s->cmd->fifo - (uint8_t *) s->fifo) { + return 0; + } + if (CMD(max) > SVGA_FIFO_SIZE) { + return 0; + } + if (CMD(max) < CMD(min) + 10 * 1024) { + return 0; + } + num = CMD(next_cmd) - CMD(stop); if (num < 0) { num += CMD(max) - CMD(min); @@ -1005,19 +1020,6 @@ static void vmsvga_value_write(void *opaque, uint32_t address, uint32_t value) case SVGA_REG_CONFIG_DONE: if (value) { s->fifo = (uint32_t *) s->fifo_ptr; - /* Check range and alignment. */ - if ((CMD(min) | CMD(max) | CMD(next_cmd) | CMD(stop)) & 3) { - break; - } - if (CMD(min) < (uint8_t *) s->cmd->fifo - (uint8_t *) s->fifo) { - break; - } - if (CMD(max) > SVGA_FIFO_SIZE) { - break; - } - if (CMD(max) < CMD(min) + 10 * 1024) { - break; - } vga_dirty_log_stop(&s->vga); } s->config = !!value;