From patchwork Tue Sep 27 08:19:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 1683052 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=UA59lVAb; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4McCpc37yJz1yq3 for ; Tue, 27 Sep 2022 18:44:08 +1000 (AEST) Received: from localhost ([::1]:49924 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1od6CE-00028q-3T for incoming@patchwork.ozlabs.org; Tue, 27 Sep 2022 04:44:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50866) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1od5oV-0005WA-LN for qemu-devel@nongnu.org; Tue, 27 Sep 2022 04:19:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:25148) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1od5oT-0000Jm-QU for qemu-devel@nongnu.org; Tue, 27 Sep 2022 04:19:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664266770; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=At+dbiBtzojIId+CkWfr7mFw/GiOsUbaxmGmx4H6iSE=; b=UA59lVAbxXI14S0Zjt9YzdZMNzwkyErjyBmjasCr5sIDA3BClHfWrR0h7fM/I6BJPsJd+P IMIS2vuL/UinZHWvwH8JSMYKZ9WYvOY9ih6pbujNACeWuGhuPUHwwA8xuD/rtt+c25QBjx CSfPDpjnqFdONIpS1hNBXoEDLJfTV/U= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-225-_vDPRKVsPFCNpEoD_mG3AA-1; Tue, 27 Sep 2022 04:19:26 -0400 X-MC-Unique: _vDPRKVsPFCNpEoD_mG3AA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 22DAF858282; Tue, 27 Sep 2022 08:19:26 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.192.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 56BF9404102C; Tue, 27 Sep 2022 08:19:25 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 892741800999; Tue, 27 Sep 2022 10:19:13 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Cc: Qiuhao Li , "Michael S. Tsirkin" , Stefan Hajnoczi , Eric Blake , Darren Kenny , Bandan Das , Alexander Bulekov , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Markus Armbruster , Akihiko Odaki , Alexandre Ratchov , Laurent Vivier , Paolo Bonzini , Thomas Huth , Gerd Hoffmann , Peter Maydell , Qiang Liu , Gaoning Pan Subject: [PULL 12/24] hcd-ohci: Drop ohci_service_iso_td() if ed->head & OHCI_DPTR_MASK is zero Date: Tue, 27 Sep 2022 10:19:00 +0200 Message-Id: <20220927081912.180983-13-kraxel@redhat.com> In-Reply-To: <20220927081912.180983-1-kraxel@redhat.com> References: <20220927081912.180983-1-kraxel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Qiang Liu An abort happens in ohci_frame_boundary() when ohci->done is 0 [1]. ``` c static void ohci_frame_boundary(void *opaque) { // ... if (ohci->done_count == 0 && !(ohci->intr_status & OHCI_INTR_WD)) { if (!ohci->done) abort(); <----------------------------------------- [1] ``` This was reported in https://bugs.launchpad.net/qemu/+bug/1911216/, https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg03613.html, and https://gitlab.com/qemu-project/qemu/-/issues/545. I can still reproduce it with the latest QEMU. This happends due to crafted ED with putting ISO_TD at physical address 0. Suppose ed->head & OHCI_DPTR_MASK is 0 [2], and we memset 0 to the phyiscal memory from 0 to sizeof(ohci_iso_td). Then, starting_frame [3] and frame_count [4] are both 0. As we can control the value of ohci->frame_number (0 to 0x1f, suppose 1), we then control the value of relative_frame_number to be 1 [6]. The control flow goes to [7] where ohci->done is 0. Have returned from ohci_service_iso_td(), ohci_frame_boundary() will abort() [1]. ``` c static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed) { // ... addr = ed->head & OHCI_DPTR_MASK; // <--------------------- [2] if (ohci_read_iso_td(ohci, addr, &iso_td)) { // <-------- [3] // ... starting_frame = OHCI_BM(iso_td.flags, TD_SF); // <-------- [4] frame_count = OHCI_BM(iso_td.flags, TD_FC); // <-------- [5] relative_frame_number = USUB(ohci->frame_number, starting_frame); // <-------- [6] if (relative_frame_number < 0) { return 1; } else if (relative_frame_number > frame_count) { // ... ohci->done = addr; // <-------- [7] // ... } ``` As only (afaik) a guest root user can manipulate ED, TD and the physical memory, this assertion failure is not a security bug. The idea to fix this issue is to drop ohci_service_iso_td() if ed->head & OHCI_DPTR_MASK is 0, which is similar to the drop operation for ohci_service_ed_list() when head is 0. Probably, a similar issue is in ohci_service_td(). I drop ohci_service_td() if ed->head & OHCI_DPTR_MASK is 0. Fixes: 7bfe577702 ("OHCI USB isochronous transfers support (Arnon Gilboa)") Reported-by: Gaoning Pan Reported-by: Alexander Bulekov Reported-by: Qiang Liu Resolves: https://gitlab.com/qemu-project/qemu/-/issues/545 Buglink: https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg03613.html Buglink: https://bugs.launchpad.net/qemu/+bug/1911216 Signed-off-by: Qiang Liu Message-Id: <20220826051557.119570-1-cyruscyliu@gmail.com> Signed-off-by: Gerd Hoffmann --- hw/usb/hcd-ohci.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c index 895b29fb8657..72bdde92617c 100644 --- a/hw/usb/hcd-ohci.c +++ b/hw/usb/hcd-ohci.c @@ -571,6 +571,11 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed) addr = ed->head & OHCI_DPTR_MASK; + if (addr == 0) { + ohci_die(ohci); + return 1; + } + if (ohci_read_iso_td(ohci, addr, &iso_td)) { trace_usb_ohci_iso_td_read_failed(addr); ohci_die(ohci); @@ -858,6 +863,11 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed) int completion; addr = ed->head & OHCI_DPTR_MASK; + if (addr == 0) { + ohci_die(ohci); + return 1; + } + /* See if this TD has already been submitted to the device. */ completion = (addr == ohci->async_td); if (completion && !ohci->async_complete) {