From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5BB2AC77B61 for ; Fri, 28 Apr 2023 09:45:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1psKe7-0003Rm-4o; Fri, 28 Apr 2023 05:44:07 -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 1psKe4-0003RK-7a for qemu-devel@nongnu.org; Fri, 28 Apr 2023 05:44:05 -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 1psKe2-0007ZG-Dx for qemu-devel@nongnu.org; Fri, 28 Apr 2023 05:44:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1682675041; 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=cXaLpd203QwVJtQ9A6szekZJ+736OD/NuahYG+Yxquo=; b=fmyPSV5y8j0jkMev4mX4fSPcnoXmmNBXJbzb1MODnwiJc603xfHMU7KLDBY9Fv85fki5vd Jv9wP0qW/6YJ2UzWpQsTj4hub1mTf144kjnAQ4hwl7QOT25WOxkg6ht7AbD23DjIrTpFSk /yTrdb42ad9kgvNB4dXsbBG21aTals0= 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-462-vnS9hBzLPTa1WQAHCbmcnA-1; Fri, 28 Apr 2023 05:44:00 -0400 X-MC-Unique: vnS9hBzLPTa1WQAHCbmcnA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EB5FA10504A2; Fri, 28 Apr 2023 09:43:59 +0000 (UTC) Received: from thuth.com (unknown [10.39.192.94]) by smtp.corp.redhat.com (Postfix) with ESMTP id EC41C1410F1E; Fri, 28 Apr 2023 09:43:58 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Richard Henderson Cc: Alexander Bulekov Subject: [PULL 06/13] memory: prevent dma-reentracy issues Date: Fri, 28 Apr 2023 11:43:39 +0200 Message-Id: <20230428094346.1292054-7-thuth@redhat.com> In-Reply-To: <20230428094346.1292054-1-thuth@redhat.com> References: <20230428094346.1292054-1-thuth@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.171, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Alexander Bulekov Add a flag to the DeviceState, when a device is engaged in PIO/MMIO/DMA. This flag is set/checked prior to calling a device's MemoryRegion handlers, and set when device code initiates DMA. The purpose of this flag is to prevent two types of DMA-based reentrancy issues: 1.) mmio -> dma -> mmio case 2.) bh -> dma write -> mmio case These issues have led to problems such as stack-exhaustion and use-after-frees. Summary of the problem from Peter Maydell: https://lore.kernel.org/qemu-devel/CAFEAcA_23vc7hE3iaM-JVA6W38LK4hJoWae5KcknhPRD5fPBZA@mail.gmail.com Resolves: https://gitlab.com/qemu-project/qemu/-/issues/62 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/540 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/541 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/556 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/557 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/827 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1282 Resolves: CVE-2023-0330 Signed-off-by: Alexander Bulekov Reviewed-by: Thomas Huth Message-Id: <20230427211013.2994127-2-alxndr@bu.edu> [thuth: Replace warn_report() with warn_report_once()] Signed-off-by: Thomas Huth --- include/exec/memory.h | 5 +++++ include/hw/qdev-core.h | 7 +++++++ softmmu/memory.c | 16 ++++++++++++++++ 3 files changed, 28 insertions(+) diff --git a/include/exec/memory.h b/include/exec/memory.h index 15ade918ba..e45ce6061f 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -767,6 +767,8 @@ struct MemoryRegion { bool is_iommu; RAMBlock *ram_block; Object *owner; + /* owner as TYPE_DEVICE. Used for re-entrancy checks in MR access hotpath */ + DeviceState *dev; const MemoryRegionOps *ops; void *opaque; @@ -791,6 +793,9 @@ struct MemoryRegion { unsigned ioeventfd_nb; MemoryRegionIoeventfd *ioeventfds; RamDiscardManager *rdm; /* Only for RAM */ + + /* For devices designed to perform re-entrant IO into their own IO MRs */ + bool disable_reentrancy_guard; }; struct IOMMUMemoryRegion { diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index bd50ad5ee1..7623703943 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -162,6 +162,10 @@ struct NamedClockList { QLIST_ENTRY(NamedClockList) node; }; +typedef struct { + bool engaged_in_io; +} MemReentrancyGuard; + /** * DeviceState: * @realized: Indicates whether the device has been fully constructed. @@ -194,6 +198,9 @@ struct DeviceState { int alias_required_for_version; ResettableState reset; GSList *unplug_blockers; + + /* Is the device currently in mmio/pio/dma? Used to prevent re-entrancy */ + MemReentrancyGuard mem_reentrancy_guard; }; struct DeviceListener { diff --git a/softmmu/memory.c b/softmmu/memory.c index b1a6cae6f5..b7b3386e9d 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -542,6 +542,18 @@ static MemTxResult access_with_adjusted_size(hwaddr addr, access_size_max = 4; } + /* Do not allow more than one simultaneous access to a device's IO Regions */ + if (mr->dev && !mr->disable_reentrancy_guard && + !mr->ram_device && !mr->ram && !mr->rom_device && !mr->readonly) { + if (mr->dev->mem_reentrancy_guard.engaged_in_io) { + warn_report_once("Blocked re-entrant IO on MemoryRegion: " + "%s at addr: 0x%" HWADDR_PRIX, + memory_region_name(mr), addr); + return MEMTX_ACCESS_ERROR; + } + mr->dev->mem_reentrancy_guard.engaged_in_io = true; + } + /* FIXME: support unaligned access? */ access_size = MAX(MIN(size, access_size_max), access_size_min); access_mask = MAKE_64BIT_MASK(0, access_size * 8); @@ -556,6 +568,9 @@ static MemTxResult access_with_adjusted_size(hwaddr addr, access_mask, attrs); } } + if (mr->dev) { + mr->dev->mem_reentrancy_guard.engaged_in_io = false; + } return r; } @@ -1170,6 +1185,7 @@ static void memory_region_do_init(MemoryRegion *mr, } mr->name = g_strdup(name); mr->owner = owner; + mr->dev = (DeviceState *) object_dynamic_cast(mr->owner, TYPE_DEVICE); mr->ram_block = NULL; if (name) { -- 2.31.1