From patchwork Mon Nov 28 20:27:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= X-Patchwork-Id: 13057926 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 D8B6DC47088 for ; Mon, 28 Nov 2022 20:28:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ozkjl-0002p5-Sj; Mon, 28 Nov 2022 15:28:21 -0500 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 1ozkjl-0002oo-5d for qemu-devel@nongnu.org; Mon, 28 Nov 2022 15:28:21 -0500 Received: from mail-wm1-x32f.google.com ([2a00:1450:4864:20::32f]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ozkjV-00029V-M9 for qemu-devel@nongnu.org; Mon, 28 Nov 2022 15:28:20 -0500 Received: by mail-wm1-x32f.google.com with SMTP id l39-20020a05600c1d2700b003cf93c8156dso9251298wms.4 for ; Mon, 28 Nov 2022 12:28:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=vyIB5NjZrVPmAFslKBgckP8KrUdTCBt+mgHvj7bYx9E=; b=f0prDy1f8r7Si5+D/mIq8FAI+n1Vw3E3oqEHeDYogYddgxop9A0scJVRpWG2o+Xj4R 3kYhs4eu10o4uyYAtWvL8270N4jz5r/isJvqk550JLQYXNMiucp+IXqaKNkxQ1HW7rK2 k97VpcWgoNg1kZLJ8G+d+QAdmkQcYCwpPBeyh+tOcv9dl9/A0gwrLFuzbFOF3FzD4HsU 8lqOXqVz1bqP/M4D70IfjkeB9F91O3mkILQbUOBLm1CLSTi88A3+77z6eRz8h+lF81Us oAZc+ps/Aveh69y3xlHLdrPx3YxKMncptFMRFQclVO3utK6zkY53//wk2WvAHtmxSZ1g 2lLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=vyIB5NjZrVPmAFslKBgckP8KrUdTCBt+mgHvj7bYx9E=; b=ub72XYHa4NUhWLA2BS3ofncuVFfKNCoyevF5MboGMTTLk7twmbWxC7RFCDWJKznfAo jxci8OwnedFZmdNYTqBJziNbWREU3XXawE0EOdkZjdulC2HQWAMpcLzVr89W66o0xbDf tHp7mvK/EVCmYp6R+B4hOQ7Mvi0+iMuTUyOD3hYzZJrtfNUjEZj+/3Pu3tICBCxHUMp4 bArdmejYFuWQ/CC7ZmijzpZ9ouf1YirW7gpbfQsqUs4NCSZ4a445//RaZPfcIhGZjgh7 19jhvcMxOFB2/1IRXOrwHEAxZj3hi5MNGx6ySrEVLMWY373OZp+S65lewG2x8TMbA/5Y RoQQ== X-Gm-Message-State: ANoB5pm9PgyflxSVREg7toz9blR6UgCk9X33q+GiwqLY3U3rxYEcqSna ZA9M61ot7qYvRWstOBu2s3msFG7H5bsOkw== X-Google-Smtp-Source: AA0mqf4a6R3uV9fGqedkgrJF5l4xvW4G+o1JM5E6I1hw/U5Q4N0WsdpJZrAldZ2RVH7A5u3hy/VCmQ== X-Received: by 2002:a7b:c8c3:0:b0:3cf:b49e:1638 with SMTP id f3-20020a7bc8c3000000b003cfb49e1638mr28554163wml.50.1669667284133; Mon, 28 Nov 2022 12:28:04 -0800 (PST) Received: from localhost.localdomain ([185.126.107.38]) by smtp.gmail.com with ESMTPSA id a7-20020a05600c348700b003cf75f56105sm18096809wmq.41.2022.11.28.12.28.03 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 28 Nov 2022 12:28:03 -0800 (PST) From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org, =?utf-8?q?Marc-Andr=C3=A9_Lureau?= Cc: Alexander Bulekov , Paolo Bonzini , Gerd Hoffmann , Peter Maydell , Mauro Matteo Cascella , =?utf-8?q?Philippe_Mathieu-Dau?= =?utf-8?q?d=C3=A9?= Subject: [RFC PATCH-for-7.2 v3 4/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144) Date: Mon, 28 Nov 2022 21:27:40 +0100 Message-Id: <20221128202741.4945-5-philmd@linaro.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221128202741.4945-1-philmd@linaro.org> References: <20221128202741.4945-1-philmd@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32f; envelope-from=philmd@linaro.org; helo=mail-wm1-x32f.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, T_SPF_HELO_TEMPERROR=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 Have qxl_get_check_slot_offset() return false if the requested buffer size does not fit within the slot memory region. Similarly qxl_phys2virt() now returns NULL in such case, and qxl_dirty_one_surface() aborts. This avoids buffer overrun in the host pointer returned by memory_region_get_ram_ptr(). Fixes: CVE-2022-4144 (out-of-bounds read) Reported-by: Wenxu Yin (@awxylitol) Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1336 Signed-off-by: Philippe Mathieu-Daudé --- hw/display/qxl.c | 27 +++++++++++++++++++++++---- hw/display/qxl.h | 2 +- 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/hw/display/qxl.c b/hw/display/qxl.c index 231d733250..0b21626aad 100644 --- a/hw/display/qxl.c +++ b/hw/display/qxl.c @@ -1424,11 +1424,13 @@ static void qxl_reset_surfaces(PCIQXLDevice *d) /* can be also called from spice server thread context */ static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, - uint32_t *s, uint64_t *o) + uint32_t *s, uint64_t *o, + size_t size_requested) { uint64_t phys = le64_to_cpu(pqxl); uint32_t slot = (phys >> (64 - 8)) & 0xff; uint64_t offset = phys & 0xffffffffffff; + uint64_t size_available; if (slot >= NUM_MEMSLOTS) { qxl_set_guest_bug(qxl, "slot too large %d >= %d", slot, @@ -1452,6 +1454,23 @@ static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, slot, offset, qxl->guest_slots[slot].size); return false; } + size_available = memory_region_size(qxl->guest_slots[slot].mr); + if (qxl->guest_slots[slot].offset + offset >= size_available) { + qxl_set_guest_bug(qxl, + "slot %d offset %"PRIu64" > region size %"PRIu64"\n", + slot, qxl->guest_slots[slot].offset + offset, + size_available); + return false; + } + size_available -= qxl->guest_slots[slot].offset + offset; + if (size_requested > size_available) { + qxl_set_guest_bug(qxl, + "slot %d offset %"PRIu64" size %zu: " + "overrun by %"PRIu64" bytes\n", + slot, offset, size_requested, + size_requested - size_available); + return false; + } *s = slot; *o = offset; @@ -1471,7 +1490,7 @@ void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id, offset = le64_to_cpu(pqxl) & 0xffffffffffff; return (void *)(intptr_t)offset; case MEMSLOT_GROUP_GUEST: - if (!qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset)) { + if (!qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset, size)) { return NULL; } ptr = memory_region_get_ram_ptr(qxl->guest_slots[slot].mr); @@ -1937,9 +1956,9 @@ static void qxl_dirty_one_surface(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, uint32_t slot; bool rc; - rc = qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset); - assert(rc == true); size = (uint64_t)height * abs(stride); + rc = qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset, size); + assert(rc == true); trace_qxl_surfaces_dirty(qxl->id, offset, size); qxl_set_dirty(qxl->guest_slots[slot].mr, qxl->guest_slots[slot].offset + offset, diff --git a/hw/display/qxl.h b/hw/display/qxl.h index bf03138ab4..7894bd5134 100644 --- a/hw/display/qxl.h +++ b/hw/display/qxl.h @@ -157,7 +157,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL) * * Returns a host pointer to a buffer placed at offset @phys within the * active slot @group_id of the PCI VGA RAM memory region associated with - * the @qxl device. If the slot is inactive, or the offset is out + * the @qxl device. If the slot is inactive, or the offset + size are out * of the memory region, returns NULL. * * Use with care; by the time this function returns, the returned pointer is