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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 63B63ECAAA1 for ; Fri, 16 Sep 2022 15:55:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4697F10E3FF; Fri, 16 Sep 2022 15:55:00 +0000 (UTC) Received: from mail-ej1-x62f.google.com (mail-ej1-x62f.google.com [IPv6:2a00:1450:4864:20::62f]) by gabe.freedesktop.org (Postfix) with ESMTPS id 04BBF10E3FF; Fri, 16 Sep 2022 15:54:56 +0000 (UTC) Received: by mail-ej1-x62f.google.com with SMTP id bj12so50294872ejb.13; Fri, 16 Sep 2022 08:54:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=EuWFWN26twjl6pnBL7u1oZiY5YRuiq7q1++u96G3pgY=; b=EoQJiVAYTrd4M3+DKqSvM9nCwEIljCqrB31LX/Mf3YTd9IN1mXiqpwdfmYb1HmzhSF hBXK9YQ4RNqyZzeDWzGuAExSL8cI7LfiyjoHgtvsnZmoTCP0xOrpNd+c46PDGFtKDrft arPkvo2nWfkQBevvVRQORFApZ7E1ncEhBKau6WEfbADES93CreFsNJaTUq2Cb3uUhb1G MoF0+YsZKJ04z84ZAfyGHcwhZIYZEMzvjx+l2SfhjkDO4OLQpIXjsNG684fnZ9HP5Y2z PBq0MP9cq0SS8L/cQGrLrtmJHJZCn04wDe3dVYkHhYn68gk8mi9PfgIMl7NNv8ut9uTM jIzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=EuWFWN26twjl6pnBL7u1oZiY5YRuiq7q1++u96G3pgY=; b=HcXQpTwiHBqNTnMrXCjjuDw9e+nX3KykB/IxW0pAnODYhlqcEUmTWiEeXt7/XIJeXw cQA/gX9uZyrzxj5NVUTkpoMAS/Fc3F0SC1bLN6dE5ynt+Q1C7E+ZC2ZKs/okPRg5zRej FsZaXXH26tMVjTSUrEIXoZ3fI9nkkfI33t3pjXhVKGlPXiZzsKhuKR90LdqCK+eL+iGj KRVFhsdh1ST9tFnr0KwhA20H7kkdweGRyKMVbF3gbWAO+OO/qffcpLCElIbt5QWZJWAw LfRIBeMAl3NXVGJb6QxhU8unSHF1h48G1wvSKnngeS8ZDUyjT1Vz3ssw/Uqj6Kj3xpfL ax6Q== X-Gm-Message-State: ACrzQf2Oc3xat3DRYbnOE76F7g5MtFVmX7zktPKDSfqEILXYP9kXSXcM n5B17LvfS1o4sL/sQg1g8UfRDyT0ryutbMdrYjspTHxfJsv1oDz0 X-Google-Smtp-Source: AMsMyM5S2RFtr9n8n8rdNH6foyfaJk78kYuOTBmn+L2hXS5/Y0XV9NEVfOYZSy1QOWTfM/qwcuFWq3lkxQaCptutRsM= X-Received: by 2002:a17:906:8a77:b0:780:a02d:ca4a with SMTP id hy23-20020a1709068a7700b00780a02dca4amr2848192ejc.488.1663343694459; Fri, 16 Sep 2022 08:54:54 -0700 (PDT) MIME-Version: 1.0 References: <20220907030754.GU1089@zhen-hp.sh.intel.com> In-Reply-To: From: Zheng Hacker Date: Fri, 16 Sep 2022 23:54:42 +0800 Message-ID: Subject: Re: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry. To: Greg KH Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "alex000young@gmail.com" , "security@kernel.org" , "tvrtko.ursulin@linux.intel.com" , "airlied@linux.ie" , "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , xmzyshypnc <1002992920@qq.com>, "rodrigo.vivi@intel.com" , "intel-gvt-dev@lists.freedesktop.org" , "zhi.a.wang@intel.com" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" >From afe79848cb74cc8e45ab426d13fa2394c87e0422 Mon Sep 17 00:00:00 2001 From: xmzyshypnc <1002992920@qq.com> Date: Fri, 16 Sep 2022 23:48:23 +0800 Subject: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry There is a double-free security bug in split_2MB_gtt_entry. Here is a calling chain : ppgtt_populate_spt->ppgtt_populate_shadow_entry->split_2MB_gtt_entry. If intel_gvt_dma_map_guest_page failed, it will call ppgtt_invalidate_spt, which will finally call ppgtt_free_spt and kfree(spt). But the caller does not notice that, and it will call ppgtt_free_spt again in error path. Fix this by only freeing spt in ppgtt_invalidate_spt in good case. Signed-off-by: Zheng Wang --- drivers/gpu/drm/i915/gvt/gtt.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index ce0eb03709c3..550519f0acca 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -959,7 +959,7 @@ static inline int ppgtt_put_spt(struct intel_vgpu_ppgtt_spt *spt) return atomic_dec_return(&spt->refcount); } -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt); +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int is_error); static int ppgtt_invalidate_spt_by_shadow_entry(struct intel_vgpu *vgpu, struct intel_gvt_gtt_entry *e) @@ -995,7 +995,7 @@ static int ppgtt_invalidate_spt_by_shadow_entry(struct intel_vgpu *vgpu, ops->get_pfn(e)); return -ENXIO; } - return ppgtt_invalidate_spt(s); + return ppgtt_invalidate_spt(s, 0); } static inline void ppgtt_invalidate_pte(struct intel_vgpu_ppgtt_spt *spt, @@ -1016,7 +1016,7 @@ static inline void ppgtt_invalidate_pte(struct intel_vgpu_ppgtt_spt *spt, intel_gvt_dma_unmap_guest_page(vgpu, pfn << PAGE_SHIFT); } -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt) +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int is_error) { struct intel_vgpu *vgpu = spt->vgpu; struct intel_gvt_gtt_entry e; @@ -1059,9 +1059,11 @@ static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt) } } - trace_spt_change(spt->vgpu->id, "release", spt, + if (!is_error) { + trace_spt_change(spt->vgpu->id, "release", spt, spt->guest_page.gfn, spt->shadow_page.type); - ppgtt_free_spt(spt); + ppgtt_free_spt(spt); + } return 0; fail: gvt_vgpu_err("fail: shadow page %p shadow entry 0x%llx type %d\n", @@ -1215,7 +1217,7 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vgpu, ret = intel_gvt_dma_map_guest_page(vgpu, start_gfn + sub_index, PAGE_SIZE, &dma_addr); if (ret) { - ppgtt_invalidate_spt(spt); + ppgtt_invalidate_spt(spt, 1); return ret; } sub_se.val64 = se->val64; @@ -1393,7 +1395,7 @@ static int ppgtt_handle_guest_entry_removal(struct intel_vgpu_ppgtt_spt *spt, ret = -ENXIO; goto fail; } - ret = ppgtt_invalidate_spt(s); + ret = ppgtt_invalidate_spt(s, 0); if (ret) goto fail; } else { -- 2.25.1