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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D34CEECAAD3 for ; Mon, 19 Sep 2022 09:56:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230017AbiISJ4K (ORCPT ); Mon, 19 Sep 2022 05:56:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230242AbiISJzy (ORCPT ); Mon, 19 Sep 2022 05:55:54 -0400 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56F8B25E9B for ; Mon, 19 Sep 2022 02:55:48 -0700 (PDT) Received: by mail-ed1-x535.google.com with SMTP id b35so40510415edf.0 for ; Mon, 19 Sep 2022 02:55:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date; bh=vnJl0L26F6/cF4LoX36tFsaUdJl5yJVNsgmOYHfsRBo=; b=Vb58P5FPswub/ju264ON0G6rNOIDPCQ3GPgtbDnL9G5e9OBp6YY93sVXlx6LwidIDc Fo0wgvT7f3ra1kG8Qxo0C/PW+CW/jHl8oUXedW/ZeTrOMcu59U4vz6luprsm8n4rKs0o LL8/pP7VsWejZczbgFWn7bDQVLHvRSUsimYgLZaiusojf3ZnzqrJPYOddQNashyMTT3D 6nbCCvedQcphnp7D/OpFqSZUvY9MMrkYFVDiovOKRP/e8NgwVnfH+d5GpLRl3vRmyevv YgjtVqSmTVsn4Pz7me5Mk+4fIBQRDlkSzXyxcoti6H2JR9XCFcnRo3xQKyVT50kpQm5+ kpzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date; bh=vnJl0L26F6/cF4LoX36tFsaUdJl5yJVNsgmOYHfsRBo=; b=8CTfexWnisOf6AqtuTNmrv2PveE/EOE68BnzULMZQbQ7kKcKbH8qNsZl7ktkfb7RfG mBnPM1lUBfRyK/+nHVCD+Ihhh8xz9JMNPsGtzHhj9R3ZvJVZarubB9k42lp9v6P4lBC3 U+Kphj/15nqIkDuAmRZt2BQm2RdzY7C0c14T0/xAx1/dyjfEYgV/M1wibVP+cXf5u5A9 uAif8job4nR3M/oTZyduldDXpTXiiUkOiNC1XUVbhsCqdwTT2i5xbRQ/ty3ftYUPv40d YKgiwlNnkRNPyoXzUu8PtF1/WKfp3eZGT4gwiCYP/g1cceICIez+1taDArgNa3udV4NV NF2Q== X-Gm-Message-State: ACrzQf1v8KPpZxSnhs7IlM9qt6TWsbhMPefZUjiFx2R2JhP5T/fEOh/o 6TlcT7o9/XpPtXnmXMcTXLCy79QqwQq8irORAMI= X-Google-Smtp-Source: AMsMyM42HTbF/UFDvgdJ38PdEt0hijqa/khgCG00F9Fw/uY27h2or8B5g7sF95ObpJXZFD0OXeAG8T7xvZxPYQltuX0= X-Received: by 2002:a05:6402:2b8f:b0:453:2e59:364d with SMTP id fj15-20020a0564022b8f00b004532e59364dmr14954390edb.254.1663581346809; Mon, 19 Sep 2022 02:55:46 -0700 (PDT) MIME-Version: 1.0 References: <87pmfrpv7q.fsf@intel.com> In-Reply-To: <87pmfrpv7q.fsf@intel.com> From: Zheng Hacker Date: Mon, 19 Sep 2022 17:55:35 +0800 Message-ID: Subject: Re: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry To: Jani Nikula Cc: Zheng Wang <1002992920@qq.com>, gregkh@linuxfoundation.org, alex000young@gmail.com, security@kernel.org, tvrtko.ursulin@linux.intel.com, airlied@linux.ie, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Got it. I'll try again later. Best Regards, Zheng Wang Jani Nikula =E4=BA=8E2022=E5=B9=B49=E6=9C=881= 9=E6=97=A5=E5=91=A8=E4=B8=80 17:30=E5=86=99=E9=81=93=EF=BC=9A > > On Mon, 19 Sep 2022, Zheng Wang <1002992920@qq.com> wrote: > > 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_ent= ry > > > > 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: xmzyshypnc <1002992920@qq.com> > > Please use git send-email. The patch is whitespace broken and line > wrapped, making it unusable. > > BR, > Jani. > > > > --- > > 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 *vg= pu, > > 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 =3D 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 =3D intel_gvt_dma_map_guest_page(vgpu, start_gfn + sub_in= dex, > > PAGE_SIZE, &dma_addr); > > if (ret) { > > - ppgtt_invalidate_spt(spt); > > + ppgtt_invalidate_spt(spt, 1); > > return ret; > > } > > sub_se.val64 =3D se->val64; > > @@ -1393,7 +1395,7 @@ static int ppgtt_handle_guest_entry_removal(struc= t > > intel_vgpu_ppgtt_spt *spt, > > ret =3D -ENXIO; > > goto fail; > > } > > - ret =3D ppgtt_invalidate_spt(s); > > + ret =3D ppgtt_invalidate_spt(s, 0); > > if (ret) > > goto fail; > > } else { > > -- > Jani Nikula, Intel Open Source Graphics Center