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 571C6C32771 for ; Wed, 21 Sep 2022 09:13:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 082E210E827; Wed, 21 Sep 2022 09:13:19 +0000 (UTC) Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by gabe.freedesktop.org (Postfix) with ESMTPS id D45C910E827; Wed, 21 Sep 2022 09:13:13 +0000 (UTC) Received: by mail-ed1-x52a.google.com with SMTP id f20so7664128edf.6; Wed, 21 Sep 2022 02:13:13 -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=l1vyb533afax2OC0XKhODZY3BbHylHPbSqXDEOL933M=; b=lexMAsGpZ4uEBXdBTpjGyZOQZbhz7PxOKpVGZx8r1n6iEClWEb2QgJhRCqVNybC4Zb umXIRTZtp4aBvlzpZOZ2hzAxKU31SiyYYjtfU+gZPLt6b9qHhGA003E8M5qtNmH2fnFK nchHZWUfq5ISXapeTIsdxmnTtZBV/QEoave+BO/SB2lPbt07zYW7r4PJRZdFzPZyhG+X VgCsD3BKY5P8SsGT6h+idC632uotCVMDnO4bMEL8tfUssm3i662dpQJ2uawr5G4TWFBL UDBGMWnbgSJ2CzHoKasq1mzIfpXFz/m4ecRfLS/c5GepOMiYEU6cmSY1VVs1zXW/jrVX 7caQ== 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=l1vyb533afax2OC0XKhODZY3BbHylHPbSqXDEOL933M=; b=xYfFfL1ZZf4KPTIMWxcY4hBDIDwPPDN7dpo9pWyyPBRNG/pQoaozOckNl9P7ztwq+S aPaEh8UdPH3GXjfImOiMMaE7YJ91w8WEEb3UBLlUO5dy4H/YJRGKOcVduhEBM1owU3Ip MRJaFV+EePiiS9C4WuNiyZXbRHiEyOXP4PBROCbs1lCCBu6hPO+NBYB45milS3QuUFSh t9xMDijl7vVY17rL1XDml06qmqHTR1+2Gwx7R4ZIkA/XSMaHNI2bdgvhWUX9y3am0WuA EwrGA9fIwuNjdlSOkXliBPiHjhMDEfHDdFno+V6UCU8q9yQp69rDzsOep87YSngr5hQg r2KA== X-Gm-Message-State: ACrzQf1U0eDsfg07x3M1Usn88kR8e5HcadwwDwAyQKOT2hKXAmLn2o/V 52A4aq6yHeN1hSpbl6nXcSo00WIXnqvzYRRoHKc= X-Google-Smtp-Source: AMsMyM6qZWoSutaGxavU1l+b7Gm2hjgycXdK2iBnT1E6FzoR1kMbyw7qnFJJdbmwW2B+f+vp5HuJ/trMQxljKzrjOS4= X-Received: by 2002:aa7:df87:0:b0:44e:2851:7e8d with SMTP id b7-20020aa7df87000000b0044e28517e8dmr24459923edy.106.1663751592281; Wed, 21 Sep 2022 02:13:12 -0700 (PDT) MIME-Version: 1.0 References: <87pmfrpv7q.fsf@intel.com> In-Reply-To: <87pmfrpv7q.fsf@intel.com> From: Zheng Hacker Date: Wed, 21 Sep 2022 17:13:00 +0800 Message-ID: Subject: Re: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry To: Jani Nikula Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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: tvrtko.ursulin@linux.intel.com, security@kernel.org, alex000young@gmail.com, airlied@linux.ie, gregkh@linuxfoundation.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Zheng Wang <1002992920@qq.com> Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" I've sent it using git send-email with another email account (zyytlz.wz@163= .com) 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