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 X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 123FFC432BE for ; Thu, 26 Aug 2021 09:53:25 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D653D610C8 for ; Thu, 26 Aug 2021 09:53:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D653D610C8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 18D2A6E5A4; Thu, 26 Aug 2021 09:53:24 +0000 (UTC) Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by gabe.freedesktop.org (Postfix) with ESMTPS id 013826E5A3 for ; Thu, 26 Aug 2021 09:53:22 +0000 (UTC) Received: by mail-wr1-x435.google.com with SMTP id v10so4090349wrd.4 for ; Thu, 26 Aug 2021 02:53:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=Ni1xy5Gepkk5NBQpOY3IACWkfMQ9OHRnfHvZ7VxtDs0=; b=EBbw5iuDgYoyjp0ztZeG08LqtiQBuGcd9QoDWNg0HwrHnneLUVjUgC7pGsSdoL6C3v uTJ9HDjYdICngR2YolnQ0jaIL+xRyz5Q9EFgSHRAwY9gqRpoLAagGbHUmySATzqhlDkh KTEbPFkHJh7n8Kyre+edSDiovcx7s92Q4Mgns= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=Ni1xy5Gepkk5NBQpOY3IACWkfMQ9OHRnfHvZ7VxtDs0=; b=ZyIoBRogKoW1v9HVytVoMR+Pim4yZipVHhVs4iyMZL0QhSc8Ir8ae6X3S9vT6wlAY2 jzNOfIXBfbrx/eLYLy/EYqZUjPn7qoKHYxzh8Igp/L4r3caIG9dCgJOjPcVgWQ9SYxbT ktKeoZasUwY1itdiBZNX4Y7Jpwh6VYeYDTfadQtgxgCk1UZcqdNazMdcjbYgMTvAXfU1 0Si/9U4/V9i1jp18ZsLdemERifovedsUMHMbKrTU3UlZfdr8i8kJ0CLEk0dCa7t1vNMV a9hyFABZCY5UBWk+q3up3LtOJZPJyo7D7psMwrkXvF3Lud+CF8tBE9CLRDFpjzEhDNC5 MQBw== X-Gm-Message-State: AOAM532+CG51GFpGYyDIm/TU6Cdie/Odzh1mhTfdb/AwapIduJPTBr7+ d3ObbSqQUUvuEaljywwmYotsRA== X-Google-Smtp-Source: ABdhPJx1lz50jPKLRZSlFYgcMNWnHQNKvfoVO+OADtOF8BUg3znumuN3XCwj3fk80kP8jB86qYRwcQ== X-Received: by 2002:a5d:47cd:: with SMTP id o13mr2937109wrc.246.1629971601523; Thu, 26 Aug 2021 02:53:21 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id o12sm2581867wro.51.2021.08.26.02.53.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Aug 2021 02:53:21 -0700 (PDT) Date: Thu, 26 Aug 2021 11:53:18 +0200 From: Daniel Vetter To: Desmond Cheong Zhi Xi Cc: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch, sumit.semwal@linaro.org, christian.koenig@amd.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, chris@chris-wilson.co.uk, ville.syrjala@linux.intel.com, matthew.auld@intel.com, dan.carpenter@oracle.com, tvrtko.ursulin@intel.com, matthew.d.roper@intel.com, lucas.demarchi@intel.com, karthik.b.s@intel.com, jose.souza@intel.com, manasi.d.navare@intel.com, airlied@redhat.com, aditya.swarup@intel.com, andrescj@chromium.org, linux-graphics-maintainer@vmware.com, zackr@vmware.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org Message-ID: Mail-Followup-To: Desmond Cheong Zhi Xi , maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@linux.ie, sumit.semwal@linaro.org, christian.koenig@amd.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, chris@chris-wilson.co.uk, ville.syrjala@linux.intel.com, matthew.auld@intel.com, dan.carpenter@oracle.com, tvrtko.ursulin@intel.com, matthew.d.roper@intel.com, lucas.demarchi@intel.com, karthik.b.s@intel.com, jose.souza@intel.com, manasi.d.navare@intel.com, airlied@redhat.com, aditya.swarup@intel.com, andrescj@chromium.org, linux-graphics-maintainer@vmware.com, zackr@vmware.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org References: <20210826020122.1488002-1-desmondcheongzx@gmail.com> <20210826020122.1488002-2-desmondcheongzx@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210826020122.1488002-2-desmondcheongzx@gmail.com> X-Operating-System: Linux phenom 5.10.0-7-amd64 Subject: Re: [Intel-gfx] [PATCH v8 1/7] drm: fix null ptr dereference in drm_master_release X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Aug 26, 2021 at 10:01:16AM +0800, Desmond Cheong Zhi Xi wrote: > drm_master_release can be called on a drm_file without a master, which > results in a null ptr dereference of file_priv->master->magic_map. The > three cases are: > > 1. Error path in drm_open_helper > drm_open(): > drm_open_helper(): > drm_master_open(): > drm_new_set_master(); <--- returns -ENOMEM, > drm_file.master not set > drm_file_free(): > drm_master_release(); <--- NULL ptr dereference > (file_priv->master->magic_map) > > 2. Error path in mock_drm_getfile > mock_drm_getfile(): > anon_inode_getfile(); <--- returns error, drm_file.master not set > drm_file_free(): > drm_master_release(); <--- NULL ptr dereference > (file_priv->master->magic_map) > > 3. In drm_client_close, as drm_client_open doesn't set up a master > > drm_file.master is set up in drm_open_helper through the call to > drm_master_open, so we mirror it with a call to drm_master_release in > drm_close_helper, and remove drm_master_release from drm_file_free to > avoid the null ptr dereference. > > Signed-off-by: Desmond Cheong Zhi Xi Reviewed-by: Daniel Vetter I guess we should also have a cc: stable on this one? I think this bug existed since pretty much forever, but maybe more prominent with the drm_client stuff added a while ago. -Daniel > --- > drivers/gpu/drm/drm_file.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c > index ed25168619fc..90b62f360da1 100644 > --- a/drivers/gpu/drm/drm_file.c > +++ b/drivers/gpu/drm/drm_file.c > @@ -282,9 +282,6 @@ void drm_file_free(struct drm_file *file) > > drm_legacy_ctxbitmap_flush(dev, file); > > - if (drm_is_primary_client(file)) > - drm_master_release(file); > - > if (dev->driver->postclose) > dev->driver->postclose(dev, file); > > @@ -305,6 +302,9 @@ static void drm_close_helper(struct file *filp) > list_del(&file_priv->lhead); > mutex_unlock(&dev->filelist_mutex); > > + if (drm_is_primary_client(file_priv)) > + drm_master_release(file_priv); > + > drm_file_free(file_priv); > } > > -- > 2.25.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch