From patchwork Tue Aug 31 06:13:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Desmond Cheong Zhi Xi X-Patchwork-Id: 504798 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 615D5C4320E for ; Tue, 31 Aug 2021 06:14:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44BE06101C for ; Tue, 31 Aug 2021 06:14:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231134AbhHaGPm (ORCPT ); Tue, 31 Aug 2021 02:15:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbhHaGPl (ORCPT ); Tue, 31 Aug 2021 02:15:41 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CE3EC061575; Mon, 30 Aug 2021 23:14:47 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id u11-20020a17090adb4b00b00181668a56d6so1605837pjx.5; Mon, 30 Aug 2021 23:14:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=tHn1bKbgKWkWnpZZfeyzrlp2g8PdlS3oPFK4wibr8zM=; b=eXIjFmJAssVk3qum2qiXCLhVDT8BHwEP00acuPJC6D3sWtXepsNRzl7WSa6QoQy99y dUAJT/Gv/isjtGOA3E207i4Tsg3jM8j5lwtN9mQ5mIE1L4CtzGYd9e/zLEhVdXiEHfEX MK3cuuw+X9WOT70++OXU9foFpZmdwQL8+ub9sVd8DFGdh2I4LBOAdF3P8oABbUdS/Y54 4Qjd1EndwTYPXWN/mnR2yMNqh9M9wuTMFPtmjSuKYEHNCteFwK4boUyHPOoTuD7my/aS UQusq/C0g8X0wUQzNjsJflhtzcsL03ZTs8shCqEgQNJ4GLN+7wm4QawSviE32FE7ZpHH +2hA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=tHn1bKbgKWkWnpZZfeyzrlp2g8PdlS3oPFK4wibr8zM=; b=EwWwjrdJmDsvQQ9LERTF8z/obLCjthiPm2o75GY2i15bDK2jnegDQXWiNZJaFAd/7e +xJjTUDUJkwHTRLKnQ91Tuuj5GSSSpqYd9nNVHWfsGT2LGshB01bdeoXiQq/cGvoAD2S YhyAyXr7BCiWlp5KwJhfebzj7cY142PHVsonvhIN53SezqpcLoJ/ePFdfJXU+hUI5rhZ LAYkBC6EtZqlf+8ln6hKYkD6o+2MrZ4fk6tyCNHkbswlu9EqxOR6lWpaA0A1EbGIbaPF aKOX/LoNUcN7iPWE75iOxPLCzb9JZLMXDH35eNZ9J6BDz/8gZEdoru0b1SepLGElwL+c UKew== X-Gm-Message-State: AOAM533JqwDsKcuWM40rTlVWgfAFxmKS8ktK5XEVXg9FMjECtuYBskyf V3EyqftYV8pzj5aTYoKVDJg= X-Google-Smtp-Source: ABdhPJzGmBXOz6okx6of+AFSntvusISTlHPl1xEvUsw8GRcQjM3xZQnn+uaj9N1kZDXhTmMeOXLoJw== X-Received: by 2002:a17:90b:390d:: with SMTP id ob13mr3460845pjb.129.1630390486636; Mon, 30 Aug 2021 23:14:46 -0700 (PDT) Received: from sanitydock.wifi-cloud.jp ([210.160.217.69]) by smtp.gmail.com with ESMTPSA id z7sm1405724pjr.42.2021.08.30.23.14.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Aug 2021 23:14:46 -0700 (PDT) From: Desmond Cheong Zhi Xi To: 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 Cc: Desmond Cheong Zhi Xi , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, stable@vger.kernel.org, Daniel Vetter Subject: [PATCH v9 1/4] drm: fix null ptr dereference in drm_master_release Date: Tue, 31 Aug 2021 14:13:45 +0800 Message-Id: <20210831061348.97696-2-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210831061348.97696-1-desmondcheongzx@gmail.com> References: <20210831061348.97696-1-desmondcheongzx@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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. Fixes: 7eeaeb90a6a5 ("drm/file: Don't set master on in-kernel clients") Signed-off-by: Desmond Cheong Zhi Xi Cc: stable@vger.kernel.org Reviewed-by: Daniel Vetter --- 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); } From patchwork Tue Aug 31 06:13:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Desmond Cheong Zhi Xi X-Patchwork-Id: 504797 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 4EB99C4320A for ; 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Mon, 30 Aug 2021 23:15:00 -0700 (PDT) Received: from sanitydock.wifi-cloud.jp ([210.160.217.69]) by smtp.gmail.com with ESMTPSA id z7sm1405724pjr.42.2021.08.30.23.14.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Aug 2021 23:14:59 -0700 (PDT) From: Desmond Cheong Zhi Xi To: 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 Cc: Desmond Cheong Zhi Xi , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, Daniel Vetter Subject: [PATCH v9 3/4] drm: lock drm_global_mutex earlier in the ioctl handler Date: Tue, 31 Aug 2021 14:13:47 +0800 Message-Id: <20210831061348.97696-4-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210831061348.97696-1-desmondcheongzx@gmail.com> References: <20210831061348.97696-1-desmondcheongzx@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org In a future patch, a read lock on drm_device.master_rwsem is held in the ioctl handler before the check for ioctl permissions. However, this inverts the lock hierarchy of drm_global_mutex --> master_rwsem. To avoid this, we do some prep work to grab the drm_global_mutex before checking for ioctl permissions. Signed-off-by: Desmond Cheong Zhi Xi Reviewed-by: Daniel Vetter --- drivers/gpu/drm/drm_ioctl.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index d25713b09b80..59c5aa850dd5 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -767,24 +767,27 @@ long drm_ioctl_kernel(struct file *file, drm_ioctl_t *func, void *kdata, { struct drm_file *file_priv = file->private_data; struct drm_device *dev = file_priv->minor->dev; + bool locked_ioctl; int retcode; if (drm_dev_is_unplugged(dev)) return -ENODEV; + /* Enforce sane locking for modern driver ioctls. */ + locked_ioctl = (unlikely(drm_core_check_feature(dev, DRIVER_LEGACY)) && + !(flags & DRM_UNLOCKED)); + if (locked_ioctl) + mutex_lock(&drm_global_mutex); + retcode = drm_ioctl_permit(flags, file_priv); if (unlikely(retcode)) - return retcode; + goto out; - /* Enforce sane locking for modern driver ioctls. */ - if (likely(!drm_core_check_feature(dev, DRIVER_LEGACY)) || - (flags & DRM_UNLOCKED)) - retcode = func(dev, kdata, file_priv); - else { - mutex_lock(&drm_global_mutex); - retcode = func(dev, kdata, file_priv); + retcode = func(dev, kdata, file_priv); + +out: + if (locked_ioctl) mutex_unlock(&drm_global_mutex); - } return retcode; } EXPORT_SYMBOL(drm_ioctl_kernel);