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 0FF50C76196 for ; Tue, 28 Mar 2023 13:10:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232170AbjC1NKU (ORCPT ); Tue, 28 Mar 2023 09:10:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232604AbjC1NKS (ORCPT ); Tue, 28 Mar 2023 09:10:18 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2488BB98 for ; Tue, 28 Mar 2023 06:09:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680008960; x=1711544960; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=hEsefQeZT5HOexkYp5BwuMTDiULU+5IKf5YZR+PdMrw=; b=WM6I0bTsizoIEvLeqeSbpMmoZA1c3MkYpzB4lOzpKGNP+sHW+4dPtHW+ Ug4ELSyqOYlZIgkPBvcMDSxbEUiC/JQwewbWYEdcXHWp+YI2Tx8dJr21v VQEu/E+b9gh3ETD7QoesReforHeF66kzUzLtiomEaKr9Jh3TIokNvbqnL g4S7mlyEBP4Pv2/vpwVg/uB9NyQ0je3z12A0xjsWCnOYukWHhpsWB+38G xB6UUvgHjR6EIWecLGe1A4LZJualy8tHUnWD9kyvpq9g28v/PvpenScF1 ELrGy9bTdNotKmdsKykenndDMFOLY6cTpTr304yWAeR0OYam+IWM+YBk4 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10662"; a="340581919" X-IronPort-AV: E=Sophos;i="5.98,297,1673942400"; d="scan'208";a="340581919" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Mar 2023 06:08:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10662"; a="748396269" X-IronPort-AV: E=Sophos;i="5.98,297,1673942400"; d="scan'208";a="748396269" Received: from wheelerj-mobl.ger.corp.intel.com (HELO [10.213.213.242]) ([10.213.213.242]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Mar 2023 06:08:49 -0700 Message-ID: Date: Tue, 28 Mar 2023 14:08:47 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl Content-Language: en-US To: Min Li , jani.nikula@linux.intel.com, Umesh Nerlige Ramappa , Lionel Landwerlin Cc: joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, airlied@gmail.com, daniel@ffwll.ch, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20230328093627.5067-1-lm0963hack@gmail.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc In-Reply-To: <20230328093627.5067-1-lm0963hack@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/03/2023 10:36, Min Li wrote: > Userspace can guess the id value and try to race oa_config object creation > with config remove, resulting in a use-after-free if we dereference the > object after unlocking the metrics_lock. For that reason, unlocking the > metrics_lock must be done after we are done dereferencing the object. > > Signed-off-by: Min Li Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface") Cc: Lionel Landwerlin Cc: Umesh Nerlige Ramappa Cc: # v4.14+ > --- > drivers/gpu/drm/i915/i915_perf.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c > index 824a34ec0b83..93748ca2c5da 100644 > --- a/drivers/gpu/drm/i915/i915_perf.c > +++ b/drivers/gpu/drm/i915/i915_perf.c > @@ -4634,13 +4634,13 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data, > err = oa_config->id; > goto sysfs_err; > } > - > - mutex_unlock(&perf->metrics_lock); > + id = oa_config->id; > > drm_dbg(&perf->i915->drm, > "Added config %s id=%i\n", oa_config->uuid, oa_config->id); > + mutex_unlock(&perf->metrics_lock); > > - return oa_config->id; > + return id; > > sysfs_err: > mutex_unlock(&perf->metrics_lock); LGTM. Reviewed-by: Tvrtko Ursulin Umesh or Lionel could you please double check? I can merge if confirmed okay. Regards, Tvrtko