From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2BB8130ADF; Fri, 16 Feb 2024 16:50:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708102219; cv=none; b=DwW+u2GDUu2OtnKetMB8mFpns4/cjK5f5hvKNPBu8ij8HUwQGmHV1OrpkMd9fizH9W8oKmTZoBZwKDbRU7lQmkM/feOE+fIotmMJyfs1F0A0tWh+CRlOOHUbDQeIcw2Na1ZVxgGLOAlN9YUNBY34dUXCb7BORUaZ7YxMxaqbjF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708102219; c=relaxed/simple; bh=9x0VAcgRR5iydeprnwWx5rGSU/WwGPjsi6M/40rCSuw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=V/VqzVHGVtu+wE7RGXWTMZbNoocMpZYcvsKafCIHhFFFJgIdCdwK8IngsGfEcCh87jaEUu8AzXi5sdUnhdgiV3OhzwS86LumtyJve3FAh1Oo3klMwJE2aoafp/TvvshSTmnHoGT7qI8fbyJ/wRhrPSawjwcubi5SgVlgJkVW02E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=OJtmy1S7; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="OJtmy1S7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708102217; x=1739638217; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=9x0VAcgRR5iydeprnwWx5rGSU/WwGPjsi6M/40rCSuw=; b=OJtmy1S7kexNi1D4GYl3chgJvnjFjn56PK2EhvLZ/KGQQX7hxNLC4Pm+ 9TbXOJhkudOqH4cAkZVa5KNzDlGiO679A30adT9cWLZyBGdRFgmf9QF9/ uAmNiCJNOy/HrHvd7jvxzPxjjl0xK5Hjri7vp5E7FXAzdpFVoEDxr53jT qApJwN31669KNbcOnPw6B782F8uLY98lo+2KeGLjg7Nth8a7WI6ofJLb7 WYjRzIHMYHSTWjVdjUOvUt2/NzD6I16xt42di60oM/JWBVtD7UNNjUCtn AXxHSuMfZQMf3p9iN3qAyYTAhjUku1w4j3J2gcVfWFZ+uCEbiom+vGpxP A==; X-IronPort-AV: E=McAfee;i="6600,9927,10986"; a="2367363" X-IronPort-AV: E=Sophos;i="6.06,165,1705392000"; d="scan'208";a="2367363" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2024 08:50:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10986"; a="912387756" X-IronPort-AV: E=Sophos;i="6.06,165,1705392000"; d="scan'208";a="912387756" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga002.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2024 08:50:13 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.97) (envelope-from ) id 1rb1Pf-000000056Gt-2LJH; Fri, 16 Feb 2024 18:50:11 +0200 Date: Fri, 16 Feb 2024 18:50:11 +0200 From: Andy Shevchenko To: "Rafael J. Wysocki" Cc: Linux ACPI , LKML , Zhang Rui , Kees Cook , "shiqiang.deng" , Sebastian Grzywna , Hang Zhang Subject: Re: [PATCH v3] ACPI: Drop the custom_method debugfs interface Message-ID: References: <6029478.lOV4Wx5bFT@kreacher> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6029478.lOV4Wx5bFT@kreacher> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Fri, Feb 16, 2024 at 05:38:55PM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > The ACPI custom_method debugfs interface is security-sensitive and > concurrent access to it is broken [1]. > > Moreover, the recipe for preparing a customized version of a given > control method has changed at one point due to ACPICA changes, which > has not been reflected in its documentation, so whoever used it before > has had to adapt and it had gone unnoticed for a long time. > > This interface was a bad idea to start with and its implementation is > fragile at the design level. It's been always conceptually questionable, > problematic from the security standpoint and implemented poorly. > > Patches fixing its most apparent functional issues (for example, [2]) don't > actually address much of the above. > > Granted, at the time it was introduced, there was no alternative, but > there is the AML debugger in the kernel now and there is the configfs > interface allowing custom ACPI tables to be loaded. The former can be > used for extensive AML debugging and the latter can be use for testing > new AML. [3] > > Accordingly, drop custom_method along with its (outdated anyway) > documentation. > > Link: https://lore.kernel.org/linux-acpi/20221227063335.61474-1-zh.nvgt@gmail.com/ # [1] > https://lore.kernel.org/linux-acpi/20231111132402.4142-1-shiqiang.deng213@gmail.com/ [2] > https://stackoverflow.com/questions/62849113/how-to-unload-an-overlay-loaded-using-acpi-config-sysfs # [3] I believe you missed Link: tags for 2 and 3. > Reported-by: Hang Zhang > Signed-off-by: Rafael J. Wysocki > Reviewed-by: Zhang Rui -- With Best Regards, Andy Shevchenko