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 B06A7C4332F for ; Tue, 18 Oct 2022 14:43:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230107AbiJROnM convert rfc822-to-8bit (ORCPT ); Tue, 18 Oct 2022 10:43:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229763AbiJROnI (ORCPT ); Tue, 18 Oct 2022 10:43:08 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44D26659E2 for ; Tue, 18 Oct 2022 07:43:07 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-277-g_jMUdj-PZ6mad37cXs9sg-1; Tue, 18 Oct 2022 15:43:03 +0100 X-MC-Unique: g_jMUdj-PZ6mad37cXs9sg-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Tue, 18 Oct 2022 15:43:01 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.042; Tue, 18 Oct 2022 15:43:01 +0100 From: David Laight To: 'Peter Zijlstra' , "x86@kernel.org" CC: Kees Cook , Sami Tolvanen , Joao Moreira , "linux-kernel@vger.kernel.org" , Mark Rutland , Josh Poimboeuf Subject: RE: [PATCH] x86/ibt: Implement FineIBT Thread-Topic: [PATCH] x86/ibt: Implement FineIBT Thread-Index: AQHY4vaTWxnEUTsnZEq6+EVM+oAeM64UOHoQ Date: Tue, 18 Oct 2022 14:43:01 +0000 Message-ID: <9bb036e48580454b81e6de7224c5f006@AcuMS.aculab.com> References: In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra > Sent: 18 October 2022 14:36 > > Implement an alternative CFI scheme that merges both the fine-grained > nature of kCFI but also takes full advantage of the coarse grained > hardware CFI as provided by IBT. Does the hash value for kCFI only depend on the function type? Or is there something like a attribute that can also be included? Otherwise all void (*)(void *) functions have the same hash. Any such additional check would also improve compile-time checks. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)