From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.2 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by inbox.vuxu.org (Postfix) with SMTP id CFAE72585E for ; Wed, 14 Feb 2024 05:44:36 +0100 (CET) Received: (qmail 20026 invoked by uid 550); 14 Feb 2024 04:41:33 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 19988 invoked from network); 14 Feb 2024 04:41:32 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=s31663417; t=1707885861; x=1708490661; i=nullplan@gmx.net; bh=e8tRZC7Y4HdBh8i9PwIwiOWjuWzABImfuNJeuR8sric=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:References: In-Reply-To; b=aZLpIkqNKovJMwngQjlnWHImoVMPJOuGl2sgkoE5bq5Fm6f8Cc4VkTyMyQgXrhYP Lc5q1bIuhd6e4tcSHoDApRFQ9ZjuKf/czL5bVfy9NKMBDiSzvr4zLAWTnq2bP5h3H z627fLlpR1U68AAruBeFttCvGkbjyo1p3cF7bJFBqfJBctXirQpmAMaXFbGsoSgPa WO7rvh5PEBIC/kLXSP3FVlMB7hxjOpTzFO3BcNjz9izsJFpV1ZQO6oZtIRNOVr4yd YJ9VfvNFBZsZ0pDTZtNZqFiivuORCvXDru7jFxF1m8Kl23iJtJGvPCOcUxmVazvfR MHP5bRXU7ArlqGOwEg== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Date: Wed, 14 Feb 2024 05:44:20 +0100 From: Markus Wichmann To: musl@lists.openwall.com Cc: enh Message-ID: References: <20240212184236.GZ4163@brightrain.aerifal.cx> <20240212224657.GA4163@brightrain.aerifal.cx> <20240213020834.GB4163@brightrain.aerifal.cx> <20240214021925.GC4163@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240214021925.GC4163@brightrain.aerifal.cx> X-Provags-ID: V03:K1:z1RD45jm0Qrv0VE+LZTQc6+yFAYn638aBqAQgSwThDv+bHpq/mC x7lYmOnNMwhL44UZhb0nPrcP83IU7uj1iq56IfzRmfjs/ZcHGCAMG0nz3ix/+oQW//NkPB6 k7Eik8WjH+AjinVaZxWaRFw25v/17kVS2+iEI6/V8TggaM3WESFLHhTYwLzEu+Pyq+hdLKC oZfAau4EnD9CymrtgCvKg== UI-OutboundReport: notjunk:1;M01:P0:C0dckDymDNo=;xIhacLHm2T8uAZRb5D9ORdoN4lG +jAVg8dyAAgR0Lpu/1zSbkW2kKIHtQlqrnqqPQhUhcsjMYEiYPEoUYqhJLpea0f5tRfL039+3 utlkL55TToCCsVL1Bkw+FkUxIOhBUKqybmJRF8v6W+EGTnnZ7FVFBA76Hthh1MLgtoUT3dJ9s HkUAmCPvdL6D8TIrvJQltTiOryk+q8Q53dT8n8S1T61dnDXPARTYVOluVskkLFTDe7MOYrxPx RYiFlh8XEFKdIkn8QTqdDU5tdXh3dfJ9Zl4373YJDlSTNnzpx1X8c4CODMbGzA21SFBk92cpq hj1wJXlzGOJ88PmYyhrKub8rQ2Gezbr4gasoepw//hbpvdmqMavFfOVxQsizuer07I7Mnv7Qq 3AuSrLVNkhn0XfUFAGtfWLKSgpmUjGx+VUWiDYSyWKp8FXqrxDbD2ICe/h0NVxIZQV1Z/Xl5y dF/Z7o83MPZtDKyGUKrzM6ebG+JW1G/Jr3VuQqmlQBPLdcsy+hFMbbhRWi0vWKoemMyUgsscl GY/x875hDoP6nKepTkzdTKu7hl8S8Z6XFcHdxjs1lgTLgC8fyxoFBb1j6Qi7GA/2/US8/Vi29 mV8QTbVvTT0Hs3ciszNr6NwR2vjG4iLVnBFNgOn5S5GR/419XqrUtSzI+qX4QBx1fLPa541ma V/nKHd/ZLHRHWvmRotA+tUTnozVzRh0yL9Lxnll/i3a/vkQ0dN54M8cydGNCsDYbJlg5rVVXY 14eyA9lbN+GRiE1wnuSGaJ6bas0DgSZnKEyf3bGH6kaKVlwVuGpZV7felwz5Lz6I2ykC4pDL3 rsLsP4C9BauV6uV6tCwJdk6pz25n/E8fkL78nkW8XmCJc= Content-Transfer-Encoding: quoted-printable Subject: Re: [musl] PAC/BTI Support on aarch64 Am Tue, Feb 13, 2024 at 09:19:25PM -0500 schrieb Rich Felker: > What is the situation on x86? Does it use the same kind of per-page > enforcement mode, or is it only global, requiring disabling it if any > DSO lacks support? Is the endbr64 opcode a guaranteed-safe nop on > older ISA levels, or does it need to be conditional? > My, what a journey. I had a look around the Internet for this question and kept finding contradictory results. Turns out that is because, as per kernel documentation, Linux only supports *kernel* IBT. The only part of CET it supports for userspace is shadow stacks. Unless the kernel docs are not up-to-date, of course. According to Intel, the ENDBR64 instruction decodes as NOP on older processors. GCC has support for emiting it, but at this point in time it appears to be useless outside of Linux itself. Ciao, Markus