From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DA79184B for ; Mon, 13 Jun 2022 17:04:14 +0000 (UTC) Received: by mail-pf1-f178.google.com with SMTP id y196so6278215pfb.6 for ; Mon, 13 Jun 2022 10:04:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=mYjZASrY0U2vsg4+Z3fayp87EJ3UDw4wIJr7nvni9Ek=; b=kNia3fP4ii7v3FKDIFgRBPRWs8JCjCOQhwBs1YRrgihciGcfP3UczdQ1NP3WROY9gc SZq3nrWT95sCnM+OdH/rH54w6vklvee85Zaway/3supSPaXdEbvAZ28Zcq2Eshaug/N/ holljJi3raKp7VZN0MKBK/+0OmDZGbgPymy7Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mYjZASrY0U2vsg4+Z3fayp87EJ3UDw4wIJr7nvni9Ek=; b=rSF/Kwk4BH3OfQWwpLKE1cb9ouUVCvkxLKlEceKsaPF0bOGEuHxGuxAtgIlhh4oc57 pCDH5juLPQdnqQiXA2ezrenZbyKF9f4kRgX8Gmy2lBxSZ4g+KmEyqpKbBp2kaDPpVlJp R+n0bCGhxfQVNrPJgT8ub4J43Uo/O48XNnLjoQyFtEiJuoWBeLQwZgoqOb9VBgh8Trm8 G8bsopziJpz9NV0Um2htTFvs1iFTCNL+xxsnxY7WYioLjAvg6MuR+AdjhtC1y8s62oh0 bm7aQqV5g+ohNvPNKlRHyF8lHt5utK2M/sJsRALQvV9F3V5dJuR9rmE1/3G8aUMitHcT 0EqA== X-Gm-Message-State: AOAM530fVFltJ0QnZzU1Xi8jrG7X0eAunC1tJp6DZ89MRbscOeba5QRj IcSxxvj8VgZjJ9+koUAw7TzMBw== X-Google-Smtp-Source: ABdhPJxK4IuPlzJj4yZnVw7e7eKF60w/wpE1r9dvdOhFJv4qrE5RYKrR7ZvbsO0AYyeNTkD2MhrnGQ== X-Received: by 2002:a05:6a00:8d3:b0:51e:740f:8d60 with SMTP id s19-20020a056a0008d300b0051e740f8d60mr269277pfu.55.1655139853944; Mon, 13 Jun 2022 10:04:13 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id h30-20020aa79f5e000000b00519cfca8e30sm5615501pfr.209.2022.06.13.10.04.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jun 2022 10:04:13 -0700 (PDT) Date: Mon, 13 Jun 2022 10:04:12 -0700 From: Kees Cook To: Sami Tolvanen Cc: linux-kernel@vger.kernel.org, Josh Poimboeuf , Peter Zijlstra , x86@kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Nathan Chancellor , Nick Desaulniers , Joao Moreira , Sedat Dilek , Steven Rostedt , linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev Subject: Re: [RFC PATCH v3 00/20] KCFI support Message-ID: <202206131001.6BA9933C@keescook> References: <20220610233513.1798771-1-samitolvanen@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220610233513.1798771-1-samitolvanen@google.com> On Fri, Jun 10, 2022 at 04:34:53PM -0700, Sami Tolvanen wrote: > KCFI is a proposed forward-edge control-flow integrity scheme for > Clang, which is more suitable for kernel use than the existing CFI > scheme used by CONFIG_CFI_CLANG. KCFI doesn't require LTO, doesn't > alter function references to point to a jump table, and won't break > function address equality. The latest LLVM patch is here: > > https://reviews.llvm.org/D119296 > > This RFC series replaces the current arm64 CFI implementation with > KCFI and adds support for x86_64. I think the "RFC" prefix for this series can be dropped. :) It looks to me like all of Peter's concerns have been addressed. I'd say let's get the Clang side landed, and once that's done, land this via x86 -tip? Peter and Will does this sound right to you? It touches arm64, so if -tip isn't okay, I could take it in one of my trees? -- Kees Cook