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 X-Spam-Level: X-Spam-Status: No, score=-14.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2CDFC433DB for ; Fri, 12 Mar 2021 20:46:12 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4BED764F4F for ; Fri, 12 Mar 2021 20:46:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4BED764F4F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References:List-Owner; bh=uR0rAR1AwufHlekopw7uoYCGHH7ZhFimp0jS1WJZ+Ik=; b=D3cA09dmoGGMqzypsGj3OaDSK TgHgF781i9YXidDl64DwVxN5saUSpA6jpZVCAYmbxGrVXiNsZohS3lnVLipbF2xFcf1TEb9zUCdD5 J28ZJ3jMtmhTfhmmxNj/1EM2V0css285s2GlniNTfn+XGXh8H3khPdUxiHmSit0qK3LiTj66mC9c9 ACFI5LHnacepIeeTQJ2Kg4uSOy3fCSykLaePiCracvNW2rJA9BWd79qtYE3ln5Yi5ybLJONOIQmTj mQ7wIySWSM0JFTVy1l15DvSIvIdsOGTQetL3Dy6oPjnuHtX2mEdp9pC2jSH5b08xtVQoxelXT1a6P XVeSwQ5UQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKobK-00CMVm-0m; Fri, 12 Mar 2021 20:41:38 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKoOs-00CLQD-Pt for linux-arm-kernel@lists.infradead.org; Fri, 12 Mar 2021 20:29:12 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id E8FA564F43; Fri, 12 Mar 2021 20:28:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615580923; bh=GH0ez+6thAFHA0R/g6PB84gv2i0cqvUAgDElmnsXr8w=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=VGaCV2AXrylOg6TdRiZrMPJOv7ON0cVJ59Gm/JCIHVTjgpVpTXKgz19cVR/N9d/2R cl8ZNHLB7lA+97wDIrdUBRH+gftY/6UzlNfMGAyOC6BpTsXGtUAu1R+U90pCvEG3Vw GvHnMVdIM9yzHj2XprFdXcYVlSCjbOvkGxNZSh7aMdxyS3TJrkPsPX+YQSLkOxk9cF BWJRoAwI38Kq7gXjQHHwTTqKRz9l/F5fsktD6Um9w6f2FjlvZgqxJtXzBXMx9bBFJM RNj5qICdALYiFE+JjspVs9n36AooGGZHEw7x216w0g65NhdOzwtSYiqO/sGbbaer2q SpgY62ZqJZ5Hw== Date: Fri, 12 Mar 2021 14:28:41 -0600 From: Bjorn Helgaas To: Sami Tolvanen Cc: Kees Cook , Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/17] cfi: add __cficanonical Message-ID: <20210312202841.GA2286570@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210312004919.669614-3-samitolvanen@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210312_202911_242998_0B179403 X-CRM114-Status: GOOD ( 23.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 11, 2021 at 04:49:04PM -0800, Sami Tolvanen wrote: > With CONFIG_CFI_CLANG, the compiler replaces a function address taken > in C code with the address of a local jump table entry, which passes > runtime indirect call checks. However, the compiler won't replace > addresses taken in assembly code, which will result in a CFI failure > if we later jump to such an address in instrumented C code. The code > generated for the non-canonical jump table looks this: > > : /* In C, &noncanonical points here */ > jmp noncanonical > ... > : /* function body */ > ... > > This change adds the __cficanonical attribute, which tells the > compiler to use a canonical jump table for the function instead. This > means the compiler will rename the actual function to .cfi > and points the original symbol to the jump table entry instead: > > : /* jump table entry */ > jmp canonical.cfi > ... > : /* function body */ > ... > > As a result, the address taken in assembly, or other non-instrumented > code always points to the jump table and therefore, can be used for > indirect calls in instrumented code without tripping CFI checks. > > Signed-off-by: Sami Tolvanen If you need it: Acked-by: Bjorn Helgaas # pci.h > --- > include/linux/compiler-clang.h | 1 + > include/linux/compiler_types.h | 4 ++++ > include/linux/init.h | 4 ++-- > include/linux/pci.h | 4 ++-- > 4 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h > index 1ff22bdad992..c275f23ce023 100644 > --- a/include/linux/compiler-clang.h > +++ b/include/linux/compiler-clang.h > @@ -57,3 +57,4 @@ > #endif > > #define __nocfi __attribute__((__no_sanitize__("cfi"))) > +#define __cficanonical __attribute__((__cfi_canonical_jump_table__)) > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h > index 796935a37e37..d29bda7f6ebd 100644 > --- a/include/linux/compiler_types.h > +++ b/include/linux/compiler_types.h > @@ -246,6 +246,10 @@ struct ftrace_likely_data { > # define __nocfi > #endif > > +#ifndef __cficanonical > +# define __cficanonical > +#endif > + > #ifndef asm_volatile_goto > #define asm_volatile_goto(x...) asm goto(x) > #endif > diff --git a/include/linux/init.h b/include/linux/init.h > index b3ea15348fbd..045ad1650ed1 100644 > --- a/include/linux/init.h > +++ b/include/linux/init.h > @@ -220,8 +220,8 @@ extern bool initcall_debug; > __initcall_name(initstub, __iid, id) > > #define __define_initcall_stub(__stub, fn) \ > - int __init __stub(void); \ > - int __init __stub(void) \ > + int __init __cficanonical __stub(void); \ > + int __init __cficanonical __stub(void) \ > { \ > return fn(); \ > } \ > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 86c799c97b77..39684b72db91 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1944,8 +1944,8 @@ enum pci_fixup_pass { > #ifdef CONFIG_LTO_CLANG > #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \ > class_shift, hook, stub) \ > - void stub(struct pci_dev *dev); \ > - void stub(struct pci_dev *dev) \ > + void __cficanonical stub(struct pci_dev *dev); \ > + void __cficanonical stub(struct pci_dev *dev) \ > { \ > hook(dev); \ > } \ > -- > 2.31.0.rc2.261.g7f71774620-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel