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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 2FCDAC49ED6 for ; Wed, 11 Sep 2019 15:15:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 005DE2085B for ; Wed, 11 Sep 2019 15:15:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728512AbfIKPP4 (ORCPT ); Wed, 11 Sep 2019 11:15:56 -0400 Received: from foss.arm.com ([217.140.110.172]:49366 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728182AbfIKPPz (ORCPT ); Wed, 11 Sep 2019 11:15:55 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 22A9828; Wed, 11 Sep 2019 08:15:55 -0700 (PDT) Received: from blommer (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 763A23F67D; Wed, 11 Sep 2019 08:15:53 -0700 (PDT) Date: Wed, 11 Sep 2019 16:15:46 +0100 From: Mark Rutland To: Sami Tolvanen Cc: Catalin Marinas , Will Deacon , Kees Cook , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: fix function types in COND_SYSCALL Message-ID: <20190911151545.GD3360@blommer> References: <20190910224044.100388-1-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190910224044.100388-1-samitolvanen@google.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 10, 2019 at 03:40:44PM -0700, Sami Tolvanen wrote: > Define a weak function in COND_SYSCALL instead of a weak alias to > sys_ni_syscall, which has an incompatible type. This fixes indirect > call mismatches with Control-Flow Integrity (CFI) checking. > > Signed-off-by: Sami Tolvanen This looks correct to me, builds fine, and I asume has been tested, so FWIW: Acked-by: Mark Rutland In looking at this, I came to the conclusion that we can drop the ifdeffery around our SYSCALL_DEFINE0(), COND_SYSCALL(), and SYS_NI(), which I evidently cargo-culted from x86 (where the ifdeffery is actually necessary). I can send a follow up for that. Thanks, Mark. > --- > arch/arm64/include/asm/syscall_wrapper.h | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h > index 507d0ee6bc69..06d880b3526c 100644 > --- a/arch/arm64/include/asm/syscall_wrapper.h > +++ b/arch/arm64/include/asm/syscall_wrapper.h > @@ -8,6 +8,8 @@ > #ifndef __ASM_SYSCALL_WRAPPER_H > #define __ASM_SYSCALL_WRAPPER_H > > +struct pt_regs; > + > #define SC_ARM64_REGS_TO_ARGS(x, ...) \ > __MAP(x,__SC_ARGS \ > ,,regs->regs[0],,regs->regs[1],,regs->regs[2] \ > @@ -35,8 +37,11 @@ > ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); \ > asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused) > > -#define COND_SYSCALL_COMPAT(name) \ > - cond_syscall(__arm64_compat_sys_##name); > +#define COND_SYSCALL_COMPAT(name) \ > + asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \ > + { \ > + return sys_ni_syscall(); \ > + } > > #define COMPAT_SYS_NI(name) \ > SYSCALL_ALIAS(__arm64_compat_sys_##name, sys_ni_posix_timers); > @@ -70,7 +75,11 @@ > #endif > > #ifndef COND_SYSCALL > -#define COND_SYSCALL(name) cond_syscall(__arm64_sys_##name) > +#define COND_SYSCALL(name) \ > + asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \ > + { \ > + return sys_ni_syscall(); \ > + } > #endif > > #ifndef SYS_NI > -- > 2.23.0.162.g0b9fbb3734-goog >