From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753737AbeDYLXp (ORCPT ); Wed, 25 Apr 2018 07:23:45 -0400 Received: from foss.arm.com ([217.140.101.70]:38272 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033AbeDYLXh (ORCPT ); Wed, 25 Apr 2018 07:23:37 -0400 Date: Wed, 25 Apr 2018 12:23:32 +0100 From: Catalin Marinas To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, drjones@redhat.com, cdall@kernel.org, arnd@arndb.de, suzuki.poulose@arm.com, marc.zyngier@arm.com, awallis@codeaurora.org, kernel-hardening@lists.openwall.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, ramana.radhakrishnan@arm.com, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCHv3 07/11] arm64: add basic pointer authentication support Message-ID: <20180425112331.hke7afxnslyrwf3h@armageddon.cambridge.arm.com> References: <20180417183735.56985-1-mark.rutland@arm.com> <20180417183735.56985-8-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180417183735.56985-8-mark.rutland@arm.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, On Tue, Apr 17, 2018 at 07:37:31PM +0100, Mark Rutland wrote: > diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h > index 39ec0b8a689e..caf0d3010112 100644 > --- a/arch/arm64/include/asm/mmu_context.h > +++ b/arch/arm64/include/asm/mmu_context.h > @@ -29,7 +29,6 @@ > #include > #include > #include > -#include > #include > #include > #include > @@ -168,7 +167,14 @@ static inline void cpu_replace_ttbr1(pgd_t *pgdp) > #define destroy_context(mm) do { } while(0) > void check_and_switch_context(struct mm_struct *mm, unsigned int cpu); > > -#define init_new_context(tsk,mm) ({ atomic64_set(&(mm)->context.id, 0); 0; }) > +static inline int init_new_context(struct task_struct *tsk, > + struct mm_struct *mm) > +{ > + atomic64_set(&mm->context.id, 0); > + mm_ctx_ptrauth_init(&mm->context); > + > + return 0; > +} > > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > static inline void update_saved_ttbr0(struct task_struct *tsk, > @@ -216,6 +222,8 @@ static inline void __switch_mm(struct mm_struct *next) > return; > } > > + mm_ctx_ptrauth_switch(&next->context); > + > check_and_switch_context(next, cpu); > } > > @@ -241,6 +249,19 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, > void verify_cpu_asid_bits(void); > void post_ttbr_update_workaround(void); > > +static inline void arch_dup_mmap(struct mm_struct *oldmm, > + struct mm_struct *mm) > +{ > + mm_ctx_ptrauth_dup(&oldmm->context, &mm->context); > +} > +#define arch_dup_mmap arch_dup_mmap IIUC, we could skip the arch_dup_mmap() and init_new_context() here for the fork() case since the ptrauth_keys would be copied as part of the dup_mm(). There is another situation where init_new_context() is called bprm_mm_init() -> mm_alloc() -> mm_init() -> init_new_context(). However, in this case the core code also calls arch_bprm_mm_init(). So I think we only need to update the latter to get a new random key. > diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h > new file mode 100644 > index 000000000000..a2e8fb91fdee > --- /dev/null > +++ b/arch/arm64/include/asm/pointer_auth.h > @@ -0,0 +1,89 @@ > +/* > + * Copyright (C) 2016 ARM Ltd. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see . > + */ Nitpick: 2018. You could also use the SPDX header, save some lines. -- Catalin