From patchwork Fri Dec 7 18:39:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kristina Martsenko X-Patchwork-Id: 153190 Delivered-To: patch@linaro.org Received: by 2002:a2e:299d:0:0:0:0:0 with SMTP id p29-v6csp831590ljp; Fri, 7 Dec 2018 10:40:31 -0800 (PST) X-Google-Smtp-Source: AFSGD/UJshP00INuhROeuwlpaxKIeOnSxBP3xYsaTb9XEm1cgmZ0vAS/LDTsgxa/yuxxhjimYqfW X-Received: by 2002:a62:1d8f:: with SMTP id d137mr3280408pfd.11.1544208030860; Fri, 07 Dec 2018 10:40:30 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1544208030; cv=none; d=google.com; s=arc-20160816; b=tjifoM5KgdtFjeiPexHx7IE07L+cZFdplO8Ma3ZShFPUeuJdKchM98RNqIXfpKLxBY 5IVIxx++AJGvXOhbwGeS9pCPRF7By97HyjzZWKnKUTaffXqFRO36TuNrOGxOCGCpznbo BdEYCmNBIeGaLsgbFnArI8/ijKgkY6wDIsZnXo7VCz+071HIEuPWNVrTlPEPLMoOCdcL PZ7miHD6yb3TcZgJIES3lfAAodyakhbPadzNHfzeyqcFJH5M9UukxDRIHcHQsb2XV6FF BOOdXjTdpwVzTZHpaizEfbUo5sN55T7/I4b+EbLRUYXPhISL5lgOBZNEkPpJzWdOQIhd 8C/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=bUXBr830mTNTZqUGk4J/17D42LTWK3fsPvWOhpWzOAc=; b=kmmFiDqLK5Y3+YsPp1TiAbJXkHO3s9xpOzj5YtC7psQAq6h61iUMVhRuN6RKTXLvRb 23qHw9uyFE4GENpDY6NI2BVdcpu049ox6Lf9PSw84TUMgkZMtnObeSOAUh6vKfNSoiJc 1+HWcWtkFFMLsuQu8PWD+fF06WfMCrqYZ+fyXBAoz+tnTRf2MTECESz0OEDh6yZNRBgc skp9CQJLkk9PA6XILmbPLA8JcaUTFHP7ytcwrfp9l8EpqgmJ9JLXRBdNEjKPQ0YMHDFY ydOo18vBS+KIcrVYIxShLu+0nJhpTxM9s5cDErRXiItrqKJi6L9ff8Z+vobGan/JjQ10 z2VA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a18si3466559pgj.77.2018.12.07.10.40.30; Fri, 07 Dec 2018 10:40:30 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726362AbeLGSk3 (ORCPT + 31 others); Fri, 7 Dec 2018 13:40:29 -0500 Received: from foss.arm.com ([217.140.101.70]:52072 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726348AbeLGSk2 (ORCPT ); Fri, 7 Dec 2018 13:40:28 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 41BF31682; Fri, 7 Dec 2018 10:40:28 -0800 (PST) Received: from moonbear.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 28B483F5AF; Fri, 7 Dec 2018 10:40:25 -0800 (PST) From: Kristina Martsenko To: linux-arm-kernel@lists.infradead.org Cc: Adam Wallis , Amit Kachhap , Andrew Jones , Ard Biesheuvel , Catalin Marinas , Christoffer Dall , Cyrill Gorcunov , Dave P Martin , Jacob Bramley , Kees Cook , Marc Zyngier , Mark Rutland , Ramana Radhakrishnan , Richard Henderson , Suzuki K Poulose , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Subject: [PATCH v6 07/13] arm64: add basic pointer authentication support Date: Fri, 7 Dec 2018 18:39:25 +0000 Message-Id: <20181207183931.4285-8-kristina.martsenko@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20181207183931.4285-1-kristina.martsenko@arm.com> References: <20181207183931.4285-1-kristina.martsenko@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Rutland This patch adds basic support for pointer authentication, allowing userspace to make use of APIAKey, APIBKey, APDAKey, APDBKey, and APGAKey. The kernel maintains key values for each process (shared by all threads within), which are initialised to random values at exec() time. The ID_AA64ISAR1_EL1.{APA,API,GPA,GPI} fields are exposed to userspace, to describe that pointer authentication instructions are available and that the kernel is managing the keys. Two new hwcaps are added for the same reason: PACA (for address authentication) and PACG (for generic authentication). Signed-off-by: Mark Rutland Signed-off-by: Kristina Martsenko Tested-by: Adam Wallis Cc: Catalin Marinas Cc: Ramana Radhakrishnan Cc: Suzuki K Poulose Cc: Will Deacon --- arch/arm64/include/asm/pointer_auth.h | 75 +++++++++++++++++++++++++++++++++++ arch/arm64/include/asm/thread_info.h | 4 ++ arch/arm64/include/uapi/asm/hwcap.h | 2 + arch/arm64/kernel/cpufeature.c | 13 ++++++ arch/arm64/kernel/cpuinfo.c | 2 + arch/arm64/kernel/process.c | 4 ++ 6 files changed, 100 insertions(+) create mode 100644 arch/arm64/include/asm/pointer_auth.h -- 2.11.0 Reviewed-by: Richard Henderson diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h new file mode 100644 index 000000000000..fc7ffe8e326f --- /dev/null +++ b/arch/arm64/include/asm/pointer_auth.h @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef __ASM_POINTER_AUTH_H +#define __ASM_POINTER_AUTH_H + +#include + +#include +#include + +#ifdef CONFIG_ARM64_PTR_AUTH +/* + * Each key is a 128-bit quantity which is split across a pair of 64-bit + * registers (Lo and Hi). + */ +struct ptrauth_key { + unsigned long lo, hi; +}; + +/* + * We give each process its own keys, which are shared by all threads. The keys + * are inherited upon fork(), and reinitialised upon exec*(). + */ +struct ptrauth_keys { + struct ptrauth_key apia; + struct ptrauth_key apib; + struct ptrauth_key apda; + struct ptrauth_key apdb; + struct ptrauth_key apga; +}; + +static inline void ptrauth_keys_init(struct ptrauth_keys *keys) +{ + if (system_supports_address_auth()) + get_random_bytes(keys, sizeof(struct ptrauth_key) * 4); + + if (system_supports_generic_auth()) + get_random_bytes(&keys->apga, sizeof(struct ptrauth_key)); +} + +#define __ptrauth_key_install(k, v) \ +do { \ + struct ptrauth_key __pki_v = (v); \ + write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \ + write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ +} while (0) + +static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) +{ + if (system_supports_address_auth()) { + __ptrauth_key_install(APIA, keys->apia); + __ptrauth_key_install(APIB, keys->apib); + __ptrauth_key_install(APDA, keys->apda); + __ptrauth_key_install(APDB, keys->apdb); + } + + if (system_supports_generic_auth()) + __ptrauth_key_install(APGA, keys->apga); +} + +#define ptrauth_thread_init_user(tsk) \ +do { \ + struct task_struct *__ptiu_tsk = (tsk); \ + ptrauth_keys_init(&__ptiu_tsk->thread_info.keys_user); \ + ptrauth_keys_switch(&__ptiu_tsk->thread_info.keys_user); \ +} while (0) + +#define ptrauth_thread_switch(tsk) \ + ptrauth_keys_switch(&(tsk)->thread_info.keys_user) + +#else /* CONFIG_ARM64_PTR_AUTH */ +#define ptrauth_thread_init_user(tsk) +#define ptrauth_thread_switch(tsk) +#endif /* CONFIG_ARM64_PTR_AUTH */ + +#endif /* __ASM_POINTER_AUTH_H */ diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index cb2c10a8f0a8..ea9272fb52d4 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -28,6 +28,7 @@ struct task_struct; #include +#include #include #include @@ -43,6 +44,9 @@ struct thread_info { u64 ttbr0; /* saved TTBR0_EL1 */ #endif int preempt_count; /* 0 => preemptable, <0 => bug */ +#ifdef CONFIG_ARM64_PTR_AUTH + struct ptrauth_keys keys_user; +#endif }; #define thread_saved_pc(tsk) \ diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 2bcd6e4f3474..22efc70aa0a1 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -49,5 +49,7 @@ #define HWCAP_ILRCPC (1 << 26) #define HWCAP_FLAGM (1 << 27) #define HWCAP_SSBS (1 << 28) +#define HWCAP_PACA (1 << 29) +#define HWCAP_PACG (1 << 30) #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index f8e3c3568a79..6daa2f451eb9 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1154,6 +1154,12 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused) #endif /* CONFIG_ARM64_RAS_EXTN */ #ifdef CONFIG_ARM64_PTR_AUTH +static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap) +{ + sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | + SCTLR_ELx_ENDA | SCTLR_ELx_ENDB); +} + static bool has_address_auth(const struct arm64_cpu_capabilities *entry, int __unused) { @@ -1431,6 +1437,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .capability = ARM64_HAS_ADDRESS_AUTH, .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_address_auth, + .cpu_enable = cpu_enable_address_auth, }, { .desc = "Generic authentication (architected algorithm)", @@ -1504,6 +1511,12 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE), #endif HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, HWCAP_SSBS), +#ifdef CONFIG_ARM64_PTR_AUTH + { .desc = "HWCAP_PACA", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_address_auth, + .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACA }, + { .desc = "HWCAP_PACG", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_generic_auth, + .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACG }, +#endif {}, }; diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index bcc2831399cb..e7c7cad8dd85 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -82,6 +82,8 @@ static const char *const hwcap_str[] = { "ilrcpc", "flagm", "ssbs", + "paca", + "pacg", NULL }; diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index d9a4c2d6dd8b..17a6b4dd6e46 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -57,6 +57,7 @@ #include #include #include +#include #include #ifdef CONFIG_STACKPROTECTOR @@ -429,6 +430,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, contextidr_thread_switch(next); entry_task_switch(next); uao_thread_switch(next); + ptrauth_thread_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -496,4 +498,6 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) void arch_setup_new_exec(void) { current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; + + ptrauth_thread_init_user(current); }