From patchwork Mon Jun 24 14:32:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 167595 Delivered-To: patch@linaro.org Received: by 2002:a92:4782:0:0:0:0:0 with SMTP id e2csp4307757ilk; Mon, 24 Jun 2019 07:33:19 -0700 (PDT) X-Google-Smtp-Source: APXvYqyyXDJ4YDOO80lbBeprZgJ3afXBh9gYQOVGwtfIPMDukZN3iHExuwF5xTWi3sVxDng9+EP4 X-Received: by 2002:a65:645a:: with SMTP id s26mr7062290pgv.70.1561386798828; Mon, 24 Jun 2019 07:33:18 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1561386798; cv=none; d=google.com; s=arc-20160816; b=eYjRkdCT9W8p/yczXU3Y7DPXBqgYA4BG2r1hNiwq6VMqIOjDXcbxMZi2IJSijkAZto k7iJWrP9z5rNMkVJPoGNPFf7IE4uv9ZFQqG4Gdz4IIySHLVmbN0xu+dAJh/++nLnHdcv 1ErISykiuQzF5M+Rc7ytHW4IunyVbKOlB779qvs0o0bXoe99MSHLPmIl/Y4L5TSmW7Yg CGB/3ks729Pe3jD+3dvVWVGpMe0r1ActlLnDTTW3nxIrB/LZyMl+u546bKgQnGYVYbbO Fl+zPJs2kKwAz4wbS2A7W5pgYVGfmB1YiSwO5q4Q+jHXjuoz9MvXSwXzdhLgeyFJLtXD gDMw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:from:subject:references :mime-version:message-id:in-reply-to:date:dkim-signature; bh=tdsFjTMGAQv67ujvxigoDDdQZRY2KjUSUmhKVVkpkn4=; b=QIdF0BsoEDMhRfenO1hx3KYAcUqLSBXHUXZ3VVQJ8Trbs47qEoZ4tA2gX3jMeCSA3v VZ8Bx5W6AZpWhVO/jYnUjvICuCjbK8FUEcPdxYxnl0pL5k2VcqwdL7MWHMA9iHNAa22X PXBG72zGE25qo9U2oa3L5YgUYrpbNduxCtmFQcW7yRi1E3ffjiMIxHIjRD2oyF/W9yYr fu8XMdSyhHZalvJk55OGG1Lz17rSXmba9W5gCt3QFRuuFRktsfPn5bpYpz1eHZLHMNcw dYKlsV32OVqo52wlYxgEMsmr7c+ZIyCVf5g0Zhx3aZDdu3QAtLdnoTmc7vi7jy6EFhvt kV7w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=FXzFphxx; 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; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id q26si10305002pgl.114.2019.06.24.07.33.18; Mon, 24 Jun 2019 07:33:18 -0700 (PDT) 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; dkim=pass header.i=@google.com header.s=20161025 header.b=FXzFphxx; 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; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729024AbfFXOdR (ORCPT + 30 others); Mon, 24 Jun 2019 10:33:17 -0400 Received: from mail-qk1-f201.google.com ([209.85.222.201]:44587 "EHLO mail-qk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728950AbfFXOdL (ORCPT ); Mon, 24 Jun 2019 10:33:11 -0400 Received: by mail-qk1-f201.google.com with SMTP id c207so16299894qkb.11 for ; Mon, 24 Jun 2019 07:33:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=tdsFjTMGAQv67ujvxigoDDdQZRY2KjUSUmhKVVkpkn4=; b=FXzFphxxhZ4gPnsyEfmwPCsKU++pk+tQLetKbeAD+kL30Os8wS6jTLC1FyOAwqzwG8 qyqQOp0cn9zhOxk5JMc5l0oFOeAxffwozBD6EHBuMf+g1H99GLA8bpnvyE5lvxYcPoDB v2rQKkSx4a1aPHdMXcrdb+qKLQ+UK6soAayiCti7WfamiWLUJerS5dovTZg3VJFuihmF +v/xLmshrLGJKdmPtygjRvR0B/9N40Gy0gePQDOh5lqArA5l4cIbWua1LmJOGhLkH+qh WyoDSORUw+ozGMLmAgsxhF4/FNkbLzS7Jm3py0t8t64ITR+1csKXPcI1wZdyVVS2QdaX HNag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=tdsFjTMGAQv67ujvxigoDDdQZRY2KjUSUmhKVVkpkn4=; b=PvOBm5owkMhfDaCZESIzCtkn9x1qYEXzgkVG+6Hlcwt90wmsLipQQYeAn/pMRltn1I ZsYycqlWQ3bpNW3EA3xsS8m9EaUONcELHXlAPJxqKpGd+4OF2IXDZybdb7zsoNS5SGQq qMVLNw2P7grE57EbeVHrVVPvIHCh5t6xzUmBxPFzXk/xAXWoYYcUgrGmch/gzt/3r5Bw uCvBJE2AFFKpSCojecHKm17BeNS8nd/jH5bjaCto6KWBUZojiy4nsdJIU9L6wjyug+8z p9CirYKWaAJHctnHPjiWcJdYvSZ8RI58rpteSou3jf91pOC92KiHMu6nR1xjkbEbsFXu AyKw== X-Gm-Message-State: APjAAAUV67pkAuJUvY8+gd19tFX0qL8cBe0P1BdiLAwPPSY9hqRZ/BL+ WN39K+tUYI7qzbE3hgJ8SYldjU9yaizVbl+F X-Received: by 2002:a05:620a:1292:: with SMTP id w18mr17480585qki.416.1561386790744; Mon, 24 Jun 2019 07:33:10 -0700 (PDT) Date: Mon, 24 Jun 2019 16:32:47 +0200 In-Reply-To: Message-Id: <653598b3cfcd80f0cc69f72a214e156bb1afde68.1561386715.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v18 02/15] arm64: Introduce prctl() options to control the tagged user addresses ABI From: Andrey Konovalov To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Luc Van Oostenryck , Dave Martin , Khalid Aziz , enh , Jason Gunthorpe , Christoph Hellwig , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Catalin Marinas It is not desirable to relax the ABI to allow tagged user addresses into the kernel indiscriminately. This patch introduces a prctl() interface for enabling or disabling the tagged ABI with a global sysctl control for preventing applications from enabling the relaxed ABI (meant for testing user-space prctl() return error checking without reconfiguring the kernel). The ABI properties are inherited by threads of the same application and fork()'ed children but cleared on execve(). A Kconfig option allows the overall disabling of the relaxed ABI. The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle MTE-specific settings like imprecise vs precise exceptions. Signed-off-by: Catalin Marinas Signed-off-by: Andrey Konovalov --- arch/arm64/Kconfig | 9 ++++ arch/arm64/include/asm/processor.h | 8 ++++ arch/arm64/include/asm/thread_info.h | 1 + arch/arm64/include/asm/uaccess.h | 4 +- arch/arm64/kernel/process.c | 72 ++++++++++++++++++++++++++++ include/uapi/linux/prctl.h | 5 ++ kernel/sys.c | 12 +++++ 7 files changed, 110 insertions(+), 1 deletion(-) -- 2.22.0.410.gd8fdbe21b5-goog diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 697ea0510729..55fbaf20af2d 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1107,6 +1107,15 @@ config ARM64_SW_TTBR0_PAN zeroed area and reserved ASID. The user access routines restore the valid TTBR0_EL1 temporarily. +config ARM64_TAGGED_ADDR_ABI + bool "Enable the tagged user addresses syscall ABI" + default y + help + When this option is enabled, user applications can opt in to a + relaxed ABI via prctl() allowing tagged addresses to be passed + to system calls as pointer arguments. For details, see + Documentation/arm64/tagged-address-abi.txt. + menuconfig COMPAT bool "Kernel support for 32-bit EL0" depends on ARM64_4K_PAGES || EXPERT diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index fd5b1a4efc70..ee86070a28d4 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -296,6 +296,14 @@ extern void __init minsigstksz_setup(void); /* PR_PAC_RESET_KEYS prctl */ #define PAC_RESET_KEYS(tsk, arg) ptrauth_prctl_reset_keys(tsk, arg) +#ifdef CONFIG_ARM64_TAGGED_ADDR_ABI +/* PR_{SET,GET}_TAGGED_ADDR_CTRL prctl */ +long set_tagged_addr_ctrl(unsigned long arg); +long get_tagged_addr_ctrl(void); +#define SET_TAGGED_ADDR_CTRL(arg) set_tagged_addr_ctrl(arg) +#define GET_TAGGED_ADDR_CTRL() get_tagged_addr_ctrl() +#endif + /* * For CONFIG_GCC_PLUGIN_STACKLEAK * diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 2372e97db29c..4f81c4f15404 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -88,6 +88,7 @@ void arch_release_task_struct(struct task_struct *tsk); #define TIF_SVE 23 /* Scalable Vector Extension in use */ #define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */ #define TIF_SSBD 25 /* Wants SSB mitigation */ +#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */ #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index a138e3b4f717..097d6bfac0b7 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -62,7 +62,9 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si { unsigned long ret, limit = current_thread_info()->addr_limit; - addr = untagged_addr(addr); + if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) && + test_thread_flag(TIF_TAGGED_ADDR)) + addr = untagged_addr(addr); __chk_user_ptr(addr); asm volatile( diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 9856395ccdb7..60e70158a4a1 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -307,11 +308,18 @@ static void tls_thread_flush(void) } } +static void flush_tagged_addr_state(void) +{ + if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI)) + clear_thread_flag(TIF_TAGGED_ADDR); +} + void flush_thread(void) { fpsimd_flush_thread(); tls_thread_flush(); flush_ptrace_hw_breakpoint(current); + flush_tagged_addr_state(); } void release_thread(struct task_struct *dead_task) @@ -541,3 +549,67 @@ void arch_setup_new_exec(void) ptrauth_thread_init_user(current); } + +#ifdef CONFIG_ARM64_TAGGED_ADDR_ABI +/* + * Control the relaxed ABI allowing tagged user addresses into the kernel. + */ +static unsigned int tagged_addr_prctl_allowed = 1; + +long set_tagged_addr_ctrl(unsigned long arg) +{ + if (!tagged_addr_prctl_allowed) + return -EINVAL; + if (is_compat_task()) + return -EINVAL; + if (arg & ~PR_TAGGED_ADDR_ENABLE) + return -EINVAL; + + update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); + + return 0; +} + +long get_tagged_addr_ctrl(void) +{ + if (!tagged_addr_prctl_allowed) + return -EINVAL; + if (is_compat_task()) + return -EINVAL; + + if (test_thread_flag(TIF_TAGGED_ADDR)) + return PR_TAGGED_ADDR_ENABLE; + + return 0; +} + +/* + * Global sysctl to disable the tagged user addresses support. This control + * only prevents the tagged address ABI enabling via prctl() and does not + * disable it for tasks that already opted in to the relaxed ABI. + */ +static int zero; +static int one = 1; + +static struct ctl_table tagged_addr_sysctl_table[] = { + { + .procname = "tagged_addr", + .mode = 0644, + .data = &tagged_addr_prctl_allowed, + .maxlen = sizeof(int), + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, + { } +}; + +static int __init tagged_addr_init(void) +{ + if (!register_sysctl("abi", tagged_addr_sysctl_table)) + return -EINVAL; + return 0; +} + +core_initcall(tagged_addr_init); +#endif /* CONFIG_ARM64_TAGGED_ADDR_ABI */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 094bb03b9cc2..2e927b3e9d6c 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -229,4 +229,9 @@ struct prctl_mm_map { # define PR_PAC_APDBKEY (1UL << 3) # define PR_PAC_APGAKEY (1UL << 4) +/* Tagged user address controls for arm64 */ +#define PR_SET_TAGGED_ADDR_CTRL 55 +#define PR_GET_TAGGED_ADDR_CTRL 56 +# define PR_TAGGED_ADDR_ENABLE (1UL << 0) + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 2969304c29fe..c6c4d5358bd3 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -124,6 +124,12 @@ #ifndef PAC_RESET_KEYS # define PAC_RESET_KEYS(a, b) (-EINVAL) #endif +#ifndef SET_TAGGED_ADDR_CTRL +# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL) +#endif +#ifndef GET_TAGGED_ADDR_CTRL +# define GET_TAGGED_ADDR_CTRL() (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2492,6 +2498,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = PAC_RESET_KEYS(me, arg2); break; + case PR_SET_TAGGED_ADDR_CTRL: + error = SET_TAGGED_ADDR_CTRL(arg2); + break; + case PR_GET_TAGGED_ADDR_CTRL: + error = GET_TAGGED_ADDR_CTRL(); + break; default: error = -EINVAL; break;