Received: by 2002:a25:b794:0:0:0:0:0 with SMTP id n20csp6089275ybh; Wed, 7 Aug 2019 17:09:23 -0700 (PDT) X-Google-Smtp-Source: APXvYqy9v5XZASIaSZsW9WvPK4EzUePF+zayrPJsw9Q79cLOIZywFYC6AhfRvABZ9RUd8+9oINYi X-Received: by 2002:a63:e901:: with SMTP id i1mr9830412pgh.451.1565222962773; Wed, 07 Aug 2019 17:09:22 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1565222962; cv=none; d=google.com; s=arc-20160816; b=cke5v6f/XZ+/vw71o2t/x4rQUFBtkUncVyZwFFcCazILLrKxGVFRaEmVBOxZX7h4/F LY5AZ2nbmN2PtgKXOXtEwqpu1NThJ54lI+PUCP4W+InpdjzNx4PEH13kjYsqCRD1c+ja c2qd84Ge8Sy+P51ngMrhG4KAfStje8qOgQsTAjEfRKy5ZRmbJqTpjhfY9TV8PzVgPVVL HMjqw6WjNnHu4kQ9axWfOGM/32FuL++UUkRWqKolAWizoQaI76IcAPa9y2Sh5nuN5Iwq JWbpsvkhbpgAEEZMBNIYIy0oPEnyjRaW7W/dLG7KjwzGi+X9qrB2cQJURLxwEpzwmSLA 71AQ== 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=klghF8F9jCh3lGq1PlqD6+/L30+aHC8n0RDXrpkxL3I=; b=0V8HUWQuEFpighFjGKHTQN8LrXRBU3uUUPxw+GHv4ImwVDw+1V/JGDzQT3r8JdViuq q38bMQLgCEzX37pRHRHCe87jqdKmSBNW6HkTYQ1gdCyvBrmKaZvaifIMdYPwo8XyHv9r Q9PNIOvP8887n/R2JdfXqp/Rd1q62v9RCF8S7E7GztKQOFlV8q5GFfhe1F/083Kg2lXP K2K3K08tYN4llkrHbe5Fm0lKcVL2Ty5GJt82T75qbHj5pt0w9L43YhFWyGq1jHfL/iwE 4rLgw9Snqp9PiSLTiOzQrxegMwpvGaYTwkO7lDIfH8H4ll2iGExyW7nXuljRTO59eez3 4/5w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=jOI6Zft9; 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 s3si50285371pgq.392.2019.08.07.17.09.07; Wed, 07 Aug 2019 17:09:22 -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=jOI6Zft9; 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 S2389656AbfHHAIH (ORCPT + 99 others); Wed, 7 Aug 2019 20:08:07 -0400 Received: from mail-vs1-f74.google.com ([209.85.217.74]:39956 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389643AbfHHAID (ORCPT ); Wed, 7 Aug 2019 20:08:03 -0400 Received: by mail-vs1-f74.google.com with SMTP id v9so23581133vsq.7 for ; Wed, 07 Aug 2019 17:08:03 -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=klghF8F9jCh3lGq1PlqD6+/L30+aHC8n0RDXrpkxL3I=; b=jOI6Zft91LaH5ULesiPku30JlGdDlh+e5fomVjEHP/R0JIaoCfDWnf8UtmRe25nGmp YThfS4C+mvfHhvlMJRTnaXzB5tTeg8/gkjENTfsrEUxPw7NhKyyD5cal4DxEIffiRAf0 BMKXHkBc5DU0Rgd5I35l4RRuq0yFOAoUAs/YjQT790Nyk19vRjoqspdFeoh6PrzLv9EE QWumUB/MT2t/cFS4hMeCCpBSWbk+COecWJcLm8yDgryR3pQk/ccrcY8A30l4C0Rxl8mD 3+CqTnfF8zaCxc7rHon+Piq1quuCtKLejUlIcNdqg1wu/Fv+Jpb1SY6r2WRO5RU461M5 paUg== 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=klghF8F9jCh3lGq1PlqD6+/L30+aHC8n0RDXrpkxL3I=; b=bakpjoSc4idHmtfS/XqL7tTKWgKPMJPrtwtqm2M8qkYHs/LiBwtyYsiLAGOsemkvSe +2af2zIu4bdfQNbOP7AsZcVXTszql01W86HM6Cs14FqPlXUBVMgdZGNghv2Al5dvON3+ GOfKjJfDEAoQgdeIBxzCyy2b8BBTB90YawzNN2GcoGXPM3I6PSJ7uNu5vOgV6nItWpdA MfBzoNkRP45G83vSu2TMgwp0oxPSxuZynPQwmoYCHFv96lhS+S7speiNdqcSuG/k92rn ePWYqSCGViiJS6EIGhBf7s1Gcp/Yyi30aAhN+jrn3aDeKkyDWIKAxyTMJu+HjkqvTvfQ 1d7w== X-Gm-Message-State: APjAAAUAQanpRtBAPiEDU1GW92WPNoGCai6GJ82h1GWAxZnNfXIU/7qm DXQq0YxzkvFL7+mLUpzY9SzvIvr9lLzPsmI1T+CG+A== X-Received: by 2002:a1f:180a:: with SMTP id 10mr4635961vky.45.1565222882784; Wed, 07 Aug 2019 17:08:02 -0700 (PDT) Date: Wed, 7 Aug 2019 17:07:07 -0700 In-Reply-To: <20190808000721.124691-1-matthewgarrett@google.com> Message-Id: <20190808000721.124691-16-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190808000721.124691-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V38 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Josh Boyer , David Howells , Matthew Garrett , Kees Cook , Dave Young , linux-acpi@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Boyer This option allows userspace to pass the RSDP address to the kernel, which makes it possible for a user to modify the workings of hardware. Reject the option when the kernel is locked down. This requires some reworking of the existing RSDP command line logic, since the early boot code also makes use of a command-line passed RSDP when locating the SRAT table before the lockdown code has been initialised. This is achieved by separating the command line RSDP path in the early boot code from the generic RSDP path, and then copying the command line RSDP into boot params in the kernel proper if lockdown is not enabled. If lockdown is enabled and an RSDP is provided on the command line, this will only be used when parsing SRAT (which shouldn't permit kernel code execution) and will be ignored in the rest of the kernel. (Modified by Matthew Garrett in order to handle the early boot RSDP environment) Signed-off-by: Josh Boyer Signed-off-by: David Howells Signed-off-by: Matthew Garrett Reviewed-by: Kees Cook cc: Dave Young cc: linux-acpi@vger.kernel.org --- arch/x86/boot/compressed/acpi.c | 19 +++++++++++++------ arch/x86/include/asm/acpi.h | 9 +++++++++ arch/x86/include/asm/x86_init.h | 2 ++ arch/x86/kernel/acpi/boot.c | 5 +++++ arch/x86/kernel/x86_init.c | 1 + drivers/acpi/osl.c | 14 +++++++++++++- include/linux/acpi.h | 6 ++++++ 7 files changed, 49 insertions(+), 7 deletions(-) diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index 15255f388a85..149795c369f2 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -26,7 +26,7 @@ struct mem_vector immovable_mem[MAX_NUMNODES*2]; */ #define MAX_ADDR_LEN 19 -static acpi_physical_address get_acpi_rsdp(void) +static acpi_physical_address get_cmdline_acpi_rsdp(void) { acpi_physical_address addr = 0; @@ -278,10 +278,7 @@ acpi_physical_address get_rsdp_addr(void) { acpi_physical_address pa; - pa = get_acpi_rsdp(); - - if (!pa) - pa = boot_params->acpi_rsdp_addr; + pa = boot_params->acpi_rsdp_addr; /* * Try to get EFI data from setup_data. This can happen when we're a @@ -311,7 +308,17 @@ static unsigned long get_acpi_srat_table(void) char arg[10]; u8 *entry; - rsdp = (struct acpi_table_rsdp *)(long)boot_params->acpi_rsdp_addr; + /* + * Check whether we were given an RSDP on the command line. We don't + * stash this in boot params because the kernel itself may have + * different ideas about whether to trust a command-line parameter. + */ + rsdp = (struct acpi_table_rsdp *)get_cmdline_acpi_rsdp(); + + if (!rsdp) + rsdp = (struct acpi_table_rsdp *)(long) + boot_params->acpi_rsdp_addr; + if (!rsdp) return 0; diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index aac686e1e005..bc9693c9107e 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -117,6 +117,12 @@ static inline bool acpi_has_cpu_in_madt(void) return !!acpi_lapic; } +#define ACPI_HAVE_ARCH_SET_ROOT_POINTER +static inline void acpi_arch_set_root_pointer(u64 addr) +{ + x86_init.acpi.set_root_pointer(addr); +} + #define ACPI_HAVE_ARCH_GET_ROOT_POINTER static inline u64 acpi_arch_get_root_pointer(void) { @@ -125,6 +131,7 @@ static inline u64 acpi_arch_get_root_pointer(void) void acpi_generic_reduced_hw_init(void); +void x86_default_set_root_pointer(u64 addr); u64 x86_default_get_root_pointer(void); #else /* !CONFIG_ACPI */ @@ -138,6 +145,8 @@ static inline void disable_acpi(void) { } static inline void acpi_generic_reduced_hw_init(void) { } +static inline void x86_default_set_root_pointer(u64 addr) { } + static inline u64 x86_default_get_root_pointer(void) { return 0; diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index ac0934189017..19435858df5f 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -134,10 +134,12 @@ struct x86_hyper_init { /** * struct x86_init_acpi - x86 ACPI init functions + * @set_root_poitner: set RSDP address * @get_root_pointer: get RSDP address * @reduced_hw_early_init: hardware reduced platform early init */ struct x86_init_acpi { + void (*set_root_pointer)(u64 addr); u64 (*get_root_pointer)(void); void (*reduced_hw_early_init)(void); }; diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 17b33ef604f3..04205ce127a1 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1760,6 +1760,11 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) e820__update_table_print(); } +void x86_default_set_root_pointer(u64 addr) +{ + boot_params.acpi_rsdp_addr = addr; +} + u64 x86_default_get_root_pointer(void) { return boot_params.acpi_rsdp_addr; diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index 1bef687faf22..18a799c8fa28 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -95,6 +95,7 @@ struct x86_init_ops x86_init __initdata = { }, .acpi = { + .set_root_pointer = x86_default_set_root_pointer, .get_root_pointer = x86_default_get_root_pointer, .reduced_hw_early_init = acpi_generic_reduced_hw_init, }, diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 9c0edf2fc0dd..d43df3a3fa8d 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -180,8 +181,19 @@ acpi_physical_address __init acpi_os_get_root_pointer(void) acpi_physical_address pa; #ifdef CONFIG_KEXEC - if (acpi_rsdp) + /* + * We may have been provided with an RSDP on the command line, + * but if a malicious user has done so they may be pointing us + * at modified ACPI tables that could alter kernel behaviour - + * so, we check the lockdown status before making use of + * it. If we trust it then also stash it in an architecture + * specific location (if appropriate) so it can be carried + * over further kexec()s. + */ + if (acpi_rsdp && !security_locked_down(LOCKDOWN_ACPI_TABLES)) { + acpi_arch_set_root_pointer(acpi_rsdp); return acpi_rsdp; + } #endif pa = acpi_arch_get_root_pointer(); if (pa) diff --git a/include/linux/acpi.h b/include/linux/acpi.h index e40e1e27ed8e..6b35f2f4cab3 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -643,6 +643,12 @@ bool acpi_gtdt_c3stop(int type); int acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem, int *timer_count); #endif +#ifndef ACPI_HAVE_ARCH_SET_ROOT_POINTER +static inline void acpi_arch_set_root_pointer(u64 addr) +{ +} +#endif + #ifndef ACPI_HAVE_ARCH_GET_ROOT_POINTER static inline u64 acpi_arch_get_root_pointer(void) { -- 2.22.0.770.g0f2c4a37fd-goog