From patchwork Fri Nov 13 19:22:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11904509 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 01281697 for ; Fri, 13 Nov 2020 19:23:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4A1D22249 for ; Fri, 13 Nov 2020 19:23:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="gs4Qky8C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726286AbgKMTWw (ORCPT ); Fri, 13 Nov 2020 14:22:52 -0500 Received: from linux.microsoft.com ([13.77.154.182]:48918 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726228AbgKMTWw (ORCPT ); Fri, 13 Nov 2020 14:22:52 -0500 Received: from localhost.localdomain (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 6A43B20C28C0; Fri, 13 Nov 2020 11:22:50 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 6A43B20C28C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1605295371; bh=Qh7VUYPFclMMyWjaiJKYdfprvYeY0xzrb/fwOTNg+5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gs4Qky8C+MDiORLtu9E9p35ld+uossKJVpx6IWJQ4otQXaY4iFDWm/yVEISJblcSG 0NqPof29nsJDYsXSZQeUHXbtki+kNvzXj39XsdFlesibHBKGkTtEzQqYmVhWtGNv69 0jgsuwKrEy3QMa/b4D4V7+LV4bFgVsuEngeOmhhc= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, bauerman@linux.ibm.com, robh@kernel.org, gregkh@linuxfoundation.org, james.morse@arm.com, catalin.marinas@arm.com, sashal@kernel.org, will@kernel.org, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, robh+dt@kernel.org, frowand.list@gmail.com, vincenzo.frascino@arm.com, mark.rutland@arm.com, dmitry.kasatkin@gmail.com, jmorris@namei.org, serge@hallyn.com, pasha.tatashin@soleen.com, allison@lohutok.net, kstewart@linuxfoundation.org, takahiro.akashi@linaro.org, tglx@linutronix.de, masahiroy@kernel.org, bhsharma@redhat.com, mbrugger@suse.com, hsinyi@chromium.org, tao.li@vivo.com, christophe.leroy@c-s.fr Cc: linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, prsriva@linux.microsoft.com, balajib@linux.microsoft.com Subject: [PATCH v9 3/8] ima: Define get_ima_kexec_buffer() in drivers/of Date: Fri, 13 Nov 2020 11:22:38 -0800 Message-Id: <20201113192243.1993-4-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201113192243.1993-1-nramas@linux.microsoft.com> References: <20201113192243.1993-1-nramas@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The function do_get_kexec_buffer(), defined in arch/powerpc/kexec/ima.c, retrieves the address and size of the given property from the device tree blob. This function does not have architecture specific code, but is currently limited to powerpc. This function correctly handles a device tree property that is a child node of the root node, but not anything other than the immediate root child nodes. Define an architecture independent function, namely get_ima_kexec_buffer(), in "drivers/of/ima_kexec.c". This function retrieves the chosen node, namely "linux,ima-kexec-buffer", from the device tree, and returns the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call. Co-developed-by: Prakhar Srivastava Signed-off-by: Prakhar Srivastava Signed-off-by: Lakshmi Ramasubramanian --- drivers/of/Makefile | 3 ++ drivers/of/ima_kexec.c | 65 ++++++++++++++++++++++++++++++++++++++++++ include/linux/kexec.h | 11 +++++++ 3 files changed, 79 insertions(+) create mode 100644 drivers/of/ima_kexec.c diff --git a/drivers/of/Makefile b/drivers/of/Makefile index 5f42aa3bbac6..5b4af994fed0 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -18,6 +18,9 @@ ifdef CONFIG_OF_FLATTREE ifdef CONFIG_KEXEC_FILE obj-y += kexec_fdt.o endif +ifdef CONFIG_HAVE_IMA_KEXEC +obj-y += ima_kexec.o +endif endif obj-$(CONFIG_OF_UNITTEST) += unittest-data/ diff --git a/drivers/of/ima_kexec.c b/drivers/of/ima_kexec.c new file mode 100644 index 000000000000..9c14777404f2 --- /dev/null +++ b/drivers/of/ima_kexec.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2020 Microsoft Corporation + * + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) + * + * File: ima_kexec.c + * Defines functions to handle IMA measurement list across + * kexec system call. + */ + +#define pr_fmt(fmt) "OF: ima-kexec: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * get_ima_kexec_buffer - Get address and size of IMA kexec buffer + * + * @fdt: Flattened Device Tree + * @chosen_node: Offset of chosen node in the FDT + * @addr: Return address of the node + * @size: Return size of the node + */ +int get_ima_kexec_buffer(void *fdt, int chosen_node, + unsigned long *addr, size_t *size) +{ + const void *prop; + int addr_cells, size_cells, prop_len; + struct device_node *root; + + root = of_find_node_by_path("/"); + if (!root) + return -EINVAL; + + addr_cells = of_n_addr_cells(root); + size_cells = of_n_size_cells(root); + + of_node_put(root); + + if (fdt) + prop = fdt_getprop(fdt, chosen_node, + "linux,ima-kexec-buffer", &prop_len); + else + prop = of_get_property(of_chosen, + "linux,ima-kexec-buffer", &prop_len); + + if (!prop) + return -ENOENT; + + if (prop_len < 4 * (addr_cells + size_cells)) + return -EINVAL; + + *addr = of_read_number(prop, addr_cells); + *size = of_read_number(prop + 4 * addr_cells, size_cells); + + return 0; +} diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 4ce09ccf2628..a4f248caa483 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -407,6 +407,17 @@ static inline int kexec_crash_loaded(void) { return 0; } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */ +#if defined(CONFIG_OF_FLATTREE) && defined(CONFIG_HAVE_IMA_KEXEC) +extern int get_ima_kexec_buffer(void *fdt, int chosen_node, + unsigned long *addr, size_t *size); +#else +static inline int get_ima_kexec_buffer(void *fdt, int chosen_node, + unsigned long *addr, size_t *size) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_OF_FLATTREE && CONFIG_HAVE_IMA_KEXEC */ + #if defined(CONFIG_OF_FLATTREE) && defined(CONFIG_KEXEC_FILE) extern int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);