Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934300AbcKJO6h (ORCPT ); Thu, 10 Nov 2016 09:58:37 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37268 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934068AbcKJO4v (ORCPT ); Thu, 10 Nov 2016 09:56:51 -0500 From: Mimi Zohar To: linux-security-module Cc: Thiago Jung Bauermann , linux-ima-devel@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Andrew Morton , Dmitry Kasatkin , Mimi Zohar Subject: [PATCHC v7 01/10] powerpc: ima: Get the kexec buffer passed by the previous kernel Date: Thu, 10 Nov 2016 09:56:11 -0500 X-Mailer: git-send-email 2.1.0 In-Reply-To: <1478789780-17719-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1478789780-17719-1-git-send-email-zohar@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16111014-0040-0000-0000-000001FD1F9B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16111014-0041-0000-0000-00000AE10931 Message-Id: <1478789780-17719-2-git-send-email-zohar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-10_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611100270 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8840 Lines: 293 From: Thiago Jung Bauermann The IMA kexec buffer allows the currently running kernel to pass the measurement list via a kexec segment to the kernel that will be kexec'd. The second kernel can check whether the previous kernel sent the buffer and retrieve it. This is the architecture-specific part which enables IMA to receive the measurement list passed by the previous kernel. It will be used in the next patch. The change in machine_kexec_64.c is to factor out the logic of removing an FDT memory reservation so that it can be used by remove_ima_buffer. Changelog v6: - The kexec_file_load patches v9 already define delete_fdt_mem_rsv, so now we just need to export it. Changelog v5: - New patch in this version. This code was previously in the kexec buffer handover patch series. Changelog relative to kexec handover patches v5: - Added CONFIG_HAVE_IMA_KEXEC. - Added arch/powerpc/include/asm/ima.h. - Moved code to arch/powerpc/kernel/ima_kexec.c. - Renamed functions to variations of ima_kexec_buffer instead of variations of kexec_handover_buffer. - Use a single property /chosen/linux,ima-kexec-buffer containing the buffer address and length, instead of /chosen/linux,kexec-handover-buffer-{start,end}. - Use #address-cells and #size-cells to read the DT property. - Use size_t instead of unsigned long for size arguments. - Always remove linux,ima-kexec-buffer and its memory reservation when preparing a device tree for kexec_file_load. Signed-off-by: Thiago Jung Bauermann Acked-by: "Eric W. Biederman" Signed-off-by: Mimi Zohar --- arch/Kconfig | 3 + arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/ima.h | 13 +++ arch/powerpc/include/asm/kexec.h | 1 + arch/powerpc/kernel/Makefile | 4 + arch/powerpc/kernel/ima_kexec.c | 132 ++++++++++++++++++++++++++++ arch/powerpc/kernel/machine_kexec_file_64.c | 5 +- 7 files changed, 158 insertions(+), 1 deletion(-) create mode 100644 arch/powerpc/include/asm/ima.h create mode 100644 arch/powerpc/kernel/ima_kexec.c diff --git a/arch/Kconfig b/arch/Kconfig index 659bdd079277..e1605ff286a1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -5,6 +5,9 @@ config KEXEC_CORE bool +config HAVE_IMA_KEXEC + bool + config OPROFILE tristate "OProfile system profiling" depends on PROFILING diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 897d0f14447d..40ee044f1915 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -458,6 +458,7 @@ config KEXEC config KEXEC_FILE bool "kexec file based system call" select KEXEC_CORE + select HAVE_IMA_KEXEC select BUILD_BIN2C depends on PPC64 depends on CRYPTO=y diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h new file mode 100644 index 000000000000..d5a72dd9b499 --- /dev/null +++ b/arch/powerpc/include/asm/ima.h @@ -0,0 +1,13 @@ +#ifndef _ASM_POWERPC_IMA_H +#define _ASM_POWERPC_IMA_H + +int ima_get_kexec_buffer(void **addr, size_t *size); +int ima_free_kexec_buffer(void); + +#ifdef CONFIG_IMA +void remove_ima_buffer(void *fdt, int chosen_node); +#else +static inline void remove_ima_buffer(void *fdt, int chosen_node) {} +#endif + +#endif /* _ASM_POWERPC_IMA_H */ diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h index 4497db7555b0..23056d2dc330 100644 --- a/arch/powerpc/include/asm/kexec.h +++ b/arch/powerpc/include/asm/kexec.h @@ -101,6 +101,7 @@ int setup_purgatory(struct kimage *image, const void *slave_code, int setup_new_fdt(void *fdt, unsigned long initrd_load_addr, unsigned long initrd_len, const char *cmdline); bool find_debug_console(const void *fdt); +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size); #endif /* CONFIG_KEXEC_FILE */ #else /* !CONFIG_KEXEC_CORE */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 424b13b1b2b0..c3b37171168c 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -111,6 +111,10 @@ obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o crash.o \ machine_kexec_$(BITS).o obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file_$(BITS).o elf_util.o \ kexec_elf_$(BITS).o +ifeq ($(CONFIG_HAVE_IMA_KEXEC)$(CONFIG_IMA),yy) +obj-y += ima_kexec.o +endif + obj-$(CONFIG_AUDIT) += audit.o obj64-$(CONFIG_AUDIT) += compat_audit.o diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c new file mode 100644 index 000000000000..36e5a5df3804 --- /dev/null +++ b/arch/powerpc/kernel/ima_kexec.c @@ -0,0 +1,132 @@ +/* + * Copyright (C) 2016 IBM Corporation + * + * Authors: + * Thiago Jung Bauermann + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include +#include +#include +#include +#include + +static int get_addr_size_cells(int *addr_cells, int *size_cells) +{ + 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); + + return 0; +} + +static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr, + size_t *size) +{ + int ret, addr_cells, size_cells; + + ret = get_addr_size_cells(&addr_cells, &size_cells); + if (ret) + return ret; + + if (len < 4 * (addr_cells + size_cells)) + return -ENOENT; + + *addr = of_read_number(prop, addr_cells); + *size = of_read_number(prop + 4 * addr_cells, size_cells); + + return 0; +} + +/** + * ima_get_kexec_buffer - get IMA buffer from the previous kernel + * @addr: On successful return, set to point to the buffer contents. + * @size: On successful return, set to the buffer size. + * + * Return: 0 on success, negative errno on error. + */ +int ima_get_kexec_buffer(void **addr, size_t *size) +{ + int ret, len; + unsigned long tmp_addr; + size_t tmp_size; + const void *prop; + + prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len); + if (!prop) + return -ENOENT; + + ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size); + if (ret) + return ret; + + *addr = __va(tmp_addr); + *size = tmp_size; + + return 0; +} + +/** + * ima_free_kexec_buffer - free memory used by the IMA buffer + */ +int ima_free_kexec_buffer(void) +{ + int ret; + unsigned long addr; + size_t size; + struct property *prop; + + prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL); + if (!prop) + return -ENOENT; + + ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size); + if (ret) + return ret; + + ret = of_remove_property(of_chosen, prop); + if (ret) + return ret; + + return memblock_free(addr, size); + +} + +/** + * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt + * + * The IMA measurement buffer is of no use to a subsequent kernel, so we always + * remove it from the device tree. + */ +void remove_ima_buffer(void *fdt, int chosen_node) +{ + int ret, len; + unsigned long addr; + size_t size; + const void *prop; + + prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len); + if (!prop) + return; + + ret = do_get_kexec_buffer(prop, len, &addr, &size); + fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer"); + if (ret) + return; + + ret = delete_fdt_mem_rsv(fdt, addr, size); + if (!ret) + pr_debug("Removed old IMA buffer reservation.\n"); +} diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c index 9acc56d199f0..7b13634f71bf 100644 --- a/arch/powerpc/kernel/machine_kexec_file_64.c +++ b/arch/powerpc/kernel/machine_kexec_file_64.c @@ -28,6 +28,7 @@ #include #include #include +#include #define SLAVE_CODE_SIZE 256 @@ -363,7 +364,7 @@ int setup_purgatory(struct kimage *image, const void *slave_code, * * Return: 0 on success, or negative errno on error. */ -static int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size) +int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size) { int i, ret, num_rsvs = fdt_num_mem_rsv(fdt); @@ -511,6 +512,8 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr, } } + remove_ima_buffer(fdt, chosen_node); + ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0); if (ret) { pr_err("Error setting up the new device tree.\n"); -- 2.1.0