[1/7] ima: on soft reboot, restore the measurement list

Message ID	1470313475-20090-2-git-send-email-zohar@linux.vnet.ibm.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Gateway: Authorized Use Only! Violators will be prosecuted for <linux-security-module@vger.kernel.org> from <zohar@linux.vnet.ibm.com>; Thu, 4 Aug 2016 22:24:54 +1000 Gateway: Authorized Use Only! Violators will be prosecuted; Thu, 4 Aug 2016 22:24:51 +1000 From: Mimi Zohar <zohar@linux.vnet.ibm.com> To: linux-security-module@vger.kernel.org Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>, linux-ima-devel@lists.sourceforge.net, Dave Young <dyoung@redhat.com>, kexec@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Subject: [PATCH 1/7] ima: on soft reboot, restore the measurement list Date: Thu, 4 Aug 2016 08:24:29 -0400 In-Reply-To: <1470313475-20090-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1470313475-20090-1-git-send-email-zohar@linux.vnet.ibm.com> Message-Id: <1470313475-20090-2-git-send-email-zohar@linux.vnet.ibm.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk

diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index c34599f..c0ce7b1 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -8,4 +8,5 @@ obj-$(CONFIG_IMA) += ima.o ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \ ima_policy.o ima_template.o ima_template_lib.o ima_buffer.o ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o +ima-$(CONFIG_KEXEC_FILE) += ima_kexec.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index b5728da..84e8d36 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -102,6 +102,13 @@ struct ima_queue_entry { }; extern struct list_head ima_measurements; /* list of all measurements */ +/* Some details preceding the binary serialized measurement list */ +struct ima_kexec_hdr { + unsigned short version; + unsigned long buffer_size; + unsigned long count; +} __packed; + /* Internal IMA function definitions */ int ima_init(void); int ima_fs_init(void); @@ -122,6 +129,9 @@ int ima_init_crypto(void); void ima_putc(struct seq_file *m, void *data, int datalen); void ima_print_digest(struct seq_file *m, u8 *digest, u32 size); struct ima_template_desc *ima_template_desc_current(void); +void ima_load_kexec_buffer(void); +int ima_restore_measurement_entry(struct ima_template_entry *entry); +int ima_restore_measurement_list(loff_t bufsize, void *buf); int ima_init_template(void); /* diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 32912bd..3ba0ca4 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -128,6 +128,8 @@ int __init ima_init(void) if (rc != 0) return rc; + ima_load_kexec_buffer(); + rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */ if (rc != 0) return rc; diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c new file mode 100644 index 0000000..6a046ad --- /dev/null +++ b/security/integrity/ima/ima_kexec.c @@ -0,0 +1,55 @@ +/* + * Copyright (C) 2016 IBM Corporation + * + * Authors: + * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> + * Mimi Zohar <zohar@linux.vnet.ibm.com> + * + * 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 <linux/fcntl.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/seq_file.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> +#include <linux/parser.h> +#include <linux/vmalloc.h> +#include <linux/kexec.h> +#include <linux/reboot.h> + +#include "ima.h" + +/* + * Restore the measurement list from the previous kernel. + */ +void ima_load_kexec_buffer(void) +{ + void *kexec_buffer = NULL; + size_t kexec_buffer_size = 0; + int rc; + + rc = kexec_get_handover_buffer(&kexec_buffer, &kexec_buffer_size); + switch (rc) { + case 0: + rc = ima_restore_measurement_list(kexec_buffer_size, + kexec_buffer); + if (rc != 0) + pr_err("Failed to restore the measurement list: %d\n", + rc); + + kexec_free_handover_buffer(); + break; + case -ENOTSUPP: + pr_debug("Restoring the measurement list not supported\n"); + break; + case -ENOENT: + pr_debug("No measurement list to restore\n"); + break; + default: + pr_debug("Error restoring the measurement list: %d\n", rc); + } +} diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 32f6ac0..4b1bb77 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -149,3 +149,13 @@ out: op, audit_cause, result, audit_info); return result; } + +int ima_restore_measurement_entry(struct ima_template_entry *entry) +{ + int result = 0; + + mutex_lock(&ima_extend_list_mutex); + result = ima_add_digest_entry(entry); + mutex_unlock(&ima_extend_list_mutex); + return result; +} diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index febd12e..c6510f0 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -205,3 +205,174 @@ int __init ima_init_template(void) return result; } + +static int ima_restore_template_data(struct ima_template_desc *template_desc, + void *template_data, + int template_data_size, + struct ima_template_entry **entry) +{ + struct binary_field_data { + u32 len; + u8 data[0]; + } __packed; + + struct binary_field_data *field_data; + int offset = 0; + int ret = 0; + int i; + + *entry = kzalloc(sizeof(**entry) + + template_desc->num_fields * sizeof(struct ima_field_data), + GFP_NOFS); + if (!*entry) + return -ENOMEM; + + (*entry)->template_desc = template_desc; + for (i = 0; i < template_desc->num_fields; i++) { + field_data = template_data + offset; + + /* Each field of the template data is prefixed with a length. */ + if (offset > (template_data_size - sizeof(field_data->len))) { + pr_err("Restoring the template field failed\n"); + ret = -EINVAL; + break; + } + offset += sizeof(field_data->len); + + if (offset > (template_data_size - field_data->len)) { + pr_err("Restoring the template field data failed\n"); + ret = -EINVAL; + break; + } + offset += field_data->len; + + (*entry)->template_data[i].len = field_data->len; + (*entry)->template_data_len += sizeof(field_data->len); + + (*entry)->template_data[i].data = + kzalloc(field_data->len + 1, GFP_KERNEL); + if (!(*entry)->template_data[i].data) { + ret = -ENOMEM; + break; + } + memcpy((*entry)->template_data[i].data, field_data->data, + field_data->len); + (*entry)->template_data_len += field_data->len; + } + + if (ret < 0) { + ima_free_template_entry(*entry); + *entry = NULL; + } + + return ret; +} + +#define MAX_TEMPLATE_NAME_LEN 30 + +/* Restore the serialized binary measurement list without extending PCRs. */ +int ima_restore_measurement_list(loff_t size, void *buf) +{ + struct binary_hdr_v1 { + u32 pcr; + u8 digest[TPM_DIGEST_SIZE]; + u32 template_name_len; + char template_name[0]; + } __packed; + char template_name[MAX_TEMPLATE_NAME_LEN]; + + struct binary_data_v1 { + u32 template_data_size; + char template_data[0]; + } __packed; + + struct ima_kexec_hdr *khdr = buf; + struct binary_hdr_v1 *hdr_v1; + struct binary_data_v1 *data_v1; + + void *bufp = buf + sizeof(*khdr); + void *bufendp = buf + khdr->buffer_size; + struct ima_template_entry *entry; + struct ima_template_desc *template_desc; + unsigned long count = 0; + int ret = 0; + + if (!buf || size < sizeof(*khdr)) + return 0; + + if (khdr->version != 1) { + pr_err("attempting to restore a incompatible measurement list"); + return 0; + } + + /* + * ima kexec buffer prefix: version, buffer size, count + * v1 format: pcr, digest, template-name-len, template-name, + * template-data-size, template-data + */ + while ((bufp < bufendp) && (count++ < khdr->count)) { + if (count > ULONG_MAX - 1) { + pr_err("attempting to restore too many measurements"); + ret = -EINVAL; + } + + hdr_v1 = bufp; + if ((hdr_v1->template_name_len > MAX_TEMPLATE_NAME_LEN) || + ((bufp + hdr_v1->template_name_len) > bufendp)) { + pr_err("attempting to restore a template name \ + that is too long\n"); + ret = -EINVAL; + break; + } + bufp += sizeof(*hdr_v1); + + /* template name is not null terminated */ + memcpy(template_name, bufp, hdr_v1->template_name_len); + template_name[hdr_v1->template_name_len] = 0; + + if (strcmp(template_name, "ima") == 0) { + pr_err("attempting to restore an unsupported \ + template \"%s\" failed\n", template_name); + ret = -EINVAL; + break; + } + data_v1 = bufp += (u_int8_t)hdr_v1->template_name_len; + + /* get template format */ + template_desc = lookup_template_desc(template_name); + if (!template_desc) { + pr_err("template \"%s\" not found\n", template_name); + ret = -EINVAL; + break; + } + + if (bufp > (bufendp - sizeof(data_v1->template_data_size))) { + pr_err("restoring the template data size failed\n"); + ret = -EINVAL; + break; + } + bufp += (u_int8_t) sizeof(data_v1->template_data_size); + + if (bufp > (bufendp - data_v1->template_data_size)) { + pr_err("restoring the template data failed\n"); + ret = -EINVAL; + break; + } + + ret = ima_restore_template_data(template_desc, + data_v1->template_data, + data_v1->template_data_size, + &entry); + if (ret < 0) + break; + + memcpy(entry->digest, hdr_v1->digest, TPM_DIGEST_SIZE); + entry->pcr = hdr_v1->pcr; + ret = ima_restore_measurement_entry(entry); + if (ret < 0) + break; + + bufp += data_v1->template_data_size; + } + return ret; +}

[1/7] ima: on soft reboot, restore the measurement list

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