[v2,06/15] ima: add parser of digest lists metadata

Message ID	20171107103710.10883-7-roberto.sassu@huawei.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-integrity-owner@kernel.org> From: Roberto Sassu <roberto.sassu@huawei.com> To: <linux-integrity@vger.kernel.org> CC: <linux-security-module@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>, <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <silviu.vlasceanu@huawei.com>, Roberto Sassu <roberto.sassu@huawei.com> Subject: [PATCH v2 06/15] ima: add parser of digest lists metadata Date: Tue, 7 Nov 2017 11:37:01 +0100 Message-ID: <20171107103710.10883-7-roberto.sassu@huawei.com> In-Reply-To: <20171107103710.10883-1-roberto.sassu@huawei.com> References: <20171107103710.10883-1-roberto.sassu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk

diff --git a/include/linux/fs.h b/include/linux/fs.h index 8d7d2850963c..06737235665b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2793,6 +2793,8 @@ extern int do_pipe_flags(int *, int); id(KEXEC_INITRAMFS, kexec-initramfs) \ id(POLICY, security-policy) \ id(X509_CERTIFICATE, x509-certificate) \ + id(DIGEST_LIST_METADATA, digest-list-metadata) \ + id(DIGEST_LIST, digest-list) \ id(MAX_ID, ) #define __fid_enumify(ENUM, dummy) READING_ ## ENUM, diff --git a/security/integrity/iint.c b/security/integrity/iint.c index c84e05866052..68c14d1dfc0c 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -209,4 +209,5 @@ void __init integrity_load_keys(void) { ima_load_x509(); evm_load_x509(); + ima_load_digest_list_metadata(); } diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 35ef69312811..fa40cee1e1a2 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -227,3 +227,22 @@ config IMA_APPRAISE_SIGNED_INIT default n help This option requires user-space init to be signed. + +config IMA_DIGEST_LIST + bool "Measure/appraise/audit files depending on uploaded digest lists" + depends on IMA + default n + help + This option allows users to load digest lists. If a measured file + has the same digest of one from loaded lists, IMA will not create + a new measurement entry or an audit log. They will be created only + when digest lists are loaded. If appraisal is enabled, access will + be permitted if the digest is in the digest list. File updates + will be permitted if, in addition, the digest is marked as mutable. + +config IMA_DIGEST_LIST_METADATA_PATH + string "IMA digest list metadata path" + depends on IMA_DIGEST_LIST + default "/etc/ima/digest_lists/metadata" + help + This option defines IMA digest list metadata path. diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 29f198bde02b..00dbe3a8cb71 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -9,4 +9,5 @@ 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-$(CONFIG_IMA_APPRAISE) += ima_appraise.o ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o +ima-$(CONFIG_IMA_DIGEST_LIST) += ima_digest_list.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 1f6591a57fea..1f43284788eb 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -158,6 +158,18 @@ int ima_restore_measurement_entry(struct ima_template_entry *entry); int ima_restore_measurement_list(loff_t bufsize, void *buf); struct ima_digest *ima_lookup_loaded_digest(u8 *digest); int ima_add_digest_data_entry(u8 *digest, u8 is_mutable); +#ifdef CONFIG_IMA_DIGEST_LIST +void __init ima_load_digest_list_metadata(void); +ssize_t ima_parse_digest_list_metadata(loff_t size, void *buf); +#else +static inline void ima_load_digest_list_metadata(void) +{ +} +static inline ssize_t ima_parse_digest_list_metadata(loff_t size, void *buf) +{ + return -ENOTSUPP; +} +#endif int ima_measurements_show(struct seq_file *m, void *v); unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); diff --git a/security/integrity/ima/ima_digest_list.c b/security/integrity/ima/ima_digest_list.c new file mode 100644 index 000000000000..28172424e5a2 --- /dev/null +++ b/security/integrity/ima/ima_digest_list.c @@ -0,0 +1,152 @@ +/* + * Copyright (C) 2017 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu <roberto.sassu@huawei.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, version 2 of the + * License. + * + * File: ima_digest_list.c + * Functions to manage digest lists. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/vmalloc.h> + +#include "ima.h" +#include "ima_template_lib.h" + +enum digest_metadata_fields {DATA_ALGO, DATA_DIGEST, DATA_SIGNATURE, + DATA_FILE_PATH, DATA_REF_ID, DATA_TYPE, + DATA__LAST}; + +static int ima_parse_digest_list_data(struct ima_field_data *data) +{ + void *digest_list; + loff_t digest_list_size; + u16 data_algo = le16_to_cpu(*(u16 *)data[DATA_ALGO].data); + u16 data_type = le16_to_cpu(*(u16 *)data[DATA_TYPE].data); + int ret; + + if (data_algo != ima_hash_algo) { + pr_err("Incompatible digest algorithm, expected %s\n", + hash_algo_name[ima_hash_algo]); + return -EINVAL; + } + + ret = kernel_read_file_from_path(data[DATA_FILE_PATH].data, + &digest_list, &digest_list_size, + 0, READING_DIGEST_LIST); + if (ret < 0) { + pr_err("Unable to open file: %s (%d)", + data[DATA_FILE_PATH].data, ret); + return ret; + } + + switch (data_type) { + default: + pr_err("Parser for data type %d not implemented\n", data_type); + ret = -EINVAL; + } + + if (ret < 0) { + pr_err("Error parsing file: %s (%d)\n", + data[DATA_FILE_PATH].data, ret); + return ret; + } + + vfree(digest_list); + return ret; +} + +ssize_t ima_parse_digest_list_metadata(loff_t size, void *buf) +{ + struct ima_field_data entry; + + struct ima_field_data entry_data[DATA__LAST] = { + [DATA_ALGO] = {.len = sizeof(u16)}, + [DATA_TYPE] = {.len = sizeof(u16)}, + }; + + DECLARE_BITMAP(data_mask, DATA__LAST); + void *bufp = buf, *bufendp = buf + size; + int ret; + + bitmap_zero(data_mask, DATA__LAST); + bitmap_set(data_mask, DATA_ALGO, 1); + bitmap_set(data_mask, DATA_TYPE, 1); + + ret = ima_parse_buf(bufp, bufendp, &bufp, 1, &entry, NULL, NULL, + ENFORCE_FIELDS, "metadata list entry"); + if (ret < 0) + return ret; + + ret = ima_parse_buf(entry.data, entry.data + entry.len, NULL, + DATA__LAST, entry_data, NULL, data_mask, + ENFORCE_FIELDS | ENFORCE_BUFEND, + "metadata entry data"); + if (ret < 0) + goto out; + + if (ima_policy_flag & IMA_APPRAISE) { + ret = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + (const char *)entry_data[DATA_SIGNATURE].data, + entry_data[DATA_SIGNATURE].len, + entry_data[DATA_DIGEST].data, + entry_data[DATA_DIGEST].len); + if (ret < 0) { + pr_err("Failed signature verification of: %s (%d)", + entry_data[DATA_FILE_PATH].data, ret); + goto out_parse_digest_list; + } + } + + ret = ima_add_digest_data_entry(entry_data[DATA_DIGEST].data, 0); + if (ret < 0) { + if (ret == -EEXIST) + ret = 0; + + goto out; + } + +out_parse_digest_list: + ret = ima_parse_digest_list_data(entry_data); +out: + return ret < 0 ? ret : bufp - buf; +} + +void __init ima_load_digest_list_metadata(void) +{ + void *datap; + loff_t size; + int ret; + + int unset_flags = ima_policy_flag & IMA_APPRAISE; + + if (!ima_policy_flag) + return; + + ima_policy_flag &= ~unset_flags; + ret = kernel_read_file_from_path(CONFIG_IMA_DIGEST_LIST_METADATA_PATH, + &datap, &size, 0, + READING_DIGEST_LIST_METADATA); + if (ret < 0) + pr_err("Unable to open file: %s (%d)", + CONFIG_IMA_DIGEST_LIST_METADATA_PATH, ret); + + ima_policy_flag |= unset_flags; + + while (size > 0) { + ret = ima_parse_digest_list_metadata(size, datap); + if (ret < 0) { + pr_err("Unable to parse file: %s (%d)", + CONFIG_IMA_DIGEST_LIST_METADATA_PATH, ret); + break; + } + datap += ret; + size -= ret; + } +} diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index e1bf040fb110..a5951879c15c 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -174,6 +174,14 @@ static inline void evm_load_x509(void) } #endif +#ifdef CONFIG_IMA_DIGEST_LIST +void __init ima_load_digest_list_metadata(void); +#else +static inline void ima_load_digest_list_metadata(void) +{ +} +#endif + #ifdef CONFIG_INTEGRITY_AUDIT /* declarations */ void integrity_audit_msg(int audit_msgno, struct inode *inode,

[v2,06/15] ima: add parser of digest lists metadata

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