mirror of https://gitee.com/openkylin/linux.git
208 lines
5.5 KiB
C
208 lines
5.5 KiB
C
/*
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* Copyright (C) 2013 Politecnico di Torino, Italy
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* TORSEC group -- http://security.polito.it
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*
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* Author: Roberto Sassu <roberto.sassu@polito.it>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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* File: ima_template.c
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* Helpers to manage template descriptors.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include "ima.h"
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#include "ima_template_lib.h"
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static struct ima_template_desc defined_templates[] = {
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{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
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{.name = "ima-ng", .fmt = "d-ng|n-ng"},
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{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
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{.name = "", .fmt = ""}, /* placeholder for a custom format */
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};
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static struct ima_template_field supported_fields[] = {
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{.field_id = "d", .field_init = ima_eventdigest_init,
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.field_show = ima_show_template_digest},
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{.field_id = "n", .field_init = ima_eventname_init,
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.field_show = ima_show_template_string},
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{.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,
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.field_show = ima_show_template_digest_ng},
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{.field_id = "n-ng", .field_init = ima_eventname_ng_init,
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.field_show = ima_show_template_string},
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{.field_id = "sig", .field_init = ima_eventsig_init,
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.field_show = ima_show_template_sig},
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};
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static struct ima_template_desc *ima_template;
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static struct ima_template_desc *lookup_template_desc(const char *name);
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static int template_desc_init_fields(const char *template_fmt,
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struct ima_template_field ***fields,
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int *num_fields);
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static int __init ima_template_setup(char *str)
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{
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struct ima_template_desc *template_desc;
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int template_len = strlen(str);
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if (ima_template)
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return 1;
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/*
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* Verify that a template with the supplied name exists.
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* If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
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*/
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template_desc = lookup_template_desc(str);
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if (!template_desc) {
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pr_err("template %s not found, using %s\n",
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str, CONFIG_IMA_DEFAULT_TEMPLATE);
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return 1;
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}
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/*
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* Verify whether the current hash algorithm is supported
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* by the 'ima' template.
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*/
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if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&
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ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {
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pr_err("template does not support hash alg\n");
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return 1;
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}
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ima_template = template_desc;
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return 1;
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}
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__setup("ima_template=", ima_template_setup);
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static int __init ima_template_fmt_setup(char *str)
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{
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int num_templates = ARRAY_SIZE(defined_templates);
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if (ima_template)
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return 1;
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if (template_desc_init_fields(str, NULL, NULL) < 0) {
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pr_err("format string '%s' not valid, using template %s\n",
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str, CONFIG_IMA_DEFAULT_TEMPLATE);
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return 1;
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}
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defined_templates[num_templates - 1].fmt = str;
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ima_template = defined_templates + num_templates - 1;
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return 1;
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}
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__setup("ima_template_fmt=", ima_template_fmt_setup);
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static struct ima_template_desc *lookup_template_desc(const char *name)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(defined_templates); i++) {
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if (strcmp(defined_templates[i].name, name) == 0)
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return defined_templates + i;
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}
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return NULL;
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}
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static struct ima_template_field *lookup_template_field(const char *field_id)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(supported_fields); i++)
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if (strncmp(supported_fields[i].field_id, field_id,
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IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)
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return &supported_fields[i];
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return NULL;
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}
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static int template_fmt_size(const char *template_fmt)
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{
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char c;
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int template_fmt_len = strlen(template_fmt);
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int i = 0, j = 0;
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while (i < template_fmt_len) {
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c = template_fmt[i];
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if (c == '|')
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j++;
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i++;
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}
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return j + 1;
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}
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static int template_desc_init_fields(const char *template_fmt,
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struct ima_template_field ***fields,
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int *num_fields)
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{
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const char *template_fmt_ptr;
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struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
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int template_num_fields = template_fmt_size(template_fmt);
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int i, len;
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if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
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pr_err("format string '%s' contains too many fields\n",
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template_fmt);
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return -EINVAL;
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}
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for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
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i++, template_fmt_ptr += len + 1) {
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char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
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len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
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if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
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pr_err("Invalid field with length %d\n", len);
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return -EINVAL;
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}
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memcpy(tmp_field_id, template_fmt_ptr, len);
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tmp_field_id[len] = '\0';
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found_fields[i] = lookup_template_field(tmp_field_id);
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if (!found_fields[i]) {
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pr_err("field '%s' not found\n", tmp_field_id);
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return -ENOENT;
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}
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}
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if (fields && num_fields) {
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*fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
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if (*fields == NULL)
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return -ENOMEM;
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memcpy(*fields, found_fields, i * sizeof(*fields));
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*num_fields = i;
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}
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return 0;
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}
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struct ima_template_desc *ima_template_desc_current(void)
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{
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if (!ima_template)
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ima_template =
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lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
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return ima_template;
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}
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int __init ima_init_template(void)
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{
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struct ima_template_desc *template = ima_template_desc_current();
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int result;
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result = template_desc_init_fields(template->fmt,
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&(template->fields),
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&(template->num_fields));
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if (result < 0)
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pr_err("template %s init failed, result: %d\n",
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(strlen(template->name) ?
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template->name : template->fmt), result);
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return result;
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}
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