437 lines
11 KiB
C
437 lines
11 KiB
C
/*
|
|
* Copyright (C) 2013 Politecnico di Torino, Italy
|
|
* TORSEC group -- http://security.polito.it
|
|
*
|
|
* Author: Roberto Sassu <roberto.sassu@polito.it>
|
|
*
|
|
* 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_template.c
|
|
* Helpers to manage template descriptors.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/rculist.h>
|
|
#include "ima.h"
|
|
#include "ima_template_lib.h"
|
|
|
|
enum header_fields { HDR_PCR, HDR_DIGEST, HDR_TEMPLATE_NAME,
|
|
HDR_TEMPLATE_DATA, HDR__LAST };
|
|
|
|
static struct ima_template_desc builtin_templates[] = {
|
|
{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
|
|
{.name = "ima-ng", .fmt = "d-ng|n-ng"},
|
|
{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
|
|
{.name = "", .fmt = ""}, /* placeholder for a custom format */
|
|
};
|
|
|
|
static LIST_HEAD(defined_templates);
|
|
static DEFINE_SPINLOCK(template_list);
|
|
|
|
static struct ima_template_field supported_fields[] = {
|
|
{.field_id = "d", .field_init = ima_eventdigest_init,
|
|
.field_show = ima_show_template_digest},
|
|
{.field_id = "n", .field_init = ima_eventname_init,
|
|
.field_show = ima_show_template_string},
|
|
{.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,
|
|
.field_show = ima_show_template_digest_ng},
|
|
{.field_id = "n-ng", .field_init = ima_eventname_ng_init,
|
|
.field_show = ima_show_template_string},
|
|
{.field_id = "sig", .field_init = ima_eventsig_init,
|
|
.field_show = ima_show_template_sig},
|
|
};
|
|
#define MAX_TEMPLATE_NAME_LEN 15
|
|
|
|
static struct ima_template_desc *ima_template;
|
|
static struct ima_template_desc *lookup_template_desc(const char *name);
|
|
static int template_desc_init_fields(const char *template_fmt,
|
|
struct ima_template_field ***fields,
|
|
int *num_fields);
|
|
|
|
static int __init ima_template_setup(char *str)
|
|
{
|
|
struct ima_template_desc *template_desc;
|
|
int template_len = strlen(str);
|
|
|
|
if (ima_template)
|
|
return 1;
|
|
|
|
ima_init_template_list();
|
|
|
|
/*
|
|
* Verify that a template with the supplied name exists.
|
|
* If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
|
|
*/
|
|
template_desc = lookup_template_desc(str);
|
|
if (!template_desc) {
|
|
pr_err("template %s not found, using %s\n",
|
|
str, CONFIG_IMA_DEFAULT_TEMPLATE);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Verify whether the current hash algorithm is supported
|
|
* by the 'ima' template.
|
|
*/
|
|
if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&
|
|
ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {
|
|
pr_err("template does not support hash alg\n");
|
|
return 1;
|
|
}
|
|
|
|
ima_template = template_desc;
|
|
return 1;
|
|
}
|
|
__setup("ima_template=", ima_template_setup);
|
|
|
|
static int __init ima_template_fmt_setup(char *str)
|
|
{
|
|
int num_templates = ARRAY_SIZE(builtin_templates);
|
|
|
|
if (ima_template)
|
|
return 1;
|
|
|
|
if (template_desc_init_fields(str, NULL, NULL) < 0) {
|
|
pr_err("format string '%s' not valid, using template %s\n",
|
|
str, CONFIG_IMA_DEFAULT_TEMPLATE);
|
|
return 1;
|
|
}
|
|
|
|
builtin_templates[num_templates - 1].fmt = str;
|
|
ima_template = builtin_templates + num_templates - 1;
|
|
|
|
return 1;
|
|
}
|
|
__setup("ima_template_fmt=", ima_template_fmt_setup);
|
|
|
|
static struct ima_template_desc *lookup_template_desc(const char *name)
|
|
{
|
|
struct ima_template_desc *template_desc;
|
|
int found = 0;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(template_desc, &defined_templates, list) {
|
|
if ((strcmp(template_desc->name, name) == 0) ||
|
|
(strcmp(template_desc->fmt, name) == 0)) {
|
|
found = 1;
|
|
break;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
return found ? template_desc : NULL;
|
|
}
|
|
|
|
static struct ima_template_field *lookup_template_field(const char *field_id)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(supported_fields); i++)
|
|
if (strncmp(supported_fields[i].field_id, field_id,
|
|
IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)
|
|
return &supported_fields[i];
|
|
return NULL;
|
|
}
|
|
|
|
static int template_fmt_size(const char *template_fmt)
|
|
{
|
|
char c;
|
|
int template_fmt_len = strlen(template_fmt);
|
|
int i = 0, j = 0;
|
|
|
|
while (i < template_fmt_len) {
|
|
c = template_fmt[i];
|
|
if (c == '|')
|
|
j++;
|
|
i++;
|
|
}
|
|
|
|
return j + 1;
|
|
}
|
|
|
|
static int template_desc_init_fields(const char *template_fmt,
|
|
struct ima_template_field ***fields,
|
|
int *num_fields)
|
|
{
|
|
const char *template_fmt_ptr;
|
|
struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
|
|
int template_num_fields;
|
|
int i, len;
|
|
|
|
if (num_fields && *num_fields > 0) /* already initialized? */
|
|
return 0;
|
|
|
|
template_num_fields = template_fmt_size(template_fmt);
|
|
|
|
if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
|
|
pr_err("format string '%s' contains too many fields\n",
|
|
template_fmt);
|
|
return -EINVAL;
|
|
}
|
|
|
|
for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
|
|
i++, template_fmt_ptr += len + 1) {
|
|
char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
|
|
|
|
len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
|
|
if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
|
|
pr_err("Invalid field with length %d\n", len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
memcpy(tmp_field_id, template_fmt_ptr, len);
|
|
tmp_field_id[len] = '\0';
|
|
found_fields[i] = lookup_template_field(tmp_field_id);
|
|
if (!found_fields[i]) {
|
|
pr_err("field '%s' not found\n", tmp_field_id);
|
|
return -ENOENT;
|
|
}
|
|
}
|
|
|
|
if (fields && num_fields) {
|
|
*fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
|
|
if (*fields == NULL)
|
|
return -ENOMEM;
|
|
|
|
memcpy(*fields, found_fields, i * sizeof(*fields));
|
|
*num_fields = i;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void ima_init_template_list(void)
|
|
{
|
|
int i;
|
|
|
|
if (!list_empty(&defined_templates))
|
|
return;
|
|
|
|
spin_lock(&template_list);
|
|
for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
|
|
list_add_tail_rcu(&builtin_templates[i].list,
|
|
&defined_templates);
|
|
}
|
|
spin_unlock(&template_list);
|
|
}
|
|
|
|
struct ima_template_desc *ima_template_desc_current(void)
|
|
{
|
|
if (!ima_template) {
|
|
ima_init_template_list();
|
|
ima_template =
|
|
lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
|
|
}
|
|
return ima_template;
|
|
}
|
|
|
|
int __init ima_init_template(void)
|
|
{
|
|
struct ima_template_desc *template = ima_template_desc_current();
|
|
int result;
|
|
|
|
result = template_desc_init_fields(template->fmt,
|
|
&(template->fields),
|
|
&(template->num_fields));
|
|
if (result < 0)
|
|
pr_err("template %s init failed, result: %d\n",
|
|
(strlen(template->name) ?
|
|
template->name : template->fmt), result);
|
|
|
|
return result;
|
|
}
|
|
|
|
static struct ima_template_desc *restore_template_fmt(char *template_name)
|
|
{
|
|
struct ima_template_desc *template_desc = NULL;
|
|
int ret;
|
|
|
|
ret = template_desc_init_fields(template_name, NULL, NULL);
|
|
if (ret < 0) {
|
|
pr_err("attempting to initialize the template \"%s\" failed\n",
|
|
template_name);
|
|
goto out;
|
|
}
|
|
|
|
template_desc = kzalloc(sizeof(*template_desc), GFP_KERNEL);
|
|
if (!template_desc)
|
|
goto out;
|
|
|
|
template_desc->name = "";
|
|
template_desc->fmt = kstrdup(template_name, GFP_KERNEL);
|
|
if (!template_desc->fmt)
|
|
goto out;
|
|
|
|
spin_lock(&template_list);
|
|
list_add_tail_rcu(&template_desc->list, &defined_templates);
|
|
spin_unlock(&template_list);
|
|
out:
|
|
return template_desc;
|
|
}
|
|
|
|
static int ima_restore_template_data(struct ima_template_desc *template_desc,
|
|
void *template_data,
|
|
int template_data_size,
|
|
struct ima_template_entry **entry)
|
|
{
|
|
int ret = 0;
|
|
int i;
|
|
|
|
*entry = kzalloc(sizeof(**entry) +
|
|
template_desc->num_fields * sizeof(struct ima_field_data),
|
|
GFP_NOFS);
|
|
if (!*entry)
|
|
return -ENOMEM;
|
|
|
|
ret = ima_parse_buf(template_data, template_data + template_data_size,
|
|
NULL, template_desc->num_fields,
|
|
(*entry)->template_data, NULL, NULL,
|
|
ENFORCE_FIELDS | ENFORCE_BUFEND, "template data");
|
|
if (ret < 0) {
|
|
kfree(*entry);
|
|
return ret;
|
|
}
|
|
|
|
(*entry)->template_desc = template_desc;
|
|
for (i = 0; i < template_desc->num_fields; i++) {
|
|
struct ima_field_data *field_data = &(*entry)->template_data[i];
|
|
u8 *data = field_data->data;
|
|
|
|
(*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, data, field_data->len);
|
|
(*entry)->template_data_len += sizeof(field_data->len);
|
|
(*entry)->template_data_len += field_data->len;
|
|
}
|
|
|
|
if (ret < 0) {
|
|
ima_free_template_entry(*entry);
|
|
*entry = NULL;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Restore the serialized binary measurement list without extending PCRs. */
|
|
int ima_restore_measurement_list(loff_t size, void *buf)
|
|
{
|
|
char template_name[MAX_TEMPLATE_NAME_LEN];
|
|
|
|
struct ima_kexec_hdr *khdr = buf;
|
|
struct ima_field_data hdr[HDR__LAST] = {
|
|
[HDR_PCR] = {.len = sizeof(u32)},
|
|
[HDR_DIGEST] = {.len = TPM_DIGEST_SIZE},
|
|
};
|
|
|
|
void *bufp = buf + sizeof(*khdr);
|
|
void *bufendp;
|
|
struct ima_template_entry *entry;
|
|
struct ima_template_desc *template_desc;
|
|
DECLARE_BITMAP(hdr_mask, HDR__LAST);
|
|
unsigned long count = 0;
|
|
int ret = 0;
|
|
|
|
if (!buf || size < sizeof(*khdr))
|
|
return 0;
|
|
|
|
if (ima_canonical_fmt) {
|
|
khdr->version = le16_to_cpu(khdr->version);
|
|
khdr->count = le64_to_cpu(khdr->count);
|
|
khdr->buffer_size = le64_to_cpu(khdr->buffer_size);
|
|
}
|
|
|
|
if (khdr->version != 1) {
|
|
pr_err("attempting to restore a incompatible measurement list");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (khdr->count > ULONG_MAX - 1) {
|
|
pr_err("attempting to restore too many measurements");
|
|
return -EINVAL;
|
|
}
|
|
|
|
bitmap_zero(hdr_mask, HDR__LAST);
|
|
bitmap_set(hdr_mask, HDR_PCR, 1);
|
|
bitmap_set(hdr_mask, HDR_DIGEST, 1);
|
|
|
|
/*
|
|
* ima kexec buffer prefix: version, buffer size, count
|
|
* v1 format: pcr, digest, template-name-len, template-name,
|
|
* template-data-size, template-data
|
|
*/
|
|
bufendp = buf + khdr->buffer_size;
|
|
while ((bufp < bufendp) && (count++ < khdr->count)) {
|
|
int enforce_mask = ENFORCE_FIELDS;
|
|
|
|
enforce_mask |= (count == khdr->count) ? ENFORCE_BUFEND : 0;
|
|
ret = ima_parse_buf(bufp, bufendp, &bufp, HDR__LAST, hdr, NULL,
|
|
hdr_mask, enforce_mask, "entry header");
|
|
if (ret < 0)
|
|
break;
|
|
|
|
if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) {
|
|
pr_err("attempting to restore a template name \
|
|
that is too long\n");
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* template name is not null terminated */
|
|
memcpy(template_name, hdr[HDR_TEMPLATE_NAME].data,
|
|
hdr[HDR_TEMPLATE_NAME].len);
|
|
template_name[hdr[HDR_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;
|
|
}
|
|
|
|
template_desc = lookup_template_desc(template_name);
|
|
if (!template_desc) {
|
|
template_desc = restore_template_fmt(template_name);
|
|
if (!template_desc)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Only the running system's template format is initialized
|
|
* on boot. As needed, initialize the other template formats.
|
|
*/
|
|
ret = template_desc_init_fields(template_desc->fmt,
|
|
&(template_desc->fields),
|
|
&(template_desc->num_fields));
|
|
if (ret < 0) {
|
|
pr_err("attempting to restore the template fmt \"%s\" \
|
|
failed\n", template_desc->fmt);
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
ret = ima_restore_template_data(template_desc,
|
|
hdr[HDR_TEMPLATE_DATA].data,
|
|
hdr[HDR_TEMPLATE_DATA].len,
|
|
&entry);
|
|
if (ret < 0)
|
|
break;
|
|
|
|
memcpy(entry->digest, hdr[HDR_DIGEST].data,
|
|
hdr[HDR_DIGEST].len);
|
|
entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) :
|
|
le32_to_cpu(*(hdr[HDR_PCR].data));
|
|
ret = ima_restore_measurement_entry(entry);
|
|
if (ret < 0)
|
|
break;
|
|
|
|
}
|
|
return ret;
|
|
}
|