1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2013 Politecnico di Torino, Italy
4 * TORSEC group -- http://security.polito.it
6 * Author: Roberto Sassu <roberto.sassu@polito.it>
9 * Helpers to manage template descriptors.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/rculist.h>
16 #include "ima_template_lib.h"
18 enum header_fields { HDR_PCR, HDR_DIGEST, HDR_TEMPLATE_NAME,
19 HDR_TEMPLATE_DATA, HDR__LAST };
21 static struct ima_template_desc builtin_templates[] = {
22 {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
23 {.name = "ima-ng", .fmt = "d-ng|n-ng"},
24 {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
25 {.name = "ima-buf", .fmt = "d-ng|n-ng|buf"},
26 {.name = "", .fmt = ""}, /* placeholder for a custom format */
29 static LIST_HEAD(defined_templates);
30 static DEFINE_SPINLOCK(template_list);
32 static const struct ima_template_field supported_fields[] = {
33 {.field_id = "d", .field_init = ima_eventdigest_init,
34 .field_show = ima_show_template_digest},
35 {.field_id = "n", .field_init = ima_eventname_init,
36 .field_show = ima_show_template_string},
37 {.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,
38 .field_show = ima_show_template_digest_ng},
39 {.field_id = "n-ng", .field_init = ima_eventname_ng_init,
40 .field_show = ima_show_template_string},
41 {.field_id = "sig", .field_init = ima_eventsig_init,
42 .field_show = ima_show_template_sig},
43 {.field_id = "buf", .field_init = ima_eventbuf_init,
44 .field_show = ima_show_template_buf},
48 * Used when restoring measurements carried over from a kexec. 'd' and 'n' don't
49 * need to be accounted for since they shouldn't be defined in the same template
50 * description as 'd-ng' and 'n-ng' respectively.
52 #define MAX_TEMPLATE_NAME_LEN sizeof("d-ng|n-ng|sig|buf")
54 static struct ima_template_desc *ima_template;
56 static int __init ima_template_setup(char *str)
58 struct ima_template_desc *template_desc;
59 int template_len = strlen(str);
64 ima_init_template_list();
67 * Verify that a template with the supplied name exists.
68 * If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
70 template_desc = lookup_template_desc(str);
72 pr_err("template %s not found, using %s\n",
73 str, CONFIG_IMA_DEFAULT_TEMPLATE);
78 * Verify whether the current hash algorithm is supported
79 * by the 'ima' template.
81 if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&
82 ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {
83 pr_err("template does not support hash alg\n");
87 ima_template = template_desc;
90 __setup("ima_template=", ima_template_setup);
92 static int __init ima_template_fmt_setup(char *str)
94 int num_templates = ARRAY_SIZE(builtin_templates);
99 if (template_desc_init_fields(str, NULL, NULL) < 0) {
100 pr_err("format string '%s' not valid, using template %s\n",
101 str, CONFIG_IMA_DEFAULT_TEMPLATE);
105 builtin_templates[num_templates - 1].fmt = str;
106 ima_template = builtin_templates + num_templates - 1;
110 __setup("ima_template_fmt=", ima_template_fmt_setup);
112 struct ima_template_desc *lookup_template_desc(const char *name)
114 struct ima_template_desc *template_desc;
118 list_for_each_entry_rcu(template_desc, &defined_templates, list) {
119 if ((strcmp(template_desc->name, name) == 0) ||
120 (strcmp(template_desc->fmt, name) == 0)) {
126 return found ? template_desc : NULL;
129 static const struct ima_template_field *
130 lookup_template_field(const char *field_id)
134 for (i = 0; i < ARRAY_SIZE(supported_fields); i++)
135 if (strncmp(supported_fields[i].field_id, field_id,
136 IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)
137 return &supported_fields[i];
141 static int template_fmt_size(const char *template_fmt)
144 int template_fmt_len = strlen(template_fmt);
147 while (i < template_fmt_len) {
157 int template_desc_init_fields(const char *template_fmt,
158 const struct ima_template_field ***fields,
161 const char *template_fmt_ptr;
162 const struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
163 int template_num_fields;
166 if (num_fields && *num_fields > 0) /* already initialized? */
169 template_num_fields = template_fmt_size(template_fmt);
171 if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
172 pr_err("format string '%s' contains too many fields\n",
177 for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
178 i++, template_fmt_ptr += len + 1) {
179 char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
181 len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
182 if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
183 pr_err("Invalid field with length %d\n", len);
187 memcpy(tmp_field_id, template_fmt_ptr, len);
188 tmp_field_id[len] = '\0';
189 found_fields[i] = lookup_template_field(tmp_field_id);
190 if (!found_fields[i]) {
191 pr_err("field '%s' not found\n", tmp_field_id);
196 if (fields && num_fields) {
197 *fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
201 memcpy(*fields, found_fields, i * sizeof(*fields));
208 void ima_init_template_list(void)
212 if (!list_empty(&defined_templates))
215 spin_lock(&template_list);
216 for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
217 list_add_tail_rcu(&builtin_templates[i].list,
220 spin_unlock(&template_list);
223 struct ima_template_desc *ima_template_desc_current(void)
226 ima_init_template_list();
228 lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
233 int __init ima_init_template(void)
235 struct ima_template_desc *template = ima_template_desc_current();
238 result = template_desc_init_fields(template->fmt,
240 &(template->num_fields));
242 pr_err("template %s init failed, result: %d\n",
243 (strlen(template->name) ?
244 template->name : template->fmt), result);
249 static struct ima_template_desc *restore_template_fmt(char *template_name)
251 struct ima_template_desc *template_desc = NULL;
254 ret = template_desc_init_fields(template_name, NULL, NULL);
256 pr_err("attempting to initialize the template \"%s\" failed\n",
261 template_desc = kzalloc(sizeof(*template_desc), GFP_KERNEL);
265 template_desc->name = "";
266 template_desc->fmt = kstrdup(template_name, GFP_KERNEL);
267 if (!template_desc->fmt)
270 spin_lock(&template_list);
271 list_add_tail_rcu(&template_desc->list, &defined_templates);
272 spin_unlock(&template_list);
274 return template_desc;
277 static int ima_restore_template_data(struct ima_template_desc *template_desc,
279 int template_data_size,
280 struct ima_template_entry **entry)
285 *entry = kzalloc(sizeof(**entry) +
286 template_desc->num_fields * sizeof(struct ima_field_data),
291 ret = ima_parse_buf(template_data, template_data + template_data_size,
292 NULL, template_desc->num_fields,
293 (*entry)->template_data, NULL, NULL,
294 ENFORCE_FIELDS | ENFORCE_BUFEND, "template data");
300 (*entry)->template_desc = template_desc;
301 for (i = 0; i < template_desc->num_fields; i++) {
302 struct ima_field_data *field_data = &(*entry)->template_data[i];
303 u8 *data = field_data->data;
305 (*entry)->template_data[i].data =
306 kzalloc(field_data->len + 1, GFP_KERNEL);
307 if (!(*entry)->template_data[i].data) {
311 memcpy((*entry)->template_data[i].data, data, field_data->len);
312 (*entry)->template_data_len += sizeof(field_data->len);
313 (*entry)->template_data_len += field_data->len;
317 ima_free_template_entry(*entry);
324 /* Restore the serialized binary measurement list without extending PCRs. */
325 int ima_restore_measurement_list(loff_t size, void *buf)
327 char template_name[MAX_TEMPLATE_NAME_LEN];
329 struct ima_kexec_hdr *khdr = buf;
330 struct ima_field_data hdr[HDR__LAST] = {
331 [HDR_PCR] = {.len = sizeof(u32)},
332 [HDR_DIGEST] = {.len = TPM_DIGEST_SIZE},
335 void *bufp = buf + sizeof(*khdr);
337 struct ima_template_entry *entry;
338 struct ima_template_desc *template_desc;
339 DECLARE_BITMAP(hdr_mask, HDR__LAST);
340 unsigned long count = 0;
343 if (!buf || size < sizeof(*khdr))
346 if (ima_canonical_fmt) {
347 khdr->version = le16_to_cpu(khdr->version);
348 khdr->count = le64_to_cpu(khdr->count);
349 khdr->buffer_size = le64_to_cpu(khdr->buffer_size);
352 if (khdr->version != 1) {
353 pr_err("attempting to restore a incompatible measurement list");
357 if (khdr->count > ULONG_MAX - 1) {
358 pr_err("attempting to restore too many measurements");
362 bitmap_zero(hdr_mask, HDR__LAST);
363 bitmap_set(hdr_mask, HDR_PCR, 1);
364 bitmap_set(hdr_mask, HDR_DIGEST, 1);
367 * ima kexec buffer prefix: version, buffer size, count
368 * v1 format: pcr, digest, template-name-len, template-name,
369 * template-data-size, template-data
371 bufendp = buf + khdr->buffer_size;
372 while ((bufp < bufendp) && (count++ < khdr->count)) {
373 int enforce_mask = ENFORCE_FIELDS;
375 enforce_mask |= (count == khdr->count) ? ENFORCE_BUFEND : 0;
376 ret = ima_parse_buf(bufp, bufendp, &bufp, HDR__LAST, hdr, NULL,
377 hdr_mask, enforce_mask, "entry header");
381 if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) {
382 pr_err("attempting to restore a template name that is too long\n");
387 /* template name is not null terminated */
388 memcpy(template_name, hdr[HDR_TEMPLATE_NAME].data,
389 hdr[HDR_TEMPLATE_NAME].len);
390 template_name[hdr[HDR_TEMPLATE_NAME].len] = 0;
392 if (strcmp(template_name, "ima") == 0) {
393 pr_err("attempting to restore an unsupported template \"%s\" failed\n",
399 template_desc = lookup_template_desc(template_name);
400 if (!template_desc) {
401 template_desc = restore_template_fmt(template_name);
407 * Only the running system's template format is initialized
408 * on boot. As needed, initialize the other template formats.
410 ret = template_desc_init_fields(template_desc->fmt,
411 &(template_desc->fields),
412 &(template_desc->num_fields));
414 pr_err("attempting to restore the template fmt \"%s\" failed\n",
420 ret = ima_restore_template_data(template_desc,
421 hdr[HDR_TEMPLATE_DATA].data,
422 hdr[HDR_TEMPLATE_DATA].len,
427 memcpy(entry->digest, hdr[HDR_DIGEST].data,
428 hdr[HDR_DIGEST].len);
429 entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) :
430 le32_to_cpu(*(hdr[HDR_PCR].data));
431 ret = ima_restore_measurement_entry(entry);