1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2013 Politecnico di Torino, Italy
4 * TORSEC group -- https://security.polito.it
6 * Author: Roberto Sassu <roberto.sassu@polito.it>
9 * Helpers to manage template descriptors.
12 #include <linux/rculist.h>
14 #include "ima_template_lib.h"
16 enum header_fields { HDR_PCR, HDR_DIGEST, HDR_TEMPLATE_NAME,
17 HDR_TEMPLATE_DATA, HDR__LAST };
19 static struct ima_template_desc builtin_templates[] = {
20 {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
21 {.name = "ima-ng", .fmt = "d-ng|n-ng"},
22 {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
23 {.name = "ima-buf", .fmt = "d-ng|n-ng|buf"},
24 {.name = "ima-modsig", .fmt = "d-ng|n-ng|sig|d-modsig|modsig"},
26 .fmt = "d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode"},
27 {.name = "", .fmt = ""}, /* placeholder for a custom format */
30 static LIST_HEAD(defined_templates);
31 static DEFINE_SPINLOCK(template_list);
32 static int template_setup_done;
34 static const struct ima_template_field supported_fields[] = {
35 {.field_id = "d", .field_init = ima_eventdigest_init,
36 .field_show = ima_show_template_digest},
37 {.field_id = "n", .field_init = ima_eventname_init,
38 .field_show = ima_show_template_string},
39 {.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,
40 .field_show = ima_show_template_digest_ng},
41 {.field_id = "n-ng", .field_init = ima_eventname_ng_init,
42 .field_show = ima_show_template_string},
43 {.field_id = "sig", .field_init = ima_eventsig_init,
44 .field_show = ima_show_template_sig},
45 {.field_id = "buf", .field_init = ima_eventbuf_init,
46 .field_show = ima_show_template_buf},
47 {.field_id = "d-modsig", .field_init = ima_eventdigest_modsig_init,
48 .field_show = ima_show_template_digest_ng},
49 {.field_id = "modsig", .field_init = ima_eventmodsig_init,
50 .field_show = ima_show_template_sig},
51 {.field_id = "evmsig", .field_init = ima_eventevmsig_init,
52 .field_show = ima_show_template_sig},
53 {.field_id = "iuid", .field_init = ima_eventinodeuid_init,
54 .field_show = ima_show_template_uint},
55 {.field_id = "igid", .field_init = ima_eventinodegid_init,
56 .field_show = ima_show_template_uint},
57 {.field_id = "imode", .field_init = ima_eventinodemode_init,
58 .field_show = ima_show_template_uint},
59 {.field_id = "xattrnames",
60 .field_init = ima_eventinodexattrnames_init,
61 .field_show = ima_show_template_string},
62 {.field_id = "xattrlengths",
63 .field_init = ima_eventinodexattrlengths_init,
64 .field_show = ima_show_template_sig},
65 {.field_id = "xattrvalues",
66 .field_init = ima_eventinodexattrvalues_init,
67 .field_show = ima_show_template_sig},
71 * Used when restoring measurements carried over from a kexec. 'd' and 'n' don't
72 * need to be accounted for since they shouldn't be defined in the same template
73 * description as 'd-ng' and 'n-ng' respectively.
75 #define MAX_TEMPLATE_NAME_LEN \
76 sizeof("d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode")
78 static struct ima_template_desc *ima_template;
79 static struct ima_template_desc *ima_buf_template;
82 * ima_template_has_modsig - Check whether template has modsig-related fields.
83 * @ima_template: IMA template to check.
85 * Tells whether the given template has fields referencing a file's appended
88 bool ima_template_has_modsig(const struct ima_template_desc *ima_template)
92 for (i = 0; i < ima_template->num_fields; i++)
93 if (!strcmp(ima_template->fields[i]->field_id, "modsig") ||
94 !strcmp(ima_template->fields[i]->field_id, "d-modsig"))
100 static int __init ima_template_setup(char *str)
102 struct ima_template_desc *template_desc;
103 int template_len = strlen(str);
105 if (template_setup_done)
109 ima_init_template_list();
112 * Verify that a template with the supplied name exists.
113 * If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
115 template_desc = lookup_template_desc(str);
116 if (!template_desc) {
117 pr_err("template %s not found, using %s\n",
118 str, CONFIG_IMA_DEFAULT_TEMPLATE);
123 * Verify whether the current hash algorithm is supported
124 * by the 'ima' template.
126 if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&
127 ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {
128 pr_err("template does not support hash alg\n");
132 ima_template = template_desc;
133 template_setup_done = 1;
136 __setup("ima_template=", ima_template_setup);
138 static int __init ima_template_fmt_setup(char *str)
140 int num_templates = ARRAY_SIZE(builtin_templates);
142 if (template_setup_done)
145 if (template_desc_init_fields(str, NULL, NULL) < 0) {
146 pr_err("format string '%s' not valid, using template %s\n",
147 str, CONFIG_IMA_DEFAULT_TEMPLATE);
151 builtin_templates[num_templates - 1].fmt = str;
152 ima_template = builtin_templates + num_templates - 1;
153 template_setup_done = 1;
157 __setup("ima_template_fmt=", ima_template_fmt_setup);
159 struct ima_template_desc *lookup_template_desc(const char *name)
161 struct ima_template_desc *template_desc;
165 list_for_each_entry_rcu(template_desc, &defined_templates, list) {
166 if ((strcmp(template_desc->name, name) == 0) ||
167 (strcmp(template_desc->fmt, name) == 0)) {
173 return found ? template_desc : NULL;
176 static const struct ima_template_field *
177 lookup_template_field(const char *field_id)
181 for (i = 0; i < ARRAY_SIZE(supported_fields); i++)
182 if (strncmp(supported_fields[i].field_id, field_id,
183 IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)
184 return &supported_fields[i];
188 static int template_fmt_size(const char *template_fmt)
191 int template_fmt_len = strlen(template_fmt);
194 while (i < template_fmt_len) {
204 int template_desc_init_fields(const char *template_fmt,
205 const struct ima_template_field ***fields,
208 const char *template_fmt_ptr;
209 const struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
210 int template_num_fields;
213 if (num_fields && *num_fields > 0) /* already initialized? */
216 template_num_fields = template_fmt_size(template_fmt);
218 if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
219 pr_err("format string '%s' contains too many fields\n",
224 for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
225 i++, template_fmt_ptr += len + 1) {
226 char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
228 len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
229 if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
230 pr_err("Invalid field with length %d\n", len);
234 memcpy(tmp_field_id, template_fmt_ptr, len);
235 tmp_field_id[len] = '\0';
236 found_fields[i] = lookup_template_field(tmp_field_id);
237 if (!found_fields[i]) {
238 pr_err("field '%s' not found\n", tmp_field_id);
243 if (fields && num_fields) {
244 *fields = kmalloc_array(i, sizeof(**fields), GFP_KERNEL);
248 memcpy(*fields, found_fields, i * sizeof(**fields));
255 void ima_init_template_list(void)
259 if (!list_empty(&defined_templates))
262 spin_lock(&template_list);
263 for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
264 list_add_tail_rcu(&builtin_templates[i].list,
267 spin_unlock(&template_list);
270 struct ima_template_desc *ima_template_desc_current(void)
273 ima_init_template_list();
275 lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
280 struct ima_template_desc *ima_template_desc_buf(void)
282 if (!ima_buf_template) {
283 ima_init_template_list();
284 ima_buf_template = lookup_template_desc("ima-buf");
286 return ima_buf_template;
289 int __init ima_init_template(void)
291 struct ima_template_desc *template = ima_template_desc_current();
294 result = template_desc_init_fields(template->fmt,
296 &(template->num_fields));
298 pr_err("template %s init failed, result: %d\n",
299 (strlen(template->name) ?
300 template->name : template->fmt), result);
304 template = ima_template_desc_buf();
306 pr_err("Failed to get ima-buf template\n");
310 result = template_desc_init_fields(template->fmt,
312 &(template->num_fields));
314 pr_err("template %s init failed, result: %d\n",
315 (strlen(template->name) ?
316 template->name : template->fmt), result);
321 static struct ima_template_desc *restore_template_fmt(char *template_name)
323 struct ima_template_desc *template_desc = NULL;
326 ret = template_desc_init_fields(template_name, NULL, NULL);
328 pr_err("attempting to initialize the template \"%s\" failed\n",
333 template_desc = kzalloc(sizeof(*template_desc), GFP_KERNEL);
337 template_desc->name = "";
338 template_desc->fmt = kstrdup(template_name, GFP_KERNEL);
339 if (!template_desc->fmt) {
340 kfree(template_desc);
341 template_desc = NULL;
345 spin_lock(&template_list);
346 list_add_tail_rcu(&template_desc->list, &defined_templates);
347 spin_unlock(&template_list);
349 return template_desc;
352 static int ima_restore_template_data(struct ima_template_desc *template_desc,
354 int template_data_size,
355 struct ima_template_entry **entry)
357 struct tpm_digest *digests;
361 *entry = kzalloc(struct_size(*entry, template_data,
362 template_desc->num_fields), GFP_NOFS);
366 digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
367 sizeof(*digests), GFP_NOFS);
373 (*entry)->digests = digests;
375 ret = ima_parse_buf(template_data, template_data + template_data_size,
376 NULL, template_desc->num_fields,
377 (*entry)->template_data, NULL, NULL,
378 ENFORCE_FIELDS | ENFORCE_BUFEND, "template data");
380 kfree((*entry)->digests);
385 (*entry)->template_desc = template_desc;
386 for (i = 0; i < template_desc->num_fields; i++) {
387 struct ima_field_data *field_data = &(*entry)->template_data[i];
388 u8 *data = field_data->data;
390 (*entry)->template_data[i].data =
391 kzalloc(field_data->len + 1, GFP_KERNEL);
392 if (!(*entry)->template_data[i].data) {
396 memcpy((*entry)->template_data[i].data, data, field_data->len);
397 (*entry)->template_data_len += sizeof(field_data->len);
398 (*entry)->template_data_len += field_data->len;
402 ima_free_template_entry(*entry);
409 /* Restore the serialized binary measurement list without extending PCRs. */
410 int ima_restore_measurement_list(loff_t size, void *buf)
412 char template_name[MAX_TEMPLATE_NAME_LEN];
413 unsigned char zero[TPM_DIGEST_SIZE] = { 0 };
415 struct ima_kexec_hdr *khdr = buf;
416 struct ima_field_data hdr[HDR__LAST] = {
417 [HDR_PCR] = {.len = sizeof(u32)},
418 [HDR_DIGEST] = {.len = TPM_DIGEST_SIZE},
421 void *bufp = buf + sizeof(*khdr);
423 struct ima_template_entry *entry;
424 struct ima_template_desc *template_desc;
425 DECLARE_BITMAP(hdr_mask, HDR__LAST);
426 unsigned long count = 0;
429 if (!buf || size < sizeof(*khdr))
432 if (ima_canonical_fmt) {
433 khdr->version = le16_to_cpu((__force __le16)khdr->version);
434 khdr->count = le64_to_cpu((__force __le64)khdr->count);
435 khdr->buffer_size = le64_to_cpu((__force __le64)khdr->buffer_size);
438 if (khdr->version != 1) {
439 pr_err("attempting to restore a incompatible measurement list");
443 if (khdr->count > ULONG_MAX - 1) {
444 pr_err("attempting to restore too many measurements");
448 bitmap_zero(hdr_mask, HDR__LAST);
449 bitmap_set(hdr_mask, HDR_PCR, 1);
450 bitmap_set(hdr_mask, HDR_DIGEST, 1);
453 * ima kexec buffer prefix: version, buffer size, count
454 * v1 format: pcr, digest, template-name-len, template-name,
455 * template-data-size, template-data
457 bufendp = buf + khdr->buffer_size;
458 while ((bufp < bufendp) && (count++ < khdr->count)) {
459 int enforce_mask = ENFORCE_FIELDS;
461 enforce_mask |= (count == khdr->count) ? ENFORCE_BUFEND : 0;
462 ret = ima_parse_buf(bufp, bufendp, &bufp, HDR__LAST, hdr, NULL,
463 hdr_mask, enforce_mask, "entry header");
467 if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) {
468 pr_err("attempting to restore a template name that is too long\n");
473 /* template name is not null terminated */
474 memcpy(template_name, hdr[HDR_TEMPLATE_NAME].data,
475 hdr[HDR_TEMPLATE_NAME].len);
476 template_name[hdr[HDR_TEMPLATE_NAME].len] = 0;
478 if (strcmp(template_name, "ima") == 0) {
479 pr_err("attempting to restore an unsupported template \"%s\" failed\n",
485 template_desc = lookup_template_desc(template_name);
486 if (!template_desc) {
487 template_desc = restore_template_fmt(template_name);
493 * Only the running system's template format is initialized
494 * on boot. As needed, initialize the other template formats.
496 ret = template_desc_init_fields(template_desc->fmt,
497 &(template_desc->fields),
498 &(template_desc->num_fields));
500 pr_err("attempting to restore the template fmt \"%s\" failed\n",
506 ret = ima_restore_template_data(template_desc,
507 hdr[HDR_TEMPLATE_DATA].data,
508 hdr[HDR_TEMPLATE_DATA].len,
513 if (memcmp(hdr[HDR_DIGEST].data, zero, sizeof(zero))) {
514 ret = ima_calc_field_array_hash(
515 &entry->template_data[0],
518 pr_err("cannot calculate template digest\n");
524 entry->pcr = !ima_canonical_fmt ? *(u32 *)(hdr[HDR_PCR].data) :
525 le32_to_cpu(*(__le32 *)(hdr[HDR_PCR].data));
526 ret = ima_restore_measurement_entry(entry);