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);
33 static const struct ima_template_field supported_fields[] = {
34 {.field_id = "d", .field_init = ima_eventdigest_init,
35 .field_show = ima_show_template_digest},
36 {.field_id = "n", .field_init = ima_eventname_init,
37 .field_show = ima_show_template_string},
38 {.field_id = "d-ng", .field_init = ima_eventdigest_ng_init,
39 .field_show = ima_show_template_digest_ng},
40 {.field_id = "n-ng", .field_init = ima_eventname_ng_init,
41 .field_show = ima_show_template_string},
42 {.field_id = "sig", .field_init = ima_eventsig_init,
43 .field_show = ima_show_template_sig},
44 {.field_id = "buf", .field_init = ima_eventbuf_init,
45 .field_show = ima_show_template_buf},
46 {.field_id = "d-modsig", .field_init = ima_eventdigest_modsig_init,
47 .field_show = ima_show_template_digest_ng},
48 {.field_id = "modsig", .field_init = ima_eventmodsig_init,
49 .field_show = ima_show_template_sig},
50 {.field_id = "evmsig", .field_init = ima_eventevmsig_init,
51 .field_show = ima_show_template_sig},
52 {.field_id = "iuid", .field_init = ima_eventinodeuid_init,
53 .field_show = ima_show_template_uint},
54 {.field_id = "igid", .field_init = ima_eventinodegid_init,
55 .field_show = ima_show_template_uint},
56 {.field_id = "imode", .field_init = ima_eventinodemode_init,
57 .field_show = ima_show_template_uint},
58 {.field_id = "xattrnames",
59 .field_init = ima_eventinodexattrnames_init,
60 .field_show = ima_show_template_string},
61 {.field_id = "xattrlengths",
62 .field_init = ima_eventinodexattrlengths_init,
63 .field_show = ima_show_template_sig},
64 {.field_id = "xattrvalues",
65 .field_init = ima_eventinodexattrvalues_init,
66 .field_show = ima_show_template_sig},
70 * Used when restoring measurements carried over from a kexec. 'd' and 'n' don't
71 * need to be accounted for since they shouldn't be defined in the same template
72 * description as 'd-ng' and 'n-ng' respectively.
74 #define MAX_TEMPLATE_NAME_LEN \
75 sizeof("d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode")
77 static struct ima_template_desc *ima_template;
78 static struct ima_template_desc *ima_buf_template;
81 * ima_template_has_modsig - Check whether template has modsig-related fields.
82 * @ima_template: IMA template to check.
84 * Tells whether the given template has fields referencing a file's appended
87 bool ima_template_has_modsig(const struct ima_template_desc *ima_template)
91 for (i = 0; i < ima_template->num_fields; i++)
92 if (!strcmp(ima_template->fields[i]->field_id, "modsig") ||
93 !strcmp(ima_template->fields[i]->field_id, "d-modsig"))
99 static int __init ima_template_setup(char *str)
101 struct ima_template_desc *template_desc;
102 int template_len = strlen(str);
107 ima_init_template_list();
110 * Verify that a template with the supplied name exists.
111 * If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
113 template_desc = lookup_template_desc(str);
114 if (!template_desc) {
115 pr_err("template %s not found, using %s\n",
116 str, CONFIG_IMA_DEFAULT_TEMPLATE);
121 * Verify whether the current hash algorithm is supported
122 * by the 'ima' template.
124 if (template_len == 3 && strcmp(str, IMA_TEMPLATE_IMA_NAME) == 0 &&
125 ima_hash_algo != HASH_ALGO_SHA1 && ima_hash_algo != HASH_ALGO_MD5) {
126 pr_err("template does not support hash alg\n");
130 ima_template = template_desc;
133 __setup("ima_template=", ima_template_setup);
135 static int __init ima_template_fmt_setup(char *str)
137 int num_templates = ARRAY_SIZE(builtin_templates);
142 if (template_desc_init_fields(str, NULL, NULL) < 0) {
143 pr_err("format string '%s' not valid, using template %s\n",
144 str, CONFIG_IMA_DEFAULT_TEMPLATE);
148 builtin_templates[num_templates - 1].fmt = str;
149 ima_template = builtin_templates + num_templates - 1;
153 __setup("ima_template_fmt=", ima_template_fmt_setup);
155 struct ima_template_desc *lookup_template_desc(const char *name)
157 struct ima_template_desc *template_desc;
161 list_for_each_entry_rcu(template_desc, &defined_templates, list) {
162 if ((strcmp(template_desc->name, name) == 0) ||
163 (strcmp(template_desc->fmt, name) == 0)) {
169 return found ? template_desc : NULL;
172 static const struct ima_template_field *
173 lookup_template_field(const char *field_id)
177 for (i = 0; i < ARRAY_SIZE(supported_fields); i++)
178 if (strncmp(supported_fields[i].field_id, field_id,
179 IMA_TEMPLATE_FIELD_ID_MAX_LEN) == 0)
180 return &supported_fields[i];
184 static int template_fmt_size(const char *template_fmt)
187 int template_fmt_len = strlen(template_fmt);
190 while (i < template_fmt_len) {
200 int template_desc_init_fields(const char *template_fmt,
201 const struct ima_template_field ***fields,
204 const char *template_fmt_ptr;
205 const struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
206 int template_num_fields;
209 if (num_fields && *num_fields > 0) /* already initialized? */
212 template_num_fields = template_fmt_size(template_fmt);
214 if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
215 pr_err("format string '%s' contains too many fields\n",
220 for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
221 i++, template_fmt_ptr += len + 1) {
222 char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
224 len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
225 if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
226 pr_err("Invalid field with length %d\n", len);
230 memcpy(tmp_field_id, template_fmt_ptr, len);
231 tmp_field_id[len] = '\0';
232 found_fields[i] = lookup_template_field(tmp_field_id);
233 if (!found_fields[i]) {
234 pr_err("field '%s' not found\n", tmp_field_id);
239 if (fields && num_fields) {
240 *fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
244 memcpy(*fields, found_fields, i * sizeof(*fields));
251 void ima_init_template_list(void)
255 if (!list_empty(&defined_templates))
258 spin_lock(&template_list);
259 for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
260 list_add_tail_rcu(&builtin_templates[i].list,
263 spin_unlock(&template_list);
266 struct ima_template_desc *ima_template_desc_current(void)
269 ima_init_template_list();
271 lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
276 struct ima_template_desc *ima_template_desc_buf(void)
278 if (!ima_buf_template) {
279 ima_init_template_list();
280 ima_buf_template = lookup_template_desc("ima-buf");
282 return ima_buf_template;
285 int __init ima_init_template(void)
287 struct ima_template_desc *template = ima_template_desc_current();
290 result = template_desc_init_fields(template->fmt,
292 &(template->num_fields));
294 pr_err("template %s init failed, result: %d\n",
295 (strlen(template->name) ?
296 template->name : template->fmt), result);
300 template = ima_template_desc_buf();
302 pr_err("Failed to get ima-buf template\n");
306 result = template_desc_init_fields(template->fmt,
308 &(template->num_fields));
310 pr_err("template %s init failed, result: %d\n",
311 (strlen(template->name) ?
312 template->name : template->fmt), result);
317 static struct ima_template_desc *restore_template_fmt(char *template_name)
319 struct ima_template_desc *template_desc = NULL;
322 ret = template_desc_init_fields(template_name, NULL, NULL);
324 pr_err("attempting to initialize the template \"%s\" failed\n",
329 template_desc = kzalloc(sizeof(*template_desc), GFP_KERNEL);
333 template_desc->name = "";
334 template_desc->fmt = kstrdup(template_name, GFP_KERNEL);
335 if (!template_desc->fmt)
338 spin_lock(&template_list);
339 list_add_tail_rcu(&template_desc->list, &defined_templates);
340 spin_unlock(&template_list);
342 return template_desc;
345 static int ima_restore_template_data(struct ima_template_desc *template_desc,
347 int template_data_size,
348 struct ima_template_entry **entry)
350 struct tpm_digest *digests;
354 *entry = kzalloc(struct_size(*entry, template_data,
355 template_desc->num_fields), GFP_NOFS);
359 digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
360 sizeof(*digests), GFP_NOFS);
366 (*entry)->digests = digests;
368 ret = ima_parse_buf(template_data, template_data + template_data_size,
369 NULL, template_desc->num_fields,
370 (*entry)->template_data, NULL, NULL,
371 ENFORCE_FIELDS | ENFORCE_BUFEND, "template data");
373 kfree((*entry)->digests);
378 (*entry)->template_desc = template_desc;
379 for (i = 0; i < template_desc->num_fields; i++) {
380 struct ima_field_data *field_data = &(*entry)->template_data[i];
381 u8 *data = field_data->data;
383 (*entry)->template_data[i].data =
384 kzalloc(field_data->len + 1, GFP_KERNEL);
385 if (!(*entry)->template_data[i].data) {
389 memcpy((*entry)->template_data[i].data, data, field_data->len);
390 (*entry)->template_data_len += sizeof(field_data->len);
391 (*entry)->template_data_len += field_data->len;
395 ima_free_template_entry(*entry);
402 /* Restore the serialized binary measurement list without extending PCRs. */
403 int ima_restore_measurement_list(loff_t size, void *buf)
405 char template_name[MAX_TEMPLATE_NAME_LEN];
406 unsigned char zero[TPM_DIGEST_SIZE] = { 0 };
408 struct ima_kexec_hdr *khdr = buf;
409 struct ima_field_data hdr[HDR__LAST] = {
410 [HDR_PCR] = {.len = sizeof(u32)},
411 [HDR_DIGEST] = {.len = TPM_DIGEST_SIZE},
414 void *bufp = buf + sizeof(*khdr);
416 struct ima_template_entry *entry;
417 struct ima_template_desc *template_desc;
418 DECLARE_BITMAP(hdr_mask, HDR__LAST);
419 unsigned long count = 0;
422 if (!buf || size < sizeof(*khdr))
425 if (ima_canonical_fmt) {
426 khdr->version = le16_to_cpu((__force __le16)khdr->version);
427 khdr->count = le64_to_cpu((__force __le64)khdr->count);
428 khdr->buffer_size = le64_to_cpu((__force __le64)khdr->buffer_size);
431 if (khdr->version != 1) {
432 pr_err("attempting to restore a incompatible measurement list");
436 if (khdr->count > ULONG_MAX - 1) {
437 pr_err("attempting to restore too many measurements");
441 bitmap_zero(hdr_mask, HDR__LAST);
442 bitmap_set(hdr_mask, HDR_PCR, 1);
443 bitmap_set(hdr_mask, HDR_DIGEST, 1);
446 * ima kexec buffer prefix: version, buffer size, count
447 * v1 format: pcr, digest, template-name-len, template-name,
448 * template-data-size, template-data
450 bufendp = buf + khdr->buffer_size;
451 while ((bufp < bufendp) && (count++ < khdr->count)) {
452 int enforce_mask = ENFORCE_FIELDS;
454 enforce_mask |= (count == khdr->count) ? ENFORCE_BUFEND : 0;
455 ret = ima_parse_buf(bufp, bufendp, &bufp, HDR__LAST, hdr, NULL,
456 hdr_mask, enforce_mask, "entry header");
460 if (hdr[HDR_TEMPLATE_NAME].len >= MAX_TEMPLATE_NAME_LEN) {
461 pr_err("attempting to restore a template name that is too long\n");
466 /* template name is not null terminated */
467 memcpy(template_name, hdr[HDR_TEMPLATE_NAME].data,
468 hdr[HDR_TEMPLATE_NAME].len);
469 template_name[hdr[HDR_TEMPLATE_NAME].len] = 0;
471 if (strcmp(template_name, "ima") == 0) {
472 pr_err("attempting to restore an unsupported template \"%s\" failed\n",
478 template_desc = lookup_template_desc(template_name);
479 if (!template_desc) {
480 template_desc = restore_template_fmt(template_name);
486 * Only the running system's template format is initialized
487 * on boot. As needed, initialize the other template formats.
489 ret = template_desc_init_fields(template_desc->fmt,
490 &(template_desc->fields),
491 &(template_desc->num_fields));
493 pr_err("attempting to restore the template fmt \"%s\" failed\n",
499 ret = ima_restore_template_data(template_desc,
500 hdr[HDR_TEMPLATE_DATA].data,
501 hdr[HDR_TEMPLATE_DATA].len,
506 if (memcmp(hdr[HDR_DIGEST].data, zero, sizeof(zero))) {
507 ret = ima_calc_field_array_hash(
508 &entry->template_data[0],
511 pr_err("cannot calculate template digest\n");
517 entry->pcr = !ima_canonical_fmt ? *(u32 *)(hdr[HDR_PCR].data) :
518 le32_to_cpu(*(__le32 *)(hdr[HDR_PCR].data));
519 ret = ima_restore_measurement_entry(entry);