1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright (C) 2016 The Android Open Source Project
4 */
5
6 #include "avb_slot_verify.h"
7 #include "avb_chain_partition_descriptor.h"
8 #include "avb_cmdline.h"
9 #include "avb_footer.h"
10 #include "avb_hash_descriptor.h"
11 #include "avb_hashtree_descriptor.h"
12 #include "avb_kernel_cmdline_descriptor.h"
13 #include "avb_sha.h"
14 #include "avb_util.h"
15 #include "avb_vbmeta_image.h"
16 #include "avb_version.h"
17
18 /* Maximum number of partitions that can be loaded with avb_slot_verify(). */
19 #define MAX_NUMBER_OF_LOADED_PARTITIONS 32
20
21 /* Maximum number of vbmeta images that can be loaded with avb_slot_verify(). */
22 #define MAX_NUMBER_OF_VBMETA_IMAGES 32
23
24 /* Maximum size of a vbmeta image - 64 KiB. */
25 #define VBMETA_MAX_SIZE (64 * 1024)
26
27 /* Helper function to see if we should continue with verification in
28 * allow_verification_error=true mode if something goes wrong. See the
29 * comments for the avb_slot_verify() function for more information.
30 */
result_should_continue(AvbSlotVerifyResult result)31 static inline bool result_should_continue(AvbSlotVerifyResult result) {
32 switch (result) {
33 case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
34 case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
35 case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
36 case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
37 case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT:
38 return false;
39
40 case AVB_SLOT_VERIFY_RESULT_OK:
41 case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
42 case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
43 case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
44 return true;
45 }
46
47 return false;
48 }
49
load_full_partition(AvbOps * ops,const char * part_name,uint64_t image_size,uint8_t ** out_image_buf,bool * out_image_preloaded)50 static AvbSlotVerifyResult load_full_partition(AvbOps* ops,
51 const char* part_name,
52 uint64_t image_size,
53 uint8_t** out_image_buf,
54 bool* out_image_preloaded) {
55 size_t part_num_read;
56 AvbIOResult io_ret;
57
58 /* Make sure that we do not overwrite existing data. */
59 avb_assert(*out_image_buf == NULL);
60 avb_assert(!*out_image_preloaded);
61
62 /* We are going to implicitly cast image_size from uint64_t to size_t in the
63 * following code, so we need to make sure that the cast is safe. */
64 if (image_size != (size_t)(image_size)) {
65 avb_errorv(part_name, ": Partition size too large to load.\n", NULL);
66 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
67 }
68
69 /* Try use a preloaded one. */
70 if (ops->get_preloaded_partition != NULL) {
71 io_ret = ops->get_preloaded_partition(
72 ops, part_name, image_size, out_image_buf, &part_num_read);
73 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
74 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
75 } else if (io_ret != AVB_IO_RESULT_OK) {
76 avb_errorv(part_name, ": Error loading data from partition.\n", NULL);
77 return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
78 }
79
80 if (*out_image_buf != NULL) {
81 if (part_num_read != image_size) {
82 avb_errorv(part_name, ": Read incorrect number of bytes.\n", NULL);
83 return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
84 }
85 *out_image_preloaded = true;
86 }
87 }
88
89 /* Allocate and copy the partition. */
90 if (!*out_image_preloaded) {
91 *out_image_buf = avb_malloc(image_size);
92 if (*out_image_buf == NULL) {
93 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
94 }
95
96 io_ret = ops->read_from_partition(ops,
97 part_name,
98 0 /* offset */,
99 image_size,
100 *out_image_buf,
101 &part_num_read);
102 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
103 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
104 } else if (io_ret != AVB_IO_RESULT_OK) {
105 avb_errorv(part_name, ": Error loading data from partition.\n", NULL);
106 return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
107 }
108 if (part_num_read != image_size) {
109 avb_errorv(part_name, ": Read incorrect number of bytes.\n", NULL);
110 return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
111 }
112 }
113
114 return AVB_SLOT_VERIFY_RESULT_OK;
115 }
116
read_persistent_digest(AvbOps * ops,const char * part_name,size_t expected_digest_size,uint8_t * out_digest)117 static AvbSlotVerifyResult read_persistent_digest(AvbOps* ops,
118 const char* part_name,
119 size_t expected_digest_size,
120 uint8_t* out_digest) {
121 char* persistent_value_name = NULL;
122 AvbIOResult io_ret = AVB_IO_RESULT_OK;
123 size_t stored_digest_size = 0;
124
125 if (ops->read_persistent_value == NULL) {
126 avb_errorv(part_name, ": Persistent values are not implemented.\n", NULL);
127 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
128 }
129 persistent_value_name =
130 avb_strdupv(AVB_NPV_PERSISTENT_DIGEST_PREFIX, part_name, NULL);
131 if (persistent_value_name == NULL) {
132 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
133 }
134 io_ret = ops->read_persistent_value(ops,
135 persistent_value_name,
136 expected_digest_size,
137 out_digest,
138 &stored_digest_size);
139 avb_free(persistent_value_name);
140 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
141 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
142 } else if (io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_VALUE) {
143 avb_errorv(part_name, ": Persistent digest does not exist.\n", NULL);
144 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
145 } else if (io_ret == AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE ||
146 io_ret == AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE ||
147 expected_digest_size != stored_digest_size) {
148 avb_errorv(
149 part_name, ": Persistent digest is not of expected size.\n", NULL);
150 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
151 } else if (io_ret != AVB_IO_RESULT_OK) {
152 avb_errorv(part_name, ": Error reading persistent digest.\n", NULL);
153 return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
154 }
155 return AVB_SLOT_VERIFY_RESULT_OK;
156 }
157
load_and_verify_hash_partition(AvbOps * ops,const char * const * requested_partitions,const char * ab_suffix,bool allow_verification_error,const AvbDescriptor * descriptor,AvbSlotVerifyData * slot_data)158 static AvbSlotVerifyResult load_and_verify_hash_partition(
159 AvbOps* ops,
160 const char* const* requested_partitions,
161 const char* ab_suffix,
162 bool allow_verification_error,
163 const AvbDescriptor* descriptor,
164 AvbSlotVerifyData* slot_data) {
165 AvbHashDescriptor hash_desc;
166 const uint8_t* desc_partition_name = NULL;
167 const uint8_t* desc_salt;
168 const uint8_t* desc_digest;
169 char part_name[AVB_PART_NAME_MAX_SIZE];
170 AvbSlotVerifyResult ret;
171 AvbIOResult io_ret;
172 uint8_t* image_buf = NULL;
173 bool image_preloaded = false;
174 uint8_t* digest;
175 size_t digest_len;
176 const char* found;
177 uint64_t image_size;
178 size_t expected_digest_len = 0;
179 uint8_t expected_digest_buf[AVB_SHA512_DIGEST_SIZE];
180 const uint8_t* expected_digest = NULL;
181
182 if (!avb_hash_descriptor_validate_and_byteswap(
183 (const AvbHashDescriptor*)descriptor, &hash_desc)) {
184 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
185 goto out;
186 }
187
188 desc_partition_name =
189 ((const uint8_t*)descriptor) + sizeof(AvbHashDescriptor);
190 desc_salt = desc_partition_name + hash_desc.partition_name_len;
191 desc_digest = desc_salt + hash_desc.salt_len;
192
193 if (!avb_validate_utf8(desc_partition_name, hash_desc.partition_name_len)) {
194 avb_error("Partition name is not valid UTF-8.\n");
195 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
196 goto out;
197 }
198
199 /* Don't bother loading or validating unless the partition was
200 * requested in the first place.
201 */
202 found = avb_strv_find_str(requested_partitions,
203 (const char*)desc_partition_name,
204 hash_desc.partition_name_len);
205 if (found == NULL) {
206 ret = AVB_SLOT_VERIFY_RESULT_OK;
207 goto out;
208 }
209
210 if ((hash_desc.flags & AVB_HASH_DESCRIPTOR_FLAGS_DO_NOT_USE_AB) != 0) {
211 /* No ab_suffix, just copy the partition name as is. */
212 if (hash_desc.partition_name_len >= AVB_PART_NAME_MAX_SIZE) {
213 avb_error("Partition name does not fit.\n");
214 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
215 goto out;
216 }
217 avb_memcpy(part_name, desc_partition_name, hash_desc.partition_name_len);
218 part_name[hash_desc.partition_name_len] = '\0';
219 } else if (hash_desc.digest_len == 0 && avb_strlen(ab_suffix) != 0) {
220 /* No ab_suffix allowed for partitions without a digest in the descriptor
221 * because these partitions hold data unique to this device and are not
222 * updated using an A/B scheme.
223 */
224 avb_error("Cannot use A/B with a persistent digest.\n");
225 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
226 goto out;
227 } else {
228 /* Add ab_suffix to the partition name. */
229 if (!avb_str_concat(part_name,
230 sizeof part_name,
231 (const char*)desc_partition_name,
232 hash_desc.partition_name_len,
233 ab_suffix,
234 avb_strlen(ab_suffix))) {
235 avb_error("Partition name and suffix does not fit.\n");
236 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
237 goto out;
238 }
239 }
240
241 /* If we're allowing verification errors then hash_desc.image_size
242 * may no longer match what's in the partition... so in this case
243 * just load the entire partition.
244 *
245 * For example, this can happen if a developer does 'fastboot flash
246 * boot /path/to/new/and/bigger/boot.img'. We want this to work
247 * since it's such a common workflow.
248 */
249 image_size = hash_desc.image_size;
250 if (allow_verification_error) {
251 if (ops->get_size_of_partition == NULL) {
252 avb_errorv(part_name,
253 ": The get_size_of_partition() operation is "
254 "not implemented so we may not load the entire partition. "
255 "Please implement.",
256 NULL);
257 } else {
258 io_ret = ops->get_size_of_partition(ops, part_name, &image_size);
259 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
260 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
261 goto out;
262 } else if (io_ret != AVB_IO_RESULT_OK) {
263 avb_errorv(part_name, ": Error determining partition size.\n", NULL);
264 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
265 goto out;
266 }
267 avb_debugv(part_name, ": Loading entire partition.\n", NULL);
268 }
269 }
270
271 ret = load_full_partition(
272 ops, part_name, image_size, &image_buf, &image_preloaded);
273 if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
274 goto out;
275 }
276
277 if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha256") == 0) {
278 AvbSHA256Ctx sha256_ctx;
279 avb_sha256_init(&sha256_ctx);
280 avb_sha256_update(&sha256_ctx, desc_salt, hash_desc.salt_len);
281 avb_sha256_update(&sha256_ctx, image_buf, hash_desc.image_size);
282 digest = avb_sha256_final(&sha256_ctx);
283 digest_len = AVB_SHA256_DIGEST_SIZE;
284 } else if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha512") == 0) {
285 AvbSHA512Ctx sha512_ctx;
286 avb_sha512_init(&sha512_ctx);
287 avb_sha512_update(&sha512_ctx, desc_salt, hash_desc.salt_len);
288 avb_sha512_update(&sha512_ctx, image_buf, hash_desc.image_size);
289 digest = avb_sha512_final(&sha512_ctx);
290 digest_len = AVB_SHA512_DIGEST_SIZE;
291 } else {
292 avb_errorv(part_name, ": Unsupported hash algorithm.\n", NULL);
293 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
294 goto out;
295 }
296
297 if (hash_desc.digest_len == 0) {
298 // Expect a match to a persistent digest.
299 avb_debugv(part_name, ": No digest, using persistent digest.\n", NULL);
300 expected_digest_len = digest_len;
301 expected_digest = expected_digest_buf;
302 avb_assert(expected_digest_len <= sizeof(expected_digest_buf));
303 ret =
304 read_persistent_digest(ops, part_name, digest_len, expected_digest_buf);
305 if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
306 goto out;
307 }
308 } else {
309 // Expect a match to the digest in the descriptor.
310 expected_digest_len = hash_desc.digest_len;
311 expected_digest = desc_digest;
312 }
313
314 if (digest_len != expected_digest_len) {
315 avb_errorv(
316 part_name, ": Digest in descriptor not of expected size.\n", NULL);
317 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
318 goto out;
319 }
320
321 if (avb_safe_memcmp(digest, expected_digest, digest_len) != 0) {
322 avb_errorv(part_name,
323 ": Hash of data does not match digest in descriptor.\n",
324 NULL);
325 ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
326 goto out;
327 }
328
329 ret = AVB_SLOT_VERIFY_RESULT_OK;
330
331 out:
332
333 /* If it worked and something was loaded, copy to slot_data. */
334 if ((ret == AVB_SLOT_VERIFY_RESULT_OK || result_should_continue(ret)) &&
335 image_buf != NULL) {
336 AvbPartitionData* loaded_partition;
337 if (slot_data->num_loaded_partitions == MAX_NUMBER_OF_LOADED_PARTITIONS) {
338 avb_errorv(part_name, ": Too many loaded partitions.\n", NULL);
339 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
340 goto fail;
341 }
342 loaded_partition =
343 &slot_data->loaded_partitions[slot_data->num_loaded_partitions++];
344 loaded_partition->partition_name = avb_strdup(found);
345 loaded_partition->data_size = image_size;
346 loaded_partition->data = image_buf;
347 loaded_partition->preloaded = image_preloaded;
348 image_buf = NULL;
349 }
350
351 fail:
352 if (image_buf != NULL && !image_preloaded) {
353 avb_free(image_buf);
354 }
355 return ret;
356 }
357
load_requested_partitions(AvbOps * ops,const char * const * requested_partitions,const char * ab_suffix,AvbSlotVerifyData * slot_data)358 static AvbSlotVerifyResult load_requested_partitions(
359 AvbOps* ops,
360 const char* const* requested_partitions,
361 const char* ab_suffix,
362 AvbSlotVerifyData* slot_data) {
363 AvbSlotVerifyResult ret;
364 uint8_t* image_buf = NULL;
365 bool image_preloaded = false;
366 size_t n;
367
368 if (ops->get_size_of_partition == NULL) {
369 avb_error("get_size_of_partition() not implemented.\n");
370 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
371 goto out;
372 }
373
374 for (n = 0; requested_partitions[n] != NULL; n++) {
375 char part_name[AVB_PART_NAME_MAX_SIZE];
376 AvbIOResult io_ret;
377 uint64_t image_size;
378 AvbPartitionData* loaded_partition;
379
380 if (!avb_str_concat(part_name,
381 sizeof part_name,
382 requested_partitions[n],
383 avb_strlen(requested_partitions[n]),
384 ab_suffix,
385 avb_strlen(ab_suffix))) {
386 avb_error("Partition name and suffix does not fit.\n");
387 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
388 goto out;
389 }
390
391 io_ret = ops->get_size_of_partition(ops, part_name, &image_size);
392 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
393 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
394 goto out;
395 } else if (io_ret != AVB_IO_RESULT_OK) {
396 avb_errorv(part_name, ": Error determining partition size.\n", NULL);
397 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
398 goto out;
399 }
400 avb_debugv(part_name, ": Loading entire partition.\n", NULL);
401
402 ret = load_full_partition(
403 ops, part_name, image_size, &image_buf, &image_preloaded);
404 if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
405 goto out;
406 }
407
408 /* Move to slot_data. */
409 if (slot_data->num_loaded_partitions == MAX_NUMBER_OF_LOADED_PARTITIONS) {
410 avb_errorv(part_name, ": Too many loaded partitions.\n", NULL);
411 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
412 goto out;
413 }
414 loaded_partition =
415 &slot_data->loaded_partitions[slot_data->num_loaded_partitions++];
416 loaded_partition->partition_name = avb_strdup(requested_partitions[n]);
417 if (loaded_partition->partition_name == NULL) {
418 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
419 goto out;
420 }
421 loaded_partition->data_size = image_size;
422 loaded_partition->data = image_buf; /* Transferring the owner. */
423 loaded_partition->preloaded = image_preloaded;
424 image_buf = NULL;
425 image_preloaded = false;
426 }
427
428 ret = AVB_SLOT_VERIFY_RESULT_OK;
429
430 out:
431 /* Free the current buffer if any. */
432 if (image_buf != NULL && !image_preloaded) {
433 avb_free(image_buf);
434 }
435 /* Buffers that are already saved in slot_data will be handled by the caller
436 * even on failure. */
437 return ret;
438 }
439
load_and_verify_vbmeta(AvbOps * ops,const char * const * requested_partitions,const char * ab_suffix,bool allow_verification_error,AvbVBMetaImageFlags toplevel_vbmeta_flags,int rollback_index_location,const char * partition_name,size_t partition_name_len,const uint8_t * expected_public_key,size_t expected_public_key_length,AvbSlotVerifyData * slot_data,AvbAlgorithmType * out_algorithm_type,AvbCmdlineSubstList * out_additional_cmdline_subst)440 static AvbSlotVerifyResult load_and_verify_vbmeta(
441 AvbOps* ops,
442 const char* const* requested_partitions,
443 const char* ab_suffix,
444 bool allow_verification_error,
445 AvbVBMetaImageFlags toplevel_vbmeta_flags,
446 int rollback_index_location,
447 const char* partition_name,
448 size_t partition_name_len,
449 const uint8_t* expected_public_key,
450 size_t expected_public_key_length,
451 AvbSlotVerifyData* slot_data,
452 AvbAlgorithmType* out_algorithm_type,
453 AvbCmdlineSubstList* out_additional_cmdline_subst) {
454 char full_partition_name[AVB_PART_NAME_MAX_SIZE];
455 AvbSlotVerifyResult ret;
456 AvbIOResult io_ret;
457 size_t vbmeta_offset;
458 size_t vbmeta_size;
459 uint8_t* vbmeta_buf = NULL;
460 size_t vbmeta_num_read;
461 AvbVBMetaVerifyResult vbmeta_ret;
462 const uint8_t* pk_data;
463 size_t pk_len;
464 AvbVBMetaImageHeader vbmeta_header;
465 uint64_t stored_rollback_index;
466 const AvbDescriptor** descriptors = NULL;
467 size_t num_descriptors;
468 size_t n;
469 bool is_main_vbmeta;
470 bool is_vbmeta_partition;
471 AvbVBMetaData* vbmeta_image_data = NULL;
472
473 ret = AVB_SLOT_VERIFY_RESULT_OK;
474
475 avb_assert(slot_data != NULL);
476
477 /* Since we allow top-level vbmeta in 'boot', use
478 * rollback_index_location to determine whether we're the main
479 * vbmeta struct.
480 */
481 is_main_vbmeta = (rollback_index_location == 0);
482 is_vbmeta_partition = (avb_strcmp(partition_name, "vbmeta") == 0);
483
484 if (!avb_validate_utf8((const uint8_t*)partition_name, partition_name_len)) {
485 avb_error("Partition name is not valid UTF-8.\n");
486 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
487 goto out;
488 }
489
490 /* Construct full partition name. */
491 if (!avb_str_concat(full_partition_name,
492 sizeof full_partition_name,
493 partition_name,
494 partition_name_len,
495 ab_suffix,
496 avb_strlen(ab_suffix))) {
497 avb_error("Partition name and suffix does not fit.\n");
498 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
499 goto out;
500 }
501
502 avb_debugv("Loading vbmeta struct from partition '",
503 full_partition_name,
504 "'.\n",
505 NULL);
506
507 /* If we're loading from the main vbmeta partition, the vbmeta
508 * struct is in the beginning. Otherwise we have to locate it via a
509 * footer.
510 */
511 if (is_vbmeta_partition) {
512 vbmeta_offset = 0;
513 vbmeta_size = VBMETA_MAX_SIZE;
514 } else {
515 uint8_t footer_buf[AVB_FOOTER_SIZE];
516 size_t footer_num_read;
517 AvbFooter footer;
518
519 io_ret = ops->read_from_partition(ops,
520 full_partition_name,
521 -AVB_FOOTER_SIZE,
522 AVB_FOOTER_SIZE,
523 footer_buf,
524 &footer_num_read);
525 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
526 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
527 goto out;
528 } else if (io_ret != AVB_IO_RESULT_OK) {
529 avb_errorv(full_partition_name, ": Error loading footer.\n", NULL);
530 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
531 goto out;
532 }
533 avb_assert(footer_num_read == AVB_FOOTER_SIZE);
534
535 if (!avb_footer_validate_and_byteswap((const AvbFooter*)footer_buf,
536 &footer)) {
537 avb_errorv(full_partition_name, ": Error validating footer.\n", NULL);
538 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
539 goto out;
540 }
541
542 /* Basic footer sanity check since the data is untrusted. */
543 if (footer.vbmeta_size > VBMETA_MAX_SIZE) {
544 avb_errorv(
545 full_partition_name, ": Invalid vbmeta size in footer.\n", NULL);
546 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
547 goto out;
548 }
549
550 vbmeta_offset = footer.vbmeta_offset;
551 vbmeta_size = footer.vbmeta_size;
552 }
553
554 vbmeta_buf = avb_malloc(vbmeta_size);
555 if (vbmeta_buf == NULL) {
556 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
557 goto out;
558 }
559
560 io_ret = ops->read_from_partition(ops,
561 full_partition_name,
562 vbmeta_offset,
563 vbmeta_size,
564 vbmeta_buf,
565 &vbmeta_num_read);
566 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
567 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
568 goto out;
569 } else if (io_ret != AVB_IO_RESULT_OK) {
570 /* If we're looking for 'vbmeta' but there is no such partition,
571 * go try to get it from the boot partition instead.
572 */
573 if (is_main_vbmeta && io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION &&
574 is_vbmeta_partition) {
575 avb_debugv(full_partition_name,
576 ": No such partition. Trying 'boot' instead.\n",
577 NULL);
578 ret = load_and_verify_vbmeta(ops,
579 requested_partitions,
580 ab_suffix,
581 allow_verification_error,
582 0 /* toplevel_vbmeta_flags */,
583 0 /* rollback_index_location */,
584 "boot",
585 avb_strlen("boot"),
586 NULL /* expected_public_key */,
587 0 /* expected_public_key_length */,
588 slot_data,
589 out_algorithm_type,
590 out_additional_cmdline_subst);
591 goto out;
592 } else {
593 avb_errorv(full_partition_name, ": Error loading vbmeta data.\n", NULL);
594 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
595 goto out;
596 }
597 }
598 avb_assert(vbmeta_num_read <= vbmeta_size);
599
600 /* Check if the image is properly signed and get the public key used
601 * to sign the image.
602 */
603 vbmeta_ret =
604 avb_vbmeta_image_verify(vbmeta_buf, vbmeta_num_read, &pk_data, &pk_len);
605 switch (vbmeta_ret) {
606 case AVB_VBMETA_VERIFY_RESULT_OK:
607 avb_assert(pk_data != NULL && pk_len > 0);
608 break;
609
610 case AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED:
611 case AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH:
612 case AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH:
613 ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
614 avb_errorv(full_partition_name,
615 ": Error verifying vbmeta image: ",
616 avb_vbmeta_verify_result_to_string(vbmeta_ret),
617 "\n",
618 NULL);
619 if (!allow_verification_error) {
620 goto out;
621 }
622 break;
623
624 case AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER:
625 /* No way to continue this case. */
626 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
627 avb_errorv(full_partition_name,
628 ": Error verifying vbmeta image: invalid vbmeta header\n",
629 NULL);
630 goto out;
631
632 case AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION:
633 /* No way to continue this case. */
634 ret = AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION;
635 avb_errorv(full_partition_name,
636 ": Error verifying vbmeta image: unsupported AVB version\n",
637 NULL);
638 goto out;
639 }
640
641 /* Byteswap the header. */
642 avb_vbmeta_image_header_to_host_byte_order((AvbVBMetaImageHeader*)vbmeta_buf,
643 &vbmeta_header);
644
645 /* If we're the toplevel, assign flags so they'll be passed down. */
646 if (is_main_vbmeta) {
647 toplevel_vbmeta_flags = (AvbVBMetaImageFlags)vbmeta_header.flags;
648 } else {
649 if (vbmeta_header.flags != 0) {
650 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
651 avb_errorv(full_partition_name,
652 ": chained vbmeta image has non-zero flags\n",
653 NULL);
654 goto out;
655 }
656 }
657
658 /* Check if key used to make signature matches what is expected. */
659 if (pk_data != NULL) {
660 if (expected_public_key != NULL) {
661 avb_assert(!is_main_vbmeta);
662 if (expected_public_key_length != pk_len ||
663 avb_safe_memcmp(expected_public_key, pk_data, pk_len) != 0) {
664 avb_errorv(full_partition_name,
665 ": Public key used to sign data does not match key in chain "
666 "partition descriptor.\n",
667 NULL);
668 ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
669 if (!allow_verification_error) {
670 goto out;
671 }
672 }
673 } else {
674 bool key_is_trusted = false;
675 const uint8_t* pk_metadata = NULL;
676 size_t pk_metadata_len = 0;
677
678 if (vbmeta_header.public_key_metadata_size > 0) {
679 pk_metadata = vbmeta_buf + sizeof(AvbVBMetaImageHeader) +
680 vbmeta_header.authentication_data_block_size +
681 vbmeta_header.public_key_metadata_offset;
682 pk_metadata_len = vbmeta_header.public_key_metadata_size;
683 }
684
685 avb_assert(is_main_vbmeta);
686 io_ret = ops->validate_vbmeta_public_key(
687 ops, pk_data, pk_len, pk_metadata, pk_metadata_len, &key_is_trusted);
688 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
689 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
690 goto out;
691 } else if (io_ret != AVB_IO_RESULT_OK) {
692 avb_errorv(full_partition_name,
693 ": Error while checking public key used to sign data.\n",
694 NULL);
695 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
696 goto out;
697 }
698 if (!key_is_trusted) {
699 avb_errorv(full_partition_name,
700 ": Public key used to sign data rejected.\n",
701 NULL);
702 ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
703 if (!allow_verification_error) {
704 goto out;
705 }
706 }
707 }
708 }
709
710 /* Check rollback index. */
711 io_ret = ops->read_rollback_index(
712 ops, rollback_index_location, &stored_rollback_index);
713 if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
714 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
715 goto out;
716 } else if (io_ret != AVB_IO_RESULT_OK) {
717 avb_errorv(full_partition_name,
718 ": Error getting rollback index for location.\n",
719 NULL);
720 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
721 goto out;
722 }
723 if (vbmeta_header.rollback_index < stored_rollback_index) {
724 avb_errorv(
725 full_partition_name,
726 ": Image rollback index is less than the stored rollback index.\n",
727 NULL);
728 ret = AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX;
729 if (!allow_verification_error) {
730 goto out;
731 }
732 }
733
734 /* Copy vbmeta to vbmeta_images before recursing. */
735 if (is_main_vbmeta) {
736 avb_assert(slot_data->num_vbmeta_images == 0);
737 } else {
738 avb_assert(slot_data->num_vbmeta_images > 0);
739 }
740 if (slot_data->num_vbmeta_images == MAX_NUMBER_OF_VBMETA_IMAGES) {
741 avb_errorv(full_partition_name, ": Too many vbmeta images.\n", NULL);
742 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
743 goto out;
744 }
745 vbmeta_image_data = &slot_data->vbmeta_images[slot_data->num_vbmeta_images++];
746 vbmeta_image_data->partition_name = avb_strdup(partition_name);
747 vbmeta_image_data->vbmeta_data = vbmeta_buf;
748 /* Note that |vbmeta_buf| is actually |vbmeta_num_read| bytes long
749 * and this includes data past the end of the image. Pass the
750 * actual size of the vbmeta image. Also, no need to use
751 * avb_safe_add() since the header has already been verified.
752 */
753 vbmeta_image_data->vbmeta_size =
754 sizeof(AvbVBMetaImageHeader) +
755 vbmeta_header.authentication_data_block_size +
756 vbmeta_header.auxiliary_data_block_size;
757 vbmeta_image_data->verify_result = vbmeta_ret;
758
759 /* If verification has been disabled by setting a bit in the image,
760 * we're done... except that we need to load the entirety of the
761 * requested partitions.
762 */
763 if (vbmeta_header.flags & AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED) {
764 AvbSlotVerifyResult sub_ret;
765 avb_debugv(
766 full_partition_name, ": VERIFICATION_DISABLED bit is set.\n", NULL);
767 /* If load_requested_partitions() fail it is always a fatal
768 * failure (e.g. ERROR_INVALID_ARGUMENT, ERROR_OOM, etc.) rather
769 * than recoverable (e.g. one where result_should_continue()
770 * returns true) and we want to convey that error.
771 */
772 sub_ret = load_requested_partitions(
773 ops, requested_partitions, ab_suffix, slot_data);
774 if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
775 ret = sub_ret;
776 }
777 goto out;
778 }
779
780 /* Now go through all descriptors and take the appropriate action:
781 *
782 * - hash descriptor: Load data from partition, calculate hash, and
783 * checks that it matches what's in the hash descriptor.
784 *
785 * - hashtree descriptor: Do nothing since verification happens
786 * on-the-fly from within the OS. (Unless the descriptor uses a
787 * persistent digest, in which case we need to find it).
788 *
789 * - chained partition descriptor: Load the footer, load the vbmeta
790 * image, verify vbmeta image (includes rollback checks, hash
791 * checks, bail on chained partitions).
792 */
793 descriptors =
794 avb_descriptor_get_all(vbmeta_buf, vbmeta_num_read, &num_descriptors);
795 for (n = 0; n < num_descriptors; n++) {
796 AvbDescriptor desc;
797
798 if (!avb_descriptor_validate_and_byteswap(descriptors[n], &desc)) {
799 avb_errorv(full_partition_name, ": Descriptor is invalid.\n", NULL);
800 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
801 goto out;
802 }
803
804 switch (desc.tag) {
805 case AVB_DESCRIPTOR_TAG_HASH: {
806 AvbSlotVerifyResult sub_ret;
807 sub_ret = load_and_verify_hash_partition(ops,
808 requested_partitions,
809 ab_suffix,
810 allow_verification_error,
811 descriptors[n],
812 slot_data);
813 if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
814 ret = sub_ret;
815 if (!allow_verification_error || !result_should_continue(ret)) {
816 goto out;
817 }
818 }
819 } break;
820
821 case AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: {
822 AvbSlotVerifyResult sub_ret;
823 AvbChainPartitionDescriptor chain_desc;
824 const uint8_t* chain_partition_name;
825 const uint8_t* chain_public_key;
826
827 /* Only allow CHAIN_PARTITION descriptors in the main vbmeta image. */
828 if (!is_main_vbmeta) {
829 avb_errorv(full_partition_name,
830 ": Encountered chain descriptor not in main image.\n",
831 NULL);
832 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
833 goto out;
834 }
835
836 if (!avb_chain_partition_descriptor_validate_and_byteswap(
837 (AvbChainPartitionDescriptor*)descriptors[n], &chain_desc)) {
838 avb_errorv(full_partition_name,
839 ": Chain partition descriptor is invalid.\n",
840 NULL);
841 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
842 goto out;
843 }
844
845 if (chain_desc.rollback_index_location == 0) {
846 avb_errorv(full_partition_name,
847 ": Chain partition has invalid "
848 "rollback_index_location field.\n",
849 NULL);
850 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
851 goto out;
852 }
853
854 chain_partition_name = ((const uint8_t*)descriptors[n]) +
855 sizeof(AvbChainPartitionDescriptor);
856 chain_public_key = chain_partition_name + chain_desc.partition_name_len;
857
858 sub_ret =
859 load_and_verify_vbmeta(ops,
860 requested_partitions,
861 ab_suffix,
862 allow_verification_error,
863 toplevel_vbmeta_flags,
864 chain_desc.rollback_index_location,
865 (const char*)chain_partition_name,
866 chain_desc.partition_name_len,
867 chain_public_key,
868 chain_desc.public_key_len,
869 slot_data,
870 NULL, /* out_algorithm_type */
871 NULL /* out_additional_cmdline_subst */);
872 if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
873 ret = sub_ret;
874 if (!result_should_continue(ret)) {
875 goto out;
876 }
877 }
878 } break;
879
880 case AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: {
881 const uint8_t* kernel_cmdline;
882 AvbKernelCmdlineDescriptor kernel_cmdline_desc;
883 bool apply_cmdline;
884
885 if (!avb_kernel_cmdline_descriptor_validate_and_byteswap(
886 (AvbKernelCmdlineDescriptor*)descriptors[n],
887 &kernel_cmdline_desc)) {
888 avb_errorv(full_partition_name,
889 ": Kernel cmdline descriptor is invalid.\n",
890 NULL);
891 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
892 goto out;
893 }
894
895 kernel_cmdline = ((const uint8_t*)descriptors[n]) +
896 sizeof(AvbKernelCmdlineDescriptor);
897
898 if (!avb_validate_utf8(kernel_cmdline,
899 kernel_cmdline_desc.kernel_cmdline_length)) {
900 avb_errorv(full_partition_name,
901 ": Kernel cmdline is not valid UTF-8.\n",
902 NULL);
903 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
904 goto out;
905 }
906
907 /* Compare the flags for top-level VBMeta struct with flags in
908 * the command-line descriptor so command-line snippets only
909 * intended for a certain mode (dm-verity enabled/disabled)
910 * are skipped if applicable.
911 */
912 apply_cmdline = true;
913 if (toplevel_vbmeta_flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) {
914 if (kernel_cmdline_desc.flags &
915 AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_NOT_DISABLED) {
916 apply_cmdline = false;
917 }
918 } else {
919 if (kernel_cmdline_desc.flags &
920 AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_DISABLED) {
921 apply_cmdline = false;
922 }
923 }
924
925 if (apply_cmdline) {
926 if (slot_data->cmdline == NULL) {
927 slot_data->cmdline =
928 avb_calloc(kernel_cmdline_desc.kernel_cmdline_length + 1);
929 if (slot_data->cmdline == NULL) {
930 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
931 goto out;
932 }
933 avb_memcpy(slot_data->cmdline,
934 kernel_cmdline,
935 kernel_cmdline_desc.kernel_cmdline_length);
936 } else {
937 /* new cmdline is: <existing_cmdline> + ' ' + <newcmdline> + '\0' */
938 size_t orig_size = avb_strlen(slot_data->cmdline);
939 size_t new_size =
940 orig_size + 1 + kernel_cmdline_desc.kernel_cmdline_length + 1;
941 char* new_cmdline = avb_calloc(new_size);
942 if (new_cmdline == NULL) {
943 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
944 goto out;
945 }
946 avb_memcpy(new_cmdline, slot_data->cmdline, orig_size);
947 new_cmdline[orig_size] = ' ';
948 avb_memcpy(new_cmdline + orig_size + 1,
949 kernel_cmdline,
950 kernel_cmdline_desc.kernel_cmdline_length);
951 avb_free(slot_data->cmdline);
952 slot_data->cmdline = new_cmdline;
953 }
954 }
955 } break;
956
957 case AVB_DESCRIPTOR_TAG_HASHTREE: {
958 AvbHashtreeDescriptor hashtree_desc;
959
960 if (!avb_hashtree_descriptor_validate_and_byteswap(
961 (AvbHashtreeDescriptor*)descriptors[n], &hashtree_desc)) {
962 avb_errorv(
963 full_partition_name, ": Hashtree descriptor is invalid.\n", NULL);
964 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
965 goto out;
966 }
967
968 /* We only need to continue when there is no digest in the descriptor.
969 * This is because the only processing here is to find the digest and
970 * make it available on the kernel command line.
971 */
972 if (hashtree_desc.root_digest_len == 0) {
973 char part_name[AVB_PART_NAME_MAX_SIZE];
974 size_t digest_len = 0;
975 uint8_t digest_buf[AVB_SHA512_DIGEST_SIZE];
976 const uint8_t* desc_partition_name =
977 ((const uint8_t*)descriptors[n]) + sizeof(AvbHashtreeDescriptor);
978
979 if (!avb_validate_utf8(desc_partition_name,
980 hashtree_desc.partition_name_len)) {
981 avb_error("Partition name is not valid UTF-8.\n");
982 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
983 goto out;
984 }
985
986 /* No ab_suffix for partitions without a digest in the descriptor
987 * because these partitions hold data unique to this device and are
988 * not updated using an A/B scheme.
989 */
990 if ((hashtree_desc.flags &
991 AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB) == 0 &&
992 avb_strlen(ab_suffix) != 0) {
993 avb_error("Cannot use A/B with a persistent root digest.\n");
994 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
995 goto out;
996 }
997 if (hashtree_desc.partition_name_len >= AVB_PART_NAME_MAX_SIZE) {
998 avb_error("Partition name does not fit.\n");
999 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
1000 goto out;
1001 }
1002 avb_memcpy(
1003 part_name, desc_partition_name, hashtree_desc.partition_name_len);
1004 part_name[hashtree_desc.partition_name_len] = '\0';
1005
1006 /* Determine the expected digest size from the hash algorithm. */
1007 if (avb_strcmp((const char*)hashtree_desc.hash_algorithm, "sha1") ==
1008 0) {
1009 digest_len = AVB_SHA1_DIGEST_SIZE;
1010 } else if (avb_strcmp((const char*)hashtree_desc.hash_algorithm,
1011 "sha256") == 0) {
1012 digest_len = AVB_SHA256_DIGEST_SIZE;
1013 } else if (avb_strcmp((const char*)hashtree_desc.hash_algorithm,
1014 "sha512") == 0) {
1015 digest_len = AVB_SHA512_DIGEST_SIZE;
1016 } else {
1017 avb_errorv(part_name, ": Unsupported hash algorithm.\n", NULL);
1018 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
1019 goto out;
1020 }
1021
1022 ret = read_persistent_digest(ops, part_name, digest_len, digest_buf);
1023 if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
1024 goto out;
1025 }
1026
1027 if (out_additional_cmdline_subst) {
1028 ret =
1029 avb_add_root_digest_substitution(part_name,
1030 digest_buf,
1031 digest_len,
1032 out_additional_cmdline_subst);
1033 if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
1034 goto out;
1035 }
1036 }
1037 }
1038 } break;
1039
1040 case AVB_DESCRIPTOR_TAG_PROPERTY:
1041 /* Do nothing. */
1042 break;
1043 }
1044 }
1045
1046 if (rollback_index_location >= AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS) {
1047 avb_errorv(
1048 full_partition_name, ": Invalid rollback_index_location.\n", NULL);
1049 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
1050 goto out;
1051 }
1052
1053 slot_data->rollback_indexes[rollback_index_location] =
1054 vbmeta_header.rollback_index;
1055
1056 if (out_algorithm_type != NULL) {
1057 *out_algorithm_type = (AvbAlgorithmType)vbmeta_header.algorithm_type;
1058 }
1059
1060 out:
1061 /* If |vbmeta_image_data| isn't NULL it means that it adopted
1062 * |vbmeta_buf| so in that case don't free it here.
1063 */
1064 if (vbmeta_image_data == NULL) {
1065 if (vbmeta_buf != NULL) {
1066 avb_free(vbmeta_buf);
1067 }
1068 }
1069 if (descriptors != NULL) {
1070 avb_free(descriptors);
1071 }
1072 return ret;
1073 }
1074
avb_slot_verify(AvbOps * ops,const char * const * requested_partitions,const char * ab_suffix,AvbSlotVerifyFlags flags,AvbHashtreeErrorMode hashtree_error_mode,AvbSlotVerifyData ** out_data)1075 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
1076 const char* const* requested_partitions,
1077 const char* ab_suffix,
1078 AvbSlotVerifyFlags flags,
1079 AvbHashtreeErrorMode hashtree_error_mode,
1080 AvbSlotVerifyData** out_data) {
1081 AvbSlotVerifyResult ret;
1082 AvbSlotVerifyData* slot_data = NULL;
1083 AvbAlgorithmType algorithm_type = AVB_ALGORITHM_TYPE_NONE;
1084 bool using_boot_for_vbmeta = false;
1085 AvbVBMetaImageHeader toplevel_vbmeta;
1086 bool allow_verification_error =
1087 (flags & AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR);
1088 AvbCmdlineSubstList* additional_cmdline_subst = NULL;
1089
1090 /* Fail early if we're missing the AvbOps needed for slot verification.
1091 *
1092 * For now, handle get_size_of_partition() not being implemented. In
1093 * a later release we may change that.
1094 */
1095 avb_assert(ops->read_is_device_unlocked != NULL);
1096 avb_assert(ops->read_from_partition != NULL);
1097 avb_assert(ops->validate_vbmeta_public_key != NULL);
1098 avb_assert(ops->read_rollback_index != NULL);
1099 avb_assert(ops->get_unique_guid_for_partition != NULL);
1100
1101 if (out_data != NULL) {
1102 *out_data = NULL;
1103 }
1104
1105 /* Allowing dm-verity errors defeats the purpose of verified boot so
1106 * only allow this if set up to allow verification errors
1107 * (e.g. typically only UNLOCKED mode).
1108 */
1109 if (hashtree_error_mode == AVB_HASHTREE_ERROR_MODE_LOGGING &&
1110 !allow_verification_error) {
1111 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
1112 goto fail;
1113 }
1114
1115 slot_data = avb_calloc(sizeof(AvbSlotVerifyData));
1116 if (slot_data == NULL) {
1117 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1118 goto fail;
1119 }
1120 slot_data->vbmeta_images =
1121 avb_calloc(sizeof(AvbVBMetaData) * MAX_NUMBER_OF_VBMETA_IMAGES);
1122 if (slot_data->vbmeta_images == NULL) {
1123 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1124 goto fail;
1125 }
1126 slot_data->loaded_partitions =
1127 avb_calloc(sizeof(AvbPartitionData) * MAX_NUMBER_OF_LOADED_PARTITIONS);
1128 if (slot_data->loaded_partitions == NULL) {
1129 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1130 goto fail;
1131 }
1132
1133 additional_cmdline_subst = avb_new_cmdline_subst_list();
1134 if (additional_cmdline_subst == NULL) {
1135 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1136 goto fail;
1137 }
1138
1139 ret = load_and_verify_vbmeta(ops,
1140 requested_partitions,
1141 ab_suffix,
1142 allow_verification_error,
1143 0 /* toplevel_vbmeta_flags */,
1144 0 /* rollback_index_location */,
1145 "vbmeta",
1146 avb_strlen("vbmeta"),
1147 NULL /* expected_public_key */,
1148 0 /* expected_public_key_length */,
1149 slot_data,
1150 &algorithm_type,
1151 additional_cmdline_subst);
1152 if (!allow_verification_error && ret != AVB_SLOT_VERIFY_RESULT_OK) {
1153 goto fail;
1154 }
1155
1156 /* If things check out, mangle the kernel command-line as needed. */
1157 if (result_should_continue(ret)) {
1158 if (avb_strcmp(slot_data->vbmeta_images[0].partition_name, "vbmeta") != 0) {
1159 avb_assert(
1160 avb_strcmp(slot_data->vbmeta_images[0].partition_name, "boot") == 0);
1161 using_boot_for_vbmeta = true;
1162 }
1163
1164 /* Byteswap top-level vbmeta header since we'll need it below. */
1165 avb_vbmeta_image_header_to_host_byte_order(
1166 (const AvbVBMetaImageHeader*)slot_data->vbmeta_images[0].vbmeta_data,
1167 &toplevel_vbmeta);
1168
1169 /* Fill in |ab_suffix| field. */
1170 slot_data->ab_suffix = avb_strdup(ab_suffix);
1171 if (slot_data->ab_suffix == NULL) {
1172 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1173 goto fail;
1174 }
1175
1176 /* If verification is disabled, we are done ... we specifically
1177 * don't want to add any androidboot.* options since verification
1178 * is disabled.
1179 */
1180 if (toplevel_vbmeta.flags & AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED) {
1181 /* Since verification is disabled we didn't process any
1182 * descriptors and thus there's no cmdline... so set root= such
1183 * that the system partition is mounted.
1184 */
1185 avb_assert(slot_data->cmdline == NULL);
1186 slot_data->cmdline =
1187 avb_strdup("root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)");
1188 if (slot_data->cmdline == NULL) {
1189 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1190 goto fail;
1191 }
1192 } else {
1193 /* Add options - any failure in avb_append_options() is either an
1194 * I/O or OOM error.
1195 */
1196 AvbSlotVerifyResult sub_ret = avb_append_options(ops,
1197 slot_data,
1198 &toplevel_vbmeta,
1199 algorithm_type,
1200 hashtree_error_mode);
1201 if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
1202 ret = sub_ret;
1203 goto fail;
1204 }
1205 }
1206
1207 /* Substitute $(ANDROID_SYSTEM_PARTUUID) and friends. */
1208 if (slot_data->cmdline != NULL) {
1209 char* new_cmdline;
1210 new_cmdline = avb_sub_cmdline(ops,
1211 slot_data->cmdline,
1212 ab_suffix,
1213 using_boot_for_vbmeta,
1214 additional_cmdline_subst);
1215 if (new_cmdline != slot_data->cmdline) {
1216 if (new_cmdline == NULL) {
1217 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
1218 goto fail;
1219 }
1220 avb_free(slot_data->cmdline);
1221 slot_data->cmdline = new_cmdline;
1222 }
1223 }
1224
1225 if (out_data != NULL) {
1226 *out_data = slot_data;
1227 } else {
1228 avb_slot_verify_data_free(slot_data);
1229 }
1230 }
1231
1232 avb_free_cmdline_subst_list(additional_cmdline_subst);
1233 additional_cmdline_subst = NULL;
1234
1235 if (!allow_verification_error) {
1236 avb_assert(ret == AVB_SLOT_VERIFY_RESULT_OK);
1237 }
1238
1239 return ret;
1240
1241 fail:
1242 if (slot_data != NULL) {
1243 avb_slot_verify_data_free(slot_data);
1244 }
1245 if (additional_cmdline_subst != NULL) {
1246 avb_free_cmdline_subst_list(additional_cmdline_subst);
1247 }
1248 return ret;
1249 }
1250
avb_slot_verify_data_free(AvbSlotVerifyData * data)1251 void avb_slot_verify_data_free(AvbSlotVerifyData* data) {
1252 if (data->ab_suffix != NULL) {
1253 avb_free(data->ab_suffix);
1254 }
1255 if (data->cmdline != NULL) {
1256 avb_free(data->cmdline);
1257 }
1258 if (data->vbmeta_images != NULL) {
1259 size_t n;
1260 for (n = 0; n < data->num_vbmeta_images; n++) {
1261 AvbVBMetaData* vbmeta_image = &data->vbmeta_images[n];
1262 if (vbmeta_image->partition_name != NULL) {
1263 avb_free(vbmeta_image->partition_name);
1264 }
1265 if (vbmeta_image->vbmeta_data != NULL) {
1266 avb_free(vbmeta_image->vbmeta_data);
1267 }
1268 }
1269 avb_free(data->vbmeta_images);
1270 }
1271 if (data->loaded_partitions != NULL) {
1272 size_t n;
1273 for (n = 0; n < data->num_loaded_partitions; n++) {
1274 AvbPartitionData* loaded_partition = &data->loaded_partitions[n];
1275 if (loaded_partition->partition_name != NULL) {
1276 avb_free(loaded_partition->partition_name);
1277 }
1278 if (loaded_partition->data != NULL && !loaded_partition->preloaded) {
1279 avb_free(loaded_partition->data);
1280 }
1281 }
1282 avb_free(data->loaded_partitions);
1283 }
1284 avb_free(data);
1285 }
1286
avb_slot_verify_result_to_string(AvbSlotVerifyResult result)1287 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result) {
1288 const char* ret = NULL;
1289
1290 switch (result) {
1291 case AVB_SLOT_VERIFY_RESULT_OK:
1292 ret = "OK";
1293 break;
1294 case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
1295 ret = "ERROR_OOM";
1296 break;
1297 case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
1298 ret = "ERROR_IO";
1299 break;
1300 case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
1301 ret = "ERROR_VERIFICATION";
1302 break;
1303 case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
1304 ret = "ERROR_ROLLBACK_INDEX";
1305 break;
1306 case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
1307 ret = "ERROR_PUBLIC_KEY_REJECTED";
1308 break;
1309 case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
1310 ret = "ERROR_INVALID_METADATA";
1311 break;
1312 case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
1313 ret = "ERROR_UNSUPPORTED_VERSION";
1314 break;
1315 case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT:
1316 ret = "ERROR_INVALID_ARGUMENT";
1317 break;
1318 /* Do not add a 'default:' case here because of -Wswitch. */
1319 }
1320
1321 if (ret == NULL) {
1322 avb_error("Unknown AvbSlotVerifyResult value.\n");
1323 ret = "(unknown)";
1324 }
1325
1326 return ret;
1327 }
1328
avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData * data,AvbDigestType digest_type,uint8_t * out_digest)1329 void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data,
1330 AvbDigestType digest_type,
1331 uint8_t* out_digest) {
1332 bool ret = false;
1333 size_t n;
1334
1335 switch (digest_type) {
1336 case AVB_DIGEST_TYPE_SHA256: {
1337 AvbSHA256Ctx ctx;
1338 avb_sha256_init(&ctx);
1339 for (n = 0; n < data->num_vbmeta_images; n++) {
1340 avb_sha256_update(&ctx,
1341 data->vbmeta_images[n].vbmeta_data,
1342 data->vbmeta_images[n].vbmeta_size);
1343 }
1344 avb_memcpy(out_digest, avb_sha256_final(&ctx), AVB_SHA256_DIGEST_SIZE);
1345 ret = true;
1346 } break;
1347
1348 case AVB_DIGEST_TYPE_SHA512: {
1349 AvbSHA512Ctx ctx;
1350 avb_sha512_init(&ctx);
1351 for (n = 0; n < data->num_vbmeta_images; n++) {
1352 avb_sha512_update(&ctx,
1353 data->vbmeta_images[n].vbmeta_data,
1354 data->vbmeta_images[n].vbmeta_size);
1355 }
1356 avb_memcpy(out_digest, avb_sha512_final(&ctx), AVB_SHA512_DIGEST_SIZE);
1357 ret = true;
1358 } break;
1359
1360 /* Do not add a 'default:' case here because of -Wswitch. */
1361 }
1362
1363 if (!ret) {
1364 avb_fatal("Unknown digest type");
1365 }
1366 }
1367