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- // SPDX-License-Identifier: MIT
- /*
- * Copyright (C) 2016 The Android Open Source Project
- */
- #include "avb_slot_verify.h"
- #include "avb_chain_partition_descriptor.h"
- #include "avb_cmdline.h"
- #include "avb_footer.h"
- #include "avb_hash_descriptor.h"
- #include "avb_hashtree_descriptor.h"
- #include "avb_kernel_cmdline_descriptor.h"
- #include "avb_sha.h"
- #include "avb_util.h"
- #include "avb_vbmeta_image.h"
- #include "avb_version.h"
- /* Maximum number of partitions that can be loaded with avb_slot_verify(). */
- #define MAX_NUMBER_OF_LOADED_PARTITIONS 32
- /* Maximum number of vbmeta images that can be loaded with avb_slot_verify(). */
- #define MAX_NUMBER_OF_VBMETA_IMAGES 32
- /* Maximum size of a vbmeta image - 64 KiB. */
- #define VBMETA_MAX_SIZE (64 * 1024)
- static AvbSlotVerifyResult initialize_persistent_digest(
- AvbOps* ops,
- const char* part_name,
- const char* persistent_value_name,
- size_t digest_size,
- const uint8_t* initial_digest,
- uint8_t* out_digest);
- /* Helper function to see if we should continue with verification in
- * allow_verification_error=true mode if something goes wrong. See the
- * comments for the avb_slot_verify() function for more information.
- */
- static inline bool result_should_continue(AvbSlotVerifyResult result) {
- switch (result) {
- case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
- case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
- case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
- case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
- case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT:
- return false;
- case AVB_SLOT_VERIFY_RESULT_OK:
- case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
- case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
- case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
- return true;
- }
- return false;
- }
- static AvbSlotVerifyResult load_full_partition(AvbOps* ops,
- const char* part_name,
- uint64_t image_size,
- uint8_t** out_image_buf,
- bool* out_image_preloaded) {
- size_t part_num_read;
- AvbIOResult io_ret;
- /* Make sure that we do not overwrite existing data. */
- avb_assert(*out_image_buf == NULL);
- avb_assert(!*out_image_preloaded);
- /* We are going to implicitly cast image_size from uint64_t to size_t in the
- * following code, so we need to make sure that the cast is safe. */
- if (image_size != (size_t)(image_size)) {
- avb_errorv(part_name, ": Partition size too large to load.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- }
- /* Try use a preloaded one. */
- if (ops->get_preloaded_partition != NULL) {
- io_ret = ops->get_preloaded_partition(
- ops, part_name, image_size, out_image_buf, &part_num_read);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error loading data from partition.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- if (*out_image_buf != NULL) {
- if (part_num_read != image_size) {
- avb_errorv(part_name, ": Read incorrect number of bytes.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- *out_image_preloaded = true;
- }
- }
- /* Allocate and copy the partition. */
- if (!*out_image_preloaded) {
- *out_image_buf = avb_malloc(image_size);
- if (*out_image_buf == NULL) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- }
- io_ret = ops->read_from_partition(ops,
- part_name,
- 0 /* offset */,
- image_size,
- *out_image_buf,
- &part_num_read);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error loading data from partition.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- if (part_num_read != image_size) {
- avb_errorv(part_name, ": Read incorrect number of bytes.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- }
- return AVB_SLOT_VERIFY_RESULT_OK;
- }
- /* Reads a persistent digest stored as a named persistent value corresponding to
- * the given |part_name|. The value is returned in |out_digest| which must point
- * to |expected_digest_size| bytes. If there is no digest stored for |part_name|
- * it can be initialized by providing a non-NULL |initial_digest| of length
- * |expected_digest_size|. This automatic initialization will only occur if the
- * device is currently locked. The |initial_digest| may be NULL.
- *
- * Returns AVB_SLOT_VERIFY_RESULT_OK on success, otherwise returns an
- * AVB_SLOT_VERIFY_RESULT_ERROR_* error code.
- *
- * If the value does not exist, is not supported, or is not populated, and
- * |initial_digest| is NULL, returns
- * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA. If |expected_digest_size| does
- * not match the stored digest size, also returns
- * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA.
- */
- static AvbSlotVerifyResult read_persistent_digest(AvbOps* ops,
- const char* part_name,
- size_t expected_digest_size,
- const uint8_t* initial_digest,
- uint8_t* out_digest) {
- char* persistent_value_name = NULL;
- AvbIOResult io_ret = AVB_IO_RESULT_OK;
- size_t stored_digest_size = 0;
- if (ops->read_persistent_value == NULL) {
- avb_errorv(part_name, ": Persistent values are not implemented.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- }
- persistent_value_name =
- avb_strdupv(AVB_NPV_PERSISTENT_DIGEST_PREFIX, part_name, NULL);
- if (persistent_value_name == NULL) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- }
- io_ret = ops->read_persistent_value(ops,
- persistent_value_name,
- expected_digest_size,
- out_digest,
- &stored_digest_size);
- // If no such named persistent value exists and an initial digest value was
- // given, initialize the named persistent value with the given digest. If
- // initialized successfully, this will recurse into this function but with a
- // NULL initial_digest.
- if (io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_VALUE && initial_digest) {
- AvbSlotVerifyResult ret =
- initialize_persistent_digest(ops,
- part_name,
- persistent_value_name,
- expected_digest_size,
- initial_digest,
- out_digest);
- avb_free(persistent_value_name);
- return ret;
- }
- avb_free(persistent_value_name);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- } else if (io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_VALUE) {
- // Treat a missing persistent value as a verification error, which is
- // ignoreable, rather than a metadata error which is not.
- avb_errorv(part_name, ": Persistent digest does not exist.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
- } else if (io_ret == AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE ||
- io_ret == AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE) {
- avb_errorv(
- part_name, ": Persistent digest is not of expected size.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error reading persistent digest.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- } else if (expected_digest_size != stored_digest_size) {
- avb_errorv(
- part_name, ": Persistent digest is not of expected size.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- }
- return AVB_SLOT_VERIFY_RESULT_OK;
- }
- static AvbSlotVerifyResult initialize_persistent_digest(
- AvbOps* ops,
- const char* part_name,
- const char* persistent_value_name,
- size_t digest_size,
- const uint8_t* initial_digest,
- uint8_t* out_digest) {
- AvbSlotVerifyResult ret;
- AvbIOResult io_ret = AVB_IO_RESULT_OK;
- bool is_device_unlocked = true;
- io_ret = ops->read_is_device_unlocked(ops, &is_device_unlocked);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_error("Error getting device lock state.\n");
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- if (is_device_unlocked) {
- avb_debugv(part_name,
- ": Digest does not exist, device unlocked so not initializing "
- "digest.\n",
- NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
- }
- // Device locked; initialize digest with given initial value.
- avb_debugv(part_name,
- ": Digest does not exist, initializing persistent digest.\n",
- NULL);
- io_ret = ops->write_persistent_value(
- ops, persistent_value_name, digest_size, initial_digest);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error initializing persistent digest.\n", NULL);
- return AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- }
- // To ensure that the digest value was written successfully - and avoid a
- // scenario where the digest is simply 'initialized' on every verify - recurse
- // into read_persistent_digest to read back the written value. The NULL
- // initial_digest ensures that this will not recurse again.
- ret = read_persistent_digest(ops, part_name, digest_size, NULL, out_digest);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- avb_errorv(part_name,
- ": Reading back initialized persistent digest failed!\n",
- NULL);
- }
- return ret;
- }
- static AvbSlotVerifyResult 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) {
- AvbHashDescriptor hash_desc;
- const uint8_t* desc_partition_name = NULL;
- const uint8_t* desc_salt;
- const uint8_t* desc_digest;
- char part_name[AVB_PART_NAME_MAX_SIZE];
- AvbSlotVerifyResult ret;
- AvbIOResult io_ret;
- uint8_t* image_buf = NULL;
- bool image_preloaded = false;
- uint8_t* digest;
- size_t digest_len;
- const char* found;
- uint64_t image_size;
- size_t expected_digest_len = 0;
- uint8_t expected_digest_buf[AVB_SHA512_DIGEST_SIZE];
- const uint8_t* expected_digest = NULL;
- if (!avb_hash_descriptor_validate_and_byteswap(
- (const AvbHashDescriptor*)descriptor, &hash_desc)) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- desc_partition_name =
- ((const uint8_t*)descriptor) + sizeof(AvbHashDescriptor);
- desc_salt = desc_partition_name + hash_desc.partition_name_len;
- desc_digest = desc_salt + hash_desc.salt_len;
- if (!avb_validate_utf8(desc_partition_name, hash_desc.partition_name_len)) {
- avb_error("Partition name is not valid UTF-8.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* Don't bother loading or validating unless the partition was
- * requested in the first place.
- */
- found = avb_strv_find_str(requested_partitions,
- (const char*)desc_partition_name,
- hash_desc.partition_name_len);
- if (found == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_OK;
- goto out;
- }
- if ((hash_desc.flags & AVB_HASH_DESCRIPTOR_FLAGS_DO_NOT_USE_AB) != 0) {
- /* No ab_suffix, just copy the partition name as is. */
- if (hash_desc.partition_name_len >= AVB_PART_NAME_MAX_SIZE) {
- avb_error("Partition name does not fit.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- avb_memcpy(part_name, desc_partition_name, hash_desc.partition_name_len);
- part_name[hash_desc.partition_name_len] = '\0';
- } else if (hash_desc.digest_len == 0 && avb_strlen(ab_suffix) != 0) {
- /* No ab_suffix allowed for partitions without a digest in the descriptor
- * because these partitions hold data unique to this device and are not
- * updated using an A/B scheme.
- */
- avb_error("Cannot use A/B with a persistent digest.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- } else {
- /* Add ab_suffix to the partition name. */
- if (!avb_str_concat(part_name,
- sizeof part_name,
- (const char*)desc_partition_name,
- hash_desc.partition_name_len,
- ab_suffix,
- avb_strlen(ab_suffix))) {
- avb_error("Partition name and suffix does not fit.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- }
- /* If we're allowing verification errors then hash_desc.image_size
- * may no longer match what's in the partition... so in this case
- * just load the entire partition.
- *
- * For example, this can happen if a developer does 'fastboot flash
- * boot /path/to/new/and/bigger/boot.img'. We want this to work
- * since it's such a common workflow.
- */
- image_size = hash_desc.image_size;
- if (allow_verification_error) {
- io_ret = ops->get_size_of_partition(ops, part_name, &image_size);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error determining partition size.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- avb_debugv(part_name, ": Loading entire partition.\n", NULL);
- }
- ret = load_full_partition(
- ops, part_name, image_size, &image_buf, &image_preloaded);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto out;
- }
- // Although only one of the type might be used, we have to defined the
- // structure here so that they would live outside the 'if/else' scope to be
- // used later.
- AvbSHA256Ctx sha256_ctx;
- AvbSHA512Ctx sha512_ctx;
- size_t image_size_to_hash = hash_desc.image_size;
- // If we allow verification error and the whole partition is smaller than
- // image size in hash descriptor, we just hash the whole partition.
- if (image_size_to_hash > image_size) {
- image_size_to_hash = image_size;
- }
- if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha256") == 0) {
- avb_sha256_init(&sha256_ctx);
- avb_sha256_update(&sha256_ctx, desc_salt, hash_desc.salt_len);
- avb_sha256_update(&sha256_ctx, image_buf, image_size_to_hash);
- digest = avb_sha256_final(&sha256_ctx);
- digest_len = AVB_SHA256_DIGEST_SIZE;
- } else if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha512") == 0) {
- avb_sha512_init(&sha512_ctx);
- avb_sha512_update(&sha512_ctx, desc_salt, hash_desc.salt_len);
- avb_sha512_update(&sha512_ctx, image_buf, image_size_to_hash);
- digest = avb_sha512_final(&sha512_ctx);
- digest_len = AVB_SHA512_DIGEST_SIZE;
- } else {
- avb_errorv(part_name, ": Unsupported hash algorithm.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- if (hash_desc.digest_len == 0) {
- /* Expect a match to a persistent digest. */
- avb_debugv(part_name, ": No digest, using persistent digest.\n", NULL);
- expected_digest_len = digest_len;
- expected_digest = expected_digest_buf;
- avb_assert(expected_digest_len <= sizeof(expected_digest_buf));
- /* Pass |digest| as the |initial_digest| so devices not yet initialized get
- * initialized to the current partition digest.
- */
- ret = read_persistent_digest(
- ops, part_name, digest_len, digest, expected_digest_buf);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto out;
- }
- } else {
- /* Expect a match to the digest in the descriptor. */
- expected_digest_len = hash_desc.digest_len;
- expected_digest = desc_digest;
- }
- if (digest_len != expected_digest_len) {
- avb_errorv(
- part_name, ": Digest in descriptor not of expected size.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- if (avb_safe_memcmp(digest, expected_digest, digest_len) != 0) {
- avb_errorv(part_name,
- ": Hash of data does not match digest in descriptor.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
- goto out;
- }
- ret = AVB_SLOT_VERIFY_RESULT_OK;
- out:
- /* If it worked and something was loaded, copy to slot_data. */
- if ((ret == AVB_SLOT_VERIFY_RESULT_OK || result_should_continue(ret)) &&
- image_buf != NULL) {
- AvbPartitionData* loaded_partition;
- if (slot_data->num_loaded_partitions == MAX_NUMBER_OF_LOADED_PARTITIONS) {
- avb_errorv(part_name, ": Too many loaded partitions.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- loaded_partition =
- &slot_data->loaded_partitions[slot_data->num_loaded_partitions++];
- loaded_partition->partition_name = avb_strdup(found);
- loaded_partition->data_size = image_size;
- loaded_partition->data = image_buf;
- loaded_partition->preloaded = image_preloaded;
- image_buf = NULL;
- }
- fail:
- if (image_buf != NULL && !image_preloaded) {
- avb_free(image_buf);
- }
- return ret;
- }
- static AvbSlotVerifyResult load_requested_partitions(
- AvbOps* ops,
- const char* const* requested_partitions,
- const char* ab_suffix,
- AvbSlotVerifyData* slot_data) {
- AvbSlotVerifyResult ret;
- uint8_t* image_buf = NULL;
- bool image_preloaded = false;
- size_t n;
- for (n = 0; requested_partitions[n] != NULL; n++) {
- char part_name[AVB_PART_NAME_MAX_SIZE];
- AvbIOResult io_ret;
- uint64_t image_size;
- AvbPartitionData* loaded_partition;
- if (!avb_str_concat(part_name,
- sizeof part_name,
- requested_partitions[n],
- avb_strlen(requested_partitions[n]),
- ab_suffix,
- avb_strlen(ab_suffix))) {
- avb_error("Partition name and suffix does not fit.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- io_ret = ops->get_size_of_partition(ops, part_name, &image_size);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(part_name, ": Error determining partition size.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- avb_debugv(part_name, ": Loading entire partition.\n", NULL);
- ret = load_full_partition(
- ops, part_name, image_size, &image_buf, &image_preloaded);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto out;
- }
- /* Move to slot_data. */
- if (slot_data->num_loaded_partitions == MAX_NUMBER_OF_LOADED_PARTITIONS) {
- avb_errorv(part_name, ": Too many loaded partitions.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- loaded_partition =
- &slot_data->loaded_partitions[slot_data->num_loaded_partitions++];
- loaded_partition->partition_name = avb_strdup(requested_partitions[n]);
- if (loaded_partition->partition_name == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- loaded_partition->data_size = image_size;
- loaded_partition->data = image_buf; /* Transferring the owner. */
- loaded_partition->preloaded = image_preloaded;
- image_buf = NULL;
- image_preloaded = false;
- }
- ret = AVB_SLOT_VERIFY_RESULT_OK;
- out:
- /* Free the current buffer if any. */
- if (image_buf != NULL && !image_preloaded) {
- avb_free(image_buf);
- }
- /* Buffers that are already saved in slot_data will be handled by the caller
- * even on failure. */
- return ret;
- }
- static AvbSlotVerifyResult load_and_verify_vbmeta(
- AvbOps* ops,
- const char* const* requested_partitions,
- const char* ab_suffix,
- AvbSlotVerifyFlags flags,
- 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) {
- char full_partition_name[AVB_PART_NAME_MAX_SIZE];
- AvbSlotVerifyResult ret;
- AvbIOResult io_ret;
- size_t vbmeta_offset;
- size_t vbmeta_size;
- uint8_t* vbmeta_buf = NULL;
- size_t vbmeta_num_read;
- AvbVBMetaVerifyResult vbmeta_ret;
- const uint8_t* pk_data;
- size_t pk_len;
- AvbVBMetaImageHeader vbmeta_header;
- uint64_t stored_rollback_index;
- const AvbDescriptor** descriptors = NULL;
- size_t num_descriptors;
- size_t n;
- bool is_main_vbmeta;
- bool look_for_vbmeta_footer;
- AvbVBMetaData* vbmeta_image_data = NULL;
- ret = AVB_SLOT_VERIFY_RESULT_OK;
- avb_assert(slot_data != NULL);
- /* Since we allow top-level vbmeta in 'boot', use
- * rollback_index_location to determine whether we're the main
- * vbmeta struct.
- */
- is_main_vbmeta = false;
- if (rollback_index_location == 0) {
- if ((flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION) == 0) {
- is_main_vbmeta = true;
- }
- }
- /* Don't use footers for vbmeta partitions ('vbmeta' or
- * 'vbmeta_<partition_name>').
- */
- look_for_vbmeta_footer = true;
- if (avb_strncmp(partition_name, "vbmeta", avb_strlen("vbmeta")) == 0) {
- look_for_vbmeta_footer = false;
- }
- if (!avb_validate_utf8((const uint8_t*)partition_name, partition_name_len)) {
- avb_error("Partition name is not valid UTF-8.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* Construct full partition name e.g. system_a. */
- if (!avb_str_concat(full_partition_name,
- sizeof full_partition_name,
- partition_name,
- partition_name_len,
- ab_suffix,
- avb_strlen(ab_suffix))) {
- avb_error("Partition name and suffix does not fit.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* If we're loading from the main vbmeta partition, the vbmeta struct is in
- * the beginning. Otherwise we may have to locate it via a footer... if no
- * footer is found, we look in the beginning to support e.g. vbmeta_<org>
- * partitions holding data for e.g. super partitions (b/80195851 for
- * rationale).
- */
- vbmeta_offset = 0;
- vbmeta_size = VBMETA_MAX_SIZE;
- if (look_for_vbmeta_footer) {
- uint8_t footer_buf[AVB_FOOTER_SIZE];
- size_t footer_num_read;
- AvbFooter footer;
- io_ret = ops->read_from_partition(ops,
- full_partition_name,
- -AVB_FOOTER_SIZE,
- AVB_FOOTER_SIZE,
- footer_buf,
- &footer_num_read);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(full_partition_name, ": Error loading footer.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- avb_assert(footer_num_read == AVB_FOOTER_SIZE);
- if (!avb_footer_validate_and_byteswap((const AvbFooter*)footer_buf,
- &footer)) {
- avb_debugv(full_partition_name, ": No footer detected.\n", NULL);
- } else {
- /* Basic footer sanity check since the data is untrusted. */
- if (footer.vbmeta_size > VBMETA_MAX_SIZE) {
- avb_errorv(
- full_partition_name, ": Invalid vbmeta size in footer.\n", NULL);
- } else {
- vbmeta_offset = footer.vbmeta_offset;
- vbmeta_size = footer.vbmeta_size;
- }
- }
- }
- vbmeta_buf = avb_malloc(vbmeta_size);
- if (vbmeta_buf == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- if (vbmeta_offset != 0) {
- avb_debugv("Loading vbmeta struct in footer from partition '",
- full_partition_name,
- "'.\n",
- NULL);
- } else {
- avb_debugv("Loading vbmeta struct from partition '",
- full_partition_name,
- "'.\n",
- NULL);
- }
- io_ret = ops->read_from_partition(ops,
- full_partition_name,
- vbmeta_offset,
- vbmeta_size,
- vbmeta_buf,
- &vbmeta_num_read);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- /* If we're looking for 'vbmeta' but there is no such partition,
- * go try to get it from the boot partition instead.
- */
- if (is_main_vbmeta && io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION &&
- !look_for_vbmeta_footer) {
- avb_debugv(full_partition_name,
- ": No such partition. Trying 'boot' instead.\n",
- NULL);
- ret = load_and_verify_vbmeta(ops,
- requested_partitions,
- ab_suffix,
- flags,
- allow_verification_error,
- 0 /* toplevel_vbmeta_flags */,
- 0 /* rollback_index_location */,
- "boot",
- avb_strlen("boot"),
- NULL /* expected_public_key */,
- 0 /* expected_public_key_length */,
- slot_data,
- out_algorithm_type,
- out_additional_cmdline_subst);
- goto out;
- } else {
- avb_errorv(full_partition_name, ": Error loading vbmeta data.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- }
- avb_assert(vbmeta_num_read <= vbmeta_size);
- /* Check if the image is properly signed and get the public key used
- * to sign the image.
- */
- vbmeta_ret =
- avb_vbmeta_image_verify(vbmeta_buf, vbmeta_num_read, &pk_data, &pk_len);
- switch (vbmeta_ret) {
- case AVB_VBMETA_VERIFY_RESULT_OK:
- avb_assert(pk_data != NULL && pk_len > 0);
- break;
- case AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED:
- case AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH:
- case AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH:
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION;
- avb_errorv(full_partition_name,
- ": Error verifying vbmeta image: ",
- avb_vbmeta_verify_result_to_string(vbmeta_ret),
- "\n",
- NULL);
- if (!allow_verification_error) {
- goto out;
- }
- break;
- case AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER:
- /* No way to continue this case. */
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- avb_errorv(full_partition_name,
- ": Error verifying vbmeta image: invalid vbmeta header\n",
- NULL);
- goto out;
- case AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION:
- /* No way to continue this case. */
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION;
- avb_errorv(full_partition_name,
- ": Error verifying vbmeta image: unsupported AVB version\n",
- NULL);
- goto out;
- }
- /* Byteswap the header. */
- avb_vbmeta_image_header_to_host_byte_order((AvbVBMetaImageHeader*)vbmeta_buf,
- &vbmeta_header);
- /* If we're the toplevel, assign flags so they'll be passed down. */
- if (is_main_vbmeta) {
- toplevel_vbmeta_flags = (AvbVBMetaImageFlags)vbmeta_header.flags;
- } else {
- if (vbmeta_header.flags != 0) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- avb_errorv(full_partition_name,
- ": chained vbmeta image has non-zero flags\n",
- NULL);
- goto out;
- }
- }
- uint32_t rollback_index_location_to_use = rollback_index_location;
- /* Check if key used to make signature matches what is expected. */
- if (pk_data != NULL) {
- if (expected_public_key != NULL) {
- avb_assert(!is_main_vbmeta);
- if (expected_public_key_length != pk_len ||
- avb_safe_memcmp(expected_public_key, pk_data, pk_len) != 0) {
- avb_errorv(full_partition_name,
- ": Public key used to sign data does not match key in chain "
- "partition descriptor.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
- if (!allow_verification_error) {
- goto out;
- }
- }
- } else {
- bool key_is_trusted = false;
- const uint8_t* pk_metadata = NULL;
- size_t pk_metadata_len = 0;
- if (vbmeta_header.public_key_metadata_size > 0) {
- pk_metadata = vbmeta_buf + sizeof(AvbVBMetaImageHeader) +
- vbmeta_header.authentication_data_block_size +
- vbmeta_header.public_key_metadata_offset;
- pk_metadata_len = vbmeta_header.public_key_metadata_size;
- }
- // If we're not using a vbmeta partition, need to use another AvbOps...
- if (flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION) {
- io_ret = ops->validate_public_key_for_partition(
- ops,
- full_partition_name,
- pk_data,
- pk_len,
- pk_metadata,
- pk_metadata_len,
- &key_is_trusted,
- &rollback_index_location_to_use);
- } else {
- avb_assert(is_main_vbmeta);
- io_ret = ops->validate_vbmeta_public_key(ops,
- pk_data,
- pk_len,
- pk_metadata,
- pk_metadata_len,
- &key_is_trusted);
- }
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(full_partition_name,
- ": Error while checking public key used to sign data.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- if (!key_is_trusted) {
- avb_errorv(full_partition_name,
- ": Public key used to sign data rejected.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED;
- if (!allow_verification_error) {
- goto out;
- }
- }
- }
- }
- /* Check rollback index. */
- io_ret = ops->read_rollback_index(
- ops, rollback_index_location_to_use, &stored_rollback_index);
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_errorv(full_partition_name,
- ": Error getting rollback index for location.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- goto out;
- }
- if (vbmeta_header.rollback_index < stored_rollback_index) {
- avb_errorv(
- full_partition_name,
- ": Image rollback index is less than the stored rollback index.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX;
- if (!allow_verification_error) {
- goto out;
- }
- }
- /* Copy vbmeta to vbmeta_images before recursing. */
- if (is_main_vbmeta) {
- avb_assert(slot_data->num_vbmeta_images == 0);
- } else {
- if (!(flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION)) {
- avb_assert(slot_data->num_vbmeta_images > 0);
- }
- }
- if (slot_data->num_vbmeta_images == MAX_NUMBER_OF_VBMETA_IMAGES) {
- avb_errorv(full_partition_name, ": Too many vbmeta images.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- vbmeta_image_data = &slot_data->vbmeta_images[slot_data->num_vbmeta_images++];
- vbmeta_image_data->partition_name = avb_strdup(partition_name);
- vbmeta_image_data->vbmeta_data = vbmeta_buf;
- /* Note that |vbmeta_buf| is actually |vbmeta_num_read| bytes long
- * and this includes data past the end of the image. Pass the
- * actual size of the vbmeta image. Also, no need to use
- * avb_safe_add() since the header has already been verified.
- */
- vbmeta_image_data->vbmeta_size =
- sizeof(AvbVBMetaImageHeader) +
- vbmeta_header.authentication_data_block_size +
- vbmeta_header.auxiliary_data_block_size;
- vbmeta_image_data->verify_result = vbmeta_ret;
- /* If verification has been disabled by setting a bit in the image,
- * we're done... except that we need to load the entirety of the
- * requested partitions.
- */
- if (vbmeta_header.flags & AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED) {
- AvbSlotVerifyResult sub_ret;
- avb_debugv(
- full_partition_name, ": VERIFICATION_DISABLED bit is set.\n", NULL);
- /* If load_requested_partitions() fail it is always a fatal
- * failure (e.g. ERROR_INVALID_ARGUMENT, ERROR_OOM, etc.) rather
- * than recoverable (e.g. one where result_should_continue()
- * returns true) and we want to convey that error.
- */
- sub_ret = load_requested_partitions(
- ops, requested_partitions, ab_suffix, slot_data);
- if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
- ret = sub_ret;
- }
- goto out;
- }
- /* Now go through all descriptors and take the appropriate action:
- *
- * - hash descriptor: Load data from partition, calculate hash, and
- * checks that it matches what's in the hash descriptor.
- *
- * - hashtree descriptor: Do nothing since verification happens
- * on-the-fly from within the OS. (Unless the descriptor uses a
- * persistent digest, in which case we need to find it).
- *
- * - chained partition descriptor: Load the footer, load the vbmeta
- * image, verify vbmeta image (includes rollback checks, hash
- * checks, bail on chained partitions).
- */
- descriptors =
- avb_descriptor_get_all(vbmeta_buf, vbmeta_num_read, &num_descriptors);
- for (n = 0; n < num_descriptors; n++) {
- AvbDescriptor desc;
- if (!avb_descriptor_validate_and_byteswap(descriptors[n], &desc)) {
- avb_errorv(full_partition_name, ": Descriptor is invalid.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- switch (desc.tag) {
- case AVB_DESCRIPTOR_TAG_HASH: {
- AvbSlotVerifyResult sub_ret;
- sub_ret = load_and_verify_hash_partition(ops,
- requested_partitions,
- ab_suffix,
- allow_verification_error,
- descriptors[n],
- slot_data);
- if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
- ret = sub_ret;
- if (!allow_verification_error || !result_should_continue(ret)) {
- goto out;
- }
- }
- } break;
- case AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: {
- AvbSlotVerifyResult sub_ret;
- AvbChainPartitionDescriptor chain_desc;
- const uint8_t* chain_partition_name;
- const uint8_t* chain_public_key;
- /* Only allow CHAIN_PARTITION descriptors in the main vbmeta image. */
- if (!is_main_vbmeta) {
- avb_errorv(full_partition_name,
- ": Encountered chain descriptor not in main image.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- if (!avb_chain_partition_descriptor_validate_and_byteswap(
- (AvbChainPartitionDescriptor*)descriptors[n], &chain_desc)) {
- avb_errorv(full_partition_name,
- ": Chain partition descriptor is invalid.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- if (chain_desc.rollback_index_location == 0) {
- avb_errorv(full_partition_name,
- ": Chain partition has invalid "
- "rollback_index_location field.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- chain_partition_name = ((const uint8_t*)descriptors[n]) +
- sizeof(AvbChainPartitionDescriptor);
- chain_public_key = chain_partition_name + chain_desc.partition_name_len;
- sub_ret =
- load_and_verify_vbmeta(ops,
- requested_partitions,
- ab_suffix,
- flags,
- allow_verification_error,
- toplevel_vbmeta_flags,
- chain_desc.rollback_index_location,
- (const char*)chain_partition_name,
- chain_desc.partition_name_len,
- chain_public_key,
- chain_desc.public_key_len,
- slot_data,
- NULL, /* out_algorithm_type */
- NULL /* out_additional_cmdline_subst */);
- if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
- ret = sub_ret;
- if (!result_should_continue(ret)) {
- goto out;
- }
- }
- } break;
- case AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: {
- const uint8_t* kernel_cmdline;
- AvbKernelCmdlineDescriptor kernel_cmdline_desc;
- bool apply_cmdline;
- if (!avb_kernel_cmdline_descriptor_validate_and_byteswap(
- (AvbKernelCmdlineDescriptor*)descriptors[n],
- &kernel_cmdline_desc)) {
- avb_errorv(full_partition_name,
- ": Kernel cmdline descriptor is invalid.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- kernel_cmdline = ((const uint8_t*)descriptors[n]) +
- sizeof(AvbKernelCmdlineDescriptor);
- if (!avb_validate_utf8(kernel_cmdline,
- kernel_cmdline_desc.kernel_cmdline_length)) {
- avb_errorv(full_partition_name,
- ": Kernel cmdline is not valid UTF-8.\n",
- NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* Compare the flags for top-level VBMeta struct with flags in
- * the command-line descriptor so command-line snippets only
- * intended for a certain mode (dm-verity enabled/disabled)
- * are skipped if applicable.
- */
- apply_cmdline = true;
- if (toplevel_vbmeta_flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) {
- if (kernel_cmdline_desc.flags &
- AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_NOT_DISABLED) {
- apply_cmdline = false;
- }
- } else {
- if (kernel_cmdline_desc.flags &
- AVB_KERNEL_CMDLINE_FLAGS_USE_ONLY_IF_HASHTREE_DISABLED) {
- apply_cmdline = false;
- }
- }
- if (apply_cmdline) {
- if (slot_data->cmdline == NULL) {
- slot_data->cmdline =
- avb_calloc(kernel_cmdline_desc.kernel_cmdline_length + 1);
- if (slot_data->cmdline == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- avb_memcpy(slot_data->cmdline,
- kernel_cmdline,
- kernel_cmdline_desc.kernel_cmdline_length);
- } else {
- /* new cmdline is: <existing_cmdline> + ' ' + <newcmdline> + '\0' */
- size_t orig_size = avb_strlen(slot_data->cmdline);
- size_t new_size =
- orig_size + 1 + kernel_cmdline_desc.kernel_cmdline_length + 1;
- char* new_cmdline = avb_calloc(new_size);
- if (new_cmdline == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto out;
- }
- avb_memcpy(new_cmdline, slot_data->cmdline, orig_size);
- new_cmdline[orig_size] = ' ';
- avb_memcpy(new_cmdline + orig_size + 1,
- kernel_cmdline,
- kernel_cmdline_desc.kernel_cmdline_length);
- avb_free(slot_data->cmdline);
- slot_data->cmdline = new_cmdline;
- }
- }
- } break;
- case AVB_DESCRIPTOR_TAG_HASHTREE: {
- AvbHashtreeDescriptor hashtree_desc;
- if (!avb_hashtree_descriptor_validate_and_byteswap(
- (AvbHashtreeDescriptor*)descriptors[n], &hashtree_desc)) {
- avb_errorv(
- full_partition_name, ": Hashtree descriptor is invalid.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* We only need to continue when there is no digest in the descriptor.
- * This is because the only processing here is to find the digest and
- * make it available on the kernel command line.
- */
- if (hashtree_desc.root_digest_len == 0) {
- char part_name[AVB_PART_NAME_MAX_SIZE];
- size_t digest_len = 0;
- uint8_t digest_buf[AVB_SHA512_DIGEST_SIZE];
- const uint8_t* desc_partition_name =
- ((const uint8_t*)descriptors[n]) + sizeof(AvbHashtreeDescriptor);
- if (!avb_validate_utf8(desc_partition_name,
- hashtree_desc.partition_name_len)) {
- avb_error("Partition name is not valid UTF-8.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- /* No ab_suffix for partitions without a digest in the descriptor
- * because these partitions hold data unique to this device and are
- * not updated using an A/B scheme.
- */
- if ((hashtree_desc.flags &
- AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB) == 0 &&
- avb_strlen(ab_suffix) != 0) {
- avb_error("Cannot use A/B with a persistent root digest.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- if (hashtree_desc.partition_name_len >= AVB_PART_NAME_MAX_SIZE) {
- avb_error("Partition name does not fit.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- avb_memcpy(
- part_name, desc_partition_name, hashtree_desc.partition_name_len);
- part_name[hashtree_desc.partition_name_len] = '\0';
- /* Determine the expected digest size from the hash algorithm. */
- if (avb_strcmp((const char*)hashtree_desc.hash_algorithm, "sha1") ==
- 0) {
- digest_len = AVB_SHA1_DIGEST_SIZE;
- } else if (avb_strcmp((const char*)hashtree_desc.hash_algorithm,
- "sha256") == 0) {
- digest_len = AVB_SHA256_DIGEST_SIZE;
- } else if (avb_strcmp((const char*)hashtree_desc.hash_algorithm,
- "sha512") == 0) {
- digest_len = AVB_SHA512_DIGEST_SIZE;
- } else {
- avb_errorv(part_name, ": Unsupported hash algorithm.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- ret = read_persistent_digest(ops,
- part_name,
- digest_len,
- NULL /* initial_digest */,
- digest_buf);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto out;
- }
- if (out_additional_cmdline_subst) {
- ret =
- avb_add_root_digest_substitution(part_name,
- digest_buf,
- digest_len,
- out_additional_cmdline_subst);
- if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto out;
- }
- }
- }
- } break;
- case AVB_DESCRIPTOR_TAG_PROPERTY:
- /* Do nothing. */
- break;
- }
- }
- if (rollback_index_location < 0 ||
- rollback_index_location >= AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS) {
- avb_errorv(
- full_partition_name, ": Invalid rollback_index_location.\n", NULL);
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
- goto out;
- }
- slot_data->rollback_indexes[rollback_index_location] =
- vbmeta_header.rollback_index;
- if (out_algorithm_type != NULL) {
- *out_algorithm_type = (AvbAlgorithmType)vbmeta_header.algorithm_type;
- }
- out:
- /* If |vbmeta_image_data| isn't NULL it means that it adopted
- * |vbmeta_buf| so in that case don't free it here.
- */
- if (vbmeta_image_data == NULL) {
- if (vbmeta_buf != NULL) {
- avb_free(vbmeta_buf);
- }
- }
- if (descriptors != NULL) {
- avb_free(descriptors);
- }
- return ret;
- }
- static AvbIOResult avb_manage_hashtree_error_mode(
- AvbOps* ops,
- AvbSlotVerifyFlags flags,
- AvbSlotVerifyData* data,
- AvbHashtreeErrorMode* out_hashtree_error_mode) {
- AvbHashtreeErrorMode ret = AVB_HASHTREE_ERROR_MODE_RESTART;
- AvbIOResult io_ret = AVB_IO_RESULT_OK;
- uint8_t vbmeta_digest_sha256[AVB_SHA256_DIGEST_SIZE];
- uint8_t stored_vbmeta_digest_sha256[AVB_SHA256_DIGEST_SIZE];
- size_t num_bytes_read;
- avb_assert(out_hashtree_error_mode != NULL);
- avb_assert(ops->read_persistent_value != NULL);
- avb_assert(ops->write_persistent_value != NULL);
- // If we're rebooting because of dm-verity corruption, make a note of
- // the vbmeta hash so we can stay in 'eio' mode until things change.
- if (flags & AVB_SLOT_VERIFY_FLAGS_RESTART_CAUSED_BY_HASHTREE_CORRUPTION) {
- avb_debug(
- "Rebooting because of dm-verity corruption - "
- "recording OS instance and using 'eio' mode.\n");
- avb_slot_verify_data_calculate_vbmeta_digest(
- data, AVB_DIGEST_TYPE_SHA256, vbmeta_digest_sha256);
- io_ret = ops->write_persistent_value(ops,
- AVB_NPV_MANAGED_VERITY_MODE,
- AVB_SHA256_DIGEST_SIZE,
- vbmeta_digest_sha256);
- if (io_ret != AVB_IO_RESULT_OK) {
- avb_error("Error writing to " AVB_NPV_MANAGED_VERITY_MODE ".\n");
- goto out;
- }
- ret = AVB_HASHTREE_ERROR_MODE_EIO;
- io_ret = AVB_IO_RESULT_OK;
- goto out;
- }
- // See if we're in 'eio' mode.
- io_ret = ops->read_persistent_value(ops,
- AVB_NPV_MANAGED_VERITY_MODE,
- AVB_SHA256_DIGEST_SIZE,
- stored_vbmeta_digest_sha256,
- &num_bytes_read);
- if (io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_VALUE ||
- (io_ret == AVB_IO_RESULT_OK && num_bytes_read == 0)) {
- // This is the usual case ('eio' mode not set).
- avb_debug("No dm-verity corruption - using in 'restart' mode.\n");
- ret = AVB_HASHTREE_ERROR_MODE_RESTART;
- io_ret = AVB_IO_RESULT_OK;
- goto out;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_error("Error reading from " AVB_NPV_MANAGED_VERITY_MODE ".\n");
- goto out;
- }
- if (num_bytes_read != AVB_SHA256_DIGEST_SIZE) {
- avb_error(
- "Unexpected number of bytes read from " AVB_NPV_MANAGED_VERITY_MODE
- ".\n");
- io_ret = AVB_IO_RESULT_ERROR_IO;
- goto out;
- }
- // OK, so we're currently in 'eio' mode and the vbmeta digest of the OS
- // that caused this is in |stored_vbmeta_digest_sha256| ... now see if
- // the OS we're dealing with now is the same.
- avb_slot_verify_data_calculate_vbmeta_digest(
- data, AVB_DIGEST_TYPE_SHA256, vbmeta_digest_sha256);
- if (avb_memcmp(vbmeta_digest_sha256,
- stored_vbmeta_digest_sha256,
- AVB_SHA256_DIGEST_SIZE) == 0) {
- // It's the same so we're still in 'eio' mode.
- avb_debug("Same OS instance detected - staying in 'eio' mode.\n");
- ret = AVB_HASHTREE_ERROR_MODE_EIO;
- io_ret = AVB_IO_RESULT_OK;
- } else {
- // It did change!
- avb_debug(
- "New OS instance detected - changing from 'eio' to 'restart' mode.\n");
- io_ret =
- ops->write_persistent_value(ops,
- AVB_NPV_MANAGED_VERITY_MODE,
- 0, // This clears the persistent property.
- vbmeta_digest_sha256);
- if (io_ret != AVB_IO_RESULT_OK) {
- avb_error("Error clearing " AVB_NPV_MANAGED_VERITY_MODE ".\n");
- goto out;
- }
- ret = AVB_HASHTREE_ERROR_MODE_RESTART;
- io_ret = AVB_IO_RESULT_OK;
- }
- out:
- *out_hashtree_error_mode = ret;
- return io_ret;
- }
- static bool has_system_partition(AvbOps* ops, const char* ab_suffix) {
- char part_name[AVB_PART_NAME_MAX_SIZE];
- char* system_part_name = "system";
- char guid_buf[37];
- AvbIOResult io_ret;
- if (!avb_str_concat(part_name,
- sizeof part_name,
- system_part_name,
- avb_strlen(system_part_name),
- ab_suffix,
- avb_strlen(ab_suffix))) {
- avb_error("System partition name and suffix does not fit.\n");
- return false;
- }
- io_ret = ops->get_unique_guid_for_partition(
- ops, part_name, guid_buf, sizeof guid_buf);
- if (io_ret == AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION) {
- avb_debug("No system partition.\n");
- return false;
- } else if (io_ret != AVB_IO_RESULT_OK) {
- avb_error("Error getting unique GUID for system partition.\n");
- return false;
- }
- return true;
- }
- AvbSlotVerifyResult avb_slot_verify(AvbOps* ops,
- const char* const* requested_partitions,
- const char* ab_suffix,
- AvbSlotVerifyFlags flags,
- AvbHashtreeErrorMode hashtree_error_mode,
- AvbSlotVerifyData** out_data) {
- AvbSlotVerifyResult ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
- AvbSlotVerifyData* slot_data = NULL;
- AvbAlgorithmType algorithm_type = AVB_ALGORITHM_TYPE_NONE;
- bool using_boot_for_vbmeta = false;
- AvbVBMetaImageHeader toplevel_vbmeta;
- bool allow_verification_error =
- (flags & AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR);
- AvbCmdlineSubstList* additional_cmdline_subst = NULL;
- /* Fail early if we're missing the AvbOps needed for slot verification. */
- avb_assert(ops->read_is_device_unlocked != NULL);
- avb_assert(ops->read_from_partition != NULL);
- avb_assert(ops->get_size_of_partition != NULL);
- avb_assert(ops->read_rollback_index != NULL);
- avb_assert(ops->get_unique_guid_for_partition != NULL);
- if (out_data != NULL) {
- *out_data = NULL;
- }
- /* Allowing dm-verity errors defeats the purpose of verified boot so
- * only allow this if set up to allow verification errors
- * (e.g. typically only UNLOCKED mode).
- */
- if (hashtree_error_mode == AVB_HASHTREE_ERROR_MODE_LOGGING &&
- !allow_verification_error) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
- goto fail;
- }
- /* Make sure passed-in AvbOps support persistent values if
- * asking for libavb to manage verity state.
- */
- if (hashtree_error_mode == AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO) {
- if (ops->read_persistent_value == NULL ||
- ops->write_persistent_value == NULL) {
- avb_error(
- "Persistent values required for "
- "AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO "
- "but are not implemented in given AvbOps.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
- goto fail;
- }
- }
- /* Make sure passed-in AvbOps support verifying public keys and getting
- * rollback index location if not using a vbmeta partition.
- */
- if (flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION) {
- if (ops->validate_public_key_for_partition == NULL) {
- avb_error(
- "AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION was passed but the "
- "validate_public_key_for_partition() operation isn't implemented.\n");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
- goto fail;
- }
- } else {
- avb_assert(ops->validate_vbmeta_public_key != NULL);
- }
- slot_data = avb_calloc(sizeof(AvbSlotVerifyData));
- if (slot_data == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- slot_data->vbmeta_images =
- avb_calloc(sizeof(AvbVBMetaData) * MAX_NUMBER_OF_VBMETA_IMAGES);
- if (slot_data->vbmeta_images == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- slot_data->loaded_partitions =
- avb_calloc(sizeof(AvbPartitionData) * MAX_NUMBER_OF_LOADED_PARTITIONS);
- if (slot_data->loaded_partitions == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- additional_cmdline_subst = avb_new_cmdline_subst_list();
- if (additional_cmdline_subst == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- if (flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION) {
- if (requested_partitions == NULL || requested_partitions[0] == NULL) {
- avb_fatal(
- "Requested partitions cannot be empty when using "
- "AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION");
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
- goto fail;
- }
- /* No vbmeta partition, go through each of the requested partitions... */
- for (size_t n = 0; requested_partitions[n] != NULL; n++) {
- ret = load_and_verify_vbmeta(ops,
- requested_partitions,
- ab_suffix,
- flags,
- allow_verification_error,
- 0 /* toplevel_vbmeta_flags */,
- 0 /* rollback_index_location */,
- requested_partitions[n],
- avb_strlen(requested_partitions[n]),
- NULL /* expected_public_key */,
- 0 /* expected_public_key_length */,
- slot_data,
- &algorithm_type,
- additional_cmdline_subst);
- if (!allow_verification_error && ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto fail;
- }
- }
- } else {
- /* Usual path, load "vbmeta"... */
- ret = load_and_verify_vbmeta(ops,
- requested_partitions,
- ab_suffix,
- flags,
- allow_verification_error,
- 0 /* toplevel_vbmeta_flags */,
- 0 /* rollback_index_location */,
- "vbmeta",
- avb_strlen("vbmeta"),
- NULL /* expected_public_key */,
- 0 /* expected_public_key_length */,
- slot_data,
- &algorithm_type,
- additional_cmdline_subst);
- if (!allow_verification_error && ret != AVB_SLOT_VERIFY_RESULT_OK) {
- goto fail;
- }
- }
- if (!result_should_continue(ret)) {
- goto fail;
- }
- /* If things check out, mangle the kernel command-line as needed. */
- if (!(flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION)) {
- if (avb_strcmp(slot_data->vbmeta_images[0].partition_name, "vbmeta") != 0) {
- avb_assert(
- avb_strcmp(slot_data->vbmeta_images[0].partition_name, "boot") == 0);
- using_boot_for_vbmeta = true;
- }
- }
- /* Byteswap top-level vbmeta header since we'll need it below. */
- avb_vbmeta_image_header_to_host_byte_order(
- (const AvbVBMetaImageHeader*)slot_data->vbmeta_images[0].vbmeta_data,
- &toplevel_vbmeta);
- /* Fill in |ab_suffix| field. */
- slot_data->ab_suffix = avb_strdup(ab_suffix);
- if (slot_data->ab_suffix == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- /* If verification is disabled, we are done ... we specifically
- * don't want to add any androidboot.* options since verification
- * is disabled.
- */
- if (toplevel_vbmeta.flags & AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED) {
- /* Since verification is disabled we didn't process any
- * descriptors and thus there's no cmdline... so set root= such
- * that the system partition is mounted.
- */
- avb_assert(slot_data->cmdline == NULL);
- // Devices with dynamic partitions won't have system partition.
- // Instead, it has a large super partition to accommodate *.img files.
- // See b/119551429 for details.
- if (has_system_partition(ops, ab_suffix)) {
- slot_data->cmdline =
- avb_strdup("root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)");
- } else {
- // The |cmdline| field should be a NUL-terminated string.
- slot_data->cmdline = avb_strdup("");
- }
- if (slot_data->cmdline == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- } else {
- /* If requested, manage dm-verity mode... */
- AvbHashtreeErrorMode resolved_hashtree_error_mode = hashtree_error_mode;
- if (hashtree_error_mode ==
- AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO) {
- AvbIOResult io_ret;
- io_ret = avb_manage_hashtree_error_mode(
- ops, flags, slot_data, &resolved_hashtree_error_mode);
- if (io_ret != AVB_IO_RESULT_OK) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
- if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- }
- goto fail;
- }
- }
- slot_data->resolved_hashtree_error_mode = resolved_hashtree_error_mode;
- /* Add options... */
- AvbSlotVerifyResult sub_ret;
- sub_ret = avb_append_options(ops,
- flags,
- slot_data,
- &toplevel_vbmeta,
- algorithm_type,
- hashtree_error_mode,
- resolved_hashtree_error_mode);
- if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) {
- ret = sub_ret;
- goto fail;
- }
- }
- /* Substitute $(ANDROID_SYSTEM_PARTUUID) and friends. */
- if (slot_data->cmdline != NULL && avb_strlen(slot_data->cmdline) != 0) {
- char* new_cmdline;
- new_cmdline = avb_sub_cmdline(ops,
- slot_data->cmdline,
- ab_suffix,
- using_boot_for_vbmeta,
- additional_cmdline_subst);
- if (new_cmdline != slot_data->cmdline) {
- if (new_cmdline == NULL) {
- ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
- goto fail;
- }
- avb_free(slot_data->cmdline);
- slot_data->cmdline = new_cmdline;
- }
- }
- if (out_data != NULL) {
- *out_data = slot_data;
- } else {
- avb_slot_verify_data_free(slot_data);
- }
- avb_free_cmdline_subst_list(additional_cmdline_subst);
- additional_cmdline_subst = NULL;
- if (!allow_verification_error) {
- avb_assert(ret == AVB_SLOT_VERIFY_RESULT_OK);
- }
- return ret;
- fail:
- if (slot_data != NULL) {
- avb_slot_verify_data_free(slot_data);
- }
- if (additional_cmdline_subst != NULL) {
- avb_free_cmdline_subst_list(additional_cmdline_subst);
- }
- return ret;
- }
- void avb_slot_verify_data_free(AvbSlotVerifyData* data) {
- if (data->ab_suffix != NULL) {
- avb_free(data->ab_suffix);
- }
- if (data->cmdline != NULL) {
- avb_free(data->cmdline);
- }
- if (data->vbmeta_images != NULL) {
- size_t n;
- for (n = 0; n < data->num_vbmeta_images; n++) {
- AvbVBMetaData* vbmeta_image = &data->vbmeta_images[n];
- if (vbmeta_image->partition_name != NULL) {
- avb_free(vbmeta_image->partition_name);
- }
- if (vbmeta_image->vbmeta_data != NULL) {
- avb_free(vbmeta_image->vbmeta_data);
- }
- }
- avb_free(data->vbmeta_images);
- }
- if (data->loaded_partitions != NULL) {
- size_t n;
- for (n = 0; n < data->num_loaded_partitions; n++) {
- AvbPartitionData* loaded_partition = &data->loaded_partitions[n];
- if (loaded_partition->partition_name != NULL) {
- avb_free(loaded_partition->partition_name);
- }
- if (loaded_partition->data != NULL && !loaded_partition->preloaded) {
- avb_free(loaded_partition->data);
- }
- }
- avb_free(data->loaded_partitions);
- }
- avb_free(data);
- }
- const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result) {
- const char* ret = NULL;
- switch (result) {
- case AVB_SLOT_VERIFY_RESULT_OK:
- ret = "OK";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
- ret = "ERROR_OOM";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
- ret = "ERROR_IO";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
- ret = "ERROR_VERIFICATION";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
- ret = "ERROR_ROLLBACK_INDEX";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
- ret = "ERROR_PUBLIC_KEY_REJECTED";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
- ret = "ERROR_INVALID_METADATA";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
- ret = "ERROR_UNSUPPORTED_VERSION";
- break;
- case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT:
- ret = "ERROR_INVALID_ARGUMENT";
- break;
- /* Do not add a 'default:' case here because of -Wswitch. */
- }
- if (ret == NULL) {
- avb_error("Unknown AvbSlotVerifyResult value.\n");
- ret = "(unknown)";
- }
- return ret;
- }
- void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data,
- AvbDigestType digest_type,
- uint8_t* out_digest) {
- bool ret = false;
- size_t n;
- switch (digest_type) {
- case AVB_DIGEST_TYPE_SHA256: {
- AvbSHA256Ctx ctx;
- avb_sha256_init(&ctx);
- for (n = 0; n < data->num_vbmeta_images; n++) {
- avb_sha256_update(&ctx,
- data->vbmeta_images[n].vbmeta_data,
- data->vbmeta_images[n].vbmeta_size);
- }
- avb_memcpy(out_digest, avb_sha256_final(&ctx), AVB_SHA256_DIGEST_SIZE);
- ret = true;
- } break;
- case AVB_DIGEST_TYPE_SHA512: {
- AvbSHA512Ctx ctx;
- avb_sha512_init(&ctx);
- for (n = 0; n < data->num_vbmeta_images; n++) {
- avb_sha512_update(&ctx,
- data->vbmeta_images[n].vbmeta_data,
- data->vbmeta_images[n].vbmeta_size);
- }
- avb_memcpy(out_digest, avb_sha512_final(&ctx), AVB_SHA512_DIGEST_SIZE);
- ret = true;
- } break;
- /* Do not add a 'default:' case here because of -Wswitch. */
- }
- if (!ret) {
- avb_fatal("Unknown digest type");
- }
- }
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