diff options
Diffstat (limited to 'roms/u-boot/lib/libavb/avb_slot_verify.c')
| -rw-r--r-- | roms/u-boot/lib/libavb/avb_slot_verify.c | 1726 |
1 files changed, 1726 insertions, 0 deletions
diff --git a/roms/u-boot/lib/libavb/avb_slot_verify.c b/roms/u-boot/lib/libavb/avb_slot_verify.c new file mode 100644 index 000000000..ae8e1dffa --- /dev/null +++ b/roms/u-boot/lib/libavb/avb_slot_verify.c @@ -0,0 +1,1726 @@ +// 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" +#include <log.h> +#include <malloc.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"); + } +} |