| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "avb_slot_verify.h" |
| #include "avb_chain_partition_descriptor.h" |
| #include "avb_footer.h" |
| #include "avb_hash_descriptor.h" |
| #include "avb_kernel_cmdline_descriptor.h" |
| #include "avb_sha.h" |
| #include "avb_util.h" |
| #include "avb_vbmeta_image.h" |
| |
| /* Maximum allow length (in bytes) of a partition name, including |
| * ab_suffix. |
| */ |
| #define PART_NAME_MAX_SIZE 32 |
| |
| /* Maximum size of a vbmeta image - 64 KiB. */ |
| #define VBMETA_MAX_SIZE (64 * 1024) |
| |
| static AvbSlotVerifyResult load_and_verify_hash_partition( |
| AvbOps* ops, const char* ab_suffix, const AvbDescriptor* descriptor, |
| AvbSlotVerifyData* slot_data) { |
| AvbHashDescriptor hash_desc; |
| const uint8_t* desc_partition_name; |
| const uint8_t* desc_salt; |
| const uint8_t* desc_digest; |
| char part_name[PART_NAME_MAX_SIZE]; |
| AvbSlotVerifyResult ret; |
| AvbIOResult io_ret; |
| uint8_t* image_buf = NULL; |
| size_t part_num_read; |
| uint8_t* digest; |
| size_t digest_len; |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| image_buf = avb_malloc(hash_desc.image_size); |
| if (image_buf == NULL) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto out; |
| } |
| |
| io_ret = |
| ops->read_from_partition(ops, part_name, 0 /* offset */, |
| hash_desc.image_size, image_buf, &part_num_read); |
| if (io_ret != AVB_IO_RESULT_OK) { |
| avb_errorv(part_name, ": Error loading data from partition.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO; |
| goto out; |
| } |
| if (part_num_read != hash_desc.image_size) { |
| avb_errorv(part_name, ": Read fewer than requested bytes.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO; |
| goto out; |
| } |
| |
| if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha256") == 0) { |
| AvbSHA256Ctx sha256_ctx; |
| avb_sha256_init(&sha256_ctx); |
| avb_sha256_update(&sha256_ctx, desc_salt, hash_desc.salt_len); |
| avb_sha256_update(&sha256_ctx, image_buf, hash_desc.image_size); |
| digest = avb_sha256_final(&sha256_ctx); |
| digest_len = AVB_SHA256_DIGEST_SIZE; |
| } else if (avb_strcmp((const char*)hash_desc.hash_algorithm, "sha512") == 0) { |
| AvbSHA512Ctx sha512_ctx; |
| avb_sha512_init(&sha512_ctx); |
| avb_sha512_update(&sha512_ctx, desc_salt, hash_desc.salt_len); |
| avb_sha512_update(&sha512_ctx, image_buf, hash_desc.image_size); |
| 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 (digest_len != hash_desc.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, desc_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; |
| |
| /* If this is the boot partition, copy to slot_data. */ |
| if (hash_desc.partition_name_len == 4 && |
| avb_memcmp(desc_partition_name, "boot", 4) == 0) { |
| if (slot_data->boot_data != NULL) { |
| avb_free(slot_data->boot_data); |
| } |
| slot_data->boot_size = hash_desc.image_size; |
| slot_data->boot_data = image_buf; |
| image_buf = NULL; |
| } |
| |
| out: |
| if (image_buf != NULL) { |
| avb_free(image_buf); |
| } |
| return ret; |
| } |
| |
| static AvbSlotVerifyResult load_and_verify_vbmeta( |
| AvbOps* ops, const char* ab_suffix, int rollback_index_slot, |
| 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) { |
| char full_partition_name[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; |
| int is_main_vbmeta; |
| |
| avb_assert(slot_data != NULL); |
| |
| is_main_vbmeta = (avb_strcmp(partition_name, "vbmeta") == 0); |
| |
| 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. */ |
| 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; |
| } |
| |
| avb_debugv("Loading vbmeta struct from partition '", full_partition_name, |
| "'.\n", NULL); |
| |
| /* If we're loading from the main vbmeta partition, the vbmeta |
| * struct is in the beginning. Otherwise we have to locate it via a |
| * footer. |
| */ |
| if (is_main_vbmeta) { |
| vbmeta_offset = 0; |
| vbmeta_size = VBMETA_MAX_SIZE; |
| } else { |
| 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_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_errorv(full_partition_name, ": Error validating footer.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA; |
| goto out; |
| } |
| |
| /* 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); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA; |
| goto out; |
| } |
| |
| 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; |
| } |
| |
| 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_OK) { |
| 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); |
| if (vbmeta_ret != AVB_VBMETA_VERIFY_RESULT_OK) { |
| avb_errorv(full_partition_name, ": Error verifying vbmeta image.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION; |
| goto out; |
| } |
| |
| /* Check if key used to make signature matches what is expected. */ |
| 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; |
| goto out; |
| } |
| } else { |
| avb_assert(is_main_vbmeta); |
| if (!ops->validate_vbmeta_public_key(ops, pk_data, pk_len)) { |
| avb_errorv(full_partition_name, |
| ": Public key used to sign data rejected.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED; |
| goto out; |
| } |
| } |
| |
| avb_vbmeta_image_header_to_host_byte_order((AvbVBMetaImageHeader*)vbmeta_buf, |
| &vbmeta_header); |
| |
| /* Check rollback index. */ |
| if (!ops->read_rollback_index(ops, rollback_index_slot, |
| &stored_rollback_index)) { |
| avb_errorv(full_partition_name, |
| ": Error getting rollback index for slot.\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; |
| 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. |
| * |
| * - 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, ab_suffix, descriptors[n], |
| slot_data); |
| if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) { |
| ret = sub_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; |
| } |
| |
| 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, ab_suffix, chain_desc.rollback_index_slot, |
| (const char*)chain_partition_name, chain_desc.partition_name_len, |
| chain_public_key, chain_desc.public_key_len, slot_data, |
| NULL /* out_algorithm_type */); |
| if (sub_ret != AVB_SLOT_VERIFY_RESULT_OK) { |
| ret = sub_ret; |
| goto out; |
| } |
| } break; |
| |
| case AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: { |
| const uint8_t* kernel_cmdline; |
| AvbKernelCmdlineDescriptor kernel_cmdline_desc; |
| |
| 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; |
| } |
| |
| 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; |
| |
| /* Explicit fall-through */ |
| case AVB_DESCRIPTOR_TAG_PROPERTY: |
| case AVB_DESCRIPTOR_TAG_HASHTREE: |
| /* Do nothing. */ |
| break; |
| } |
| } |
| |
| ret = AVB_SLOT_VERIFY_RESULT_OK; |
| |
| /* So far, so good. Copy needed data to user, if requested. */ |
| if (is_main_vbmeta) { |
| if (slot_data->vbmeta_data != NULL) { |
| avb_free(slot_data->vbmeta_data); |
| } |
| /* 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. |
| */ |
| slot_data->vbmeta_size = sizeof(AvbVBMetaImageHeader) + |
| vbmeta_header.authentication_data_block_size + |
| vbmeta_header.auxiliary_data_block_size; |
| slot_data->vbmeta_data = vbmeta_buf; |
| vbmeta_buf = NULL; |
| } |
| |
| if (rollback_index_slot >= AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_SLOTS) { |
| avb_errorv(full_partition_name, ": Invalid rollback_index_slot.\n", NULL); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA; |
| goto out; |
| } |
| |
| slot_data->rollback_indexes[rollback_index_slot] = |
| vbmeta_header.rollback_index; |
| |
| if (out_algorithm_type != NULL) { |
| *out_algorithm_type = (AvbAlgorithmType)vbmeta_header.algorithm_type; |
| } |
| |
| out: |
| if (vbmeta_buf != NULL) { |
| avb_free(vbmeta_buf); |
| } |
| if (descriptors != NULL) { |
| avb_free(descriptors); |
| } |
| return ret; |
| } |
| |
| /* Substitutes all variables (e.g. $(ANDROID_SYSTEM_PARTUUID)) with |
| * values. Returns NULL on OOM, otherwise the cmdline with values |
| * replaced. |
| */ |
| static char* sub_cmdline(AvbOps* ops, const char* cmdline, |
| const char* ab_suffix) { |
| const int NUM_GUIDS = 2; |
| const char* part_name_str[NUM_GUIDS] = {"system", "boot"}; |
| const char* replace_str[NUM_GUIDS] = {"$(ANDROID_SYSTEM_PARTUUID)", |
| "$(ANDROID_BOOT_PARTUUID)"}; |
| char* ret = NULL; |
| |
| /* Replace unique partition GUIDs */ |
| for (size_t n = 0; n < NUM_GUIDS; n++) { |
| char part_name[PART_NAME_MAX_SIZE]; |
| char guid_buf[37]; |
| char* new_ret; |
| |
| if (!avb_str_concat(part_name, sizeof part_name, part_name_str[n], |
| avb_strlen(part_name_str[n]), ab_suffix, |
| avb_strlen(ab_suffix))) { |
| avb_error("Partition name and suffix does not fit.\n"); |
| goto fail; |
| } |
| |
| if (!ops->get_unique_guid_for_partition(ops, part_name, guid_buf, |
| sizeof guid_buf)) { |
| avb_error("Error getting unique GUID for partition.\n"); |
| goto fail; |
| } |
| |
| if (ret == NULL) { |
| new_ret = avb_replace(cmdline, replace_str[n], guid_buf); |
| } else { |
| new_ret = avb_replace(ret, replace_str[n], guid_buf); |
| } |
| if (new_ret == NULL) { |
| goto fail; |
| } |
| ret = new_ret; |
| } |
| |
| return ret; |
| |
| fail: |
| if (ret != NULL) { |
| avb_free(ret); |
| } |
| return NULL; |
| } |
| |
| static int cmdline_append_option(AvbSlotVerifyData* slot_data, const char* key, |
| const char* value) { |
| size_t offset, key_len, value_len; |
| char* new_cmdline; |
| |
| key_len = avb_strlen(key); |
| value_len = avb_strlen(value); |
| |
| offset = 0; |
| if (slot_data->cmdline != NULL) { |
| offset = avb_strlen(slot_data->cmdline); |
| if (offset > 0) { |
| offset += 1; |
| } |
| } |
| |
| new_cmdline = avb_calloc(offset + key_len + value_len + 2); |
| if (new_cmdline == NULL) { |
| return 0; |
| } |
| if (offset > 0) { |
| avb_memcpy(new_cmdline, slot_data->cmdline, offset - 1); |
| new_cmdline[offset - 1] = ' '; |
| } |
| avb_memcpy(new_cmdline + offset, key, key_len); |
| new_cmdline[offset + key_len] = '='; |
| avb_memcpy(new_cmdline + offset + key_len + 1, value, value_len); |
| if (slot_data->cmdline != NULL) { |
| avb_free(slot_data->cmdline); |
| } |
| slot_data->cmdline = new_cmdline; |
| |
| return 1; |
| } |
| |
| static int cmdline_append_uint64_base10(AvbSlotVerifyData* slot_data, |
| const char* key, uint64_t value) { |
| const int MAX_DIGITS = 32; |
| char rev_digits[MAX_DIGITS]; |
| char digits[MAX_DIGITS]; |
| size_t n, num_digits; |
| |
| for (num_digits = 0; num_digits < MAX_DIGITS - 1;) { |
| rev_digits[num_digits++] = (value % 10) + '0'; |
| value /= 10; |
| if (value == 0) { |
| break; |
| } |
| } |
| |
| for (n = 0; n < num_digits; n++) { |
| digits[n] = rev_digits[num_digits - 1 - n]; |
| } |
| digits[n] = '\0'; |
| |
| return cmdline_append_option(slot_data, key, digits); |
| } |
| |
| static int cmdline_append_hex(AvbSlotVerifyData* slot_data, const char* key, |
| const uint8_t* data, size_t data_len) { |
| char hex_digits[17] = "0123456789abcdef"; |
| char* hex_data; |
| int ret; |
| size_t n; |
| |
| hex_data = avb_malloc(data_len * 2 + 1); |
| if (hex_data == NULL) return 0; |
| |
| for (n = 0; n < data_len; n++) { |
| hex_data[n * 2] = hex_digits[data[n] >> 4]; |
| hex_data[n * 2 + 1] = hex_digits[data[n] & 0x0f]; |
| } |
| hex_data[n] = '\0'; |
| |
| ret = cmdline_append_option(slot_data, key, hex_data); |
| avb_free(hex_data); |
| return ret; |
| } |
| |
| AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, const char* ab_suffix, |
| AvbSlotVerifyData** out_data) { |
| AvbSlotVerifyResult ret; |
| AvbSlotVerifyData* slot_data = NULL; |
| AvbAlgorithmType algorithm_type = AVB_ALGORITHM_TYPE_NONE; |
| |
| if (out_data != NULL) { |
| *out_data = NULL; |
| } |
| |
| slot_data = avb_calloc(sizeof(AvbSlotVerifyData)); |
| if (slot_data == NULL) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| |
| ret = load_and_verify_vbmeta( |
| ops, ab_suffix, 0 /* rollback_index_slot */, "vbmeta", |
| avb_strlen("vbmeta"), NULL /* expected_public_key */, |
| 0 /* expected_public_key_length */, slot_data, &algorithm_type); |
| |
| /* If things check out, mangle the kernel command-line as needed. */ |
| if (ret == AVB_SLOT_VERIFY_RESULT_OK) { |
| /* Substitute $(ANDROID_SYSTEM_PARTUUID) and friends. */ |
| if (slot_data->cmdline != NULL) { |
| char* new_cmdline = sub_cmdline(ops, slot_data->cmdline, ab_suffix); |
| if (new_cmdline == NULL) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| avb_free(slot_data->cmdline); |
| slot_data->cmdline = new_cmdline; |
| } |
| |
| /* Add androidboot.slot_suffix, if applicable. */ |
| if (avb_strlen(ab_suffix) > 0) { |
| if (!cmdline_append_option(slot_data, "androidboot.slot_suffix", |
| ab_suffix)) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| } |
| |
| /* Set androidboot.avb.device_state to "locked" or "unlocked". */ |
| bool is_device_unlocked; |
| if (!ops->read_is_device_unlocked(ops, &is_device_unlocked)) { |
| avb_error("Error getting device state.\n"); |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO; |
| goto fail; |
| } |
| if (!cmdline_append_option(slot_data, "androidboot.vbmeta.device_state", |
| is_device_unlocked ? "unlocked" : "locked")) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| |
| /* Set androidboot.vbmeta.{hash_alg, size, digest} - use same hash |
| * function as is used to sign vbmeta. |
| */ |
| switch (algorithm_type) { |
| /* Explicit fallthrough. */ |
| case AVB_ALGORITHM_TYPE_NONE: |
| case AVB_ALGORITHM_TYPE_SHA256_RSA2048: |
| case AVB_ALGORITHM_TYPE_SHA256_RSA4096: |
| case AVB_ALGORITHM_TYPE_SHA256_RSA8192: { |
| AvbSHA256Ctx ctx; |
| avb_sha256_init(&ctx); |
| avb_sha256_update(&ctx, slot_data->vbmeta_data, slot_data->vbmeta_size); |
| if (!cmdline_append_option(slot_data, "androidboot.vbmeta.hash_alg", |
| "sha256") || |
| !cmdline_append_uint64_base10(slot_data, "androidboot.vbmeta.size", |
| slot_data->vbmeta_size) || |
| !cmdline_append_hex(slot_data, "androidboot.vbmeta.digest", |
| avb_sha256_final(&ctx), |
| AVB_SHA256_DIGEST_SIZE)) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| } break; |
| /* Explicit fallthrough. */ |
| case AVB_ALGORITHM_TYPE_SHA512_RSA2048: |
| case AVB_ALGORITHM_TYPE_SHA512_RSA4096: |
| case AVB_ALGORITHM_TYPE_SHA512_RSA8192: { |
| AvbSHA512Ctx ctx; |
| avb_sha512_init(&ctx); |
| avb_sha512_update(&ctx, slot_data->vbmeta_data, slot_data->vbmeta_size); |
| if (!cmdline_append_option(slot_data, "androidboot.vbmeta.hash_alg", |
| "sha512") || |
| !cmdline_append_uint64_base10(slot_data, "androidboot.vbmeta.size", |
| slot_data->vbmeta_size) || |
| !cmdline_append_hex(slot_data, "androidboot.vbmeta.digest", |
| avb_sha512_final(&ctx), |
| AVB_SHA512_DIGEST_SIZE)) { |
| ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; |
| goto fail; |
| } |
| } break; |
| case _AVB_ALGORITHM_NUM_TYPES: |
| avb_assert_not_reached(); |
| break; |
| } |
| |
| if (out_data != NULL) { |
| *out_data = slot_data; |
| } else { |
| avb_slot_verify_data_free(slot_data); |
| } |
| } |
| |
| return ret; |
| |
| fail: |
| if (slot_data != NULL) { |
| avb_slot_verify_data_free(slot_data); |
| } |
| return ret; |
| } |
| |
| void avb_slot_verify_data_free(AvbSlotVerifyData* data) { |
| if (data->boot_data != NULL) { |
| avb_free(data->boot_data); |
| } |
| if (data->cmdline != NULL) { |
| avb_free(data->cmdline); |
| } |
| avb_free(data); |
| } |