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author | 2023-10-10 14:33:42 +0000 | |
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committer | 2023-10-10 14:33:42 +0000 | |
commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/u-boot/lib/libavb/avb_vbmeta_image.c | |
parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/u-boot/lib/libavb/avb_vbmeta_image.c')
-rw-r--r-- | roms/u-boot/lib/libavb/avb_vbmeta_image.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/roms/u-boot/lib/libavb/avb_vbmeta_image.c b/roms/u-boot/lib/libavb/avb_vbmeta_image.c new file mode 100644 index 000000000..384f5ac19 --- /dev/null +++ b/roms/u-boot/lib/libavb/avb_vbmeta_image.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright (C) 2016 The Android Open Source Project + */ + +#include "avb_vbmeta_image.h" +#include "avb_crypto.h" +#include "avb_rsa.h" +#include "avb_sha.h" +#include "avb_util.h" +#include "avb_version.h" + +AvbVBMetaVerifyResult avb_vbmeta_image_verify( + const uint8_t* data, + size_t length, + const uint8_t** out_public_key_data, + size_t* out_public_key_length) { + AvbVBMetaVerifyResult ret; + AvbVBMetaImageHeader h; + uint8_t* computed_hash; + const AvbAlgorithmData* algorithm; + AvbSHA256Ctx sha256_ctx; + AvbSHA512Ctx sha512_ctx; + const uint8_t* header_block; + const uint8_t* authentication_block; + const uint8_t* auxiliary_block; + int verification_result; + + ret = AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER; + + if (out_public_key_data != NULL) { + *out_public_key_data = NULL; + } + if (out_public_key_length != NULL) { + *out_public_key_length = 0; + } + + /* Before we byteswap or compare Magic, ensure length is long enough. */ + if (length < sizeof(AvbVBMetaImageHeader)) { + avb_error("Length is smaller than header.\n"); + goto out; + } + + /* Ensure magic is correct. */ + if (avb_safe_memcmp(data, AVB_MAGIC, AVB_MAGIC_LEN) != 0) { + avb_error("Magic is incorrect.\n"); + goto out; + } + + avb_vbmeta_image_header_to_host_byte_order((const AvbVBMetaImageHeader*)data, + &h); + + /* Ensure we don't attempt to access any fields if we do not meet + * the specified minimum version of libavb. + */ + if ((h.required_libavb_version_major != AVB_VERSION_MAJOR) || + (h.required_libavb_version_minor > AVB_VERSION_MINOR)) { + avb_error("Mismatch between image version and libavb version.\n"); + ret = AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION; + goto out; + } + + /* Ensure |release_string| ends with a NUL byte. */ + if (h.release_string[AVB_RELEASE_STRING_SIZE - 1] != '\0') { + avb_error("Release string does not end with a NUL byte.\n"); + goto out; + } + + /* Ensure inner block sizes are multiple of 64. */ + if ((h.authentication_data_block_size & 0x3f) != 0 || + (h.auxiliary_data_block_size & 0x3f) != 0) { + avb_error("Block size is not a multiple of 64.\n"); + goto out; + } + + /* Ensure block sizes all add up to at most |length|. */ + uint64_t block_total = sizeof(AvbVBMetaImageHeader); + if (!avb_safe_add_to(&block_total, h.authentication_data_block_size) || + !avb_safe_add_to(&block_total, h.auxiliary_data_block_size)) { + avb_error("Overflow while computing size of boot image.\n"); + goto out; + } + if (block_total > length) { + avb_error("Block sizes add up to more than given length.\n"); + goto out; + } + + uintptr_t data_ptr = (uintptr_t)data; + /* Ensure passed in memory doesn't wrap. */ + if (!avb_safe_add(NULL, (uint64_t)data_ptr, length)) { + avb_error("Boot image location and length mismatch.\n"); + goto out; + } + + /* Ensure hash and signature are entirely in the Authentication data block. */ + uint64_t hash_end; + if (!avb_safe_add(&hash_end, h.hash_offset, h.hash_size) || + hash_end > h.authentication_data_block_size) { + avb_error("Hash is not entirely in its block.\n"); + goto out; + } + uint64_t signature_end; + if (!avb_safe_add(&signature_end, h.signature_offset, h.signature_size) || + signature_end > h.authentication_data_block_size) { + avb_error("Signature is not entirely in its block.\n"); + goto out; + } + + /* Ensure public key is entirely in the Auxiliary data block. */ + uint64_t pubkey_end; + if (!avb_safe_add(&pubkey_end, h.public_key_offset, h.public_key_size) || + pubkey_end > h.auxiliary_data_block_size) { + avb_error("Public key is not entirely in its block.\n"); + goto out; + } + + /* Ensure public key metadata (if set) is entirely in the Auxiliary + * data block. */ + if (h.public_key_metadata_size > 0) { + uint64_t pubkey_md_end; + if (!avb_safe_add(&pubkey_md_end, + h.public_key_metadata_offset, + h.public_key_metadata_size) || + pubkey_md_end > h.auxiliary_data_block_size) { + avb_error("Public key metadata is not entirely in its block.\n"); + goto out; + } + } + + /* Bail early if there's no hash or signature. */ + if (h.algorithm_type == AVB_ALGORITHM_TYPE_NONE) { + ret = AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED; + goto out; + } + + /* Ensure algorithm field is supported. */ + algorithm = avb_get_algorithm_data(h.algorithm_type); + if (!algorithm) { + avb_error("Invalid or unknown algorithm.\n"); + goto out; + } + + /* Bail if the embedded hash size doesn't match the chosen algorithm. */ + if (h.hash_size != algorithm->hash_len) { + avb_error("Embedded hash has wrong size.\n"); + goto out; + } + + /* No overflow checks needed from here-on after since all block + * sizes and offsets have been verified above. + */ + + header_block = data; + authentication_block = header_block + sizeof(AvbVBMetaImageHeader); + auxiliary_block = authentication_block + h.authentication_data_block_size; + + switch (h.algorithm_type) { + /* Explicit fall-through: */ + case AVB_ALGORITHM_TYPE_SHA256_RSA2048: + case AVB_ALGORITHM_TYPE_SHA256_RSA4096: + case AVB_ALGORITHM_TYPE_SHA256_RSA8192: + avb_sha256_init(&sha256_ctx); + avb_sha256_update( + &sha256_ctx, header_block, sizeof(AvbVBMetaImageHeader)); + avb_sha256_update( + &sha256_ctx, auxiliary_block, h.auxiliary_data_block_size); + computed_hash = avb_sha256_final(&sha256_ctx); + break; + /* Explicit fall-through: */ + case AVB_ALGORITHM_TYPE_SHA512_RSA2048: + case AVB_ALGORITHM_TYPE_SHA512_RSA4096: + case AVB_ALGORITHM_TYPE_SHA512_RSA8192: + avb_sha512_init(&sha512_ctx); + avb_sha512_update( + &sha512_ctx, header_block, sizeof(AvbVBMetaImageHeader)); + avb_sha512_update( + &sha512_ctx, auxiliary_block, h.auxiliary_data_block_size); + computed_hash = avb_sha512_final(&sha512_ctx); + break; + default: + avb_error("Unknown algorithm.\n"); + goto out; + } + + if (avb_safe_memcmp(authentication_block + h.hash_offset, + computed_hash, + h.hash_size) != 0) { + avb_error("Hash does not match!\n"); + ret = AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH; + goto out; + } + + verification_result = + avb_rsa_verify(auxiliary_block + h.public_key_offset, + h.public_key_size, + authentication_block + h.signature_offset, + h.signature_size, + authentication_block + h.hash_offset, + h.hash_size, + algorithm->padding, + algorithm->padding_len); + + if (verification_result == 0) { + ret = AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH; + goto out; + } + + if (h.public_key_size > 0) { + if (out_public_key_data != NULL) { + *out_public_key_data = auxiliary_block + h.public_key_offset; + } + if (out_public_key_length != NULL) { + *out_public_key_length = h.public_key_size; + } + } + + ret = AVB_VBMETA_VERIFY_RESULT_OK; + +out: + return ret; +} + +void avb_vbmeta_image_header_to_host_byte_order(const AvbVBMetaImageHeader* src, + AvbVBMetaImageHeader* dest) { + avb_memcpy(dest, src, sizeof(AvbVBMetaImageHeader)); + + dest->required_libavb_version_major = + avb_be32toh(dest->required_libavb_version_major); + dest->required_libavb_version_minor = + avb_be32toh(dest->required_libavb_version_minor); + + dest->authentication_data_block_size = + avb_be64toh(dest->authentication_data_block_size); + dest->auxiliary_data_block_size = + avb_be64toh(dest->auxiliary_data_block_size); + + dest->algorithm_type = avb_be32toh(dest->algorithm_type); + + dest->hash_offset = avb_be64toh(dest->hash_offset); + dest->hash_size = avb_be64toh(dest->hash_size); + + dest->signature_offset = avb_be64toh(dest->signature_offset); + dest->signature_size = avb_be64toh(dest->signature_size); + + dest->public_key_offset = avb_be64toh(dest->public_key_offset); + dest->public_key_size = avb_be64toh(dest->public_key_size); + + dest->public_key_metadata_offset = + avb_be64toh(dest->public_key_metadata_offset); + dest->public_key_metadata_size = avb_be64toh(dest->public_key_metadata_size); + + dest->descriptors_offset = avb_be64toh(dest->descriptors_offset); + dest->descriptors_size = avb_be64toh(dest->descriptors_size); + + dest->rollback_index = avb_be64toh(dest->rollback_index); + dest->flags = avb_be32toh(dest->flags); +} + +const char* avb_vbmeta_verify_result_to_string(AvbVBMetaVerifyResult result) { + const char* ret = NULL; + + switch (result) { + case AVB_VBMETA_VERIFY_RESULT_OK: + ret = "OK"; + break; + case AVB_VBMETA_VERIFY_RESULT_OK_NOT_SIGNED: + ret = "OK_NOT_SIGNED"; + break; + case AVB_VBMETA_VERIFY_RESULT_INVALID_VBMETA_HEADER: + ret = "INVALID_VBMETA_HEADER"; + break; + case AVB_VBMETA_VERIFY_RESULT_UNSUPPORTED_VERSION: + ret = "UNSUPPORTED_VERSION"; + break; + case AVB_VBMETA_VERIFY_RESULT_HASH_MISMATCH: + ret = "HASH_MISMATCH"; + break; + case AVB_VBMETA_VERIFY_RESULT_SIGNATURE_MISMATCH: + ret = "SIGNATURE_MISMATCH"; + break; + /* Do not add a 'default:' case here because of -Wswitch. */ + } + + if (ret == NULL) { + avb_error("Unknown AvbVBMetaVerifyResult value.\n"); + ret = "(unknown)"; + } + + return ret; +} |