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Diffstat (limited to 'include/pinweaver_cr50.h')
| -rw-r--r-- | include/pinweaver_cr50.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/include/pinweaver_cr50.h b/include/pinweaver_cr50.h new file mode 100644 index 0000000000..4d4f553097 --- /dev/null +++ b/include/pinweaver_cr50.h @@ -0,0 +1,191 @@ +/* Copyright 2018 The ChromiumOS Authors + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef __CROS_EC_INCLUDE_PINWEAVER_H +#define __CROS_EC_INCLUDE_PINWEAVER_H + +/* This is required before pinweaver_types.h to provide __packed and __aligned + * while preserving the ability of pinweaver_types.h to be used in code outside + * of src/platform/ec. + */ +#include <common.h> +#include <pinweaver_cr50_types.h> + +#ifdef __cplusplus +extern "C" { +#endif + +#define PW_STORAGE_VERSION 0 + +#define BITS_PER_LEVEL_MIN 1 +#define BITS_PER_LEVEL_MAX 5 +#define HEIGHT_MIN 1 +/* This will crash for logk == 0 so that condition must not be allowed when + * using this. + */ +#define HEIGHT_MAX(logk) ((sizeof(struct label_t) * 8) / logk) + +#define PW_LOG_ENTRY_COUNT 2 + +/* Persistent information used by this feature. */ +struct merkle_tree_t { + /* log2(Fan out). */ + struct bits_per_level_t bits_per_level; + /* Height of the tree or param_l / bits_per_level. */ + struct height_t height; + + /* Root hash of the Merkle tree. */ + uint8_t root[PW_HASH_SIZE]; + + /* Random bits used as part of the key derivation process. */ + uint8_t key_derivation_nonce[16]; + + /* Key used to compute the HMACs of the metadata of the leaves. */ + uint8_t PW_ALIGN_TO_WRD hmac_key[32]; + + /* Key used to encrypt and decrypt the metadata of the leaves. */ + uint8_t PW_ALIGN_TO_WRD wrap_key[32]; +}; + +/* Long term flash storage for tree metadata. */ +struct PW_PACKED pw_long_term_storage_t { + uint16_t storage_version; + + /* log2(Fan out). */ + struct bits_per_level_t bits_per_level; + /* Height of the tree or param_l / bits_per_level. */ + struct height_t height; + + /* Random bits used as part of the key derivation process. */ + uint8_t key_derivation_nonce[16]; +}; + +struct PW_PACKED pw_log_storage_t { + uint16_t storage_version; + uint32_t restart_count; + struct pw_get_log_entry_t entries[PW_LOG_ENTRY_COUNT]; +}; + +/* Do not remove fields within the same PW_LEAF_MAJOR_VERSION. */ +/* Encrypted part of the leaf data. + */ +struct PW_PACKED PW_ALIGN_TO_BLK leaf_sensitive_data_t { + uint8_t low_entropy_secret[PW_SECRET_SIZE]; + uint8_t high_entropy_secret[PW_SECRET_SIZE]; + uint8_t reset_secret[PW_SECRET_SIZE]; +}; + +/* Represents leaf data in a form that can be exported for storage. */ +struct PW_PACKED wrapped_leaf_data_t { + /* This is first so that head.leaf_version will be the first field + * in the struct to keep the meaning of the struct from becoming + * ambiguous across versions. + */ + struct leaf_header_t head; + /* Covers .head, .pub, and .cipher_text. */ + uint8_t hmac[PW_HASH_SIZE]; + uint8_t iv[PW_WRAP_BLOCK_SIZE]; + struct leaf_public_data_t pub; + uint8_t cipher_text[sizeof(struct leaf_sensitive_data_t)]; +}; + +/* Represents encrypted leaf data after the lengths and version in the header + * have been validated. + */ +struct imported_leaf_data_t { + /* This is first so that head.leaf_version will be the first field + * in the struct to keep the meaning of the struct from becoming + * ambiguous across versions. + */ + const struct leaf_header_t *head; + /* Covers .head, .pub, and .cipher_text. */ + const uint8_t *hmac; + const uint8_t *iv; + const struct leaf_public_data_t *pub; + const uint8_t *cipher_text; + const uint8_t (*hashes)[PW_HASH_SIZE]; +}; + +/* The leaf data in a clear text working format. */ +struct leaf_data_t { + struct leaf_public_data_t pub; + struct leaf_sensitive_data_t sec; +}; + +/* Key names for nvmem_vars */ +#define PW_TREE_VAR "pwT0" +#define PW_LOG_VAR0 "pwL0" +/* The maximum key-value pair space allowed for the values of PinWeaver until + * the Cr50 NVRAM implementation is updated to use a separate object per + * key value pair. + */ +#define PW_MAX_VAR_USAGE 192 + +/* Initializes the PinWeaver feature. + * + * This needs to be called prior to handling any messages. + */ +void pinweaver_init(void); + +/* Handler for incoming messages after they have been reconstructed. + * + * merkle_tree->root needs to be updated with new_root outside of this function. + */ +int pw_handle_request(struct merkle_tree_t *merkle_tree, + struct pw_request_t *request, + struct pw_response_t *response); + +/******************************************************************************/ +/* Struct helper functions. + */ + +/* Sets up pointers to the relevant fields inside an wrapped leaf based on the + * length fields in the header. These fields should be validated prior to + * calling this function. + */ +void import_leaf(const struct unimported_leaf_data_t *unimported, + struct imported_leaf_data_t *imported); + +/* Calculate how much is needed to add to the size of structs containing + * an struct unimported_leaf_data_t because the variable length fields at the + * end of the struct are not included by sizeof(). + */ +#define PW_LEAF_PAYLOAD_SIZE (sizeof(struct wrapped_leaf_data_t) - \ + sizeof(struct unimported_leaf_data_t)) + + +/******************************************************************************/ +/* Utility functions exported for better test coverage. + */ + +/* Computes the total number of the sibling hashes along a path. */ +int get_path_auxiliary_hash_count(const struct merkle_tree_t *merkle_tree); + +/** + * Computes the parent hash for an array of child hashes. + * Return EC_SUCCESS if successful. + */ +int compute_hash(const uint8_t hashes[][PW_HASH_SIZE], uint16_t num_hashes, + struct index_t location, + const uint8_t child_hash[PW_HASH_SIZE], + uint8_t result[PW_HASH_SIZE]); + +/* This should only be used in tests. */ +void force_restart_count(uint32_t mock_value); + +/* NV RAM log functions exported for use in test code. */ +int store_log_data(const struct pw_log_storage_t *log); +int store_merkle_tree(const struct merkle_tree_t *merkle_tree); +int log_insert_leaf(struct label_t label, const uint8_t root[PW_HASH_SIZE], + const uint8_t hmac[PW_HASH_SIZE]); +int log_remove_leaf(struct label_t label, const uint8_t root[PW_HASH_SIZE]); +int log_auth(struct label_t label, const uint8_t root[PW_HASH_SIZE], int code, + struct pw_timestamp_t timestamp); + +#ifdef __cplusplus +} +#endif + +#endif /* __CROS_EC_INCLUDE_PINWEAVER_H */ |