pinweaver.h - chromium.googlesource.com/chromiumos/platform/pinweaver - Gitiles

 /* Copyright 2018 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef __PINWEAVER_PINWEAVER_H
 #define __PINWEAVER_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.
  */
 #ifndef __aligned
 #define __aligned(n) __attribute__((aligned(n)))
 #endif

 #ifndef __packed
 #define __packed __attribute__((packed))
 #endif

 #include <pinweaver_types.h>

 #ifndef BUILD_ASSERT
 /* Test an important condition at compile time, not run time */
 #define _BA1_(cond, file, line, msg) \
 	_Static_assert(cond, file ":" #line ": " msg)
 #define _BA0_(c, f, l, msg) _BA1_(c, f, l, msg)
 /* Pass in an option message to display after condition */
 #define BUILD_ASSERT(cond, ...) _BA0_(cond, __FILE__, __LINE__, __VA_ARGS__)
 #endif

 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif

 #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 raw incoming messages.
  *
  * Supports the case when request_buf and response_buf point to the same
  * memory location---are backed by the same buffer.
  */
 enum pinweaver_command_res_t {
 	PW_CMD_RES_SUCCESS = 0,
 	PW_CMD_RES_TOO_SMALL,
 	PW_CMD_RES_SIZE,
 };
 enum pinweaver_command_res_t pinweaver_command(void *request_buf,
 					       size_t request_size,
 					       void *response_buf,
 					       size_t *response_size);

 /* 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. */
 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  /* __PINWEAVER_PINWEAVER_H */
	/* Copyright 2018 The Chromium OS Authors. All rights reserved.
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef __PINWEAVER_PINWEAVER_H
	#define __PINWEAVER_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.
	*/
	#ifndef __aligned
	#define __aligned(n) __attribute__((aligned(n)))
	#endif

	#ifndef __packed
	#define __packed __attribute__((packed))
	#endif

	#include <pinweaver_types.h>

	#ifndef BUILD_ASSERT
	/* Test an important condition at compile time, not run time */
	#define _BA1_(cond, file, line, msg) \
	_Static_assert(cond, file ":" #line ": " msg)
	#define _BA0_(c, f, l, msg) _BA1_(c, f, l, msg)
	/* Pass in an option message to display after condition */
	#define BUILD_ASSERT(cond, ...) _BA0_(cond, __FILE__, __LINE__, __VA_ARGS__)
	#endif

	#ifndef ARRAY_SIZE
	#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
	#endif

	#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 raw incoming messages.
	*
	* Supports the case when request_buf and response_buf point to the same
	* memory location---are backed by the same buffer.
	*/
	enum pinweaver_command_res_t {
	PW_CMD_RES_SUCCESS = 0,
	PW_CMD_RES_TOO_SMALL,
	PW_CMD_RES_SIZE,
	};
	enum pinweaver_command_res_t pinweaver_command(void *request_buf,
	size_t request_size,
	void *response_buf,
	size_t *response_size);

	/* 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. */
	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 /* __PINWEAVER_PINWEAVER_H */