/*
* ks.h
* ----
* Keystore, generic parts anyway. This is internal within libhal.
*
* Copyright (c) 2015-2017, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _KS_H_
#define _KS_H_
#include "hal.h"
#include "hal_internal.h"
/*
* Size of a keystore "block".
*
* This must be an integer multiple of the flash subsector size, among
* other reasons because that's the minimum erasable unit.
*/
#ifndef HAL_KS_BLOCK_SIZE
#define HAL_KS_BLOCK_SIZE (KEYSTORE_SUBSECTOR_SIZE * 1)
#endif
/*
* Known block states.
*
* C does not guarantee any particular representation for enums, so
* including enums directly in the block header isn't safe. Instead,
* we use an access method which casts when reading from the header.
* Writing to the header isn't a problem, because C does guarantee
* that enum is compatible with *some* integer type, it just doesn't
* specify which one.
*/
typedef enum {
HAL_KS_BLOCK_TYPE_ERASED = 0xFF, /* Pristine erased block (candidate for reuse) */
HAL_KS_BLOCK_TYPE_ZEROED = 0x00, /* Zeroed block (recently used) */
HAL_KS_BLOCK_TYPE_KEY = 0x55, /* Block contains key material */
HAL_KS_BLOCK_TYPE_PIN = 0xAA, /* Block contains PINs */
HAL_KS_BLOCK_TYPE_UNKNOWN = -1, /* Internal code for "I have no clue what this is" */
} hal_ks_block_type_t;
/*
* Block status.
*/
typedef enum {
HAL_KS_BLOCK_STATUS_LIVE = 0x66, /* This is a live block */
HAL_KS_BLOCK_STATUS_TOMBSTONE = 0x44, /* This is a tombstone left behind during an update */
HAL_KS_BLOCK_STATUS_UNKNOWN = -1, /* Internal code for "I have no clue what this is" */
} hal_ks_block_status_t;
/*
* Common header for all keystore block types.
* A few of these fields are deliberately omitted from the CRC.
*/
typedef struct {
uint8_t block_type;
uint8_t block_status;
hal_crc32_t crc;
} hal_ks_block_header_t;
/*
* Key block. Tail end of "der" field (after der_len) used for attributes.
*/
typedef struct {
hal_ks_block_header_t header;
hal_uuid_t name;
hal_key_type_t type;
hal_curve_name_t curve;
hal_key_flags_t flags;
size_t der_len;
unsigned attributes_len;
uint8_t der[]; /* Must be last field -- C99 "flexible array member" */
} hal_ks_blockkey_block_t;
#define SIZEOF_KS_BLOCKKEY_BLOCK_DER \
(HAL_KS_BLOCK_SIZE - offsetof(hal_ks_blockkey_block_t, der))
/*
* PIN block. Also includes space for backing up the KEK when
* HAL_MKM_FLASH_BACKUP_KLUDGE is enabled.
*/
typedef struct {
hal_ks_block_header_t header;
hal_ks_pin_t wheel_pin;
hal_ks_pin_t so_pin;
hal_ks_pin_t user_pin;
#if HAL_MKM_FLASH_BACKUP_KLUDGE
uint32_t kek_set;
uint8_t kek[KEK_LENGTH];
#endif
} hal_ks_blockpin_block_t;
#define FLASH_KEK_SET 0x33333333
/*
* One keystore block.
*/
typedef union {
uint8_t bytes[HAL_KS_BLOCK_SIZE];
hal_ks_block_header_t header;
hal_ks_blockkey_block_t key;
hal_ks_blockpin_block_t pin;
} hal_ks_block_t;
/*
* In-memory cache.
*/
typedef struct {
unsigned blockno;
unsigned lru;
hal_ks_block_t block;
} hal_ks_cache_block_t;
/*
* Keystore object. hal_internal.h typedefs this to hal_ks_t.
*
* We expect this to be a static variable, but we expect the arrays in
* it to be allocated at runtime using hal_allocate_static_memory()
* because they can get kind of large.
*
* Driver-specific stuff is handled by a form of subclassing: the
* driver embeds the hal_ks_t structure at the head of whatever else
* it needs, and performs (controlled, type-safe) casts as needed.
*
* Core of this is the keystore index. This is intended to be usable
* by both memory-based and flash-based keystores. Some of the
* features aren't necessary for memory-based keystores, but should be
* harmless, and let us keep the drivers simple.
*
* General approach is multiple arrays, all but one of which are
* indexed by "block" numbers, where a block number might be a slot in
* yet another static array, the number of a flash sub-sector, or
* whatever is the appropriate unit for holding one keystore record.
*
* The index array only contains block numbers. This is a small data
* structure so that moving data within it is relatively cheap.
*
* The index array is divided into two portions: the index proper, and
* the free queue. The index proper is ordered according to the names
* (UUIDs) of the corresponding blocks; the free queue is a FIFO, to
* support a simplistic form of wear leveling in flash-based keystores.
*
* Key names are kept in a separate array, indexed by block number.
*
* The all-zeros UUID, which (by definition) cannot be a valid key
* UUID, is reserved for the (non-key) block used to stash PINs and
* other small data which aren't really part of the keystore proper
* but are kept with it because the keystore is the flash we have.
*
* Note that this API deliberately says nothing about how the keys
* themselves are stored, that's up to the keystore driver.
*/
typedef struct hal_ks_driver hal_ks_driver_t;
struct hal_ks {
const hal_ks_driver_t *driver;/* Must be first */
unsigned size; /* Blocks in keystore */
unsigned used; /* How many blocks are in use */
uint16_t *index; /* Index/freelist array */
hal_uuid_t *names; /* Keyname array */
unsigned cache_lru; /* Cache LRU counter */
unsigned cache_size; /* Size (how many blocks) in cache */
hal_ks_cache_block_t *cache; /* Cache */
int per_session; /* Whether objects have per-session semantics (PKCS #11, sigh) */
};
/*
* Keystore driver. This is just a dispatch vector for low-level
* keystore operations, and the code is very repetitive. We opt for
* expressing this in a terse form via C macros over expressing it
* as huge chunks of repetitive code: both are difficult to read, but
* the terse form has the advantage of fitting in a single screen.
* The KS_DRIVER_METHODS macro is the protein, the rest is just the
* machinery to expand the method definitions into a struct of typed
* function pointers and a set of static inline wrapper functions.
*/
#define KS_DRIVER_END_LIST
#define KS_DRIVER_METHODS \
KS_DRIVER_METHOD(init, hal_ks_t *ks, const int alloc) \
KS_DRIVER_METHOD(read, hal_ks_t *ks, const unsigned blockno, hal_ks_block_t *block) \
KS_DRIVER_METHOD(write, hal_ks_t *ks, const unsigned blockno, hal_ks_block_t *block) \
KS_DRIVER_METHOD(deprecate, hal_ks_t *ks, const unsigned blockno) \
KS_DRIVER_METHOD(zero, hal_ks_t *ks, const unsigned blockno) \
KS_DRIVER_METHOD(erase, hal_ks_t *ks, const unsigned blockno) \
KS_DRIVER_METHOD(erase_maybe, hal_ks_t *ks, const unsigned blockno) \
KS_DRIVER_METHOD(set_owner, hal_ks_t *ks, const unsigned blockno, \
const hal_client_handle_t client, const hal_session_handle_t session) \
KS_DRIVER_METHOD(test_owner, hal_ks_t *ks, const unsigned blockno, \
const hal_client_handle_t client, const hal_session_handle_t session) \
KS_DRIVER_END_LIST
#define KS_DRIVER_METHOD(_name_, ...) hal_error_t (*_name_)(__VA_ARGS__);
struct hal_ks_driver { KS_DRIVER_METHODS };
#undef KS_DRIVER_METHOD
#define KS_DRIVER_METHOD(_name_, ...) \
static inline hal_error_t hal_ks_block_##_name_(__VA_ARGS__) \
{ \
return \
ks == NULL || ks->driver == NULL ? HAL_ERROR_BAD_ARGUMENTS : \
ks->driver->_name_ == NULL ? HAL_ERROR_NOT_IMPLEMENTED : \
ks->driver->_name_(__VA_ARGS__); \
}
KS_DRIVER_METHODS
#undef KS_DRIVER_METHOD
#undef KS_DRIVER_METHODS
#undef KS_DRIVER_END_LIST
#endif /* _KS_H_ */
/*
* Keystore utilities. Some or all of these may end up static within ks.c.
*/
extern hal_error_t hal_ks_alloc_common(hal_ks_t *ks,
const unsigned ks_blocks,
const unsigned cache_blocks);
extern hal_error_t hal_ks_init_common(hal_ks_t *ks,
const hal_ks_driver_t * const driver);
extern hal_error_t hal_ks_index_heapsort(hal_ks_t *ks);
extern hal_error_t hal_ks_index_find(hal_ks_t *ks,
const hal_uuid_t * const name,
unsigned *blockno,
int *hint);
extern hal_error_t hal_ks_index_add(hal_ks_t *ks,
const hal_uuid_t * const name,
unsigned *blockno,
int *hint);
extern hal_error_t hal_ks_index_delete(hal_ks_t *ks,
const hal_uuid_t * const name,
unsigned *blockno,
int *hint);
extern hal_error_t hal_ks_index_replace(hal_ks_t *ks,
const hal_uuid_t * const name,
unsigned *blockno,
int *hint);
extern hal_error_t hal_ks_index_fsck(hal_ks_t *ks);
extern const size_t hal_ks_attribute_header_size;
extern hal_error_t hal_ks_attribute_scan(const uint8_t * const bytes,
const size_t bytes_len,
hal_pkey_attribute_t *attributes,
const unsigned attributes_len,
size_t *total_len);
extern hal_error_t hal_ks_attribute_delete(uint8_t *bytes,
const size_t bytes_len,
hal_pkey_attribute_t *attributes,
unsigned *attributes_len,
size_t *total_len,
const uint32_t type);
extern hal_error_t hal_ks_attribute_insert(uint8_t *bytes, const size_t bytes_len,
hal_pkey_attribute_t *attributes,
unsigned *attributes_len,
size_t *total_len,
const uint32_t type,
const uint8_t * const value,
const size_t value_len);
/*
* Local variables:
* indent-tabs-mode: nil
* End:
*/
