FIDO2 CTAP flash

FIDO2 CTAP flash memory helper. More...

Detailed Description

FIDO2 CTAP flash memory helper.

Files
file	ctap_mem.h
	Definitions for CTAP flash memory helper functions.

Macros
#define	CONFIG_FIDO2_CTAP_NUM_FLASHPAGES   4
	Default amount of flashpages to use.
#define	CTAP_FLASH_ALIGN_PAD(x)
	Calculate padding needed to align struct size for saving to flash.
#define	CTAP_FLASH_RK_SZ
	Resident key size with alignment padding.
#define	CTAP_FLASH_STATE_SZ
	State struct size with alignment padding.
#define	CTAP_FLASH_MAX_NUM_RKS
	Max amount of resident keys that can be stored on device.
#define	CTAP_FLASH_MIN_SECTOR_SZ   _MAX(CTAP_FLASH_STATE_SZ, CTAP_FLASH_RK_SZ)
	Minimum flash sector size needed to hold CTAP related data.
#define	CTAP_FLASH_PAGES_PER_SECTOR   ((CTAP_FLASH_MIN_SECTOR_SZ / FLASHPAGE_SIZE) + 1)
	Pages per sector needed.
#define	CTAP_FLASH_RK_OFF   0x1
	Offset of flashpage for storing resident keys.

Functions
int	fido2_ctap_mem_init (void)
	Initialize memory helper.
int	fido2_ctap_mem_read (void *buf, uint32_t page, uint32_t offset, uint32_t len)
	Read from flash memory.
int	fido2_ctap_mem_erase_flash (void)
	Erase all flashpages containing CTAP data.
int	fido2_ctap_mem_read_state_from_flash (ctap_state_t *state)
	Read authenticator state from flash.
int	fido2_ctap_mem_write_state_to_flash (ctap_state_t *state)
	Write authenticator state to flash.
int	fido2_ctap_mem_read_rk_from_flash (ctap_resident_key_t *key, uint8_t *rp_id_hash, uint32_t *addr)
	Find resident credential for rp_id_hash in flash.
int	fido2_ctap_mem_write_rk_to_flash (ctap_resident_key_t *rk)
	Write resident credential to flash.
#define	_MAX(a, b)   ((a) > (b) ? (a) : (b))
	MAX function for internal use.

Macro Definition Documentation

_MAX

#define _MAX	(		a,
			b
	)		((a) > (b) ? (a) : (b))

MAX function for internal use.

Definition at line 39 of file ctap_mem.h.

CONFIG_FIDO2_CTAP_NUM_FLASHPAGES

#define CONFIG_FIDO2_CTAP_NUM_FLASHPAGES   4

Default amount of flashpages to use.

Definition at line 47 of file ctap_mem.h.

CTAP_FLASH_ALIGN_PAD

#define CTAP_FLASH_ALIGN_PAD

(

x

)

Value:

                                 (sizeof(x) % FLASHPAGE_WRITE_BLOCK_SIZE == \
                                 0 ? \
                                 0 : FLASHPAGE_WRITE_BLOCK_SIZE - \
                                 sizeof(x) % FLASHPAGE_WRITE_BLOCK_SIZE)

Calculate padding needed to align struct size for saving to flash.

Definition at line 57 of file ctap_mem.h.

CTAP_FLASH_MAX_NUM_RKS

#define CTAP_FLASH_MAX_NUM_RKS

Value:

                                ((CONFIG_FIDO2_CTAP_NUM_FLASHPAGES - 1) * \
                                FLASHPAGE_SIZE / CTAP_FLASH_RK_SZ)

Max amount of resident keys that can be stored on device.

Definition at line 77 of file ctap_mem.h.

CTAP_FLASH_MIN_SECTOR_SZ

#define CTAP_FLASH_MIN_SECTOR_SZ   _MAX(CTAP_FLASH_STATE_SZ, CTAP_FLASH_RK_SZ)

Minimum flash sector size needed to hold CTAP related data.

This is needed to ensure that the MTD work_area buffer is big enough

Definition at line 85 of file ctap_mem.h.

CTAP_FLASH_PAGES_PER_SECTOR

#define CTAP_FLASH_PAGES_PER_SECTOR   ((CTAP_FLASH_MIN_SECTOR_SZ / FLASHPAGE_SIZE) + 1)

Pages per sector needed.

Definition at line 90 of file ctap_mem.h.

CTAP_FLASH_RK_OFF

#define CTAP_FLASH_RK_OFF   0x1

Offset of flashpage for storing resident keys.

The offset is in units of flashpages from the beginning of the flash memory area dedicated for storing CTAP data.

Definition at line 98 of file ctap_mem.h.

CTAP_FLASH_RK_SZ

#define CTAP_FLASH_RK_SZ

Value:

                          (sizeof(ctap_resident_key_t) + \
                          CTAP_FLASH_ALIGN_PAD(ctap_resident_key_t))

Resident key size with alignment padding.

Definition at line 65 of file ctap_mem.h.

CTAP_FLASH_STATE_SZ

#define CTAP_FLASH_STATE_SZ

Value:

                             (sizeof(ctap_state_t) + \
                             CTAP_FLASH_ALIGN_PAD(ctap_state_t))

State struct size with alignment padding.

Definition at line 71 of file ctap_mem.h.

Function Documentation

fido2_ctap_mem_erase_flash()

int fido2_ctap_mem_erase_flash

(

void

)

Erase all flashpages containing CTAP data.

Returns

ctap_status_codes_t

fido2_ctap_mem_init()

int fido2_ctap_mem_init

(

void

)

Initialize memory helper.

Returns

ctap_status_codes_t

fido2_ctap_mem_read()

int fido2_ctap_mem_read	(	void *	buf,
		uint32_t	page,
		uint32_t	offset,
		uint32_t	len
	)

Read from flash memory.

Parameters

[out]	buf	buffer to fil in
[in]	page	page to read from
[in]	offset	offset from the start of the page (in bytes)
[in]	len	number of bytes to write

Returns

ctap_status_codes_t

fido2_ctap_mem_read_rk_from_flash()

int fido2_ctap_mem_read_rk_from_flash	(	ctap_resident_key_t *	key,
		uint8_t *	rp_id_hash,
		uint32_t *	addr
	)

Find resident credential for rp_id_hash in flash.

The function stores the flash address of the next credential in addr. This allows for consecutive calls of the function in order to find all stored credentials stored for the relying party identified by rp_id_hash.

Parameters

[in]	key	pointer to authenticator state
[in]	rp_id_hash	pointer to hash of rp domain string
[in]	addr	pointer to address where to read from

Returns

ctap_status_codes_t

fido2_ctap_mem_read_state_from_flash()

int fido2_ctap_mem_read_state_from_flash

(

ctap_state_t *

state

)

Read authenticator state from flash.

Parameters

[in]

state

pointer to authenticator state

Returns

ctap_status_codes_t

fido2_ctap_mem_write_rk_to_flash()

int fido2_ctap_mem_write_rk_to_flash

(

ctap_resident_key_t *

rk

)

Write resident credential to flash.

Parameters

[in]

rk

pointer to resident credential

Returns

ctap_status_codes_t

fido2_ctap_mem_write_state_to_flash()

int fido2_ctap_mem_write_state_to_flash

(

ctap_state_t *

state

)

Write authenticator state to flash.

Parameters

[in]

state

pointer to authenticator state

Returns

ctap_status_codes_t